Effect of Hyd r

Authors

Affiliations nbecty

Key wordsl" water immersionl" recoveryl" performance

accepted after revisionAugust 22, 2007

BibliographyDOI 10.1055/s-2007-989267Published online Nov. 30, 2007Int J Sports Med 2008; 29:539544 Georg ThiemeVerlag KG Stuttgart New York ISSN 0172-4622

CorrespondenceJoanna VaileAustralian Institute of SportDepartment of PhysiologyPO Box 176, Belconnen2616 CanberraAustraliaPhone: + 61 2 62 14 12 37Fax: + 61 26 21 41 60 3Jo.Vaile@ausport.gov.au

539Physiology & BiochemistryAbstract!

The present study investigated the effects of

rotherapy on Recove

J. Vaile1, S. Halson1, N. Gill2, B. Dawson3

1 Department of Physiology, Australian Institute of Sport, Ca2 School of Sport and Exercise Science, Waikato Institute of T3 School of Human Movement and Exercise Science, UniversiIntroduction!

In elite cycling events, athletes require the abilityto maintain a consistently high level of perfor-mance. This is especially important in stage rac-ing where cyclists are required to produce de-manding and consistent performances on multi-ple days. However, when athletes are required toperform on consecutive days, the ability to recov-er well, referring to a period of both physiologicaland psychological restoration and regeneration,becomes very important.Anecdotal evidence suggests that the sport of cy-cling has traditionally favoured a recovery profileconsisting predominantly of massage and nutri-tional replacement strategies. However, the useof various recovery interventions and in particu-lar the use of postexercise hydrotherapy has be-come increasingly popular [5, 24]. Nonetheless,there is insufficient evidence to reach firm con-clusions and little quality research has been con-ducted in this field, particularly following fa-tigue-inducing exercise. Despite limited scien-tific evidence the use of cold water immersion

three hydrotherapy interventions on next dayperformance recovery following strenuous train-ing. Twelve cyclists completed four experimentaltrials differing only in 14-min recovery interven-tion: cold water immersion (CWI), hot water im-mersion (HWI), contrast water therapy (CWT), orpassive recovery (PAS). Each trial comprised fiveconsecutive exercise days of 105-min duration,including 66 maximal effort sprints. Additionally,subjects performed a total of 9-min sustained ef-fort (time trial TT). After completing each exer-cise session, athletes performed one of four re-covery interventions (randomly assigned to each

Vaile J et al. Eftrial). Performance (average power), core temper-ature, heart rate (HR), and rating of perceived ex-ertion (RPE) were recorded throughout each ses-

y from Fatigue

erra, Australiahnology, Hamilton, New Zealandof Western Australia, Perth, Australia(CWI), hot water immersion (HWI), and contrastwater therapy (CWT) as postexercise recovery in-terventions have become common practice with-in many athletic settings [5, 24].Cryotherapy has been recognised as the mostcommonly used treatment for acute soft tissuesports injuries and in different forms has alsobeen utilised as a postexercise recovery interven-tion. Additionally, CWI has been shown to be ef-fective in the treatment of muscle damage andinflammation, or when significant increases incore temperature may affect performance [9,13,16]. In a recent review, it was concluded thatapart from an analgesic effect, there appears tobe limited scientific evidence to suggest any en-hancement in postexercise recovery from muscledamage by CWI [4]. However, the effect of CWIon repeat high-intensity exercise performancehas not been fully elucidated.Hot water immersion (HWI) is a thermothera-peutic intervention in which the body is im-mersed in water exceeding 36 8C [23]. Very littlescientific evidence exists to support the use ofHWI as a postexercise recovery intervention;

sion. Sprint (0.1 2.2%) and TT (0.0 1.7%) per-formance were enhanced across the five-day trialfollowing CWI and CWT, when compared to HWIand PAS. Additionally, differences in rectal tem-perature were observed between interventionsimmediately and 15-min post-recovery; how-ever, no significant differences were observed inHR or RPE regardless of day of trial/intervention.Overall, CWI and CWT appear to improve recov-ery from high-intensity cycling when comparedto HWI and PAS, with athletes better able tomaintain performance across a five-day period.

fect of Hydrotherapy Int J Sports Med 2008; 29: 539 544

vestigated further. Therefore, the purpose of the present study

Subjects completed a 10-min self-paced warm-up followed by3 3-s sprints at a perceived intensity of 70%, 80% and 90% ofmaximum effort respectively. The main exercise task completeddaily for five consecutive days totalled approximately 105-minin duration, consisting of 66 maximal effort sprints of 5 15 s du-ration with specific work to rest ratios of 1 :6, 1 : 3, 1: 1 [15]. Ad-ditionally, a total of 9-min of sustained effort was incorporatedinto the protocol consisting of 2 2-min and one 5-min time trial(TT) (l" Fig. 2). This protocol was used in an attempt to simulatethe demands of cycling races and to provide an indication of re-peat performance capabilities; and has previously been used inour laboratory with elite cyclists. Typical error of this protocolwas 17.4 Watts and 2.1%. Throughout each testing session of thefive-day trial, strong verbal encouragement and support was giv-en to the subjects by the same person and in the same fashioneach day, remaining consistent for the duration of the study.The work phase of the interval session involved a maximal ef-fort while the rest phase involved the subjects cycling at an in-

540 Physiology & Biochemistrywas to investigate the effect of three different hydrotherapy in-terventions (CWI, HWI, CWT) on the recovery of exercise-in-duced fatigue and next day performance.

Methods!

Twelve endurance trained male cyclists volunteered to partici-pate in this study. Their mean standard deviation age, height,body mass, VO2max and sum of seven skinfolds were 32.2 4.3years, 176.6 4.5 cm, 68.8 7.2 kg, 68.8 3.6 ml kg1 min1 and58.2 16.9 mm, respectively. Prior to involvement, all subjectswere informed of the study requirements and risks and providedinformed written consent. Subjects were required to refrainfrom any strenuous exercise 24 h prior to testing, perform no ad-ditional strenuous activity during the five-day data collectionperiod, and abstain from caffeine (24 h) and alcohol (48 h) priorto and throughout the five-day testing period. The study was ap-proved by the Australian Institute of Sport Research Ethics Com-mittee.

Experimental designPrior to participation all subjects completed a VO test on aspecifically, the effect of HWI on physiological variables and sub-sequent performance are largely unknown.Contrast water therapy (CWT) utilises both cold and hot waterimmersion and has become a very popular postexercise recoveryintervention [5, 23]. Similar to CWI, CWT has been shown to bean effective treatment strategy for muscle damage, sorenessand inflammation and to enhance the recovery of performance[22]. Additionally, CWT has been associated with an increase inthe perception of recovery and a quicker reduction of lactatepostexercise [6]. However, further research must be conductedto confirm the potential recovery benefits of CWT and to investi-gate possible mechanisms and protocols.While the aforementioned recovery interventions have beenshown to be effective in various settings or following specifictypes of exercise (e.g., eccentric exercise), the effect of such in-terventions on repeated days of high-intensity cycling exerciseremains largely unknown. Due to the current popularity of post-exercise hydrotherapy [5, 24], this is an area that needs to be in-2max

cycle ergometer (Lode, Groningen, Netherlands) as well as threefamiliarisation sessions, including protocols and proceduresidentical to the five-day trial, to minimise any learning effect inthe first week of the study. On four separate occasions separatedby nine days (randomised crossover design), each subject com-pleted a fatigue-inducing cycle protocol on five consecutivedays, each followed by one of four recovery interventions (CWI,HWI, CWT, or passive recovery [PAS, control]) (l" Fig. 1). Recov-ery intervention remained the same for each day of the five-daytrial. Subjects were required to complete a training and food di-

Vaile J et al. Effect of Hydrotherapy Int J Sports Med 2008; 29: 539 544ary throughout the eight-week period, in which training duringoff weeks was matched for volume and intensity throughoutthe study and to ensure food intake throughout the testingweeks remained consistent.

Fatigue-inducing protocol

Fig. 1 Experimental design indicating preliminarytesting (VO2max test), familiarisation of testingprotocol, and four trials (T1 T4) consisting of theexercise protocol, performed on five consecutivedays. Each session was followed by one of four re-covery strategies (RS1 RS4; randomised crossoverdesign).

Fig. 2 Breakdown ofhigh-intensity exercisetask performed dailyfor five consecutivedays. Athletes had 5-min active recovery be-tween sets 1 2, 2 3,4 5, 5 6, 7 8, and8 9 [12].tensity of 40 50% of their individual peak power output. Duringthe TT efforts, the subjects were instructed to complete as muchwork as possible in the specified time (2- or 5-min effort).

Recovery interventionsImmediately postexercise, subjects completed a 5-min cyclingwarm down at approximately 40% of individual peak power out-put followed by one of four recovery interventions. The same re-covery intervention was performed for all five days of each trial.Cold Water Immersion (CWI): Subjects immersed their entire

tween hot and cold water baths was approximately 5 s. PassiveRecovery/Control (PAS): Subjects remained seated with minimal

nine min of TT performance are presented inl Table 1. Althoughno significant differences were observed between treatments onday one of each exercise week, it is acknowledged that both CWIand CWT groups produced marginally less total work comparedto HWI and PAS. Following PAS, TT performance (average power)had decreased by 3.8% during the five consecutive days of high-intensity exercise. However, in comparison, CWT and CWI re-sulted in a significantly better maintenance of performancecompared to PAS (p < 0.05) (l" Fig. 4). Across the five exercisedays performance was decreased by 2.6 3.8% following PAS, incontrast, performance was maintained and slightly improvedfollowing CWI (range of 0.1 1.0%) and CWT (0.0 1.7%); withperformance ranging from an improvement of 1.5% to a decreaseof 3.4% throughout the five-day period following HWI. Whilethere were no significant differences (p > 0.05) observed in aver-age power between CWT and CWI or HWI and CWI, there weresignificant differences observed between HWI and PAS(p = 0.02) on day three and between CWT and HWI (p = 0.01) onday four of exercise.

Rectal core temperatureNo significant differences (p > 0.05) in rectal temperature wereobserved between groups at baseline (pre-exercise) or immedi-ately postexercise (l" Fig. 5). Average pre-exercise rectal temper-ature regardless of intervention group or day of exercise was37.3 0.2 8C with an average rectal temperature of 38.5 0.2 8Cat the completion of the high-intensity exercise task. Immedi-

541Physiology & Biochemistrymovement for 14 min.

Recovery assessmentPerformance assessmentSubjects repeated the fatigue-inducing cycle exercise protocolon five consecutive days; peak and average power output and to-tal work completed were recorded via an SRM powermetre(SRM, Schoberer Rad Metechnik, Jlich, Germany) fitted to eachsubjects bicycle, which was in turn mounted on a windtrainer(Kinetic fluid trainers, Kurt Kinetic, Jordan, MN, USA). This al-lowed data to be collected throughout each of the testing ses-sions to establish performance, with reduction in power and/orwork completed over a session and between days being indica-tive of fatigue.

Core temperatureCore temperature was monitored via disposable rectal probe(Monatherm, Mallinckrodt Medical, St. Louis, MO, USA) insertedat least 12 cm beyond the anal sphincter prior to testing [19, 25].Core temperature (Zentemp 5000, Zencor Pty Ltd., Victoria, Aus-tralia) was recorded pre- and postexercise, pre- and post-recov-ery as well as 15-min post-recovery.

Heart rate (HR)Heart rate was monitored using a Polar heart rate (Kempele, Fin-land) monitor fitted to the subject for the duration of the testingsession. Heart rate was recorded at the end of each sprint set, aswell as pre- and post-recovery.

Rating of perceived exertion (RPE)Subjects rated their perceived exertion on a scale of zero (no ex-ertion at all) to ten (maximal exertion) [18] at the end of eachsprint set and at the end of the 5-min TT which concluded theexercise session.

Statistical analysisMean effects were calculated for each intervention (significantchanges p < 0.05) and 95% confidence limits were estimatedwith a spreadsheet [2] via the unequal-variances t statistic com-puted for change scores between pre- and post-tests of the fourgroups. Each subjects change score was expressed as a percent-age of baseline score via analysis of log-transformed values, inorder to reduce bias arising from nonuniformity of error.

Results!

Sprint performanceWhen CWI and CWT were performed following the high-inten-sity exercise bout on five consecutive days, there was a signifi-cantly (p < 0.01) better maintenance/improvement of averagepower on days four and five compared to PAS (l" Fig. 3). How-body (excluding the neck and head) in a plunge pool set at 15 8Cfor 14 min. HotWater Immersion (HWI): Subjects immersed theirentire body (excluding the neck and head) in a spa bath set at38 8C for 14 min (no jets). Contrast Water Therapy (CWT): Sub-jects immersed their entire body (excluding the neck and head)alternating between cold (15 8C one min) and hot (38 8C one min)water for a total of 14 min (seven cycles). Transition time be-ever, there were no significant differences (p > 0.05) betweenother treatments on any of the five days. Across the five exercisedays average power was decreased by 1.7 4.9% following PAS,and 0.6 3.7% following HWI, while improvements of 0.5 2.2%were observed following CWT and 0.1 1.4% following CWI.

Time trial (TT) performanceAbsolute values of overall total work (kJ) completed during the

"

1 2 3 4 5

CWIHWICWTPAS

Day

**

***

*

Pe

rce

nt

cha

ng

e(%

)

5

4

3

2

1

0

1

2

3

4

5

6

7

Fig. 3 Changes in sprint performance (average power; percent changefrom baseline/day one) on five consecutive days of high-intensity cycleexercise. * Indicates a significant difference (p < 0.05) between CWI andPAS. ** Indicates a significant difference (p < 0.05) between CWT and PAS.ately post-recovery rectal temperature was 37.3 0.2 8C (CWI),

Vaile J et al. Effect of Hydrotherapy Int J Sports Med 2008; 29: 539 544

n o

D

15

16

16

15

) a

em

p

37.4

542 Physiology & BiochemistryTable 1 Absolute values of total work (kJ) completed during the total nine mi

Work (kj)

Recovery Day 1 Day 2

CWI 157 20 158 21

HWI 159 21 158 22

CWT 157 21 160 22

PAS 161 20 160 20

* Indicates a significant difference (p < 0.05) between the stated treatment (CWI or CWT

**

**

*

***

#

##

**

en

tch

an

ge

(%)

5

4

3

2

1

0

1

237.6 0.2 8C (HWI), 37.5 0.2 8C (CWT), and 37.4 0.2 8C (PAS).Significant differences (p < 0.02) were observed between HWIvs. CWI and PAS, as well as CWI vs. CWT. However, 15-min post-recovery rectal temperature was 36.8 0.2 8C (CWI), 37.7 0.2 8C(HWI) and 37.3 0.2 8C (CWT and PAS). Significant differences(p < 0.03) were observed between HWI vs. CWI, CWT and PAS,as well as CWI vs. CWT and PAS.

Heart rate (HR)Heart rate recorded immediately post-TT (5 min) on days 1 5were 174, 175, 175, 169, 170 bpm, respectively, following PAS;173, 173, 174, 174, 169 bpm following CWI; 173, 171, 172, 167, 167bpm following HWI; and 174, 171, 169, 172, 172 bpm followingCWT. While there were no significant differences in HR immedi-ately post-TT, there were some noteworthy effects sizes (ES) sug-gesting there may be some small to large effects in HR responseduring exercise between interventions. For example, post-TT HRtended to be lower on days 2 5 following HWI when comparedto PAS representing a moderate effect (ES > 0.6). In addition,when compared to PAS, HR tended to be higher on day 4 andday 5 following CWT (ES = 0.6), and a similar but larger effectwas evident on day 4 following CWI (ES = 1.2).

1 2 3 4 5

CWIHWICWTPAS

Day

Pe

rc 3

4

5

6

7

Fig. 4 Changes in time trial performance (average power; percentchange from baseline/day one) on five consecutive days of high-intensitycycle exercise. * Indicates a significant difference (p < 0.05) between CWTand PAS. ** Indicates a significant difference (p < 0.05) between CWI andPAS. # Indicates a significant difference (p < 0.05) between HWI and PAS.## Indicates a significant difference (p < 0.05) between CWT and HWI.

Vaile J et al. Effect of Hydrotherapy Int J Sports Med 2008; 29: 539 544PreEx PostEx PostRec 15PostEx

Day

Co

reT

37.1

36.8

36.5f time trial performed daily on five consecutive days

ay 3 Day 4 Day 5

9 21 161 21* 160 20*

1 23 153 21 156 22

0 20 162 22* 161 20*

7 22 155 22 155 22

nd both HWI and PAS

CWIHWICWTPAS

***

era

ture

(C

)

38.9

38.6

38.3

38.0

37.7Rate of perceived exertion (RPE)There were no significant differences or changes in the subjectsperception of exertion throughout the exercise protocol regard-less of recovery intervention or day of trial. The average RPE re-ported throughout the study (independent of intervention andday of trial) was observed to be between 8 and 9, on a scale of0 10 with 10 being maximal exertion.

Discussion!

The main finding of the present study was that both CWI andCWT significantly better maintained performance compared toHWI and PAS throughout the five consecutive days of testing.Sprint performance was maintained and slightly improved fol-lowing CWI and CWT (0.5 2.2% and 0.1 1.4%, respectively)with similar trends observed throughout TT performances (CWI0.1 1.0%; CWT 0.0 1.7%). In contrast, following HWI and PAS, adecline of 0.6 3.7% and 1.7 4.9% was observed throughoutsprint performance and up to 3.4% and 3.8% throughout TTperformance, respectively. Interestingly, the effects of hydro-therapy appeared to be more pronounced during TT perfor-mance compared to sprint performance, with some of the hydro-therapy interventions proving to be significantly better than PASfrom the second day of exercise as opposed to just the fourth andfifth day of exercise in sprint performance. These are noteworthyfindings in regard to athlete workloads, as recovery is generally

Fig. 5 Changes in core temperature (Trec) recorded pre- and postexer-cise, immediately post-recovery (CWI, HWI, CWT, or PAS), and 15-minpost-recovery. Values represent the average Trec at the given time pointsacross the five-day trial for each individual intervention. * Indicates signif-icant differences (p < 0.02) between HWI vs. CWI and PAS, CWI vs. CWT.** Indicates a significant difference (p < 0.03) between HWI vs. CWI, CWTand PAS, CWI vs. CWT and PAS.

543Physiology & Biochemistryconsidered an important aspect of training and competition, in-appropriate and/or inadequate recovery may result in a decreasein performance ability [5,10].In a similar randomised cross-over design, Lane and Wenger [11]investigated the effect of CWI, active recovery and massage onrepeat cycling performance separated by 24 h. Following thecompletion of a cycle sprint protocol, subjects performed one offour 15-min recovery interventions (CWI, active recovery, mas-sage, or passive recovery/control), then 24 h after the first exer-cise session the cycle sprint protocol was repeated. When activerecovery, CWI and massage were performed between exercisebouts, the ability to maintain power in the second exercise boutwas significantly enhanced. The authors concluded that CWI, ac-tive recovery and massage can all facilitate recovery betweentwo high-intensity exercise bouts separated by 24 h [11]. How-ever, CWI provided the only improvement in performance, sug-gesting it was the most beneficial of the three treatments. Theresults of the present study are in agreement with the findingsof Lane and Wenger [11], in that CWI also provided a mainte-nance and slight improvement in performance over consecutivedays.Despite the significant improvements in performance followingCWI and CWT, there were no significant changes in RPE or HRthroughout the study, regardless of intervention. Due to the na-ture of the maximal effort exercise task, it is not surprising thatperceptions of the effort and HR were not significantly differentthroughout the study. Therefore, the findings of this study sug-gest that during maximal effort exercise, measures of HR andRPE may not be sensitive enough for assessing physiological orpsychological responses to tasks of this nature. This may becomemore apparent during submaximal exercise.In a recent review [24], it was noted that a major contraindica-tion of CWT and its subsequent research is the concurrent expo-sure to both hot and cold water, and that outcomes have notbeen compared to either hot or cold water immersion protocolsindependently. Therefore, recovery interventions in the presentstudy were selected to investigate the isolated effect of immer-sion in hot and cold water individually as well as when alter-nated (CWT), with duration of water exposure (14 min) identicalregardless of intervention. Results suggest that intermittent ex-posure to both hot and cold water of prescribed temperaturesand duration should not be a concern from a physiological orperformance viewpoint. Indeed, the present results support theuse of CWT as a postexercise recovery intervention to supple-ment recovery from high-intensity repeat cycling. Additionally,there is an increasing body of knowledge to support the use ofCWT as a recovery intervention and while not all studies havefound a performance benefit, it has not been found harmful ordetrimental in any way [6,22].There is limited scientific research into the physiological mecha-nisms by which various postexercise hydrotherapy interventionsmay be advantageous. However, the effects of CWI in varioustemperatures has been investigated, with physiological re-sponses including reductions in core and tissue temperature [8,17], decreased heart rate and cardiac output, increased periph-eral resistance and arterial blood pressure [21], fluid shifts [8,23], and reduced swelling [5, 20] being reported. Data from thepresent study support previous findings of a reduction in coretemperature following CWI [14]. While a reduced HR was notobserved in the present study, it must be noted that the effec-tiveness of recovery was assessed 24 h post-recovery. In addi-

tion, reduced perceptions of pain have also been observed [20].Due to the nature of the exercise task, requiring maximal effort,subjects RPE remained unchanged throughout the five-day exer-cise period. However, a submaximal exercise component to theprotocol may have resulted in a different finding.Unlike CWI, research investigating the effects of water immer-sion in hot temperatures is limited. However, HWI has been sug-gested to increase heart rate, cardiac output, and peripheral vas-odilation, resulting in increased tissue temperatures [3, 23]. Thepresent study observed significantly higher post-recovery coretemperatures following HWI when compared to CWI, CWT andPAS. The inflammatory response and swelling are also exacer-bated following the application of heat [7,23], and while per-formance appeared to be compromised in this study followingHWI, specific mechanisms must be further investigated. Con-trast water therapy protocols utilise the effects of both hot andcold water exposure and therefore may enhance recovery by in-creasing blood flow, circulation, lactate removal, and range ofmotion, and by decreasing the inflammatory response, pain,stiffness and the effects of exercise-induced muscle damage[23]. In the present study, performance appeared to be bettermaintained following the use of CWT; however, a more mecha-nistic approach in future studies may provide further informa-tion regarding the process by which CWT may be effective.In addition to temperature aspects, the effects of hydrostaticpressure during water immersion may be an important aspectof the success of hydrotherapy as a recovery intervention. Thepressure applied to the body during water immersion may causea displacement of fluid from the extremities, increasing centralblood volume [1,12, 23]. Although this beneficial effect of hydro-static pressure is evident, regardless of temperature, all inter-ventions in the present study (CWI, HWI, CWT) were performedin identical conditions with pressure exerted and duration ofwater exposure identical. Therefore, although hydrostatic pres-sure may contribute to the effectiveness of hydrotherapy, tem-perature must also play an integral role, with findings suggest-ing CWI and CWT to be more beneficial than HWI. Physiologi-cally, continuous HWI may be more detrimental than exposureto cooler water due to the increase in cardiovascular strain.Research into the recovery from repetitive bouts of training orcompetition provides valuable knowledge regarding the adapta-tion to specific stress. Such information is essential if the pur-pose of a particular training session or competition regime is toproduce improved performances. The results from the presentstudy are unique and novel from a training perspective. Data ex-amining recovery must be gathered in applied and practical en-vironments to allow transfer of results to the real world of ath-letic performance. The current findings suggest that CWI andCWT are useful interventions for maintaining and even slightlyimproving consecutive daily cycling performance in both TTand repetitive sprint performance. Whether such results arefrom a reduction in cumulative fatigue or an accelerated adapta-tion is unknown. Indeed, the precise mechanism/s by which thisoccurs is unclear and requires further investigation.

Practical applicationsThe results of the present study suggest that CWI and CWT maybe beneficial recovery interventions following and betweenevents such as track cycling where the task requires short maxi-mal efforts, as well as longer events such as stage races wherethe task requires continuous high-intensity efforts on successivedays.Vaile J et al. Effect of Hydrotherapy Int J Sports Med 2008; 29: 539 544

Future researchFuture scientific research should be conducted to further inves-tigate the effect of hydrotherapy techniques, following high-in-tensity exercise, particularly when repeat performances are re-quired. The present study suggests CWI and CWT to be promis-ing recovery interventions; however, future studies must be con-ducted to enhance the body of knowledge and understanding ofhydrotherapy and its associated mechanisms.

Acknowledgements!

The authors would like to acknowledge and thank the partici-pants for their generous time commitment and effort through-out study.

References1 Arborelius M Jr, Ballidin UI, Lilja B, Lundgren CE. Hemodynamic changes

in man during immersion with the head above water. Aerosp Med1972; 43: 592 598

2 Batterham A, Hopkins W. A decision tree for controlled trials. Sport-science 2005; 9: 33 39

3 Bonde-Petersen F, Schultz-Pedersen L, Dragsted N. Peripheral and cen-tral blood flow in man during cold, thermoneutral, and hot water im-mersion. Aviat Space Environ Med 1992; 63: 346 350

4 Cheung K, Hume P, Maxwell L. Delayed onset muscle soreness: treat-

10 Halson SL, Jeukendrup AE. Does overtraining exist? An analysis of over-reaching and overtraining research. Sports Med 2004; 34: 967981

11 Lane KN, Wenger HA. Effect of selected recovery conditions on per-formance of repeated bouts of intermittent cycling separated by 24hours. J Strength Cond Res 2004; 18: 855 860

12 Lollgen H, von Nieding G, Koppenhagen K, Kersting F, Just H. Hemody-namic response to graded water immersion. Klin Wochenschr 1981;59: 623 628

13 Marino FE. Methods, advantages, and limitations of body cooling forexercise performance. Br J Sports Med 2002; 36: 89 94

14 Marsh D, Sleivert G. Effect of precooling on high intensity cycling per-formance. Br J Sports Med 1999; 33: 393 397

15 Martin DT, Kinsman TE, Eastwood A, Platt M, Paton C, Hahn AG. Altitudetents do no impair performance response to short-term high-intensitycycling training. Med Sci Sports Exerc 2005; 37: S294

16 Merrick M, Ranin J, Andres F, Hinman C. A preliminary examination ofcryotherapy and secondary injury in skeletal muscle. Med Sci SportsExerc 1999; 31: 15161521

17 Myrer JW, Measom G, Durrant E, Fellingham GW. Cold- and hot-packcontrast therapy: subcutaneous and intramuscular temperaturechange. J Athl Train 1997; 32: 238 241

18 Noble BJ, Borg GA, Jacobs I, Ceci R, Kaiser P. A category-ratio perceivedexertion scale: relationship to blood and muscle lactates and heartrate. Med Sci Sports Exerc 1983; 15: 523 528

19 OBrien C, Young AJ, Lee DT, Shitzer A, Sawka MN, Pandolf KB. Role ofcore temperature as a stimulus for cold acclimation during repeatedimmersion in 20 degrees C water. J Appl Physiol 2000; 89: 242250

20 Smith LL. Acute inflammation: the underlying mechanism in delayedonset muscle soreness? Med Sci Sports Exerc 1991; 23: 542 551

21 Sramek P, Simeckova M, Jansky L, Savlikova J, Vybiral S. Human physio-logical responses to immersion into water of different temperatures.

544 Physiology & Biochemistryment strategies and performance factors. Sports Med 2003; 33: 145 164

5 Cochrane DJ. Alternating hot and cold water immersion for athlete re-covery: a review. Phys Ther Sport 2004; 5: 26 32

6 Coffey V, Leveritt M, Gill N. Effect of recovery modality on 4-hour re-peated treadmill running performance and changes in physiologicalvariables. J Sci Med Sport 2004; 7: 110

7 Cote DJ, Prentice WE Jr, Hooker DN, Shields EW. Comparison of threetreatment procedures for minimizing ankle sprain swelling. Phys Ther1988; 68: 10721076

8 Enwemeka CS, Allen C, Avila P, Bina J, Konrade J, Munns S. Soft tissuethermodynamics before, during, and after cold pack therapy. Med SciSports Exerc 2002; 34: 45 50

9 Eston R, Peters D. Effects of cold water immersion on the symptoms ofexercise-induced muscle damage. J Sports Sci 1999; 17: 231 238Vaile J et al. Effect of Hydrotherapy Int J Sports Med 2008; 29: 539 544Eur J Appl Physiol 2000; 81: 436 44222 Vaile J, Gill N, Blazevich AJ. The effect of contrast water therapy on

symptoms of delayed onset muscle soreness (DOMS) and explosiveathletic performance. J Strength Cond Res 2007; 21: 697702

23 Wilcock IM, Cronin JB, Hing WA. Physiological response to water im-mersion: a method for sport recovery? Sports Med 2006; 36: 747765

24 Wilcock IM, Cronin JB, Hing WA. Water immersion: does it enhance re-covery from exercise? Int J Sport Physiol Perform 2006; 1: 195 206

25 Zhang P, Tokura H. Thermoregulatory responses in humans during ex-ercise after exposure to two different light intensities. Eur J ApplPhysiol 1999; 79: 285 289