Dissertation Final PDF

Effects of Chronic Zinc Magnesium Aspartate (ZMA) Supplementation on

Strength & Acute Recovery In Recreational Male Resistance Athletes

by

Arsalan Javaid13843290

A dissertation

submitted in partial fulfillment of the requirements for the degree of:

BACHELOR OF SCIENCE (HONOURS) SPORT AND EXERCISE SCIENCE (WITH NUTRITION)

2016

Abstract

Background: Resistance or Strength training is a modality of exercise with anabolic foundations and implications (Fleck and Kraemer, 2014). Athletes are constantly striving to break plateaus and optimise performances using nutritional interventions and ergogenic aids. Doping and the use of anabolic steroids is a trend amongst competitive bodybuilders and power lifters (Haff and Travis, 2015), although there are competitors who seek ergogenic aids through natural and legal means. ZMA is a supplement marketed as having anabolic properties, primarily, boosting testosterone and recovery combining the synergistic effects of Zinc Monomethionine Aspartate, Magnesium Aspartate and Vitamin B6 (Villepigue and Rivera, 2012).

Aims: To investigate the effects of 4 weeks of ZMA supplementation on 1RM strength and acute recovery in recreational resistance athletes,

Methods: 14 healthy recreational resistance athletes (mean ± SD), age 22.9 ± 2.9 years, height 180 ± 4.7 cm and body mass 83.6 kg ± 9.4 kg , participated in a study approved by the University of Brighton’s Ethics committee. Participants completed familiarisation protocols prior to preliminary testing using a Concept2 Dyno Dynamometer to perform the following exercises: chest press, diverging row, and leg press. 14 participants were randomly assigned to one of two conditions: ZMA (n = 7) or Placebo (n = 7). Participants performed 3 reps at a minimal-maximal exertion effort: 25% (minimal), 50% (medial) 100% (maximal – 1RM). There was a static-recovery period of 5 minutes in between exercises. Data analysis consisted of a separated two-way mixed design ANOVA [2x3; Time (pre vs. post) x Condition (placebo vs. ZMA)] to determine significant changes between conditions (P<0.05).

Results: A significant interaction effect was not found between time (pre & post) and supplement (PL & ZMA) in strength on the chest press with ZMA: F (1,12) = 1.96, P = 0.187 and diverging row: F (1,12) = 0.02, P = 0.884; A significant interaction effect was found for 1RM strength on the leg press: F (1,12) = 1.96, P = 0.000. Average hours slept (HS) for the ZMA group increased by 5.8%, average awakenings decreased by -31.3%, and Quality of Sleep (QoS) increased by 22.1%.

Conclusions: It remains equivocal as to whether ZMA supplementation has anabolic properties as the findings of this study would suggest otherwise. An improvement in solely 1RM leg press strength is not sufficient and there are no clear explanations as to why no changes were observed in the chest press or diverging row. The increases in recovery values are open to interpretation and further research, although it would be suggested that these improvements are a synergistic effect of Magnesium (Mn). Further research is required analysing a broader range of variables and possibly comparing the effects of the synergist components of ZMA against the supplement as a complete formula.

Keywords: Zinc, Magnesium, Vitamin B6, Resistance, Training, Strength, Recovery, Hypertrophy, Testosterone

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Acknowledgements

I would first and foremost like to thank Dr Alan Richardson for giving me the opportunity to enter this course. A huge thank you to my dissertation supervisor Dr Gary Brickley for giving me guidance as well as patience during the completion of my dissertation, and a further thank you and appreciation to all the other staff at The University of Brighton who guided me along the way. Thank you and eternal gratitude to Rabia Alam, who gave me the encouragement to persist and the belief to reach the stage that I am at. Furthermore, I would like to thank my supportive family, my personal and university friends (Oliver Wise, Zarthast Bajwa, Marcel Illés & Shuaib Dalvi) for their continual and moral support. Last but not least, my grandfather who is no longer with me but gives me strength spiritually and faithfully. My weakness is sometimes my self belief, but the patience that you show gives me new found strengths and eliminates all of my weaknesses and doubts, every time. Thank you all, once again. لله الَحْمد .

TABLE OF CONTENTS

ABSTRACT ...........................................................................................IACKNOWLEDGEMENTS .......................................................................IITABLE OF CONTENTS .........................................................................IIILIST OF TABLES...................................................................................VILIST OF FIGURES ..............................................................................VIILIST OF ABBREVIATIONS ..................................................................VIII

Chapter I INTRODUCTION ......................................................................1

1.1 Purpose and significance of the study..................................2Chapter

II LITERATURE REVIEW .............................................................32.1 The Physical Nature And Demands of Resistance

Training 3 2.1.1 The Correlation Between Muscle CSA and

Strength......................................................................................9 2.1.2 Effects of Resistance Training on Recovery..........132.2 The Endocrine System ...................................................15 2.2.1 Hormonal Response to Resistance Training..........16

2.3 Limitations Of Strength & Recovery– Peripheral Factors............................................................................................17 2.3.1 Physiological Response To Specific Exercise

Movements Intensity & Duration.....................................................17 2.3.2 Recovery & Restoration........................................20 2.4 Ergogenic Aids – Nutritional Intervention Strategies........21

II

2.4.1 Zinc Aspartate......................................................22 2.4.2 Magnesium Aspartate...........................................22

2.4.3 Vitamin B6............................................................22 2.4.4 Role Of ZMA & Effect on Strength & Recovery.....23 2.5 Dosage, Administration & Timing......................................26 2.5 Dosage, Administration & Timing....................................26 2.5.1 Dosage & Safety For Human Consumption............27 2.5.2 Timing....................................................................27 2.5.3 Performance Measures & Test Reliability.............29 2.6 Summary of Literature.....................................................30 2.7 Specific Research Aims....................................................31 2.8 Research Hypothesis.......................................................32 2.9 Assumptions....................................................................32 2.10 Delimitations..................................................................33 2.11 Limitations.....................................................................34Chapter III METHODS ..............................................................................34

3.1 Experimental Approach To The Problem .......................343.2 Participants ...................................................................363.3 Experimental Procedure..................................................38

3.3.1 3-Day Sleep Diary..................................................38 3.4 Supplementation...........................................................39

3.5 Statistical Analysis...........................................................39Chapter IV RESULTS ...............................................................................39

4.1 1RM Performance............................................................404.2 Recovery.........................................................................42

Chapter V DISCUSSION .........................................................................43

III

5.1 Summary of Findings ..................................................44 5.2 Differences In Hormonal Response...............................45

5.3 Mechanisms of Hypertrophy.........................................46 5.4 Critical Analysis............................................................48 5.5 Limitations....................................................................50

Chapter VI CONCLUSION ......................................................................50

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APPENDICES.......................................................................................52 APPENDIX A- Participation Information Sheet.........................52 APPENDIX B- Informed Consent Form.....................................57 APPENDIX C- Medical Questionnaire.......................................58 APPENDIX D- Sessional Medical Form.....................................59 APPENDIX E- Risk Assessment Form.......................................60 APPENDIX F- COSSH Form......................................................62 APPENDIX G- Sleep Diary........................................................70 APPENDIX E- Pilot Testing.......................................................71

REFERENCES.......................................................................................73

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LIST OF TABLES

Table 1 Summary of Long-Term Studies Evaluating the Effects of Training Intensity on Muscle Hypertrophy (Schoenfeld, 2013)

Table 2 Descriptive statistics (mean ± SD) for the seated bench

press, seated bench pull, and seated leg press from the 3 trials for both the whole sample and the subsample.*† (Bampouras et al., 2014)

Table 3 Reliability and sensitivity statistics for all exercises between trials, for both the whole sample and the subsample.*‡

(Bampouras et al., 2014)

Table 4 Changes in strength pre & post supplementation. Compared means are represented as SD

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LIST OF FIGURES

Figure 1 Significance in both HL & LL groups for muscle thickness increase in the elbow flexors from baseline to post via ultrasound imaging (HL=5.3 vs. LL=8.6%,) (p < 0.01) (Schoenfeld et al., 2015)

Figure 1.1 Significance in both HL & LL groups for muscle thickness increase in the elbow extensors from baseline to post via ultrasound imaging (HL=6.0% vs. LL=5.2%,) (p <0.05). (Schoenfeld et al., 2015)

Figure 1.2 Significance in both HL & LL groups for muscle thickness increase in the quadriceps femoris from baseline to post via ultrasound imaging (HL=9.3% vs. LL=9.5%,) (p <0.05) (Schoenfeld et al., 2015)

Figure 1.3 Significant difference in 1RM back squat from baseline to post (HL=19.6%=sig. vs. LL=8.8%=non-sig.) (Schoenfeld et al., 2015)

Figure 1.4 Significant different in 1RM bench press from baseline to post (HL=6.5%=sig. vs. LL=2.0%=non-sig. )(Schoenfeld et al., 2015)

Figure 1.5 Significant difference in muscular endurance from baseline to post (HL=0%=non-sig. vs. LL=2.0%=16.6%=sig.). (Schoenfeld et al., 2015)

Figure 2 Diagram showing major divisions of the nervous system (Plowman and Smith, 2011)

Figure 3 Mean GH concentrations at each time point between SLEEP and SLD sessions during exercise and recovery. (Ritsche, Nindl and Wideman, 2014)

Figure 4 Schematic of Experimental Procedure from Baseline to Post

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Figure 5 Schematic of Exercise & Testing protocol

Figure 6 Mean percentage change (%) pre and post supplementation on 1RM strength. SD (±) represented by error bars.

Figure 7 Mean percentage change (%) pre and post supplementation on sleep (average hours slept, average awakenings, average quality of sleep) across 3 days. SD (±) represented by error bars.

Definition of Abbreviations (Terms)

LIST OF ABBREVIATIONS

1RM 1 Repetition MaximumCM Centimeters CNS Central Nervous SystemCSA Cross Sectional AreaCT Computerised TomographyDHEA DehydroepiandrosteroneEIGR Exercise-induced Growth Hormone ResponseEMG ElectromyographyFAD Filament Area DensityGH Growth HormoneHG Hand GripHGH Human Growth HormoneHL High LoadHMB Beta-Hydroxy Beta-Methylbutyric AcidHR Heart Ratekg KilogramsLL Low LoadMcg MicrogramMg MilligramMFP Muscular Force ProductionMIT Minimum Intensity Threshold Mn Magnesium

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MP Mean PowerMRI Magnetic Resonance ImagingPP Peak PowerRPE Rate of Perceived ExertionSLD Sleep DeprivationV O2 max Maximal Oxygen UptakeZn Zi

VIII

1.0 Introduction

1.1 Purpose and significance of the study

ZMA (Zinc Monomethionine Aspartate, Magnesium Aspartate and Vitamin B6) is a synergistic supplement, which is said to possess ergogenic benefits such as increasing anabolic hormone levels, improving recovery time and increasing strength and muscle (Brilla and Conte, 2000). Zinc (Zn) & Magnesium (Mg) are said to increase levels of Insulin-like Growth Factor-I (IGF-I). Zn, as a single chemical element, could contribute towards the elevation of serum testosterone (Maggio et al., 2014; Shafiei et al., 2011). The increase in IGF-I and testosterone would mean an improvement in muscle function and physical performance as both hormones have anabolic properties (Maggio et al., 2011). Vitamin B-6 completes the formulation of the ZMA supplement. It is needed to aid the body’s metabolism; it is especially essential in protein metabolism and the production of more proteins such as hormones, neurotransmitters and enzymes (Manore, 2000; Stover and Field, 2015). Early research has suggested that exercises decreases Mn & Zn, thus, resulting in testosterone and strength reductions, emphasising the role ZMA is suggested to play (Greenwood et al., 2015)

Strength in sport and exercise is defined as the ability to produce force to overcome the most resistance in a single effort; strength is used in short periods and is one of the key foundations in resistance-based training and also contributes to muscular endurance and power (Brown, 2001; McArdle et al., 2001). Strength is vastly important within sport & exercise as it can make a huge difference in athletic performance; the greater the level to overcome or resist in a sport or physical activity demands a greater requirement of strength (Joyce and Lewingdon, 2014). Beattie et al.

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(2014) investigated the effect of strength training on performance in trained endurance athletes using 26 previously published journals that fit a specific criteria (athletes had to be trained endurance athletes with ≥6 months endurance training, training ≥6 h per week OR V˙O2max≥50 mL/min/kg, the strength interventions had to be ≥5 weeks in duration, and control groups used); suggesting that the inclusion of strength training within an endurance athletes training protocol would improve economy, muscle power and performance (Beattie et al., 2014).

Kellmann & Kallus, (2001) define recovery as an inter- and intra-individual multilevel (e.g. psychological, physiological, social) process over time for the re-establishment of performance abilities (Kellmann & Kallus, 2001). Recovery is a very important aspect of any sport or exercise modality in order to achieve maximal results from performance (Beckmann and Elbe, 2015). As well as possessing anabolic properties, it is suggested that ZMA improves recovery. However, there is clear equivocality on the recovery properties of the supplement, as there appears to be limited or non-existing evidence to support this claim.

The demand for ergogenic supplements is at a constant increase, as athletes and the general population are using these as a means to improve athletic performance, particularly in hypertrophy and recovery (Fink and Mikesky, 2013). The International Society of Sports Nutrition has declared ZMA’s anabolic effect as unknown, and the Australian Institute of Sport, which advises athletes about ergogenic aids, has concluded that ZMA lacks clear evidence of benefits (Burke, 2007; Wilborn et al., 2004). The aim of the study was to investigate whether 28-days of chronic ZMA supplementation would improve 1RM strength performance and acute recovery in recreational male resistance-exercise athletes.

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2.0 Literature Review

2.1 The Physical Nature and Demands of Resistance Training

Resistance training improves muscular strength and power, as well as decreasing muscular fatigue and resulting in many other health and physiological benefits (Ehrman et al., 2013). The intensity of resistance-based exercise increases the activation of fast-twitch muscle fibers resulting in a greater importance on mechanical stress (Sherwood, 2012; Trappe et al., 2000). In order to fully stimulate muscle activation for programs that target metabolic stress (Resistance exercise), a minimum intensity threshold (MIT) is required (Ratamess et al. 2009).

Table 1 Summary of Long-Term Studies Evaluating the Effects of Training Intensity on Muscle Hypertrophy (Schoenfeld, 2013)

Study Subjects Design Volume Equated?

Train to Failure?

Measurement

Findings

Campos et al. (44)

32 untrained young men (5 served as non- exercising controls)

Random assignment to either low intensity (3-5 RM), intermediate intensity (9-11 RM) for 3 sets with 2 minute rest intervals,

Yes Yes Muscle biopsy

Significant increases in CSA for high-intensity exercise; no significant

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or; high intensity (20-28 RM) exercise. Exercise consisted of 2-4 sets of squat, leg press and leg extension, performed 3 days a week for 8 weeks.

increase in CSA for low-intensity exercise

Leger et al. (45)

24 untrained middle-aged men

Random assignment to either low intensity (3-5 RM) or a high intensity (20-28 RM) exercise. Exercise consisted of 2-4 sets of squat, leg press and leg extension, performed 3 days a week for 8 weeks..

Yes Yes CT

No differences in CSA between low- and high- intensity exercise

Lamon et al. (46)

25 untrained middle-aged men

Random assignment to either low intensity (3-5 RM) or a high intensity (20-

Yes Yes CT No differences in CSA between low- and high-

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28 RM) exercise. Exercise consisted of 2-4 sets of squat, leg press and leg extension, performed 3 days a week for 8 weeks.

intensity exercise

Tanimoto and Ishii (40)

24 untrained young men

Random assignment to either 50% RM with a 6 second tempo and no relaxing phase between repetitions, 80% RM with a 2 second tempo and 1 second relaxation between repetitions, or 50% RM with a 2 second tempo and 1 second relaxation between repetitions. Exercise consisted of 3

No Yes MRI

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sets of knee extensions,performed 3 days a week for 12 weeks.

Tanimoto et al. (47)

36 untrained young men (12 served as non- exercising controls)

Random assignment to either 55-60% RM with a 6 second tempo and no relaxing phase between repetitions or 80-90% RM with a 2 second tempo and 1 second relaxation between repetitions. Exercise consisted of 3 sets of squat, chest press, lat pulldown, abdominal bend, and back extension, performed 2 days a week for 13 weeks.

No YesB-mode ultrasound


Holm et al. (48)

11untrained young men

Random, counterbalanced

Yes No MRI Significantly greater increases

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performance of 10 sets of unilateral leg extensions, training one leg at 70% 1RM and the contralateral leg at 15.5% 1RM, performed 3 days a week for 12 weeks.

in CSA in high intensity versus low intensity exercise

Mitchell et al. (50).


Randomly assignment to perform 2 of 3 unilateral leg extension protocols: 3 sets at 30% RM; 3 at 80% RM; 1 set at 80% RM. Training was carried out 3 days per week for 10 weeks.

No YesMRI, muscle biopsy


Schuenke et al. (51)

34 untrained young women

Randomized assignment to either moderate intensity (80-85% RM) at a tempo of 1-2 seconds, a low intensity

No Yes Muscle biopsy

Significant increases in CSA for high-intensity exercise; no significant increase in CSA for

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(~40-60% RM) at a tempo of 1-2 seconds, or slow-speed (~40-60% RM) at a tempo of10 seconds concentric and 4 seconds eccentric. Exercise consisted of 3 sets of squat, leg press, and leg extension, performed 2-3 days a week for 6 weeks

low-intensity exercise

Ogasaw ara et al. (52)


Non-randomized crossover design to perform 4 sets of bench press exercise at 75% 1RM. Training was carried out 3 days a week for 6 weeks. After a 12 month washout period, the same protocol was

No Yes MRI No differences in CSA between low- and high- intensity exercise

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performed at 30% 1RM.

Schoenfeld (2013) collected and compared long-term studies that evaluated the effects of training intensity on muscle hypertrophy (see table 1); intensities above 30% are needed for complete muscle fiber recruitment during resistance training to achieve the MIT. The literature compared in table 1 shows equivocality as to what, if any, hypertrophic effects are discovered with low-intensity exercise in well-trained subjects, as experimental studies on the topic in this population are insufficient (Schoenfeld, 2013).

2.1.1 The Correlation Between Muscle CSA & Strength

There is a positive relationship between muscle CSA and strength (Baechle and Earle, 2008). Recovery results in myofibrillar hypertrophy (leading to an increase in muscle CSA) and strength gains increase when the muscles grow and become stronger; these three factors are relative to one another and are required to work in tandem for optimal results (Schoenfield, 2016). Sarcoplasmic hypertrophy (which is very common amongst resistance athletes) stimulates muscle growth but does not have an incremental effect on muscular force production (MFP); the filament area density (FAD) decreases and the CSA increases (Whipple and Eckhardt, 2012). When the numbers of myosin and actin filaments/sarcomeres expand inside the cell an increase in myofibrillar hypertrophy commences; resulting in greater strength and size of the contractile unit of muscle, which subsequently develops the ability to produce a greater force. Myofibrillar hypertrophy is usually achieved by using

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heavier loads and lower repetitions and the opposite for sarcoplasmic hypertrophy (Hoeger and Hoeger, 2016).

Jenkins et al. (2015) looked at how forearm flexion resistance exercises differed amongst subjects individually (15 male subjects); comparing electromyographic (EMG) amplitude, the number of repetitions completed, and exercise volume during three sets to failure of high- (80% 1RM) versus low-load (30% 1RM). The results of the study showed that the numbers of repetitions completed were greater for the 30% 1RM group, while the volume of exercise were similar in both 1RM groups (Jenkins et al., 2015). Similarly, Schoenfeld (2015) studied the effects of Low Load (LL) Versus High Load (HL) Resistance Training in 18 young trained males. The results of the study found that both HL & LL conditions produced significant increases in thickness of the elbow flexors (HL=5.3 vs. LL=8.6%,), elbow extensors (HL=6.0 vs. LL=5.2%,), and quadriceps femoris (HL=9.3 vs. LL=9.5%,) there were no significant differences between groups. Strength for the back squat was considerably greater for HL (HL=19.6 vs. LL=8.8%,) and significance was also prevalent for the 1RM bench press (HL=6.5 vs. LL=2.0%). Upper body muscle endurance was assessed via the bench press at 50% 1RM to failure and LL was vastly significant in comparison to HL (LL=16.6% vs. –HL=1.2%) (See figures 1,2,3,4) (Schoenfeld et al., 2015). The literature supports the hypothesis of Hoeger & Hoeger (2016) as both HL & LL groups achieve the same amount of volume, but instigate either types of hypertrophy; HL and lower repetitions results in sarcoplasmic hypertrophy and LL and higher repetitions in myofibrillar.

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Figure 1 Significance in both HL & LL groups for muscle thickness increase in the elbow flexors from baseline to post via ultrasound imaging (HL=5.3 vs. LL=8.6%,) (p < 0.01) (Schoenfeld et al., 2015)

Figure 1.1 Significance in both HL & LL groups for muscle thickness increase in the elbow extensors from baseline to post via ultrasound imaging (HL=6.0% vs. LL=5.2%,) (p <0.05). (Schoenfeld et al., 2015)

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Figure 1.2 Significance in both HL & LL groups for muscle thickness increase in the quadriceps femoris from baseline to post via ultrasound imaging (HL=9.3% vs. LL=9.5%,) (p <0.05) (Schoenfeld et al., 2015)

Figure 1.4 Significant differences in 1RM bench press from baseline to post (HL=6.5%=sig. vs. LL=2.0%=non-sig. )(Schoenfeld et al., 2015)

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Figure 1.3 Significant differences in 1RM back squat from baseline to post (HL=19.6%=sig. vs. LL=8.8%=non-sig.) (Schoenfeld et al., 2015)

Figure 1.5 Significant differences in muscular endurance from baseline to post (HL=0%=non-sig. vs. LL=2.0%=16.6%=sig.). (Schoenfeld et al., 2015)

Muscle fibers are the cells of which make up muscle and are of three different types (Type I, Type IIA, Type IIB), each type plays is responsible for different muscle functions. Invidividual muscles are

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made up of individual muscle fibers that are formed into motor units within each muscle (Katch et al., 2010). Type II fibers (fast-twitch), grow at a faster rate than type I fibers (slow twitch) (Aagaard et al., 2001). The rate of muscle contraction in Type II fibers is also of a greater rate, which means that they possess a higher strength and power potential than type I fibers (Harber and Trappe, 2008). Evidence suggests, that no significant differences are observed in the proportions of muscle fiber types between untrained and resistance trained individuals (Fry et al., 2003; Ogborn and Schoenfeld, 2014).

2.1.2 Effects of Resistance Training on Recovery

Resistance training is a modality of exercise that is vastly beneficial but heavily taxing on the body requiring adequate nutrition and a minimum of 48 hours of rest before training the particular muscle group(s) again, although a full muscle recovery could take up to several weeks (Hausswirth and Mujika, 2013; Hoeger and Hoeger, 2016). After a resistance based training session there is minuscule damage or tears to the muscle cells and a break down of the muscle fiber, which is known as catabolism (Bean, 2015; Stone et al., 2007). After the catabolism occurs, the body works through a cellular process where the muscles fibers conjoin to produce new muscle protein strands or myofibrils that increase in thickness and quantity – resulting in myofibrillar hypertrophy (muscular enlargement) and an increase in the cross-sectional area (CSA) of the existing fibers (Baechle and Earle, 2008).

Post-exercise recovery and hypertrophy are only effective through adequate rest and nutrition (Lanham-New, 2011). Insufficient rest can lead to overtraining which can trigger an increase in cortisol levels and decrease in dehydroepiandrosterone (DHEA); the body’s long-acting stress hormones (Constantini and Hackney, 2013;

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Jenkins, 2005). DHEA and cortisol are to some extent antagonists to one another; DHEA has anabolic properties whereas cortisol has a catabolic influence on the body; these hormones should remain balanced. The sudden imbalance (due to lack of rest) of these hormones may lead to the following effects: Reduction of protein synthesis, reduced growth hormone (GH) release, vitamin depletion, compromised immune function and disrupted sleep patterns – all of which will have a further adverse impact on recovery and anabolism (Hausenblas and Rhodes, 2016; Kitaeff, 2011; Seifter et al. , 2005).

Fallon and Gerrard (2007) reported that athletes and coaches expressed that the number one factor for fatigue or tiredness was sleep (Fallon and Gerrard, 2007). Most athletes suffer from sleep deprivation prior to an event for numerous reasons, including noise, light, anxiety, and nervousness (Fullagar et al., 2015). Sleep deprivation can cause downward changes in glucose metabolism and neuroendocrine function. Furthermore, lack of sleep or partial sleep may result in alterations in carbohydrate metabolism, appetite/food intake and protein synthesis harnessing a detrimental effect on recovery and performance, especially for resistance athletes who seek anabolic responses (Chittora et al., 2015; Knutson et al., 2007). These factors could be detrimental to an athlete’s nutritional, metabolic and endocrine status (Halson, 2014). Sleep is the foundation to recovery, particularly in order to instigate anabolism. Other than exercise, sleep is the most powerful non-pharmacological Human Growth Hormone (HGH) stimulus. During sleep, a signal is sent to the brain via the pituitary gland, which then releases HGH into the bloodstream in order for recovery and restoration of the body (Lee-Chiong, 2008). Oliver et al. (2009) found that one night of sleep deprivation decreased endurance performance with limited effect on pacing, cardio-respiratory or thermoregulatory function. The sleep-deprived group had covered less of a distance than the control group, however altered

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perception for the sleep-deprived group was greater within a shorter distance, signifying that altered perception of effort may be the cause for decreased endurance performance (Oliver et al., 2009). This suggests that lack of sleep (recovery) can have negative implications upon athletic performance, although this remains equivocal.

2.2 The Endocrine System The Endocrine System (ES) is comprised of numerous different glands throughout the body. The role of the ES is to send signals to the body by manufacturing and secreting specific hormones (e.g. insulin, growth hormone, thyroxine), which circulate throughout the body (McDowell, 2011). The nervous system and ES may function cohesively (neuroendocrinology) (Neal, 2016). Exercise and recovery are both primary factors in influencing hormonal secretion. During the beginning of an exercise, the thyroid gland directs hormones in order to regulate heart rate, blood pressure and body temperature, It is also responsible for the regulation of neuroendocrine functions such as alertness and focus; the Adrenal gland is responsible for the release of cortisol and controls the blood pressure, glucose and acts as an anti-inflammatory agent as well as reacting to emotional responses (i.e. sporting event); the Pancreas secretes insulin (responsible for directing glucose for energy to the muscles and tissues that require it) and glucagon (helps breakdown of glycogen to glucose into the liver) (Amitrano and Tortora, 2012; McArdle, et al., 2010). Athletes are increasingly using ergogenic aids, particularly in nutrition, the effects of many supplements or ergogenic aids are related to hormonal response and can influence hormone secretion. Hormonal secretion is of huge significance in athletic performance; the significance of hormones in sport and exercise can be related to doping and the usage of performance enhancing drugs, which imitate androgenic hormones known as

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anabolic steroids; hormones are fundamental in their influence in sport and exercise science (Jameson and De Groot, 2015).

2.2.1 Hormonal Response To Resistance Training

The exercise-induced growth hormone response (EIGR) is of course the counterpart to sleep in being the major non-pharmacological anabolic stimulus for hG, although the specific mechanisms of exercise that trigger this remain equivocal; direct stimulation, nitric oxide and lactate appear to be the primary elicitors (Clelland, 2011). Resistance training prompts a significant EIGR, however, protein synthesis has predominantly been due to IGF-1 with a diminutive contribution from the hGH-GH receptor interaction on the cell membrane (Ritsche et al., 2014).

In males, testosterone is the primary and major circulating androgenic steroid, which is secreted more than 95% by the testis, producing approximately 6-7mg per day (Nieschlag and Behre, 2012). The role of testosterone in male resistance athletes is of great significance as it triggers GH responses in the pituitary gland, which influences protein synthesis in muscles for hypertrophy (Scanlon and Sanders, 2014). The International Rietjens et al. (2015) analysed the effect resistance training induces on the circulating testosterone response. Four resistance training protocols were followed and total volume of work was held constant: moderate intensity (70% 1RM) upper body (bench press, bent barbell row, and military press), moderate intensity lower body (squat and deadlift), high intensity (90% 1RM) upper body, high intensity lower body. Both upper and lower body for moderate intensity resistance protocols resulted in a significant increase of testosterone concentration (p=0.026, and p=0.024), whereas the high intensity protocols increased testosterone but had no significance (upper p=0.272, lower p=0.658) (Rietjens et al., 2015).

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In contrast, Ahtiainen et al. (2015) investigated the effects of resistance training on testosterone metabolism in younger (n = 5, 28 ± 3 yrs.) and older men (n = 8, 70 ± 2 yrs.) performing heavy 5x10RM leg presses before and after 12 months of resistance training. The results of this study found that there was no effect on testosterone metabolism due to resistance training in either age group (Ahtiainen et al., 2015); Similarly, Molsted et al. (2014) investigated the effects of testosterone and resistance training on male dialysis patients who performed HL leg press, leg curl and leg extensions thrice weekly; the study concluded that testosterone values remained normal (Molsted et al., 2014). Although these studies conclude reciprocally, Shaner et al. (2014) analysed the contrasting acute effects on hormonal response via free weight and machine weight RT and discovered that testosterone levels were significantly higher on the squat versus the leg press (Shaner et al., 2014). The literature is equivocal, but suggests that hormonal responses and testosterone increments could be exercise-type/intensity specific.

West et al. (2009) compared the effects of a high-trial 2 (HH) versus low hormone (LH) state-trial 1, using a single exercise trial to determine which had a greater effect on protein synthesis of the bicep brachii. This study consisted of two trials. To trigger a significant hormonal response, a bicep curl was performed in the other arm followed by five sets with 10 repetitions of leg press at ∼90% of 10RM and three sets of 12 repetitions of leg extension/leg curl ‘supersets’ (1 set of each back-to-back with no rest between sets). Rest periods in between sets were 120s and 60s, for bicep curl and leg exercise superset, respectively. No changes were observed in serum testosterone, GH or IGF-1 after the LH protocol, however there were elevations after HH. Exercise prompted a rise in muscle protein synthesis in the biceps brachii in both groups, but no effect of elevated hormones (West et al., 2009). Similarly, West &

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Phillips (2010) used the same exercise protocol for LH and HH state, but extended to 15 weeks. Identical to the previous study, results showed that the HH group had a significant increase of serum testosterone, GH or IGF-1 post exercise compared to the LH group. An increase of 78% in Myofibrillar protein synthesis was found for the LH group and 61% for the HH group. Between both groups, no differences were observed for 10RM strength and 1RM strength. There was also a significant difference in increase of Maximal Voluntary Contraction between groups (LH 20±4%, range 3%-49% vs. HH 19±3%, range 2-34%), and no difference in CSA between groups. (LH: 12±2% % HH: 10±2%). The results of this study indicate that 15 weeks of a bicep curl in a LH state is more effective than completing a bicep curl in a HH state (West & Phillips, 2010).

2.3 Limitations Of Strength & Recovery– Peripheral Factors

2.3.1 Physiological Response To Specific Exercise Movements, Intensity & Duration

The measurement of strength can be subjective due to many direct and indirect physiological factors from biological (age and recovery) to chemical responses such as endocrine status, which are relative to one other, respectively. Shaner et al. (2014) found that testosterone levels were significantly greater on the squat versus the leg press. Although both exercises stimulate the targeted muscles, they do not have the same impact on the central nervous system (CNS). It is believed that increases in muscle mass, strength and hormones can only occur via the CNS, not the stress nor load imposed on the muscle (Plowman and Smith, 2011). The CNS works via the brain and spinal cord and interacts with the muscles through the peripheral nervous system. The CNS controls the muscle fibers by propelling a signal to the brain and spinal cord, which connect to

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the individual muscle motor units via the neuromuscular junction, causing muscular contraction. (Raven et al., 2012; Rhoades and Bell, 2009)

Figure 2 Diagram showing major divisions of the nervous system (Plowman and Smith, 2011)

Escamilla et al. (2001) reported that both narrow and wide stance variations of the squat resulted in greater rectus femoris, vastus lateralis, vastus medialis, lateral hamstring, medial hamstring, and gastrocnemius activity than narrow (low foot placement) and wide stance (high foot placement) variations of the leg press. Similarly, found that there was greater activation of the medial deltoid on the free weight bench press than on the Smith machine bench press.). The literature would suggest that strength testing is inconsistent, as exercises must be similar in energy demand, intensity, muscular

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recruitment and activation of the CNS in order to produce rational results and physiological responses (Escamilla et al., 2001; Schick et al., 2010)

2.3.2 Recovery And Restoration

Sleep is generally distinguished as the prime component of recovery, and general consensus is that sleep is a necessity in order to restore and replenish the body to its most optimal state. According to the aforementioned literature, sleep is known as the major non-pharmacological HgH stimulus; hypertrophy is dependent on HgH and the level of HgH . Ritsche, Nindl and Wideman’s (2014) study on Exercise-Induced growth hormone during acute sleep deprivation (SLD) found that early morning resting GH concentration was unchanged by sleep deprivation, and exercise-induced GH area under the curve (168%), peak GH concentration (123%) and Δ GH (122%) were significantly greater after a night of sleep deprivation (see figure 3) (Ritsche, Nindl and Wideman, 2014). Similarly, HajSalem et al. (2013) investigated the effect of partial SLD at the end of the night on anaerobic performances during the Wingate test (peak (PP) and mean (MP) power) and the hand grip (HG) test in 21 judokas; it was discovered that strength decreased and Rated Perceived Exertion (RPE) was non-significantly affected by partial SLD. Partial SLD reduced muscle power during the Wingate test and did not affect muscle strength during the HG test (HajSalem et al., 2013). The aforementioned studies would suggest that the relationship between sleep and HgH is equivocal and that hypertrophy may not be entirely dependent on sleep.

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Figure 3 Mean GH concentrations at each time point between SLEEP and SLD sessions during exercise and recovery. (Ritsche, Nindl and Wideman, 2014)

2.4 Ergogenic Aids – Nutritional Intervention Strategies

Ergogenic (from Greek) is defined as “work creating”. Therefore, ergogenic aids have the common characteristics of increasing the rate of work (i.e. sport or exercise performance) (Stone, Stone and Sands, 2007). Many ergogenic aids become popular due to the success of an athlete that uses and/or endorses the product (Kraemer, Fleck and Deschenes, 2011). Athletes are growingly looking for nutritional interventions to further enhance their performances and coaches are recommending them to do so (Gregory and Travis, 2015). Supplement manufacturers claim that athletes require these nutritional aids to increase performance because the substances are either unavailable through a normal diet or are required in greater amounts than the body can acquire through regular dietary habits (Pfeiffer et al., 2014).

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2.4.1 Zinc Aspartate

Zinc (Zn) is a trace mineral responsible for the reproduction of cells, regeneration of tissue and wound recovery, sexual maturity, and optimal growth. Zn is a needed for various enzymatic functions throughout the body, and also aids in regulating the immune system and insulin metabolism. Preferably, the dosage of zinc included is from 2 to 30 mg as Zn Aspartate (Slaga et al., 2002). A feature of Zn concentration in the human body is its localisation; the male reproductive system is a zone of high Zn concentration; Zn is a hormonal trigger (Mills, 2013).

2.4.2 Magnesium Aspartate

Magnesium is a mineral essential for all biological processes including the metabolism of glucose, protein and nucleic acid synthesis, electrical balance of cells, and the transmission of nerve impulses. Magnesium has an effect on the heart and its functions, structure integrity and contractions, and all other muscles. Preferably, the dosage of magnesium included is from about 10 to about 500 mg as Magnesium Aspartate (Slaga et al., 2002).

2.4.3 Vitamin B6

Vitamin B6 is a general term for the group of three vitamins: pyridoxine, pyridoxal and pyridoxamine. They are significant in protein and amino acid metabolism and aid in regulating blood glucose levels. These vitamins are required to synthesise hemoglobin and are central in the optimal function of the CNS. The dosage of vitamin B6 is preferably from about 200 mcg to about 3 mg (Slaga et al., 2002).

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2.4.4 Role Of ZMA & Effect on Strength & Recovery

ZMA supplementation has gained popularity and recognition for being marketed as a “natural testosterone booster”. In an age where steroid usage is prevalent amongst the general public, as well as mainstream sport, elite athletes are searching for legal and natural ergogenic aids to enhance performance (Beamish, 2011). Vitamin B6 is included in the formulation to aid the uptake and utilisation (metabolism) of Zn & Mn, not as an ergogenic factor (Greenwood, Kalman and Antonio, 2015). Studies that have clinically trialled ZMA have been contrasting, although a lot of the literature would suggest that the marketing behind the supplement could be substantiated by scientific evidence.

Brilla & Conte (2000) used A ZMA capsules (30 mg zinc monomethionine aspartate, 450 mg magnesium aspartate, and 10.5 mg vitamin B-6) to test the effects on hormones and strength on 57 varsity football players. All subjects took three capsules nightly between dinner and bedtime. The results of this study showed that the ZMA group increases significantly differed from the placebo group. There was a 10%-range increases in quadriceps torque and 12.7% to 15.2% increases in quadriceps power for ZMA supplementation in comparison to the -0.8% to 2.4% change in quadriceps torque and 8.6% to 10.8% change in quadriceps power for the placebo group. As a result of randomization, baseline differences were observed in muscle torque and power, which resulted in higher values for the placebo group versus the treatment group from the beginning. Both groups had overall increases in the training and supplementation period, but the ZMA supplementation

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resulted in greater increases in comparison to placebo (Brilla & Conte, 2000). In contrast, Wilborn et al. (2004) examined the effects of ZMA supplementation on training adaptations in 42 resistance-trained athletes. Results of this study conveyed that no statistically significant changes were observed between groups in mean bench press 1-RM (P 3.6 ± 5.5 kg and ZMA 5.6 ± 5.9 kg, p = 0.24), leg press 1-RM (P 24.6 ± 25 kg and ZMA 25.4 ± 32 kg, p = 0.92), bench press lifting volume (P -51 ± 206 kg; ZMA 4 ± 186 kg, p = 0.38), or leg press lifting volume (P 480 ± 1,022 kg; ZMA 724 ± 1,258 kg, p = 0.48) (Wilborn et al., 2004). Both of these studies show antagonistic results to one another, however both have a sense of equivocality due to the participants, as they have dissimilar sporting/athletic backgrounds and experience of strength training, as resistance-athletes are more disposed to strength training protocols.

Sheykh & Bordbar (2012) studied the effect of ZMA supplementation singularly and in combination with carbohydrates, with six weeks of resistance training on anabolic hormone levels in 27 untrained males. Despite the relative increase in anabolic hormones in the supplement groups, no significant differences were observed between the three groups in serum testosterone and IGF-1 levels. Conversely, ZMA supplementation with resistance training resulted in a significant increase in bench press 1RM strength in all 3 groups (Sheykh & Bordbar, 2012). Likewise, Moëzzi, Peeri and Homaei, (2014) looked at the effects of zinc, magnesium and vitamin B6 supplementation on hormones and performance in weightlifters by investigating military press strength and squat strength. Shoulder strength in military presses in ZMA and dextrose groups increased significantly by 8.3% and 7.78%, respectively. Squat strength significantly increased by 4.9% and 3.56% in ZMA and dextrose groups, respectively, but there was no significant difference in squats records before and after training course in both supplement groups. The findings of the hormonal response showed that there

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were significant differences in the rate of total testosterone (p=0.695), free testosterone (p=0.379), cortisol (p=0.346) and ratio of testosterone to cortisol (p=0.718) (Moëzzi, Peeri and Homaei, 2014). These results show that ZMA increases strength, however, there are dissimilar results for hormonal response.

Abbasi et al. (2012) analysed the effects of Mn supplementation on primary insomnia in 46 elderly subjects. Findings showed that Mn supplementation appears to improve subjective measures of insomnia such as ISI score, sleep efficiency, sleep time and sleep onset latency, early morning awakening, and likewise, insomnia objective measures such as concentration of serum renin, melatonin, and serum cortisol, in elderly people (Abassi et al., 2012). Similarly, Abassi et al. (2013)’s study analysed the effect of Mn supplementation on the physical activity of 46 overweight insomniac subjects using 500mg of Mn. The results of this study concluded that there were no significant differences observed in assessed variables between the two groups at baseline. But results showed that Mn supplementation significantly increased sleep indices and physical activity level (Abassi et al., 2013). Mn is clearly suggested to improve the quality of sleep, which would support the proclamation of ZMA’s recovery properties. Kass and Poeira (2015) found that 1-RM bench press strength showed a significant increase of 17.7% compared to baseline, with acute Mn (300mg) supplementation. No significant strength gains were observed in the chronic intervention group (Kass and Poeira, 2015). Literature on Mn and strength/resistance training is generally limited, however, the findings of Kass and Poeira (2015) are very noteworthy when discussing the effects of Mn as a synergist in the ZMA supplement.

Shafiei et al. (2011) studied the effect of Zinc and Selenium Supplementation on Serum Testosterone in 24 cyclists after one bout of exhaustive exercise. The particpants were divided into four

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groups; placebo; Zn group (30 mg/day); selenium supplement (Se) (200 μg/day); and Zn-Se group. Results revealed that Zn supplementation increased levels of total testosterone in comparison with Se group, and also increased free testosterone versus the other groups (Shafiei et al., 2011). In contrast, Femiano & Morris (2015) discovered that ZMA supplementation with a 90–120 mg zinc component (greater amount than common ZMA) for 7 to 8 weeks in 17 previously active men did not increase serum testosterone levels (Femiano & Morris, 2015). Although contrasting and equivocal, the opposing results of these studies would vaguely suggest that Zn could have testosterone enhancing properties, although this may not be the case. It is also worth noting that the dosage amount may have had an impact on these results.

Previous research on strength using ZMA as a combined formula (30 mg zinc monomethionine aspartate, 450 mg magnesium aspartate, and 10.5 mg vitamin B-6) is mostly archaic and limited; literature on each component of ZMA as singular supplements (Zn and Mn) is readily accessible. The suggestion is that Mn improves sleep, which could rationalise the recovery properties of the ZMA supplement and Zn improves testosterone, which would rationalise the anabolic properties, yet this remains ambivalent and needs to be looked into more depth.

2.5 Dosage, Administration & Timing

2.5.1 Dosage & Safety For Human Consumption

ZMA is a supplement that is commonly distributed and used in capsule form. Numerous studies on ZMA use capsules (serving size of 3) containing 11 mg of Vitamin B-6 (pyridoxine hcl), 450 mg of magnesium (as magnesium aspartate), 30 mg of zinc (as aspartate), all in accordance to the recommendation stated by Slaga et al.,

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(2002) and affirmed by the National Insititute of Health (2016) (National Institute of Health, 2016; Slaga et al., 2002). Studies have also shown the aforementioned dosage amount to increase anabolic hormone levels and muscle strength in trained athletes. (Brilla & Conte, 2000; Koehler et al., 2007; Koehler et al., 2009; Wilborn et al., 2004). No side effects were observed during previous studies and affirm that the supplement is safe for human consumption.

2.5.2 Timing

The aforementioned studies asked participants to take the ZMA supplement on an empty stomach 60 minutes prior to sleep; 3 capsules, once nightly (Brilla & Conte, 2000; Koehler et al., 2007; Koehler et al., 2009; Wilborn et al., 2004). Ingesting the supplement approximately 60 minutes before bed will optimise its uptake and utilization and enhance sleep quality as magnesium can normalise and extend stage 3 and 4 slow-wave sleep (Pizzorno and Murray, 2013).

2.5.3 Performance Measures & Test Reliability

Bampouras et al. (2014) evaluated the Test-retest reliability and sensitivity of the Concept2 Dyno dynamometer using 46 competitive male athletes. Reliability was evaluated by examining systematic bias, intraclass correlation coefficient, coefficient of variation (CV), and 95% limits of agreement (LoA). Each experimental trial comprised of 3 maximal efforts across the three exercises; chest press, diverging row and leg press. No systematic bias was discovered for any of the exercises. Intraclass correlation coefficients were high (0.89-0.98) with relatively low CV (6.2-4.3%).

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95% LoA suggested that subsequent testing could underestimate by a factor of 0.87 or overestimate by a factor of 1.17, on average. These results indicate that Concept2 Dyno dynamometer is reliable and can be used to efficiently assess strength performance (Bampouras et al., 2014). Numerous studies have used the Concept2 Dyno dynamometer in strength research (Cronin et al., 2014; Grujic et al., 2013 Lawton et al., 2013; Lawton et al., 2013; Popadic Gacesa et al., 2012).

Table 2 Descriptive statistics (mean ± SD) for the seated bench press, seated bench pull, and seated leg press from the 3 trials for both the whole sample and the subsample.*† (Bampouras et al., 2014)

Table 3 Reliability and sensitivity statistics for all exercises between trials, for both the whole sample and the subsample.*‡ (Bampouras et al., 2014)

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2.6 Summary of Literature

Resistance training holds many health and physiological benefits such as elevating hormone levels and increasing hypertrophy & muscle CSA (Ehrman et al., 2013). The strenuous demands of resistance training requires athletes to turn to ergogenic aids in order to replenish the body post exercise and to enhance and maximise general performance. Ergogenic aids are becoming ever in demand, although there is always uncertainty about their effects. The aim of this study was to determine whether a 28-day chronic ZMA supplementation would improve 1RM strength and recovery in resistance athletes.

ZMA is a synergistic supplement made up of Zinc (Zn) (30mg), Magnesium (Mn) (450mg) and vitamin B6 (10.5mg). Each one of the synergists of the ZMA formulation plays a collaborative role in the

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ergogenic effects the supplement is believed to possess. It is marketed to possess ergogenic benefits, primarily increasing testosterone levels, although literature is conflicting and equivocal. West et al. (2009) and West & Phillips (2010) concluded no significant differences were observed in muscle protein synthesis and CSA when comparing high hormonal state participants versus low hormonal state, these findings are significant as ZMA is said to be a hormone stimulator.

Brilla & Conte (2000) found a significant increase in hormone levels and leg strength, but this was negated by the study of Wilborn et al. (2004), which found no significant increase of hormone or 1RM-strength for bench press and leg press. Other studies on ZMA have found significance in squat strength (?) and bench press strength, but no significant differences were observed in hormone levels. Literature on ZMA as a whole supplement is very minimal and generally out-dated, however, literature is more readily available for its synergist components Zn & Mn. Abassi et al. (2012) and Abassi et al. (2013) have found that Mn improves sleep and Kass and Poeira, (2015) found Mn to improve 1-RM bench press strength. Zinc has been suggested to improve free and total testosterone levels, according to the results of a study by Shafiei et al. (2011). However, these findings contradict the findings of Femiano & Morris (2015), where no increases of serum testosterone levels were observed with a higher dosage of Zn.

The suggestion from the literature is that Mn improves sleep, which could rationalise the recovery properties of the ZMA supplement and Zn improves testosterone, which would rationalise the anabolic properties, yet this remains ambivalent and needs to be looked into more depth.

2.7 Specific Research Aims

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This study was undertaken with the following specific research aims:

1. The primary aim of this study was to analyse and evaluate the effects of a 28-day ZMA supplementation load versus placebo (Maltodextrin) on 1RM strength performance (kg) across 3 movements: chest press, diverging row, leg press.

The additional research aim(s) when conducting this study included:

2. Evaluate the effects of a 28-day ZMA supplementation load on acute recovery (sleep) across 3 variables: duration of sleep (hours), awakenings, and quality of sleep (Likert scale).

3. Evaluate the mechanisms of strength and hypertrophy, and the relationship with recovery.

2.8 Research Hypothesis

Hypothesis 1:

HA1= There will be a significant interaction effect (pre versus post supplementation) in strength (kg) for the chest press following 28-days of ZMA supplementation in contrast to Placebo.

HN1 = There will be no significant interaction effect (pre versus post supplementation) in strength (kg) for the chest press following 28-days of ZMA supplementation in contrast to Placebo.

Hypothesis 2:

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HA2 = There will be a significant interaction effect (pre versus post supplementation) in strength (kg) for the diverging row following 28-days of ZMA supplementation in contrast to Placebo.

HN2 = There will be no significant interaction effect (pre versus post supplementation) in strength (kg) for the diverging row following 28-days of ZMA supplementation in contrast to Placebo.

Hypothesis 3:

HA3 = There will be a significant interaction effect (pre versus post supplementation) in strength (kg) for the leg press following 28-days of ZMA supplementation in contrast to Placebo.

HN3= There will be no significant interaction effect (pre versus post supplementation) in strength (kg) for the leg press following 28-days of ZMA supplementation in contrast to Placebo.

2.9 Assumptions This study made the following assumptions:

1. Participants provided a truthful representation on all consent, medical forms, evidence sheets and questionnaires.

2. Participants followed the supplement protocol and had taken the given and required amount accordingly to fulfil the demands of the study during the 28-day period.

3. Participants completed their individual sleep diaries and gave a true representation

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4. Participants followed all instructions and demonstrations provided by the experimenter.

5. Participants gave their truest representation maximal effort in pre (baseline) and post testing.

The following assumptions were made as participant’s information, data and results were secured with anonymity and confidentiality. Volunteers for the study also had the right and freedom to withdraw from participation at any given time without any justification or ramifications.

2.10 Delimitations

1. Participants of the study had not consumed any ergogenic aids containing creatine, glutamine, arginine, HMB, androstendione, thermogenics, or any other ergogenic supplement at the time of study (or in the last 6 months).

2. Participants had not resistance trained 48 hours prior to testing.

3. All participants were resistance-trained athletes aged between 18-28 in healthy physical condition, and participating in a resistance based exercise programme a minimum of thrice per week.

4. Duration of the study was a maximum of 7 weeks per participant, including a 28-day supplement load, and a 3-day sleep diary before and after the 28-day period.

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2.11 Limitations

1. The inability to control physical activity (frequency, intensity, duration)/physical activity hiatus and supplementation adherence between pre (baseline) and post testing.

2. Participants who have had previous experience with ergogenic aids may have recognised their supplementation group and that could have affected consumption and adherence to their maximal effort in post testing.

3. Recruitment process comprised of resistance athletes of varying experiences (not specific) from the University of Brighton and The Gym Group, Brighton.

5. The inabilities to control sleep activity (time of sleep, hours slept, awakenings) and daily schedules and routines, which could have affected sleep.

3.0 Methods

3.1 Experimental Approach To The Problem

This study was conducted over a 7-week period as a randomised, repeated measures, mixed, double blind, placebo controlled clinical trial. Each participant individually attained familiarisation with the equipment (Concept2 Dyno dynamometer). Participants later participated in baseline testing (pre) before being randomly assigned to a Maltodextrin placebo group or ZMA supplement group. A placebo. Participants followed the experimental design and performed 1RM strength testing procedures on 3 exercises (chest press, diverging row and leg press) using the Concept2 Dyno dynamometer before and after the 28-day supplementation period.

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The participants were also informed about and provided with a form for the 3-day sleep diary (Appendix G), which they were requested to complete, and hand-in before and after the supplementation period. It was hypothesised that chronic ZMA supplementation would have a significant effect on 1RM strength and recovery (sleep) in the ZMA group compared to the placebo.

3.2 Participants

Fourteen resistance-trained male subjects participated in this study. Candidates were recruited verbally from The University of Brighton and The Gym Group, Brighton. Subjects were excluded from the study if they were not actively participating in resistance exercise at least 3 times a week; have suspended training due to current or reoccurring muscular or joint injuries; were diagnosed with cardiovascular, pulmonary or medical disorders and/or disease; had abnormal heart rate or blood pressure; and/or had been recently instructed by a physician or doctor not to participate in any form of resistance exercise, in accordance to the ACSM screening guidelines (ACSM.org, 2016). Candidates were also disregarded for participation if they were currently (or in the last 6 months) taking any ergogenic aids containing creatine, glutamine, arginine, HMB, androstendione, thermogenics, or any other ergogenic supplement (Wilborn et al., 2004). Prior to initial testing and recruitment, candidates were provided with a participant information sheet (Appendix A), which provided a detailed insight and overview into the study and study background. Candidates meeting the eligibility criteria were informed of the requirements of the study and signed an informed consent (Appendix B) and medical questionnaire (Appendix C & D) in compliance with the Guidance on Good Practice in Research Ethics and Governance of University of Brighton (University of Brighton, 2016). Candidates who were selected for participation were asked to refrain from any caffeinated

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drinks, pills or tablets 48 hours prior to testing, as caffeine has been suggested to have an ergogenic effect on strength performance (H Brooks and Wyld, 2015); candidates were further asked to refrain from resistance training 48 hours prior to testing to ensure optimal performance. Subjects were descriptively 22.9 ± 2.9 years; height 180 ± 4.7 cm; 83.6 kg ± 9.4 body mass. Candidates were assured that all informed data would be confidential and withdrawal of participation was allowed at any given time without justification or any ramifications. This study was overlooked and approved by The University of Brighton ethics committee.

Supplement Age (Years) Height (cm) Weight/Mass (kg)

Maltodextrin [Placebo] (n = 7)

23. 4 ± 3.3 180 ± 6 85.6 ± 9.8

ZMA (n = 7) 22.4 ± 2.2 180 ± 2.8 81.6 ± 8.4

3.3 Experimental Procedure

Pre-testing involved recording the anthropometric measures of the participants; age (years); height (cm); weight/body-mass (kg) recorded prior to familiarisation and baseline testing. Participants attended each lab session between 9am-12pm on either occasion. Familiarisation included a demonstration and explanation prior to participants operating the Concept-2 Dyno dynamometer. Participants were randomised into either group (Placebo/Group A or ZMA/Group B) using an online research randomizer (Randomizer.org, 2016). There were 4 weeks between pre (Baseline) and post (Placebo/ZMA) supplementation testing periods. Post testing took place within a week after the 28-day

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supplementation period to avoid development of washout. Baseline and post-supplementation experimental procedures were identical. Empty bags (dispenser) of the supplements were handed in after the post-supplementation period to determine the usage of the supplement and to ensure that participants complied (Wilborn et al., 2004). A number of studies have validated beneficial effects following an identical 28-days, pre-exercise supplementation protocol (Ormsbee et al., 2012; Shelmadine et al., 2009).

Figure 4: Schematic of Experimental Procedure from Baseline to Post

The testing procedure consisted of assessing the 1 rep max (1RM) on the chest press, diverging row and the leg press (kg) (Appendix E). Participants performed 3 reps at a minimal-maximal exertion effort: 25% (minimal), 50% (medial) 100% (maximal – 1RM). There was a static-recovery period of 5 minutes in between exercises in order for the body to return to its pre – exercise state (Porcari, Bryant and Comana, 2015). The exercises were performed in the following order; chest press; diverging row; leg press, respectively. Each rep was performed with a delayed eccentric motion of

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approximately 3 seconds in order to optimally increase the mechanisms relating to strength via time under tension (Hoffman, 2014), and exploding during the concentric phase at maximal speed as it optimises the response of the CNS (Bartlett and Bussey, 2012).

Figure 5: Schematic of Exercise & Testing protocol

3.3.1 3-Day Sleep Diary

Participants were requested to record a 3-day sleep diary before and after the supplement load period. The sleep diary was structured using previous literature and an identical protocol to Karolinska Sleep Diary (Akerstedt et al., 1994), however variables were condensed and made relevant to the present study (Lichstein et al., 2007; Lin et al., 2011). The variables recorded were; hours of sleep; awakenings; and quality of sleep on a likert scale of 1-10 (1 representing the poorest quality and 10 representing the greatest quality).

3.4 Supplementation

The study design consisted of a placebo-controlled, double blind clinical study. The supplementation period commenced after preliminary (baseline) testing and once 3-day sleep records were collected from participants. Participants were randomised for allocation into either group A (placebo-controlled group; Maltodextrin) or group B (ZMA supplement group). The

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supplementation load was a 28-day period with supplements ingested orally (3 capsules). Supplements were dispensed in sealed bags. Participants were informed to ingest 3 capsules on a nightly basis, on an empty stomach 60 minutes prior to sleep. Subjects were requested to report any possible side effects (such as tingling) that may occur during the supplementation period (Insel et al., 2015).

3.5 Statistical Analysis

Data collected from the study was reported and presented as means (±SD), unless otherwise stated. Three two-way mixed design repeated measures ANOVA’s [2x3; Time (Pre versus Post x Condition aka Treatment or Supplementation (Placebo versus ZMA)]. Data normality, homogeneity, and specificity were assumed with a significance level of P<0.05. Post-Hoc analysis was used in order to analyse any reported statistical effects found within the data output. Three separate repeated measures ANOVA (significance P<0.05; Bonferroni correction) were used on each group and test to determine differences in fourteen separate strength outputs. All statistical analysis was conducted using SPSS version 22 software. For all statistical analyses α level of P ≤ 0.05 was accepted as significant.

4.0 Results

The 14 participants completed the pre and post supplementation testing. The participants adhered to completing the sleep diaries, and the returning empty supplementation dispensaries showed that all subjects had followed the requested supplementation protocol accordingly. Compliance of protocols was reciprocally corresponded to the assumptions, resulting in all collected data to be used in the

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statistical analysis. The inferential statistical analysis outcomes were reported with descriptive data sets reported as mean (±SD).

A Two Way mixed-design repeated measures ANOVA was run to test for an interaction effect between time (pre/post) and supplementation group (placebo/ZMA) on strength (kg) across each of the three exercises; chest press, diverging row and leg press.

4.1 1RM Performance On Strength

Table 4: Changes in strength pre & post supplementation. Compared means are represented as SD

Placebo (n = 7) ZMA (n = 7)

Before After ∆ Before After ∆

Age (y) 23.4 ± 3.3 N/A N/A 22.4 ± 2.2 N/A N/AHeight (cm) 180 ± 6 N/A N/A 180 ± 2.8 N/A N/ABody Mass (kg) 85.6 ± 9.8 N/A N/A 81.6 ± 8.4 N/A N/AChest Press (kg)

82 ± 22 82.7 ± 22 0.7 ± 0 88.6 ± 29.6 91.7 ± 31.7 3.1 ± 2.1

Diverging Row (kg)

91.3 ± 35.7

91.1 ± 19.5 -0.2 ± 16.2 98.6 ± 25.4 98.1 ± 28.1 -0.5 ± 2.7

Leg Press (kg) 146 ± 25.2 146.1 ± 26.1 0.1 ± 09 147.3 ± 32.1 †155.4 ± 33.2

8.1 ± 1.1

† = P ≤ 0.05, significantly different from before values.

Chest Press - ANOVA did not find a significant interaction effect between time (pre & post) and supplement (PL & ZMA) for strength on the chest press with ZMA: F (1,12) = 1.96, P = 0.187. Therefore, the alternate hypothesis (HA1) can be rejected.

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Diverging Row - ANOVA did not find a significant interaction effect between time (pre & post) and supplement (PL & ZMA) for strength on the diverging row with ZMA: F (1,12) = 0.02, P = 0.884. Therefore, the alternate hypothesis (HA2) can be rejected.

Leg Press: - ANOVA found a significant Interaction effect between time (pre & post) and supplement (PL & ZMA) for strength on the leg press for ZMA: F (1,12) = 1.96, P = 0.000. Therefore, the alternate hypothesis (HA3) can be accepted.

Figure 6 displays percentage changes (%) across all movement protocols for placebo controlled and ZMA group. There was a statistically non-significant increase of 0.87% in 1RM chest press strength (kg) for the placebo group & a statistically non-significant percentage increase of 3.5% for the ZMA group. The percentage changes in the diverging row show that there was a decrease of -0.16% in 1RM strength for the placebo group and 0.43% for the ZMA group, respectively. There was a statistically non-significant increase of 0.10% in 1RM leg press strength (kg) for the placebo group & a significant percentage increase of 5.5% for the ZMA group.

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Chest Press Diverging Row Leg Press-1

0

1

2

3

4

5

6 Placebo ZMA

Perc

enta

ge C

hang

e (%

)

Figure 6: Mean percentage change (%) pre and post supplementation on 1RM strength. SD (±) represented by error bars.

4.2 Recovery

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Hours Slept Awakenings Quality of Sleep-40%

-30%

-20%

-10%

0%

10%

20%

30%

Placebo ZMA

Perc

enta

ge C

hang

e (%

)

Figure 7: Mean percentage change (%) pre and post supplementation on sleep (average hours slept, average awakenings, average quality of sleep) across 3 days. SD (±) represented by error bars.

Figure 7 displays mean percentage changes (%) in average hours slept (Hs), awakenings and Quality of sleep (QoS) across 3-days (pre and post) for both supplement groups. The percentage change in the PL group shows an increase of 14.9% in HS; 5.8% in awakenings; and an increase of 3.1% in QoS. The ZMA group shows an increase of 5.8% in HS, a decrease of -31.3% in awakenings, and an increase of 22.1% in QoS, respectively.

5.0 Discussion

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5.1 Summary of Findings

The aim of this study was to investigate whether 28-days of chronic ZMA supplementation would improve 1RM strength performance and acute recovery in recreational male resistance-trained athletes. The primary aim was to establish if 1RM strength would improve post-supplementation. Mixed ANOVA reported no significant interaction effect on 1RM with supplement intervention for the chest press & diverging row, however 1RM for the leg press showed a significant increase (P<0.05), therefore HN3 was rejected. The additional aim of the study was to assess whether recovery would improve post-supplementation. Findings from the participants 3-day sleep diaries revealed a post supplement mean increase of 5.8% for hours slept; a -31.3% mean decrease of awakenings; a 22.1% mean increase in QoS.

The significant increase of 1RM leg press strength post-ZMA shows that the supplement could hold some credibility in improving strength, although this remains equivocal, as there were no significant results for the chest press or diverging row. ZMA is known for its anabolic properties, and how it is suggested to improve hypertrophy is via the increase of hormonal responses. Ahtiainen (2015) and Molsted (2014) both found that resistance training for exercises targeting the lower limb/leg muscles resulted in no significant effect or change in hormone levels. If the aforementioned research were to correspond with the present study, it would suggest that hormonal responses which trigger hypertrophic processes are not exercise dependent, thus, the increase of strength in the leg press from the current study may be either from a peripheral source or perhaps in-fact the effects of the supplementation. Recovery appeared to be prominent post-supplementation as all the sleep measures, which were recorded

45

improved substantially. There was only a slight increase of strength by 5.8%, however the vast increase of awakenings (31.3%) and QoS (22.1%) would suggest that the increase in hours slept were due to the decrease of awakenings, thus, resulting in a better-perceived QoS for the participants.

The current study has produced similar results to that of Brilla & Conte (2000) & Sheykh & Bordbar (2012). Both studies, including the present study, indicated a significant increase in leg strength, although the findings from Wilborn et al. (2004) are antagonistic, and observed no significant improvement in leg strength. Findings from Moëzzi et al. (2014) showed that ZMA supplementation significantly increased bench press strength; the current study revealed an increase in chest press strength, however this was a statistically non-significant result. When comparing the results of these studies, no clear interpretation can be made, there is no scientific explanation as to why there was no significant change in the upper body exercises (chest press & diverging row) but there was with leg press post ZMA supplementation. Due to the ambiguity of strength significance in the literature and current study, assessing hormonal responses from previous literature can provide a clearer interpretation of these findings.

5.2 Differences In Hormonal Responses

Moëzzi et al. (2014) found an increase of testosterone levels post ZMA in comparison to baseline; leading to a 11.42% and 21.36% increase respectively in free and total testosterone, while the levels of these hormones in the placebo group showed 6.48% and 21.15% increases, respectively. The results of Wilborn et al. (2004) support the findings of Moëzzi et al. (2014). In contrast, Brilla and Conte (2000) reported a 30% increase in total and free testosterone in the ZMA group, as well as a 10% decrease in the placebo group. This

46

would support the notion that the lack of significant differences may be a result of routine training of participants and since the identical increases were observed in free and total testosterone levels in both supplement and placebo groups. This suggests that, although Moezzi et al., (2014) found a significant increase of 1RM strength on the bench press, there was no significant hormonal response, thus, the strength increase (which is believed to be produced via anabolic hormone responses) is inconclusive of the ZMA supplementation. Similarly, the findings from Sheykh & Bordbar (2012) showed a significant increase of squat strength, however, despite the relative increase in anabolic hormones in the groups receiving ZMA, no significant differences between the three groups (ZMA, ZMA & CHO, placebo) in serum testosterone and IGF-1 levels were observed. Furthermore, the implications this has for the present study can suggest that, the increase of 1RM leg press strength can be attributed to the effects of regular and continuous training outside of the study and not ZMA.

5.3 Mechanisms of Hypertrophy

It is generally believed that hypertrophy is primarily instigated through the increase of anabolic hormones, which, is suggested to be the result of ZMA supplementation. The studies by West et al. (2009) & West & Phillips (2010) (See 2.2.1) contradict the general notion that hypertrophy is primarily hormone dependent, and show that performing a compound exercise on the same day as assistance exercise will increase in anabolic hormone production, but with no increase in hypertrophy nor protein synthesis. Exploring the mechanisms of hypertrophy further, myofibrillar hypertrophy and protein synthesis are structured entirely upon local factors that trigger intracellular signaling pathways (Schoenfeld, 2016). Calcineurin (one of two calcium dependent pathways) dephosphorylates cytoplasmic proteins, which allows the proteins to

47

transport into the nucleus for gene transcription (Hill and Olson, 2012; Schoenfeld, 2016). Calcium Calmodulin Protein Kinase signaling pathway is the second pathway. Similarly to calcineurin, it is regulated by intracellular calcium, but it is activated by short intensity high amplitude calcium signals (Borer, 2013). Literature is however equivocal when providing an explanation of the role calcium calmodulin plays in muscle hypertrophy and phenotype changes.

A review by Tu et al. (2016) discussed evidence with conclusions that Calcium hydroxide (Ca2+) is an important component of the signaling promoting muscle formation, muscle homeostasis, and regeneration. In particular, Ca2+ changes may translocate muscle satellite cells to maintain their inert state, increase, or separate into functional muscle (Tu et al., 2016). The literature would suggest the increase of leg press strength for the present study or that of Brilla & Conte (2000) might not be attributed to the effects of ZMA. There are indifferent and inconsistent results for strength and hormone levels in each ZMA study, current and previous. It can only be assumed that there are other factors and instigators of myofibrillar hypertrophy, other than testosterone, GH or IGF-1 (instigated by ZMA). Peripheral factors for the main findings of the present study will be discussed in the limitations (See 5.5).

5.4 Critical Analysis

The study by Wilborn et al. (2004) uses a larger sample size of 42 participants, in comparison to that of the current study and that of the study by Moëzzi et al. (2014). The participants in the study by Wilborn et al. (2004) also have a mean age of 27 ± 9 years in comparison to 22.9 ± 2.9 years for the present study. Age-related changes in skeletal muscle can be impaired by the normally

48

decreasing levels of physical activity associated with advancing age and also by metabolic changes and oxidative stresses that that prompts the accumulation of intracellular damage from free radicals (Meng & Yu, 2010). Even frequently active elite athletes and healthy older adults also show a gradual wasting of muscle mass, loss of strength and power output (Yamauchi et al., 2009). Furthmore, Age-related changes in circulating muscle anabolic hormones and growth factors are also prevalent (Lynch, 2011). These factors may have influenced the results due to the broad range of age of the study by Wilborn et al. (2004). The exercise protocols in the literature differentiate. Wilborn et al. (2004) implemented a warm-up protocol and particpants worked their way up towards the 1RM, whereas Brilla & Conte (2000) looked at torque and power at different angles, both, which are unrelated to the methods of the current study. According to Niewiadomski et al. (2008) 1RM is a reputable and universal measure of muscular strength and is defined as the amount of resistance against which a given movement can be performed only in one attempt/repetition. A general evaluation of 1RM is time consuming, and may lead to muscle soreness as well as temporary weakening of the tested muscles, which can discount accuracy and consistency of further attempts. Attempts at determining 1RM indirectly based on the maximum number of repetitions performed have projected 1RM with an adaptable degree of accuracy (Niewiadomski et al., 2008). This suggests that a build up or several different sets and rep ranges would have implications on the end output due to weakening and fatigue of the muscles.

There is no previous literature on ZMA’s effect on recovery, however, literature for Mn improving sleep (recovery) is readily accessible. Results for recovery in the current study show notable results as the QoS significantly increased post-ZMA supplementation, with a significant decrease in awakenings during

49

the night. Numerous studies have shown that Mn improves sleep; studies by Abassi et al. (2012) and Abassi et al. (2013) both observed significant improvements in sleep. Interestingly, Kass & Poeira (2015) found that acute Mn supplementation at a lower dosage (300mg) than ZMA (450mg) significantly improves 1RM strength in the bench press. This could imply that Mn, exclusive of ZMA could have anabolic properties, although further research is required in resistance athletes and exercise.

5.5 Limitations

The current study has various limitations from internal to peripheral factors, which were not controlled during the supplementation period.

ZMA supplementation alone could not (if effective) induce the development of hypertrophy and strength. Muscular hypertrophy is tremendously complex and requires a number of physiological processes and adaptations (Hall, 2015), dietary intake being one of the foundations of these, however it was not monitored for the present study. In resistance training especially, protein intake is an important aspect of muscle development and functionality and provides the body with essential amino acids that release HGH in order for muscle hypertrophy to occur (Rajendram, Preedy and Patel, 2014). Fontana et al. (2008) discovered that the protein intake and micronutrients of a diet are key determinants of IGF-1 (Fontana et al., 2008). By not monitoring dietary intake, an explanation as to why a significant effect has occurred in strength

50

cannot be explained in greater depth. Furthermore, individual implications on the study can also not be explained.

Schoenfield et al. (2015) & Schoenfield et al. (2016), found that different variations and durations of repetitions and frequencies of training per week in resistance training elicited differing levels of muscle hypertrophy (Schoenfeld et al., 2015; Schoenfeld et al., 2016). Resistance training is an exercise modality, which induces different responses based on exercise volume, exercise type, intensity and duration. A study by Netreba et al. (2013) looked at the responses of knee extensor muscles to leg press training of various types in human and discovered that fiber hypertrophy, fatigue resistance and VO2max changes were related to the type of training (Netreba et al., 2013). Resistance exercise imposes stress upon many of the metabolic pathways. Resistance exercise may prompt muscle biochemical adaptations that increase micronutrient needs. Regular exercise may result in the turnover and losses of these micronutrients, thus, requiring a substitute of additional micronutrient intake in order for the body to function, repair and grow (Driskell and Wolinsky, 2016). Training programs were not monitored or controlled for the study and may have had implications on the results.

Individual differences, muscular structures, CSA and fiber-type determine how much force is exerted, as force generation capacities differ (Katch et al., 2010). According to Aagaard et al. (2001) Type II fibers (fast-twitch), grow at a faster rate than type I fibers. The rate of muscle contraction in Type II fibers is also of a greater rate, which suggests that they possess a higher strength and power potential than type I fibers. This is significant to the present study as individuals differ in fiber type for different muscle groups. This could explain the significant increase in leg press strength could simply be

51

response-specific to each individual. Future research could focus more on individual responses due to these differences.

The present study used the Concept2 Dyno Dynamometer to test 1RM strength and did not simulate actual exercise movements. The most commonly used exercises for upper and lower body muscular strength testing are the traditional bench press and leg press, respectively. This may have had an impact on the results and may not define true strength because of not simulating actual exercise movements and exercise conditions. Furthermore, The 1RM is the heaviest weight that can be lifted in one attempt whilst maintaining proper form. This type of maximal strength testing is considered the gold standard for evaluating dynamic strength (ACSM, 2015). Form and heavy resistance were not factors, thus, the present study did not entirely follow the exercise protocol of which is considered ‘gold standard’ for strength testing.

ZMA is marketed as a ‘natural testosterone booster’, thus, highlighting the importance of its hormonal effect. Hormone testing is concurrent in previous literature for ZMA, along with strength testing. As there was no testing for hormone status in the present study, it is inconsistent with other literature. Hormone testing may have provided further analysis of the results and the interaction effect of the supplement. It may have expanded on current ideas and literature on explaining the significant effects and how hormone levels may have elicited these,

Individual responses and a broader range of results for both ZMA and placebo supplements may have been analysed had the present study used a crossover design.

6.0 Conclusion

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Despite the present study there has been very limited research on the anabolic effects of ZMA, and no research on the recovery properties of the supplement as a complete formulation. The anabolic effects of the supplement remain equivocal, as there is a dissimilarity of results, including that of the present study. The present study however, looks at the recovery properties of the supplement and found positive responses, which leaves for open interpretation in comparison to past literature and that of the future. Additionally, although a significant effect was observed for 1RM leg press strength, this does not substantiate the anabolic effects of ZMA as no significant effect was observed for two out of the three exercises, however, literature would suggest that ZMA Supplementation coupled with resistance training may increase the secretion of anabolic hormones and reduce the cellular damage. Furthermore, these results would indicate biological factors peripheral to ZMA may have attributed to the causality of the outcomes. The results of the recovery protocol would suggest that ZMA’s recovery properties has some substance, although further research is required to accredit or negate these findings. Future research should look at the effects of recovery, hormone status, muscle size and strength to get a complete overview and analysis, and to have consistency in-comparison to the previous literature. Individual controls such as dietary intake and training programs should also be controlled, as mechanisms peripheral to the supplement can have causality in the outcome. Additionally, a crossover design should be implemented, as it would validate any correlated significant effects, as well as determine a washout period (Chumney and Simpson, 2006). Furthermore, future research should compare the effects of ZMA against Mn and Zn as synergists in order to evaluate whether the ZMA supplement as a complete formulation is an essential in sport and exercise.

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APPENDICESAppendix A - Participant information sheet

PARTICIPANT INFORMATION SHEET

54

WELKIN HUMAN PERFORMANCE LABORATORIES SCHOOL OF SPORT AND SERVICE MANAGEMENT

The Effects of Chronic Zinc Magnesium Aspartate (ZMA) Supplementation on

Strength & Acute Recovery In Recreational Male Resistance Athletes

LOCATION OF PROJECT: (ON-SITE)

Welkin LaboratoriesEastbourneBN20 7SP

INVESTIGATORS:

Arsalan Javaid:Telephone contact: +44 (0)7702583568

Email: [email protected]

Gary Brickley:Telephone contact: +44 (0)1273 643760

Email: [email protected]

The participation information sheet provides an explanation and insight into why the experiment is being conducted and the experimental procedures involved. Potential risks and side effects may occur during the time of the study and participants will be informed and made aware of the possible implications. Confidentiality and the private information of the candidates for this study will be explained. After reading the participation information sheet, please make a conscious decision of your participation (withdrawal from the study is permissible at any time without any implications of ramifications). If you need further assistance, please consider seeking advice from a family member, friend or relevant professional.

BACKGROUND - EXPLANATION OF THE RESEARCH PROJECT

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mailto:[email protected]

Athletes are constantly striving to break plateaus and optimise performances using nutritional interventions and ergogenic aids. Doping and the use of anabolic steroids is a trend amongst competitive bodybuilders and power lifters (Haff and Travis, 2015), although there are competitors who seek ergogenic aids through natural and legal means. ZMA is a supplement marketed as having anabolic properties, primarily, boosting testosterone and recovery combining the synergistic effects of Zinc Monomethionine Aspartate, Magnesium Aspartate and Vitamin B6 (Villepigue and Rivera, 2012). Strength will be assessed through 1RM testing on three exercises (chest press, seated row and leg press), using the Concept-2 dynamometer strength rig.

This study will consist of three visits to the labs; familiarisation and baseline testing (pre) and post-supplementation testing. Testing will involve performing maximal tests on three exercises on the Concept-2 Dyno Dynamometer. Appropriate familiarization, demonstration and guidance will be given beforehand. 3 capsules of ZMA are to be ingested the night before.

PARTICIPANT INCLUSION CRITERIA

Volunteers will:

1) Male resistance athletes aged 18 – 30 years.2) Minimum of 1 year experience of resistance training3) Be injury free and healthy4) Resistance train at a minimum of 3 times per week5) Refrain from strenuous exercise 48 hours prior to any testing6) Have no personal history of cardiovascular or neurological disease7) Refrain from alcohol consumption 48 hours prior to any testing.8) Refrain from consuming caffeine 24 hours prior to any testing.9) Have a body mass index (BMI) less than 30 kg/m2 i.e.: not classified obese.10) Not currently be taking any anabolic steroids, and/or any other performance

enhancing drugs11) Not currently be taking any ergogenic aids containing creatine, glutamine,

arginine, HMB, androstendione, thermogenics, or any other ergogenic supplement at the time of study (or in the last 6 months).

WHAT WILL MY PARTICIPATION INVOLVE?Laboratory Testing

Visit 1 – Familiarisation session.The familiarisation session is in place to provide you with an overview of the whole experimental procedure, and allow you to experience and attain familiarisation for the techniques that will be used in each lab visit for testing. Demonstrations will be shown and will have a practical opportunity to try the testing apparatus. You will also have another opportunity to read through the participant information sheet and will be

56

required to complete a medical screening questionnaire and consent form. You will be free to ask any questions during the familiarisation session.

Visit 2 – Baseline testing (pre)Participants will perform maximal tests on three exercises (chest press, diverging row and leg press) using the Concept-2-Dyno Dynamometer strength. Participants will have already attained familiarisation from the previous lab visit, but can ask for a ‘practice’ set if necessary. Participants will perform 3 reps on each exercise (See schematic below.)

- 1 repetition at 25% of 1RM- 1 repetition at 75% of 1RM- 1 repetition at 100% of 1RM

Each participant’s final and maximal effort of each set (100% of 1RM) will display a number represented in kilograms (kg), which will be your score. This will be recorded. Participants will rest for 5 minutes seated in between exercises. You are required to fill in a 3-day sleep diary after this visit and before the supplementation period.

28-day supplementation periodDuring this period participants will consume 3 capsules of ZMA orally, on a nightly basis. The supplement is to be ingested 60 minutes prior to sleep on an empty stomach, failure to do so will void your participation from the study.

Visit 3 – Post-supplementation testingPost supplementation testing will be no different to baseline testing. You will be required to return any supplement dispensaries and/or unused supplements. You will be asked to complete and return your 3-day sleep diary three days after testing.

IS THERE ANYTHING I NEED TO DO BEFORE COMING TO THE LABORATORY?

Recording your sleep: You will be asked to record the number of hours you slept, the times you woke up during the night and the overall quality of your sleep for 3 days after preliminary testing and 3 days after supplement load. You will be provided a 3-day sleep diary form.

57

Controlling physical activity: This is crucial to the success of the study. Whilst we do not ask you to refrain from physical activity, it is required for you to not take part in any strenuous or demanding exercise 48 hours prior to testing.

Travelling to the laboratory: If you live locally, you can walk at a slow pace to the laboratory for testing, but please DO NOT run or cycle as this may intervene with research results. If you close by, it would be advised that you drive or catch public transport to Welkin laboratory. If this is not possible then please let us know, and we will arrange for your transport.

IS THERE ANYTHING I NEED TO BRING WITH ME?

Clothing: You will need to bring appropriate clothing for exercise i.e.: shorts, t-shirt or vest, socks and trainers. The laboratories are climate controlled to 19 (°C)Hydration: Ensure you are hydrated before each visit of testing to avoid dehydration. You will be allowed to drink water during testing. We can provide you with water.Showers/Changing rooms: The laboratories are equipped with shower facilities, so feel free to bring towels and a fresh pair of clothes for after the session.

ONCE I HAVE SIGNED UP FOR THIS STUDY, CAN I CHANGE MY MIND?

Withdrawal is permitted at any given time. After reading the information sheet and asking any questions you may have regarding the study, you will be asked to sign an informed consent sheet. Please be aware that the signing of these forms is not legally binding and you are allowed to withdraw your participation from the study at any given time, with no explanation and no implications.

WILL MY DATA BE KEPT CONFIDENTIAL?

Your information will be stored on computer; you will be provided with and referred to as a number, in order to keep your personal information private and confidential, in accordance with the Data Protection Acts of 1984 and 1998. Data will be used for research purposes only and confidentiality will be maintained in any publications arising from the study. Participants are able to access their own individual data upon request. Data will not be kept longer than is necessary for the purposes of this investigation and will be erased as applicable.

WHAT DO I GET FOR PARTICIPATING?

The study will provide you with Laboratory experience and an insight of how the sport and exercise science world works. You will also be gain an insight of your 1RM performance on 3 different exercises and your recovery, and how this is affected by

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a 28-day supplementation period. After the study we will provide you with feedback regarding your own results.

ARE THERE ANY RISKS AND/OR DISCOMFORT?

Maximal testing may cause breathlessness, dizziness and some discomfort. However, due to the short period of testing, participants are not expected to experience any of these. Resistance athletes with a minimum of one years experience should not have any problems with the exercise protocol; however, safety measures will still be implemented. Muscoskeletal injuries may occur during the time of the study, however, risks are minimal and measures will be implemented to prevent any occurrences. Guidance and demonstrations on the correct posture, technique and execution will be given to eliminate risk of injury. Each candidate for this study will be supervised carefully and accordingly.

REMINDER: THIS STUDY IS RELIANT ON VOLUNTEERS, HOWEVER IF AT ANYTIME THROUGHOUT THROUGH OUT THE STUDY YOU WISH TO WITHDRAW YOUR PARTICIPATION THEN YOU ARE FREE TO DO SO WITHOUT EXPLANATION AT ANY TIME WITHOUT ANY RAMAFICATIONS.

CONTACTS

Please feel free to ask any questions, at any stage. Contact details for the staff involved in the study are as follows:

Arsalan Javaid:Telephone contact: +44 (0)7702583568Email: [email protected]

Gary Brickley:Telephone contact: +44 (0)1273 643760Email: [email protected] B - Informed Consent

INFORMED CONSENT FORM

59

mailto:[email protected]

WELKIN HUMAN PERFORMANCE LABORATORIES SCHOOL OF SPORT AND SERVICE MANAGEMENT

The Effects of Chronic Zinc Magnesium Aspartate (ZMA) Supplementation on Strength & Acute Recovery In Recreational Male

Resistance Athletes

The purpose and details of the above study have been explained to me and I understand that this study is designed for the primary reason of furthering scientific research and knowledge. All procedures involved have been approved by the University of Brighton Ethical Advisory Committee.

I have read and understood all information contained in the participant information sheet and this consent form.

I have had the opportunity to ask any questions about my participation in this study.

I understand I am under no obligation to volunteer in the study. I understand I have the right to withdraw from thre study at any stage

without giving any reason and/or explanation. I understand that all information I provide will be dealt with in a strict

confidential manner. I agree to participate in this study and am aware of all procedures that will

take place and I have been informed of risks associated to these activities. I agree for my information to be kept on an evidence file that will be kept on

a secure computer with no other use or distribution.

Name:

Your signature:

Signature of investigator:

Date:

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Appendix C – Medical Questionairre (Part A)

61

Appendix E – Risk Assessment Forms

Appendix D– Medical Questionairre (Part B)

62

Appendix F – COSSH Forms

COSHH RISK ASSESSMENT FORMFor single substances

Activity and hazard propertiesCollege: University of Brighton School/Department: Sport and Ex.

64

ScienceLocation of activity: Hillbrow Sports Centre

Description of activity: Subjects will ingest 3 ZMA capsules on an empty stomach the night before testing [Wilborn et al., 2004].

Substance name Zinc Monomethionine/Magnesium Aspartate [ZMA]

CAS Number

Quantity used(grams/litres)

Serving Size = 3 CapsulesZinc: 30 mg

Magnesium: 450 mgVitamin B6: 10.5 mg

Intake referenced from Effects of Zinc Magnesium Aspartate (ZMA) Supplementation on Training

Adaptations and Markers of Anabolism and Catabolism [Wilborn et al., 2004]

Workplace exposure limit

Harmful/

irritant

Flammable/ highly

flammable

Dangerous to the

environment

Corrosive

Health hazard

Oxidiser

Toxic/ very toxic

Explosive

Please attach MSDS for the substance to the hard copy of this sheetCan this product be substituted

with a less hazardous ones? Yes No

If yes give reason for not doing so:Is the substance being decanted

from a larger container? Yes No

If yes what size is that container?How is the substance used?

(e.g. diluted, applied, dissolved)

Swallowed as capsule.

Persons at risk

Staff Students Visitors Contractors Public

65

How often is the

substance used?

Multiple times daily

Daily Weekly Monthly Rarely

3 capsules on a daily

basis.How long are people exposed to

thesubstance when used?(mins)

The supplement will take 1.5 hours to digest after consumption.

When is the substance

In contact with eyes

In contact with skin

Inhaled Ingested Injected

May cause

choking when

swallowed as

capsule.What is the level of

risk posed by exposure

Low Medium High

Control measures

General precautions Instructions will be in place to ensure the safety of the particpants.

Engineering controls

Training/briefing requirements The participants are required to consume the capsules on a nightly basis.

Do the control measures reduce the risk to an acceptable level? If recommended isntructions are followed

accordingly, risk is reduced signficantly.

Are there any further control measures required?

Required PPE

Other: Other:

HygienicType: Wear

Type: Goggles

Type: Type: Type: General

Type: Type: Type: Wash thoroughly with

66

general work gloves to minimize

skin contact.

or safety glasses.

(mechanical) room ventilatio

n satisfacto

ry

soap and water after handling

product.

First aid procedureArea exposed Risk to health First aid procedure

Skin Exposure to liquid or mists may cause minor

irritation

Wash contacted skin areas with soap and water. Change soaked

clothing.

Eyes Direct contact may cause temporary

discomfort with redness and dryness.

Wash eyes thoroughly with water for a minimum of 15

minutes. If irritation occurs, call a physician.

Inhalation May be irritating to nose, mouth, throat and lungs.

If irritation occurs remove to fresh air.

Ingestion May cause nausea, vomiting, diarrhea and

abdominal pain.

Drink several glasses of water Do not induce vomiting. Consult

a physician.

67

Waste and spillage procedures

Storage requirements MUST be kept in a cool dry place out of direct sunlight

Spillage procedureContain spill and sweep up. Not a hazard if

uncontaminated.

Ecological controls

Disposal procedureDispose of in accordance with applicable

Federal, State and Local regulations.

Fire controls

Water Powder Foam CO2 Wet Chemical

Additional commentsAny side effects or accidental misuse of the supplement will require immediate

professional health care.

Assessor: Arsalan Javaid Date completed:

Manager’s signature:

Gary Brickley Date:

Review date:

68

COSHH RISK ASSESSMENT FORMFor single substancesActivity and hazard properties

College: University of Brighton School/Department: Sport and Ex. Science

Location of activity: Hillbrow Sports Centre

Description of activity: Subjects will ingest 3 Maltodextrin capsules on an empty stomach the night before testing [Wilborn et al., 2004].

Substance name Maltodextrin

CAS Number

Quantity used(grams/litres)

Workplace exposure limit

Harmful/ irritant

Flammable/ highly

flammable

Dangerous to the

environment

Corrosive Health hazard

Oxidiser Toxic/ very toxic

Explosive

Maltodextrin becomes a flammable dust when

finely divided and suspended

in air. Keep product away from sources of ignition, sparks and

open flames. Provide

adequate dust control and ventilation. Exposure to extreme heat

builds up pressure in

closed containers.

69

Cool with water stream.

Please attach MSDS for the substance to the hard copy of this sheetCan this product be substituted

with a less hazardous ones? Yes No

If yes give reason for not doing so:Is the substance being decanted

from a larger container? Yes No

If yes what size is that container?How is the substance used?

(e.g. diluted, applied, dissolved)Swallowed as capsule.

Persons at risk

Staff Students Visitors Contractors Public

How often is the

substance used?

Multiple times daily

Daily Weekly Monthly Rarely

3 capsules on a daily

basis.How long are people exposed to the

substance when used?(mins)The supplement will take 1.5 hours to digest after

consumption.

When is the substance

hazardous?

In contact with eyes

In contact with skin

Inhaled Ingested Injected

May cause

choking when

swallowed as

capsule.What is the level of risk

posed by exposureLow Medium High

Control measures

General precautions Instructions will be in place to ensure the safety of the particpants.

Engineering controls

Training/briefing requirements The participants are required to consume the capsules on a nightly basis.

70

Do the control measures reduce the risk to an acceptable level? If recommended isntructions are followed

accordingly, risk is reduced signficantly.

Are there any further control measures required?

Required PPE

Other: Other:

HygienicType: Wear general work

gloves to minimize skin

contact.

Type: Goggles or safety glasses.

Type: Type: Type: General

(mechanical) room ventilatio

n satisfactor

y

Type: Type: Type: Wash thoroughly with

soap and water after handling product.

First aid procedureArea exposed Risk to health First aid procedure

Skin Exposure to liquid or mists may cause minor irritation

Wash contacted skin areas with soap and water. Change soaked

clothing.

Eyes Direct contact may cause temporary discomfort with

redness and dryness.

Wash eyes thoroughly with water for a minimum of 15 minutes. If

irritation occurs, call a physician.

Inhalation May be irritating to nose, mouth, throat and lungs.

If irritation occurs remove to fresh air.

Ingestion May cause nausea, vomiting, diarrhea and

abdominal pain.

Drink several glasses of water Do not induce vomiting. Consult a

physician.

71

Waste and spillage procedures

Storage requirements MUST be kept in a cool dry place out of direct sunlight

Spillage procedureContain spill and sweep up. Not a hazard if

uncontaminated.

Ecological controls

Disposal procedureDispose of in accordance with applicable

Federal, State and Local regulations.

Fire controlsWater Powder Foam CO2 Wet Chemical

Additional commentsAny side effects or accidental misuse of the supplement will require immediate

professional health care.

Assessor: Arsalan Javaid Date completed:

Manager’s signature: Gary Brickley Date:

Review date:

72

Appendix G – Sleep Diary

Participant Number: (This is the number you were provided)

As a participant, it is necessary for you to fill in this sleep diary 3-days after preliminary testing and 3 days immediately after supplement testing, as informed.

You will need to bring this in after completing the first phase (Before supplement testing), failure to do this may result in your exclusion of the study. PLEASE keep this safe, as you are required to return this once completed.

Hours Slept – The approximate amount of hours you slept.

Awakenings – The approximate amount of times you awoke during the night.

Quality of Sleep - 1 being the poorest quality (of sleep) and 10 being the greatest.

Before Supplement Testing:Hours Slept Awakenings Quality of Sleep

(1-10)Day 1

Day 2

Day 3

After Supplement Testing:Hours Slept Awakenings Quality of Sleep

(1-10)Day 1

Day 2

Day 3

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Appendix G – Pilot Testing

Pilot Testing Of Concept-2 Dyno Dynamometer Strength Rig

The pilot testing consisted of performing 10 x 1 Rep Max repetitions on the Concept 2 Dyno dynamometer. For each of the three exercises: chest press, diverging row and leg press. Each exercise was performed ten times to give ten 1RM scores (kg) for a participant.

Exercise Protocol:

Attained correct posture/position for each exercise. 1 repetition at 25% (Of perceived maximal effort) 1 repetition at 70% (Of perceived maximal effort) 1 repetition at 100% (Of perceived maximal effort) A 5 minute rest after each 1RM (Static rest)

Standard deviation of repeated trials:

The Standard Deviation (SD) of repeated trials may be applied to several trials in one testing session and are used to prove consistency and dependability of measures.

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Results:

Table 1. Reproducibility: standard deviation of repeated 1RM tests for each exercise. All 1RM tests on each exercise were tested on the same day. The 1RM variation was expressed as the standard deviation (SD) of the mean of each of the 10 test results for each exercise. The coefficient of variation for each exercise was calculated by the sum SD/MEAN x 100.

Results:

As displayed in table 1 the coefficient variation for chest press = 0.76; diverging row = 0.69; leg press = 0.33. The coefficient variation is a statistic used to display variability of distribution when looking at data (Hanneman, Kposowa and Riddle, 2013). Distributions with coefficient variation of less than 1 are considered low-variance (Erlang distribution), representing very low variability in 1RM scores across 10 attempts (Ghatak, 2010). This is evidence to validate and support the means of testing using the Concept-2 Dyno Dynamometer as an accurate means of testing with low variance across 1RM strength testing. These findings are in accordance to the test-retest reliability of Bampouras et al. (2014) for the Concept-2 Dyno Dynamometer (Bampouras et al., 2014)

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