Parker Simpson & Kordi - 2016 - Comparison of Critical Power and wprime derived from two or three...
-
Upload
mehdi-kordi -
Category
Documents
-
view
7 -
download
0
Transcript of Parker Simpson & Kordi - 2016 - Comparison of Critical Power and wprime derived from two or three...
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
Note. This article will be published in a forthcoming issue of the
International Journal of Sports Physiology and Performance. The article
appears here in its accepted, peer-reviewed form, as it was provided by
the submitting author. It has not been copyedited, proofread, or
formatted by the publisher.
Section: Original Investigation
Article Title: Comparison of Critical Power and W Derived from Two or Three Maximal Tests
Authors: Len Parker Simpson1, 2 and Mehdi Kordi1, 3
Affiliations: 1English Institute of Sport, Manchester, UK. 2University of Kent, UK. 3Northumbria University, UK.
Journal: International Journal of Sports Physiology and Performance
Acceptance Date: October 21, 2016
©2016 Human Kinetics, Inc.
DOI: http://dx.doi.org/10.1123/ijspp.2016-0371
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
Title: Comparison of Critical Power and W Derived from Two or Three Maximal Tests.
Submission Type: Original Investigation
Authors & Affiliations
Len Parker Simpson 1, 2.; 1English Institute of Sport, Manchester, UK, 2University of Kent, UK.
Mehdi Kordi 1, 3; 1English Institute of Sport, Manchester, UK, 3Northumbria University, UK.
Corresponding Author:
Dr Len Parker Simpson
English Institute of Sport
MIHP 299 Alan Turing Way
Manchester, UK
M11 3BS
T: +44 (0)7714 564 367
Running Head: Measuring CP & W′ in the Applied Setting
Abstract Word Count: 198
Text Only Word Count: 3370
Number of Figures: 5
Number of Tables: 0
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
ABSTRACT
PURPOSE: Typically, accessing the asymptote (Critical Power; CP) and curvature constant
(W) parameters of the hyperbolic power-duration relationship requires multiple constant-power,
exhaustive exercise trials, spread over several visits. However, more recently single-visit
protocols and personal power meters have been used. We investigated the practicality of using a
two-trial, single-visit protocol in providing reliable CP & W estimates. METHODS: 8 trained
cyclists underwent 3- and 12-min maximal exercise trials in a single session to derive (2-trial)
CP & W estimates. On a separate occasion a 5-min trial was performed providing a third trial to
calculate (3-trial) CP & W. RESULTS: There were no differences in CP (283 ± 66 vs. 282 ± 65
W) or W′ (18.72 ± 6.21 vs. 18.27 ± 6.29 kJ) obtained from either the 2-trial or 3-trial methods
respectively. Following two familiarisation sessions (completing a 3- & 12-min trial on both
occasions), both CP and W remained reliable over additional, separate measurements.
CONCLUSIONS: The present study demonstrates that following two familiarisation sessions,
reliable CP & W parameters can be obtained from trained cyclists using only two maximal
exercise trials. These results offer practitioners a practical, time-efficient solution for
incorporating power-duration testing into applied athlete support.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
INTRODUCTION
The hyperbolic power-duration relationship is a fundamental characteristic of human
physiology at both the muscle- 1,2 and whole body-level 3–5. The hyperbolic relationship has
an asymptote, termed ‘Critical Power’ (CP) which represents an inherent characteristic of the
sustainable aerobic capabilities of the body 5. The curvature constant of the hyperbola, termed
W′, represents a fixed quantity of work which may be completed at exercise intensities above CP
5. The CP thus demarcates distinct exercise-intensity domains; below CP (heavy-intensity
domain) physiological homeostasis is attained 4,6 above CP (severe-intensity domain) is
driven toward its maximum 4 and multiple metabolites project inexorably toward their nadirs, at
which point, exhaustion ensues 6,7.
The power-duration relationship parameters, CP & W′, provide a full picture of
mechanical performance capability of an athlete. Once CP & W′ are known, mechanical exercise
performance capability can be accurately determined 8–10. Both the CP and W′ can alter with
exercise training 11–14. Changes in either or both the CP and/or W′ help explain changes in
mechanical performance capability observed in other mechanical assessments (e.g. ramp test
performance etc.). Thus, CP & W′ offer the coach, athlete and practitioner greater physiological
insight into training-induced changes in performance capabilities than other commonly used
assessment methods such as a ramp test, step-incremental sub-maximal test, maximal lactate
steady state assessment or functional threshold power tests. However, most alternative
assessments to the CP assessment require less than ~ 90 min of an athlete’s time, whereas the CP
assessment has been more drawn-out.
The traditional method of assessing CP & W′ requires a cyclist to perform multiple (3 to
5), exhaustive, constant-power exercise trials of varying intensity over a number of days 3,4. The
VO2
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
advent of a single, 3-min all-out test helped expedite the estimation of CP & W′ 15 but still
required specific, expensive laboratory equipment. More recently, there has been increasing
interest in obtaining the power-duration relationship of athletes and doing so in a more practical
manner 10,16,17. Karsten et al. have previously reported valid CP estimates using a 3-trial (trials
separated by 30 min recoveries) method conducted outdoors on bicycles fitted with power meters
17. An approach akin to this would be an attractive option to athletes and coaches due to the
ostensibly higher ecological validity of the results. Furthermore, it should help eliminate any
additional error in the CP & W′ parameter estimates brought about through testing on one power
meter yet training and racing on another.
Strictly, two maximal or exhaustive exercise trials only are required to obtain CP & W′
estimates. However, when using only two trials, the linear relationship between work done and
time (or power and time-1) will be ‘perfect’ (R2 = 1.00). In this scenario, any change (under-
performance) in either of the two trials will have a large effect on the CP & W′ parameter
estimates 18. Once a third trial is introduced, it is possible to assess the goodness of fit of the
linear relationship and determine the error in both the CP & W′ estimates. While this additional
information is of interest to the practitioner and coach, it is unlikely to appeal to the athlete who
has to perform an additional maximal effort. Thus, if reliable CP & W′ estimates were
obtainable from just two trials, this may promote the inclusion of power-duration testing.
Elite athletes often follow demanding racing and training schedules. Integrating objective
assessment of an athlete’s physiological condition and capabilities can be a perennial challenge
for coaches and practitioners. Providing a scientifically valid and time efficient assessment
method, which provides athlete and coach with insightful information, could allow for more
frequent assessment of these parameters. A power-duration assessment requires only a power
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
meter and a stopwatch 18,19. With the addition of a stationary trainer, the assessment can be
conducted anywhere, anytime with laboratory-style reproducible conditions. Using a series of
self-paced, fixed-duration time trials (TT) where the objective is to average the highest power
output possible for a given duration, CP & W′ can be obtained over a number of days 10 or within
a single session 17. Although previously it has been demonstrated that CP & W′ estimates derived
from multiple trials conducted on the same day are not different to the multiple-day protocol, the
duration of rest between trials was 3-hours 20. A 3-h recovery window between trials would make
a 1-day protocol difficult to implement within the applied field. However, Karsten et al.
successfully employed just a 30-min recovery window between all three trials on a single day 17.
A 30-min recovery window is likely to enable the full ‘replenishment’ of W′ based on the W′
reconstitution time course 21. An option for 30-min recovery windows would instantly become
more attractive for athletes as the full assessment could be completed within ~ 90-
min. Furthermore, in elite athletes who maintain a persistent high-level of performance, the
reproducibility of exercise tasks is likely to be very high 22. If this were the case, it would
mitigate the issues with an underperformance in one (or both) trial(s) when employing only two
trials in characterising the power-duration relationship.
The purpose of the present study was to determine the effects of using a 2-trial or 3-trial
protocol on both CP & W′. Additionally, we wanted to determine the number of familiarisation
sessions required before consistent CP & W parameters were obtained. We hypothesized that in
well-familiarized participants, the addition of a third trial would add no practical difference to
the CP and W′ parameters derived from the 2-trial protocol.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
METHODS
Participants.
Eight (7 male and 1 female) healthy, trained cyclists (mean ± SD: age 31 ± 4 yrs; body
mass 68.5 ± 10.0 kg; height 1.79 ± 0.13 m) gave written informed consent to participate in the
study, which was approved by the University of Kent ethics committee. All participants were
competitive amateur road cyclists, at least ‘Category 2’ standard, with a minimum weekly
training volume of 14-h. Before testing, participants were informed of the protocol and the
potential risks associated with the study. Participants were instructed to arrive for each testing
session at the same time of day (+/- 2-h), 3-h post prandial, and to have refrained from
exhaustive exercise for 24-h.
Study Design.
During each test occasion, participants each used their own road racing bicycle fitted with
a power meter (PowerTap G3 wheel; CycleOps, Madison, USA) attached to a custom-made, air-
resisted stationary trainer (United Kingdom Sport Institute). The trainer’s resistance unit was
secured against the rear wheel with a spring-mounted mechanism ensuring resistance on the rear
wheel was consistent for all participants and all trials. Before beginning each trial, the power
meter had its zero-offset manually checked in accordance with the manufacturer’s instructions.
Participants self-selected pedal cadences and gear ratios, and were free to change these during
the tests. For the peak power output tests participants were allowed to change gear ratios between
efforts but not during an effort. Participants visited the laboratory on five separate occasions.
Each visit was separated by at least 1-d and no more than 7-d. All testing sessions were
completed within five weeks and conducted during the racing season.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
All participants completed three supervised familiarization sessions in the laboratory that
were identical to the first experimental testing session (Figure 1). Each visit began with the
participant(s) performing a 20-min self-selected warm up prior to the experimental trials. Data
from the 20-min warm up period was not recorded, but following the warm-up, the zero-offset of
the power meter was re-set.
Experimental Protocol 1
Experimental protocol 1 consisted of (i) peak power output (PPO) assessment, (ii) 3-min
TT and (iii) 12-min TT, conducted in that order. At least 5-min of passive and/or active rest was
prescribed between finishing the PPO assessments and the 3-min TT. Following the 3-min TT, a
40-min passive and/or active recovery window was prescribed; permitting a 30-min window for
W reconstitution plus an additional 10 minutes for re-warm-up. This order was chosen so that
the 3-min TT trial was not compromised due to the prior performance of an exhaustive exercise
bout. As both central and peripheral muscle fatigue will likely contribute to the highest average
power output achieved in a 12-min TT 23, prior performance of an exhaustive exercise bout
would have a relatively smaller effect on the 12-min trial outcome.
Experimental Protocol 2
Experimental protocol 2 consisted of only (i) 5-min TT.
Peak Power Output (PPO)
Participants completed three ~ 5-s repeat efforts to determine PPO, interspersed with a 3-
min active recovery period. Each effort began when participants reached 90 rpm in their selected
gear. At that point, a maximal effort was initiated and maintained for ~ 5-s. Participants were
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
instructed to accelerate as hard and as fast as possible in a seated position. PPO was taken as the
highest 1-s value recorded across the three PPO efforts.
Fixed-duration time trials (TT)
TT efforts began from a rolling start. Participants were instructed to increase their power
output in the 10- to 15-s period prior to the start of the effort. The participants were instructed to
average the highest power they could for the duration (3- 5- or 12-min) of the trial and to finish
the trial with nothing more to give (“empty the tank”). It was explained that a power profile
resembling a ‘square-wave’ was preferable. Gear choice, and thus cadence were freely adaptable
throughout each trial to help achieve this. Participants had access to elapsed and remaining time
feedback throughout each trial as well as real-time power output and cadence feedback.
3-min TT
Participants were offered a guide power output to not exceed at the beginning of the 3-
min TT. This guide was issued to help avoid a power profile resembling an ‘all-out’ pacing
strategy.
12-min TT
The 12-min TT posed the highest ‘risk’ to invalidating the CP & W′ estimates. If, at any
point throughout the 12-min TT, power output fell below a participants CP (unknown until
completion of the 12-min TT) the parameter estimates would be incorrect 24. Thus to help
provide a guide power output with which to begin the 12-min TT, a conservative estimation for
W′ (typically ~ 11.0 kJ) was subtracted from the total work done within the 3-min TT. The result
was divided by the duration of the 3-min trial (180 s) to provide a conservative estimate
(overestimation) of CP. This value (± 10 W) was suggested as a starting intensity for the 12-min
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
TT. After ~ 1-3 min of the 12-min TT, participants were free to adjust the intensity to enable
them to maximise the average power achievable.
5-min TT
The 5-min TT power guideline was simply to not exceed the average power achieved
during the 3-min TT at the start of the trial.
Data Capture and Analysis
Throughout all exercise trials, power output and cadence were recorded every second
using an ANT+ wireless cycle computer (Garmin Edge 500, Garmin International, Kansas,
USA). Data were downloaded into desktop software (Golden Cheetah training software,
goldencheetah.org) where the highest 1-s, 3-, 5-, and 12-min power output windows were found.
These data were extracted and subsequently analysed in spreadsheet software (Excel, Microsoft
Corporation, Redmond, WA) to calculate CP & W′ estimates using both the linear work-time and
linear power-time-1 models (equation 1).
P = (W′/t) + CP [Eq. 1]
The linear model providing the best fit (highest R2) and least standard error of the
estimate (SEE) was used to provide the CP & W′ parameters. The same linear model providing
the least error was also used for the two-trial method (3- and 12-min trials only).
Statistical Analysis
All data were analysed using SPSS statistical software (IBM SPSS Inc., Chicago, IL.). A
one-way repeated measures ANOVA was employed to check for differences in CP & W′
estimates in the 2-trial method between familiarisation and experimental protocol 1. Where a
significant difference was discovered, post-hoc tests were conducted (with Bonferroni
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
adjustment applied to the alpha level) to confirm where differences occurred between group
means. A paired sample t-test was used to compare the CP & W′ obtained from the 2-trial and 3-
trial methods. Pearson product moment correlation analysis was used to provide an indication of
the strength of any relationship between the 3-trial and 2-trial values for CP and W′. All data are
reported as mean ± SD unless otherwise stated.
RESULTS
3-trial and 2-trial CP (Figure 2) and W’ (Figure 3) values were significantly correlated
(R2 = 0.999; P <0.01 and R2 = 0.973; P<0.01, respectively). There were no differences in either
the CP (283 ± 66 W vs. 282 ± 65 W; t= 0.012; P = 0.990) nor W′ (18.72 ± 6.21 kJ vs. 18.27 ±
6.29 kJ; t = 0.145; P = 0.886) obtained from either the 2-trial or 3-trial methods
respectively. The SEE for CP and W’ (3-trial model) was 1.25 W (0.44%) and 1.11 kJ (5.8%),
respectively.
CP derived from familiarisation sessions 1 (272 ± 58 W, P = 0.011) and 2 (274 W ± 51
W, P = 0.028) were significantly different to CP from experimental protocol 1 (288 ± 63 W).
However, from familiarisation session 3 onward, CP remained unchanged compared with that
obtained from experimental protocol 1 (Figure 4). W′ remained consistent across all
familiarisation sessions and experimental protocol 1 (Figure 5).
DISCUSSION
The primary findings of the present study are; (i) in accordance with our hypothesis, the
addition of a third trial when calculating CP and W’ does not significantly nor meaningfully alter
the power-duration parameter estimates and (ii) following two familiarisation sessions, CP and
W′ estimates remain consistent.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
Previously a number of others have assessed the test-retest reliability of CP & W′ 11,20,25,26
reporting retest increases in CP of between 3.4 to 6% and changes in W′ ranging from -1.8 to
11.1%. However, in each of these cases, the methodology employed differed to the present
study, in that in all previous cases a cycle ergometer has been used and a fixed power output
imposed until exhaustion was reached. Recently, Black et al. (2015) demonstrated a difference in
CP & W′ estimates obtained from constant-power exhaustive trials and self-paced (fixed quantity
of work done) ‘time trials’. When self-pacing trials were used, CP was 7% higher than CP
derived from constant-power exhaustive trials. However, W′ was 12% (non-significant) lower
when derived from the time trial efforts. Black et al. (2015) found that when self-paced trials
were performed, they were completed in a significantly shorter time than their equivalent
constant-power exhaustive trials. These are important considerations for the longitudinal support
of athletes, where repeat measurements will be taken over years. Fixing the power output
(exhaustive) or work done to be completed (self-paced) have the potential to vary considerably in
trial duration as an athlete matures and improves. This is important as Bishop et al (1998) have
clearly shown the effect of trial duration on CP & W′ parameter estimates. When trial durations
become shorter, CP estimates artificially inflate and W′ estimates reduce. The opposite is true
when trial durations lengthen. For this reason, fixing the duration of trials used in the
determination of CP & W′, especially in applied, longitudinal athlete support, seems most
appropriate.
The trial durations chosen for the present study (3- and 12-min for the shortest and
longest trials and 5-min for the middle trial) were selected for a number of reasons. The shortest
duration of exercise permitting the attainment of max and ostensibly the complete
‘expenditure’ of W′ is ~ 150 s 27. Thus, we selected 3 min as the shortest trial duration to permit
VO2
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
an additional 30 s to help accommodate participants with perhaps slower oxygen uptake
kinetics. The difference between the shortest and longest trials was also an important
consideration. While Housh et al (1990) recommended that shortest and longest trials be
separated by at least 5-min, it is a common recommendation within the literature that trial
durations span 1- to 10- min 28,29. This provides a 9-min difference between shortest and longest
trial. Given that the shortest duration chosen was 3-min in the present study, to uphold a 9-min
difference between shortest and longest trials necessitated a long trial of 12-min duration. This
too satisfied the suggestion of Bishop et al (1998) that as trial duration extends, other factors
(e.g. motivation, temperature etc.) may detract from exercise performance. Theoretically the
additional ‘middle-duration’ trial could be any duration between 3- and 12-min and would fall
along the linear work-time (or power-time-1) regression. Since the 3- and 12-min trials total 15
min of effort required from an athlete, and given that elsewhere in the ‘scientific’ support of
cyclists a 20-min functional threshold power test 30 is commonplace, a 5-min middle-duration
trial was selected to equal the total time commitment of the functional threshold test.
Characterising the power-duration relationship offers many advantages over the common
alternatives. Most notably once CP and W′ are known, it is possible to accurately predict
exercise performance over a range of durations 9,10 and with different exercise tasks (ramp-
incremental 8, intermittent intervals 9). In addition, obtaining these physiologically underpinned
parameters (CP & W′) requires only a power meter and a stopwatch. No invasive or intrusive
measurements are needed and from an athlete support perspective, where teams or squads of
athletes often follow a similar training and racing schedule, multiple athletes can be ‘assessed’
simultaneously. In the absence of multiple ergometers (and other equipment), it is not possible to
conduct alternative assessments (e.g. ramp-incremental test, step-incremental sub maximal test,
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
maximum lactate steady state) in this manner. While alternative assessments have their
physiological merits, they all lack the mechanical performance insight offered by the CP
concept. Additionally, and similarly to Karsten et al. (2014), assessing CP & W′ using a self-
paced, fixed-duration method does not require the additional visit and test mandated by
numerous other assessment procedures; the ramp-incremental max test. The self-pacing of the
discrete trials eliminates the requirement to set exercise intensities relative to an individual’s
metabolic or mechanical parameters. Again, this is an important consideration when attempting
to ensure consistent monitoring can be incorporated into longitudinal athlete support, as is the
number of familiarisation sessions required to elicit reliable CP & W parameters.
The present study shows that in trained cyclists, previously unfamiliar with fixed-
duration, self-paced TTs, two familiarisation sessions were necessary before CP estimates
became reproducible. This is something to consider when assessing athletes for the first (and
second) time using this method. However, the relative stability of the W estimates, even from
familiarisation trial 1, could prove extremely useful. Arguably, W is an important parameter for
success in endurance events which last between ~ 2 and 8 min. The ability to gain insight into an
athlete’s W from the first power-duration assessment could be useful for talent ID purposes, or
for guiding athletes toward certain sporting disciplines.
PRACTICAL APPLICATIONS
The power-duration parameters, CP & W′, have great practical importance across many
aspects within cycling and other endurance sports.
1. Fundamentally, CP demarcates distinct physiological intensity domains, and thus is an
important parameter for both setting training ‘zones’ and monitoring training intensity
distribution.
VO2
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
2. The W′ is an important parameter which dictates exercise capacity across a range of
durations. To enhance performance over shorter durations (~ < 6 min), attempting to
enlarge the W′ could be a viable option.
3. When supporting/monitoring athletes over time (months to years), fixing the duration of
the trials used in the determination of CP & W′ becomes important to limit alterations in
either parameter simply due to trial duration.
4. The combination of CP & W′ enables real-world performance to be modelled or
simulated. It is therefore possible to predict the required changes in either CP or W to
elicit the performance change desired.
5. The method(s) presented here provide athletes, coaches and practitioners simple,
applicable tools with which power-duration monitoring can be incorporated into training
programmes.
CONCLUSIONS
The present study offers a method to assess a cycling-trained individual’s power-duration
relationship requiring only two discrete exercise trials of 3- and 12-min duration. Following only
two familiarisation sessions, each consisting of a 3- and 12-min TT, CP & W′ estimates
remained reliable thereafter and did not differ when compared to CP & W′ derived from the 3-
trial protocol. Combined, these results offer practitioners a viable, single-visit protocol to obtain
CP & W′ estimates from trained athletes.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
ACKNOWLEDGEMENTS
The authors would like to thank the riders for their time and participation in this study as well as
Professor Louis Passfield and Dr Chris Fullerton for reviewing the manuscript.
CONFLICTS OF INTEREST
The authors of this manuscript have no conflicts of interest to declare.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
REFERENCES
1. Monod H, Scherrer J. The work capacity of a synergic muscular group. Ergonomics.
1965;8(3):329-338.
2. Burnley M. Estimation of critical torque using intermittent isometric maximal voluntary
contractions of the quadriceps in humans. J Appl Physiol Bethesda Md 1985.
2009;106(3):975-983. doi:10.1152/japplphysiol.91474.2008.
3. Moritani T, Nagata A, deVries HA, Muro M. Critical power as a measure of physical
work capacity and anaerobic threshold. Ergonomics. 1981;24(5):339-350.
doi:10.1080/00140138108924856.
4. Poole DC, Ward SA, Gardner GW, Whipp BJ. Metabolic and respiratory profile of the
upper limit for prolonged exercise in man. Ergonomics. 1988;31(9):1265-1279.
doi:10.1080/00140138808966766.
5. Jones AM, Vanhatalo A, Burnley M, Morton RH, Poole DC. Critical power: implications
for determination of V˙O2max and exercise tolerance. Med Sci Sports Exerc.
2010;42(10):1876-1890. doi:10.1249/MSS.0b013e3181d9cf7f.
6. Jones AM, Wilkerson DP, DiMenna F, Fulford J, Poole DC. Muscle metabolic responses
to exercise above and below the “critical power” assessed using 31P-MRS. Am J Physiol
Regul Integr Comp Physiol. 2008;294(2):R585-593. doi:10.1152/ajpregu.00731.2007.
7. Vanhatalo A, Fulford J, DiMenna FJ, Jones AM. Influence of hyperoxia on muscle
metabolic responses and the power-duration relationship during severe-intensity exercise
in humans: a 31P magnetic resonance spectroscopy study. Exp Physiol. 2010;95(4):528-
540. doi:10.1113/expphysiol.2009.050500.
8. Morton RH. Critical power test for ramp exercise. Eur J Appl Physiol. 1994;69(5):435-
438.
9. Chidnok W, Dimenna FJ, Bailey SJ, Wilkerson DP, Vanhatalo A, Jones AM. Effects of
pacing strategy on work done above critical power during high-intensity exercise. Med
Sci Sports Exerc. 2013;45(7):1377-1385. doi:10.1249/MSS.0b013e3182860325.
10. Black MI, Jones AM, Bailey SJ, Vanhatalo A. Self-pacing increases critical power and
improves performance during severe-intensity exercise. Appl Physiol Nutr Metab Physiol
Appliquée Nutr Métabolisme. 2015;40(7):662-670. doi:10.1139/apnm-2014-0442.
11. Gaesser GA, Wilson LA. Effects of continuous and interval training on the parameters of
the power-endurance time relationship for high-intensity exercise. Int J Sports Med.
1988;9(6):417-421. doi:10.1055/s-2007-1025043.
12. Poole DC, Ward SA, Whipp BJ. The effects of training on the metabolic and respiratory
profile of high-intensity cycle ergometer exercise. Eur J Appl Physiol. 1990;59(6):421-
429.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
13. Jenkins DG, Quigley BM. Endurance training enhances critical power. Med Sci Sports
Exerc. 1992;24(11):1283-1289.
14. Vanhatalo A, Doust JH, Burnley M. A 3-min all-out cycling test is sensitive to a change
in critical power. Med Sci Sports Exerc. 2008;40(9):1693-1699.
doi:10.1249/MSS.0b013e318177871a.
15. Burnley M, Doust JH, Vanhatalo A. A 3-min all-out test to determine peak oxygen
uptake and the maximal steady state. Med Sci Sports Exerc. 2006;38(11):1995-2003.
doi:10.1249/01.mss.0000232024.06114.a6.
16. Karsten B, Jobson SA, Hopker J, Jimenez A, Beedie C. High agreement between
laboratory and field estimates of critical power in cycling. Int J Sports Med.
2014;35(4):298-303. doi:10.1055/s-0033-1349844.
17. Karsten B, Jobson SA, Hopker J, Stevens L, Beedie C. Validity and reliability of critical
power field testing. Eur J Appl Physiol. 2015;115(1):197-204. doi:10.1007/s00421-014-
3001-z.
18. Housh DJ, Housh TJ, Bauge SM. A methodological consideration for the determination
of critical power and anaerobic work capacity. Res Q Exerc Sport. 1990;61(4):406-409.
doi:10.1080/02701367.1990.10607506.
19. Hill DW. The critical power concept. A review. Sports Med Auckl NZ. 1993;16(4):237-
254.
20. Bishop D, Jenkins DG. The influence of recovery duration between periods of exercise
on the critical power function. Eur J Appl Physiol. 1995;72(1-2):115-120.
21. Skiba PF, Chidnok W, Vanhatalo A, Jones AM. Modeling the expenditure and
reconstitution of work capacity above critical power. Med Sci Sports Exerc.
2012;44(8):1526-1532. doi:10.1249/MSS.0b013e3182517a80.
22. Sporer BC, McKenzie DC. Reproducibility of a laboratory based 20-km time trial
evaluation in competitive cyclists using the Velotron Pro ergometer. Int J Sports Med.
2007;28(11):940-944. doi:10.1055/s-2007-964977.
23. Thomas K, Elmeua M, Howatson G, Goodall S. Intensity-dependent Contribution of
Neuromuscular Fatigue after Constant-Load Cycling. Med Sci Sports Exerc. May 2016.
doi:10.1249/MSS.0000000000000950.
24. Fukuba Y, Whipp BJ. A metabolic limit on the ability to make up for lost time in
endurance events. J Appl Physiol Bethesda Md 1985. 1999;87(2):853-861.
25. Nebelsick-Gullett LJ, Housh TJ, Johnson GO, Bauge SM. A comparison between
methods of measuring anaerobic work capacity. Ergonomics. 1988;31(10):1413-1419.
doi:10.1080/00140138808966785.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
26. Hill DW, Smith JC. A comparison of methods of estimating anaerobic work capacity.
Ergonomics. 1993;36(12):1495-1500. doi:10.1080/00140139308968017.
27. Hill DW, Stevens EC. VO2 response profiles in severe intensity exercise. J Sports Med
Phys Fitness. 2005;45(3):239-247.
28. Poole DC, Gaesser GA. Response of ventilatory and lactate thresholds to continuous and
interval training. J Appl Physiol Bethesda Md 1985. 1985;58(4):1115-1121.
29. Hinckson EA, Hopkins WG. Reliability of time to exhaustion analyzed with critical-
power and log-log modeling. Med Sci Sports Exerc. 2005;37(4):696-701.
30. Allen H, Coggan A. Training and Racing with a Power Meter. 2nd ed. VeloPress; 2010.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
Figure 1. A schematic of the lab sessions. Familiarization sessions 1, 2 and 3 and Experimental
session 1 were identical. Each session included three peak power output efforts, a 3-min TT and
a 12-min TT. Experimental session 2 was a 5-min TT.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
Figure 2. Correlation between 3-trial and t-trial Critical Power (CP).
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
Figure 3. Correlation between 3-trial and 2-trial W’.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
Figure 4. Mean power output for the 3-min and 12-min TT as well as the Critical Power between
all three familiarization sessions (Fam 1, 2 and 3) and the experimental session (Exp 1); *denotes
significant difference from Exp 1.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0
“Comparison of Critical Power and W Derived from Two or Three Maximal Tests” by Parker Simpson L, Kordi M
International Journal of Sports Physiology and Performance
© 2016 Human Kinetics, Inc.
Figure 5. W’ and peak power output (PPO) of all familiarization (Fam 1, 2 and 3) and
Experimental (Exp) sessions.
Dow
nloa
ded
by U
nive
rsiti
es a
t Med
way
on
12/0
6/16
, Vol
ume
0, A
rtic
le N
umbe
r 0