Determination Of Critical Power Research Articles

Effect of acute heat exposure on the determination of critical power and W′ in women and men

ABSTRACT The goal of this study was to investigate to what extent acute heat exposure would affect the parameters of the power-duration relationship, i.e. CP and W′, using multiple constant workload tests to task failure, in women and men. Twenty four young physically active participants (12 men, 12 women) performed 3-5 constant load tests to determine CP and W′, both in temperate (TEMP; 18°C) and hot (HOT; 36°C) environmental conditions. A repeated-measures ANOVA was executed to find differences between TEMP and HOT, and between women and men. In HOT, CP was reduced by 6.5% (227 ± 50 vs. 212 ± 47 W), while W′ increased 12.4% (16.4 ± 4.4 vs. 18.5 ± 5.6 kJ). No significant two-way sex × temperature interactions were observed, indicating that the environmental conditions did not have a different effect in men compared with women. The intersection of the average curvatures in TEMP and HOT occurred at 137 s and 280 W in women, and 153 s and 397 W in men. Acute heat exposure had an impact on the parameters CP and W′, i.e. CP decreased whereas W′ increased. The increase in W′ might be a consequence of the mathematical modelling for the used test methodology, rather than a physiological accurate value of W′ in HOT. No differences induced by heat exposure were observed between women and men.

Determination of Critical Power Using Different Possible Approaches among Endurance Athletes: A Review.

Critical power represents an important parameter of aerobic function and is the highest average effort that can be sustained for a period of time without fatigue. Critical power is determined mainly in the laboratory. Many different approaches have been applied in testing methods, and it is a difficult task to determine which testing protocol it the most suitable. This review aims to evaluate all possible tests on bicycle ergometers or bicycles used to estimate critical power and to compare them. A literature search was conducted in four databases (PubMed, Scopus, SPORTDiscus, and Web of Science) published from 2012 to 2022 and followed the PRISMA guidelines to process the review. Twenty-one articles met the eligibility criteria: records with trained or experienced endurance athletes (adults > 18), bicycle ergometer, a description of the testing protocol, and comparison of the tests. We found that the most widely used tests were the 3-min all-out tests set in a linear mode and the traditional protocol time to exhaustion. Some other alternatives could have been used but were not as regular. To summarize, the testing methods offered two main approaches in the laboratory (time to exhaustion test andthe 3-min all-out test with different protocols) and approach in the field, which is not yet completely standardized.

Methodological Approaches and Related Challenges Associated With the Determination of Critical Power and Curvature Constant.

Muniz-Pumares, D, Karsten, B, Triska, C, and Glaister, M. Methodological approaches and related challenges associated with the determination of critical power and W'. J Strength Cond Res 33(2): 584-596, 2019-The relationship between exercise intensity and time to task failure (P-T relationship) is hyperbolic, and characterized by its asymptote (critical power [CP]) and curvature constant (W'). The determination of these parameters is of interest for researchers and practitioners, but the testing protocol for CP and W' determination has not yet been standardized. Conventionally, a series of constant work rate (CWR) tests to task failure have been used to construct the P-T relationship. However, the duration, number, and recovery between predictive CWR and the mathematical model (hyperbolic or derived linear models) are known to affect CP and W'. Moreover, repeating CWR may be deemed as a cumbersome and impractical protocol. Recently, CP and W' have been determined in field and laboratory settings using time trials, but the validity of these methods has raised concerns. Alternatively, a 3-minute all-out test (3MT) has been suggested, as it provides a simpler method for the determination of CP and W', whereby power output at the end of the test represents CP, and the amount of work performed above this end-test power equates to W'. However, the 3MT still requires an initial incremental test and may overestimate CP. The aim of this review is, therefore, to appraise current methods to estimate CP and W', providing guidelines and suggestions for future research where appropriate.

Influence of upright versus time trial cycling position on determination of critical power and W′ in trained cyclists

Body position is known to alter power production and affect cycling performance. The aim of this study was to compare mechanical power output in two riding positions, and to calculate the effects on critical power (CP) and W′ estimates. Seven trained cyclists completed three peak power output efforts and three fixed-duration trial (3-, 5- and 12-min) riding with their hands on the brake lever hoods (BLH), or in a time trial position (TTP). A repeated-measures analysis of variance showed that mean power output during the 5-min trial was significantly different between BLH and TTP positions, resulting in a significantly lower estimate of CP, but not W′, for the TTP trial. In addition, TTP decreased the performance during each trial and increased the percentage difference between BLH and TTP with greater trial duration. There were no differences in pedal cadence or heart rate during the 3-min trial; however, TTP results for the 12-min trial showed a significant fall in pedal cadence and a significant rise in heart rate. The findings suggest that cycling position affects power output and influences consequent CP values. Therefore, cyclists and coaches should consider the cycling position used when calculating CP.

The effect of mental fatigue on critical power during cycling exercise

PurposeTime to exhaustion (TTE) tests used in the determination of critical power (CP) and curvature constant (W′) of the power–duration relationship are strongly influenced by the perception of effort (PE). This study aimed to investigate whether manipulation of the PE alters the CP and W′.MethodsEleven trained cyclists completed a series of TTE tests to establish CP and W′ under two conditions, following a mentally fatiguing (MF), or a control (CON) task. Both cognitive tasks lasted 30 min followed by a TTE test. Ratings of PE and heart rate (HR) were measured during each TTE. Blood lactate was taken pre and post each TTE test. Ratings of perceived mental and physical fatigue were taken pre- and post-cognitive task, and following each TTE test.ResultsPerceived MF significantly increased as a result of the MF task compared to baseline and the CON task (P < 0.05), without a change in perceived physical fatigue (P > 0.05). PE was significantly higher during TTE in the MF condition (P < 0.05). Pre-post blood lactate accumulation was significantly lower after each TTE in MF condition (P < 0.05). HR was not significant different between conditions (P > 0.05). Neither cognitive task induced any change in CP (MF 253 ± 51 vs. CON 247 ± 58W; P > 0.05), although W′ was significantly reduced in the MF condition (MF 22.8 ± 4.5 vs. CON 29.3 ± 6.3 kJ; P < 0.01).ConclusionMF has no effect of CP, but reduces the W′ in trained cyclists. Lower lactate accumulation during TTE tests following MF suggests that cyclists were not able to fully expend W′ even though they exercised to volitional exhaustion.

Determination of Critical Power and Anaerobic Work Capacity

In a recent issue of the Journal of Strength & Conditioning Research, Bergstrom et al. (1) presented a “New single work rate test to estimate Critical Power and Anaerobic Work Capacity.” The basic question of this project was simple: can the critical power (CP) and anaerobic work capacity (AWC or W′) be accurately estimated from a single exercise test, requiring no a priori information on subject fitness (i.e., gas-exchange threshold)?

Determination of critical power using the first low steady state in the power profile of a 3-min all-out test

Determination of critical power using the first low steady state in the power profile of a 3-min all-out test

Determination of critical power in trained rowers using a three-minute all-out rowing test

The purpose of this study was to determine whether the hyperbolic relationship between power output and time to exhaustion (work - time and power - [1/time] models) could be estimated from a modified version of a three-minute all-out rowing test (3-min RT), and to investigate the test-retest reliability of the 3-min RT. Eighteen male rowers volunteered to participate in this study and underwent an incremental exercise test (IRT), three constant-work rate tests to establish the critical power (CP) and the curvature constant (W'), and two 3-min RTs against a fixed resistance to estimate the end-test power (EP) and work-done-above-EP (WEP) on a rowing ergometer. Peak VO(2max) and maximal VO(2max) oxygen uptakes were calculated as the highest 30 s average achieved during the 3-min RT and IRT tests. The results showed that EP and WEP determinations, based on the 3-min RT, have moderate reproducibility (P = 0.002). EP (269 ± 39 W) was significantly correlated with CP (work - time, 272 ± 30 W; power - [1/time], 276 ± 32 W) (P = 0.000), with no significant differences observed between the EP and CP values (P = 0.474). However, WEP did not significantly correlate with W' (P = 0.254), and was significantly higher than the W' values. There was a significant correlation between the VO(2max) (60 ± 3 ml kg(-1) min(-1)) and VO(2max) (61 ± 4 ml kg(-1) min(-1)) (P = 0.003). These results indicate that the 3-min RT has moderate reliability, and is able to appropriately estimate the aerobic capacity in rowers, particularly for the CP and VO(2max) parameters.

Determination Of Critical Power In Rowing By Using 3-min All-out Test

The traditional critical power (CP) test which requires a subject to exercise to exhaustion at several constant work loads on separate days is not convenient for practical utilization. Recently, a single test which named a 3-min all-out test was developed and was able to accurately determine the CP and maximal oxygen consumption (VO2max) on a cycling ergometer. However, there are no studies to demonstrate if this new method could be used in rowing exercise. PURPOSE: To investigate the test-retest reliability and validity of 3-min all-out test on a rowing ergometer. METHODS: Eighteen male rowers (age, 17.7 ± 1.9 yrs; height, 178.0 ± 4.3 cm; weight, 70.7 ± 5.0 kg) volunteered to participate in this study. All subjects underwent the incremental exercise test (IRT), traditional CP test and 3-min all-out test (3-min RT) on the rowing ergometer, separated by at least 48 hours. The peak oxygen consumption (VO2peak) and VO2max were respectively determined by the 3-min RT and IRT. During the CP test, the values of the CP and anaerobic work capacity (W') were calculated by work-time and power-1/time models. The end-test power (EP) and work done above the EP (WEP) were calculated during the 3-min RT. Each subject was required to perform the 3-min RT twice for evaluating the test-retest reliability. RESULTS: The results of intraclass correlation coefficient (ICC) indicated that the EP and WEP during the 3-min RT have good test-retest reliabilities (ICC = 0.79 and 0.63, p<0.05). The EP (269.22 ± 39.20 W) was significantly correlated to the CP (r = 0.75 and 0.80, p<0.05) which were calculated by work-time (271.99 ± 29.82 W) and power-1/time (275.71 ± 31.60 W) models, and it was not significantly different from the CP calculated by these two models. However, the WEP (16.63 ± 4.03 kJ) was not significantly correlated to the W' (r = 0.30 and 0.25, p>0.05), and it was significantly higher than the W' calculated by the traditional CP models (work-time, 13.23 ± 2.99 kJ; power-1/time, 12.33 ± 3.23 kJ). There was significant correlation between the VO2peak and VO2max (r = 0.66, p<0.05). CONCLUSION: These results indicate that the 3-min RT has a good reliability, and is able to accurately estimate the aerobic capacity in male rowers, especially in CP and VO2max.

Determination of Critical Power Using a 3-min All-out Cycling Test

Determination of Critical Power Using a 3-min All-out Cycling Test

Determination of Critical Power Using a 3-min All-out Cycling Test

We tested the hypothesis that the power output attained at the end of a 3-min all-out cycling test would be equivalent to critical power. Ten habitually active subjects performed a ramp test, two 3-min all-out tests against a fixed resistance to establish the end-test power (EP) and the work done above the EP (WEP), and five constant-work rate tests to establish the critical power (CP) and the curvature constant parameter (W') using the work-time and 1/time models. The power output in the 3-min trial declined to a steady level within 135 s. The EP was 287 +/- 55 W, which was not significantly different from, and highly correlated with, CP (287 +/- 56 W; P = 0.37, r = 0.99). The standard error for the estimation of CP using EP was approximately 6 W, and in 8 of 10 cases, EP agreed with CP to within 5 W. Similarly, the WEP derived from the 3-min test (15.0 +/- 4.7 kJ) was not significantly different from, and correlated with, W' (16.0 +/- 3.8 kJ; P = 0.35; r = 0.84). During a 3-min all-out cycling test, power output declined to a stable value in approximately the last 45 s, and this power output was not significantly different from the independently measured critical power.

Determination of critical power by pulmonary gas exchange.

Although the physiological underpinnings of critical power (CP) have yet to be fully elucidated, it has been proposed that CP demarcates the heavy and severe exercise intensity domains and that each domain is associated with a different pattern of metabolic response and mechanism of fatigue. Severe intensity has been defined such that, during exercise at intensities above CP, the slow component of the VO2 response will drive VO2 to VO2max at the point of fatigue. In this study, two parameters were derived for each of 8 participants: (a) CP, the asymptote of the relationship between power and time to exhaustion, and (b) a related parameter; CP', the asymptote of the relationship between power and time to VO2max. CP' theoretically represents the threshold intensity above which VO2max will be elicited during exercise of sufficient duration. Participants performed two exhaustive tests at CP. There were three important findings: First, there was a practice effect on time to exhaustion at CP, and times increase 27% in the second test. Second, both CP and CP' could be obtained with good precision. Third, and most important, CP was equal to CP', thereby providing a physiological description of the mathematically derived CP parameter. It was concluded that VO2max cannot be elicited at intensities equal to or less than CP.

The relationship between critical power and running performance.

Critical power is a theoretical concept that presumes there is a certain work-rate which may be maintained without exhaustion. The extent to which critical power predicts running performance over varying distances has not been determined, and so the aim of this study was to correlate measurements of critical power in the laboratory to running performances in the field at 40 m and 1, 10 and 21.1 km in a group of .17 male long-distance runners (mean +/- S.D. age = 31.7 +/- 7.3 years). Each subject ran to exhaustion on the treadmill in the laboratory at six different speeds, ranging from 17 to 25 km h-1. Least squares analyses were used to fit an exponential decay to the relationship between the running speed (y) versus time to exhaustion (x). Critical power was calculated as the running speed (y) coinciding with the asymptote or C parameter of the y = A.e(-Bx) + C relationship. The VO2 max was also measured in all subjects. For the data in the field, each subject was timed over 40 m and 1 km and participated in 10- and 21.1-km races. The mean critical power of the subjects in this study was 18.5 +/- 1.6 km h-1. The test-retest correlation coefficient for the determination of critical power was r = 0.99. The mean VO2 max, measured in a progressive exercise protocol starting at 13 km h-1 and increasing by 1 km h-1 every minute, was 59.2 +/- 4.6 ml O2 kg-1 min-1.(ABSTRACT TRUNCATED AT 250 WORDS)