Article

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

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## Abstract

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.

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... Another concept that can be used to differentiate between aerobic and anaerobic power contributions to external PO is the critical power (CP) method. With the CP concept, the CP threshold equals the maximal PO that is generated by primarily aerobic energy sources and can, at least in theory, be maintained indefinitely, whereas the exercise duration above CP is finite (Vanhatalo et al. 2007(Vanhatalo et al. , 2011. For determining CP, the hyperbolic relationship between exercise duration and PO for maximal exercise first needs to be established. ...
... This requires participants to complete ≥ 4 separate maximal tests to exhaustion at several different fixed power outputs (Vanhatalo et al. 2011). In contrast to this traditional and time-consuming approach of determining CP, a modified version of the CP protocol has been proposed, which involves just a single 3-min all-out time trial (TT) (Vanhatalo et al. 2007). Due to depletion of the anaerobic energy reserve during the initial stages of exercise (≤ 2 min of exercise), the average PO during the final 30 s (referred to as "end power") of the 3-min all-out test is considered to represent CP (Vanhatalo et al. 2007). ...
... In contrast to this traditional and time-consuming approach of determining CP, a modified version of the CP protocol has been proposed, which involves just a single 3-min all-out time trial (TT) (Vanhatalo et al. 2007). Due to depletion of the anaerobic energy reserve during the initial stages of exercise (≤ 2 min of exercise), the average PO during the final 30 s (referred to as "end power") of the 3-min all-out test is considered to represent CP (Vanhatalo et al. 2007). With the CP method, the total mechanical work above critical power (W′) is calculated as PO above CP integrated over time and is often referred to as a marker of AnWC (Hill 1993;Morton 2006). ...
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Purpose To compare the anaerobic work capacity (AnWC, i.e., attributable anaerobic mechanical work) assessed using four different approaches/models applied to time-trial (TT) cycle-ergometry exercise. Methods Fifteen male cyclists completed a 7 × 4-min submaximal protocol and a 3-min all-out TT (TTAO). Linear relationships between power output (PO) and submaximal metabolic rate were constructed to estimate TT-specific gross efficiency (GE) and AnWC, using either a measured resting metabolic rate as a Y-intercept (7 + YLIN) or no measured Y-intercept (7-YLIN). In addition, GE of the last submaximal bout (GELAST) was used to estimate AnWC, and critical power (CP) from TTAO (CP3´AO) was used to estimate mechanical work above CP (W’, i.e., “AnWC”). Results Average PO during TTAO was 5.43 ± 0.30 and CP was 4.48 ± 0.23 W∙kg⁻¹. The TT-associated GE values were ~ 22.0% for both 7 + YLIN and 7-YLIN and ~ 21.1% for GELAST (both P < 0.001). The AnWC were 269 ± 60, 272 ± 55, 299 ± 61, and 196 ± 52 J∙kg⁻¹ for the 7 + YLIN, 7-YLIN, GELAST, and CP3´AO models, respectively (7 + YLIN and 7-YLIN versus GELAST, both P < 0.001; 7 + YLIN, 7-YLIN, and GELAST versus CP3´AO, all P < 0.01). For the three pair-wise comparisons between 7 + YLIN, 7-YLIN, and GELAST, typical errors in AnWC values ranged from 7 to 11 J∙kg⁻¹, whereas 7 + YLIN, 7-YLIN, and GELAST versus CP3´AO revealed typical errors of 55–59 J∙kg⁻¹. Conclusion These findings demonstrate a substantial disagreement in AnWC between CP3´AO and the other models. The 7 + YLIN and 7-YLIN generated 10% lower AnWC values than the GELAST model, whereas 7 + YLIN and 7-YLIN generated similar values of AnWC.
... Originally, CP was determined in the lab via protocols consisting of multiple Time to Exhaustion (TTE) tests at various workloads over the course of several days (Moritani, Nagata, & DeVries, 1981). More recently, a 3min all-out test has been adopted as a more easily recorded estimate of CP and W' (work done above CP) during a single bout of exercise (Burnley, Doust, & Vanhatalo, 2006;Vanhatalo, Doust, & Burnley, 2007). ...
... Early studies validated the 3-min all out test to determine CP with various equipment (Burnley et al., 2006;Francis, Quinn, Amann, & Laroche, 2010;Vanhatalo et al., 2007). Studies using the 3-min all-out test to determine CP have enrolled participants of varying competition levels, but who are generally younger. ...
... Burnley et al. (2006) determined CP for recreationally active participants with mean age 27 y. Other studies enrolled participants of mixed competition levels whose mean age were ~33 y (Vanhatalo et al., 2007;Wright, Bruce-Low, & Jobson, 2017). Francis et al. (2010), Karsten, Jobson, Hopker, Passfield, andBeedie (2014), andMcClave, LeBlanc, andHawkins (2011) studied CP in competitive cyclists with mean ages of 32.4 y, 33 y and 40.5 y, respectively. ...
Article
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External reviewer of Journal of Science and Cycling. This study aimed to determine differences in angular kinematics and critical power between younger and older cyclists during the 3-min all-out test. Younger (n = 15, 21.8 ± 2.4y) and Older (n = 15, 53.3 ± 6.6 y) Category 1 or 2 riders completed maximal aerobic testing and a 3-min all-out test on separate days using their own road bicycle on a cycle ergometer. Eight retroreflective markers determined right side sagittal plane angular kinematics during the 3-min all-out test. Younger cyclists displayed higher ̇2 max, ̇2 @ VEbp, HRmax, Power@̇2max and Critical Power (p < 0.05) than Older cyclists. Cadence decreased over time for the combined group (time 1 (T1) = 87.3 ± 4.5 rpm, time 2 (T2) = 83.7 ± 4.6 rpm, and time 3 (T3) = 83.6 ± 5.0 rpm) where T1 was significantly higher than T2 and T3 (p < 0.001), but there were no differences between age groups. Ankle (T1 > T2 > T3, p < 0.026) and foot ranges of motion (T1, T2 > T3, p < 0.01) decreased over time for both age groups. Additionally, Younger cyclists had larger ankle and foot ranges of motion (ROM) compared to Older cyclists (23.2 ± 5.9° vs. 19.3 ± 5.6°; p = 0.036 and 49.8 ± 6.6° vs. 44.8 ± 6.5°; p = 0.032, respectively). Age related differences in physiological measures occurred as expected, although the skill level of the cyclists may explain their similar cadence. Smaller ankle and foot ROM may be strategies to assist force and power generation, particularly in Older cyclists as they attempt to overcome aging related physiological declines. With smaller ROM, Older cyclists may aim to strengthen ankle musculature and deemphasize high cadence to maintain force generation and critical power.
... These studies should differ in terms of rest and work-interval duration, hypoxic exposure duration, or hypoxia level. More studies are needed to compare effects of SIH and SIN on critical power (CP), which draws the border between heavy and severe exercise and is the indicator of the highest sustainable work rate of oxidative metabolism [19]. ...
... The Critical Power test on the 3rd measurement day was performed using the Monark 894E cycle ergometer, as previously described [19]. In the warm-up period, participants cycled for 5 min at 70 watts. ...
... At the beginning and end of the each sprint bout, ratings of perceived exertion (RPE), muscle pain status, and oxygen saturation in the tissues were measured with the BORG (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), VAS and the oximeter (Oxycon, USA) attached to the participant's finger, respectively. Heart rate (HR), peak power (PP) (w/kg), mean power (MP) (w/kg), Work (kJ), and the percentage decrease (%) of each sprint bout were taken from the Monark Anaerobic Testing Software (Version 3.3.0.0) and recorded. ...
Article
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Sprint interval training (SIT) is a concept that has been shown to enhance aerobic-anaero-bic training adaptations and induce larger effects in hypoxia. The purpose of this study was to examine the effects of 4 weeks of SIT with 15 or 30 s in hypoxia on aerobic, anaerobic performance and critical power (CP). A total of 32 male team players were divided into four groups: SIT with 15 s at FiO2: 0.209 (15 N); FiO2: 0.135 (15 H); SIT with 30 s at FiO2: 0.209 (30 N); and FiO2: 0.135 (30 H). VO2max did not significantly increase, however time-to-exhaustion (TTE) was found to be significantly longer in the post test compared to pre test (p = 0.001) with no difference between groups (p = 0.86). Mean power (MPw.kg) after repeated wingate tests was significantly higher compared to pre training in all groups (p = 0.001) with no difference between groups (p = 0.66). Similarly, CP was increased in all groups with 4 weeks of SIT (p = 0.001) with no difference between groups (p = 0.82). This study showed that 4 weeks of SIT with 15 and 30 s sprint bouts in normoxia or hypoxia did not increased VO2max in trained athletes. However, anerobic performance and CP can be increased with 4 weeks of SIT both in normoxia or hypoxia with 15 or 30 s of sprint durations.
... The power-duration relationship predicts that when W′ has been fully depleted (i.e. at task failure), the highest power output that can be sustained is CP (Coats et al. 2003;Chidnok et al. 2013). Hence, Vanhatalo et al. (2007) demonstrated that during the final 30 s of an all-out 3-min bout of cycle exercise, power output plateaued to a work rate that was not different from, and highly correlated with, CP (i.e. end-test power; EP). ...
... More recently, Murgatroyd et al. (2014) demonstrated that CP could be accurately and reliably determined from the EP attained during a single exercise test, incorporating a 3-min all-out bout of exercise performed immediately following task failure during a maximal rampincremental exercise test, whereas W′ was underestimated by the work above EP (WEP). This approach represents a significant advance over 1- (Clark et al. 2013) or 2-day (Vanhatalo et al. 2007;Bergstrom et al. 2012) testing procedures, because additional parameters of aerobic function (i.e., the gas exchange threshold, GET; mean response time of V O 2 kinetics; V O 2max ) and thus the boundaries between moderate, heavy, and severe exercise intensity domains can be determined in a single visit. However, the validity of this test has not been confirmed by more than one study , nor have the robustness of its underlying principles been tested using alternative exercise modes. ...
... work-rate = linear factor × cadence 2 ). Participants then immediately undertook an all-out effort for 3 min, as this duration has demonstrated to reliably result in a plateau in power output during the final 30 s (Burnley et al. 2006;Vanhatalo et al. 2007;Murgatroyd et al. 2014). Strong verbal encouragement was provided throughout the duration of the test to ensure that participants maintained their cadence as high as possible throughout the test. ...
Article
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Purpose The purpose of the present study was to determine whether a contiguous ramp and all-out exercise test could accurately determine critical power (CP) in a single laboratory visit during both upright and supine cycle exercise. Methods Healthy males completed maximal ramp-incremental exercise on a cycle ergometer in the upright ( n = 15) and supine positions ( n = 8), with task failure immediately followed by a 3-min all-out phase for determination of end-test power (EP). On separate days, participants undertook four constant-power tests in either the upright or supine positions with the limit of tolerance ranging from ~ 2 to 15 min for determination of CP. Results During upright exercise, EP was highly correlated with ( R ² = 0.93, P < 0.001) and not different from CP (CP = 221 ± 40 W vs. EP = 226 ± 46 W, P = 0.085, 95% limits of agreement − 30, 19 W). During supine exercise, EP was also highly correlated with ( R ² = 0.94, P < 0.001) and not different from CP (CP = 140 ± 42 W vs. EP = 136 ± 40 W, P = 0.293, 95% limits of agreement − 16, 24 W). Conclusion The present data suggest that EP derived from a contiguous ramp all-out exercise test is not different from the gold-standard method of CP determination during both upright and supine cycle exercise when assessed at the group level. However, the wide limits of agreement observed within the present study suggest that EP and CP should not be used interchangeably.
... Investigators have also explored the estimation of CP from a single, 3-min all-out test (3MT). This can be completed with [28,29] or without [30,31] a prior graded exercise test (GXT). The CP is estimated as the average end power (EP) over the final 30 s of the test, after the W has been depleted [28,29]. ...
... This can be completed with [28,29] or without [30,31] a prior graded exercise test (GXT). The CP is estimated as the average end power (EP) over the final 30 s of the test, after the W has been depleted [28,29]. Therefore, the amount of work done above EP (WEP) is equal to the W [29]. Thus, CP can be estimated from multiple work bouts or from a single work bout, with both methods producing similar estimates of CP; however, the accuracy of the estimate may depend on the fitness level of the subject. ...
... The CP is estimated as the average end power (EP) over the final 30 s of the test, after the W has been depleted [28,29]. Therefore, the amount of work done above EP (WEP) is equal to the W [29]. Thus, CP can be estimated from multiple work bouts or from a single work bout, with both methods producing similar estimates of CP; however, the accuracy of the estimate may depend on the fitness level of the subject. ...
Article
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The study and application of the critical power (CP) concept has spanned many decades. The CP test provides estimates of two distinct parameters, CP and W′, that describe aerobic and anaerobic metabolic capacities, respectively. Various mathematical models have been used to estimate the CP and W′ parameters across exercise modalities. Recently, the CP model has been applied to dynamic constant external resistance (DCER) exercises. The same hyperbolic relationship that has been established across various continuous, whole-body, dynamic movements has also been demonstrated for upper-, lower-, and whole-body DCER exercises. The asymptote of the load versus repetition relationship is defined as the critical load (CL) and the curvature constant is L′. The CL and L′ can be estimated from the same linear and non-linear mathematical models used to derive the CP. The aims of this review are to (1) provide an overview of the CP concept across continuous, dynamic exercise modalities; (2) describe the recent applications of the model to DCER exercise; (3) demonstrate how the mathematical modeling of DCER exercise can be applied to further our understanding of fatigue and individual performance capabilities; and (4) make initial recommendations regarding the methodology for estimating the parameters of the CL test.
... (1) is fit to the data. Vanhatalo and colleagues [39] proposed the 3-min all out intensity test (3MT) to determine CP and W' in one test; thereby, reducing the number of testing days. From the 3MT, CP is calculated as the average power of the last 30 s while W' is the area under the power curve and above CP [10,39]. ...
... Vanhatalo and colleagues [39] proposed the 3-min all out intensity test (3MT) to determine CP and W' in one test; thereby, reducing the number of testing days. From the 3MT, CP is calculated as the average power of the last 30 s while W' is the area under the power curve and above CP [10,39]. The 3MT has been validated by comparing the parameters to those from CWR tests [21,25,39]. ...
... From the 3MT, CP is calculated as the average power of the last 30 s while W' is the area under the power curve and above CP [10,39]. The 3MT has been validated by comparing the parameters to those from CWR tests [21,25,39]. However, the 3MT has been shown to overestimate CP and underestimate W' in previous studies [2,4,26,31]. ...
Article
PurposeThe constant work-rate to exhaustion tests must be repeated several times at each work-rate to estimate subject-level trial-to-trial variance (intra-individual variability, IIV) of critical power (CP) and work capacity (W'). Alternatively, these parameters and their variance can be estimated by repeating the 3-min all-out test (3MT) fewer times. The purpose of this study was to propose a method to determine subject-level repeatability of the 3MT and demonstrate the need to repeat the test multiple times to estimate IIV.Methods Seven cyclists performed a ramp test and four 3MTs on a CompuTrainer. The parameters CP, W', peak power (Pp), and total work (TW) were compared across trials using repeated measures ANOVA, Bland–Altman analysis, Intraclass Correlation Coefficients (ICC), Typical Error (TE) of measurement, and Coefficient of Variation (CV).ResultsFor the group, average CP and W' were 284 ± 58 W and 10.214 ± 3.143 kJ. The reliability statistics, CP (ICC = 0.97, TE = 8 W, CV = 2.94%) and W' (ICC = 0.88, TE = 1.11 kJ, CV = 10.87%), indicated strong agreement. Subject-level repeatability was determined by comparing time-to-peak power (TPp), absolute difference in Pp (δPp), and TW (δTW) for pairs of 3MTs. The average IIVs estimated by the 95% confidence intervals were ± 15 W for CP and ± 1.68 kJ for W'.Conclusions Thresholds are proposed for TPp (7 s), δPp (10%), and δTW (3%) to determine subject-level repeatability of the 3MT before computing the IIV of CP and W'. It is suggested that the 3MT is repeated at least three times to estimate the IIV, which aids in personalized measurement of training improvements and performance optimization.
... The three-minute all-out test [40,41] was designed to elicit maximal oxygen uptake, and profile the rate of decay to critical power-capturing the asymptote of the severe intensity domain. The three-minute duration is important, as this appears to be the duration above (and the intensity below) which athletes demonstrate an increased aerobic contribution to energy production [38,39,42]. ...
... SD and >1.2 SD, respectively. Data for power output and respiratory variables are presented in 30 s increments, commencing at 15 s and concluding at 165 s (i.e., the middle 150 s), this minimises variability due to the removal of time associated with initial acceleration and (fatigue as a result of) an end-spurt effort [41,57,58]. ...
... Pacing strategies amongst individuals during the tests differed despite all athletes having been familiarised and having had experience of maximal effort cycling on Watt-bikes™ prior to study commencement. This is a limitation of the present study but is also an acknowledged limitation of the three-minute all-out test [40,41], with authors suggesting that if maximal exercise is not performed then the test should be repeated i.e., the test should be performed in a manner similar to the shorter duration Wingate test(s) [71]. Given the multiple conditions in the present trial, this would be taxing on resources and the participant, and may have actually reduced transferability of the present findings to applied competitive and training settings. ...
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Previous menthol studies have demonstrated ergogenic effects in endurance-based activity. However, there is a need for research in sports whose physiological requirements exceed maximal aerobic capacity. This study assessed the effects of 0.1% menthol mouth-rinsing upon a modified three-minute maximal test in the heat (33.0 ± 3.0 °C; RH 46.0 ± 5.0%). In a randomised crossover single blind placebo-controlled study, 11 participants completed three modified maximal tests, where each trial included a different mouth rinse: either menthol (MEN), cold water (WAT) or placebo (PLA). Participants were asked to rate their thermal comfort (TC), thermal sensation (TS) and rating of perceived exertion (RPE) throughout the test. Heart rate, core temperature, oxygen uptake (VȮ2), ventilation (VĖ) and respiratory exchange ratio (RER) were monitored continuously throughout the test, alongside cycling power variables (W; W/kg). A blood lactate (BLa) level was taken pre-and post-test. Small to moderate effects (Cohen's d and accompanying 90% confidence intervals) between solutions MEN, WAT and PLA were observed towards the end of the test in relation to relative power. Specifically, from 75-105 s between solutions MEN and WAT (ES: 0.795; 90% CI: 0.204 to 1.352) and MEN and PLA (ES: 1.059; 90% CI: 0.412 to 1.666), this continued between MEN and WAT (ES: 0.729; 90% CI: 0.152 to 1.276) and MEN and PLA (ES: 0.791; 90% CI: 0.202 to 1.348) from 105-135 s. Between 135-165 s there was a moderate difference between solutions MEN and WAT (ES: 1.058; 90% CI: 0.411 to 1.665). This indicates participants produced higher relative power for longer durations with the addition of the menthol mouth rinse, compared to cold water or placebo. The use of menthol (0.1%) as a mouth rinse showed small performance benefits for short duration high intensity exercise in the heat.
... Three-minute all-out test Vanhatalo et al. (2007) reported that a 3MAOT provides statistically similar estimates of critical power (CP) and W 0 , 210 defined as the maximal rate of steady state oxidative metabolism (Monod & Scherrer, 1965) and the amount of work that can be performed above CP, respectively (Vanhatalo et al., 2007). Following the 3MAOT procedures proposed by Vanhatalo et al. (2007), participants performed 3 min of base-215 line cycling against 20 W, immediately followed by a 3MAOT for estimation of peak power (PP), end power (EP) and anaerobic capacity [work done above EP (WEP)] (Vanhatalo et al., 2007). ...
... Three-minute all-out test Vanhatalo et al. (2007) reported that a 3MAOT provides statistically similar estimates of critical power (CP) and W 0 , 210 defined as the maximal rate of steady state oxidative metabolism (Monod & Scherrer, 1965) and the amount of work that can be performed above CP, respectively (Vanhatalo et al., 2007). Following the 3MAOT procedures proposed by Vanhatalo et al. (2007), participants performed 3 min of base-215 line cycling against 20 W, immediately followed by a 3MAOT for estimation of peak power (PP), end power (EP) and anaerobic capacity [work done above EP (WEP)] (Vanhatalo et al., 2007). ...
... Three-minute all-out test Vanhatalo et al. (2007) reported that a 3MAOT provides statistically similar estimates of critical power (CP) and W 0 , 210 defined as the maximal rate of steady state oxidative metabolism (Monod & Scherrer, 1965) and the amount of work that can be performed above CP, respectively (Vanhatalo et al., 2007). Following the 3MAOT procedures proposed by Vanhatalo et al. (2007), participants performed 3 min of base-215 line cycling against 20 W, immediately followed by a 3MAOT for estimation of peak power (PP), end power (EP) and anaerobic capacity [work done above EP (WEP)] (Vanhatalo et al., 2007). Participants were instructed to increase their cadence to approximately 120 rev/min during the last 5 s of baseline 220 pedaling. ...
Article
Purpose: We compared aerobic capacity (V˙O2max), mitochondrial capacity (mV˙O2), anaerobic power, strength, and muscle endurance in healthy, active men from strength (STR), endurance (END) and high-intensity functional training (HIFT) backgrounds. Methods: Twenty-four men (n = 8/group) completed a cycle ergometer test to determine V˙O2max, followed by a 3-min all-out test to determine peak (PP) and end power (EP), and to estimate anaerobic [work done above EP (WEP)] and aerobic work capacity. Strength was determined by knee extensor maximal voluntary contraction at various flexion angles. The endurance index (EI) of the vastus lateralis (VL) was assessed by measuring muscle contraction acceleration during electrical twitch mechanomyography. mV˙O2max of the VL was assessed using near-infrared spectroscopy to estimate muscle oxygen consumption during transient femoral artery occlusions. Results: V˙O2max was significantly different among groups (p < .05). PP was significantly higher in HIFT and STR versus END (p < .05). EP was significantly higher in HIFT and END compared to STR (p < .05). WEP was significantly higher in STR compared to END (p < .05), whereas total work done was significantly higher in HIFT and END compared to STR (p < .05). mV˙O2max and EI were comparable between HIFT and END but significantly lower in STR versus END (p < .05). Torque production was significantly lower in END compared to STR and HIFT at all flexion angles (p < .05), with no difference between STR and HIFT. Conclusion: HIFT participants can exert similar power outputs and absolute strength compared to strength focused participants but exhibit fatigue resistance and mitochondrial capacity comparable to those who train for endurance.
... Relying heavily on the bioenergetic basis of the traditional critical power model, an all-out test lasting three minutes (AO3) has been described in the late 2000s as an advantageous alternative to determine the critical power (CP) on a cycle ergometer [1][2][3]. The proposition of AO3 stems from its ability to predict the power-duration relationship in a single test session. ...
... Considering Eq 1, when W 0 is completely depleted, P equals CP. So, one sufficiently long all-out effort would be an interesting alternative to obtain CP based on the test's end power (EP), while the area above EP (WEP) could serve as an estimate of W 0 [2]. Early data on the AO3 performed on a cycle ergometer had shown test-retest reliability for end power (3% of CV; ICC at 0.99) [1] and close agreement between CP and EP (6 W of typical error; Pearson's r = 0.99). ...
... Early data on the AO3 performed on a cycle ergometer had shown test-retest reliability for end power (3% of CV; ICC at 0.99) [1] and close agreement between CP and EP (6 W of typical error; Pearson's r = 0.99). Further, despite limitations that have been reported when comparing W 0 and WEP (2.8 kJ of typical error; Pearson's r = 0.84) [2], both are often considered equivalent and valuable for practical applications [6,7]. ...
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This study aimed to compare four constructs from the three-minute all-out test (AO3)–end power (EP), the area above EP (WEP), maximum power (Pmax), and attained V ˙ O 2 peak −to those derived from the classical CP model in tethered running. Seventeen male recreational runners underwent two experiments to test for reliability and agreement of AO3 parameters with those obtained from the classical CP model (Wꞌ and CP), a graded exercise test ( V ˙ O 2 max ) and a 30-second all-out test (AO30s; Pmax); all performed on a non-motorized treadmill (NMT). Significance levels were set at p<0.05. There were no significant differences between test-retest for Pmax (p = 0.51), WEP (p = 0.39), and EP (p = 0.64), showing generally close to zero bias. Further, retest ICC were high for Pmax and EP (ICC > 0.86) but moderate for WEP (ICC = 0.69). Pmax showed no difference between AO3 and AO30s (p = 0.18; CV% = 9.5%). EP and WEP disagreed largely with their classical critical power model counterparts (p = 0.05; CV%>32.7% and p = 0.23; CV%>39.7%, respectively), showing greater error than their test-retest reliability. V ˙ O 2 peak from AO3 was not different (p = 0.13) and well related (CV% = 8.4; ICC = 0.87) to the incremental test V ˙ O 2 max . Under the studied conditions, the agreement of EP and WEP to CP and Wꞌ was not strong enough to assure their use interchangeably. Pmax and V ˙ O 2 max were closer to their criterion parameters.
... Fourteen participants (nine males and five females; weight: 67.6 ± 9.9 kg; height: 175.9 ± 6.9 cm; age: 23.9 ± 5.5 years [mean ± SD]) completed a 3-min all-out test [56] to determine CP and W'. Participants first performed a warm-up at 100 W, followed by 5 min of rest. ...
... Participants then started 3 min of unloaded baseline pedaling, followed by the all-out 3-min effort. The procedure followed the example of Vanhatalo and colleagues [56]. Visual analysis of the SmO 2 data quickly identified the similarity between the power profile and the SmO 2 profile (see Fig. 1). ...
... This realization yielded a simple analysis and results. CP and W' were analyzed as prescribed by Vanhatalo et al. [56] and the principle of the path of least resistance demanded that the SmO 2 data be analyzed in the same manner (see Fig. 2). This generated model 1 with the following results, assessed at a significance level set at an alpha of 0.05. ...
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The power-duration relationship is well documented for athletic performance and is formulated out mathematically in the critical power (CP) model. The CP model, when applied properly, has great predictive power, e.g. pedaling at a specific power output on an ergometer the model precisely calculates the time over which an athlete can sustain this power. However, CP presents physiological inconsistencies and process-oriented problems. The rapid development of near-infrared spectroscopy (NIRS) to measure muscle oxygenation (SmO2) dynamics provides a physiological exploration of the CP model on a conceptual and empirical level. Conceptually, the CP model provides two components: first CP is defined as the highest metabolic rate that can be achieved through oxidative means. And second, work capacity above CP named W’. SmO2 presents a steady-state in oxygen supply and demand and thereby represents CP specifically at a local level of analysis. Empirically, exploratory data quickly illustrates the relationship between performance and SmO2, as shown during 3-min all-out cycling tests to assess CP. During these tests, performance and SmO2 essentially mirror each other, and both CP and W’ generate solid correlation with what would be deemed their SmO2 counterparts: first, the steady-state of SmO2 correlates with CP. And second, the tissue oxygen reserve represented in SmO2, when calculated as an integral corresponds to W’. While the empirical data presented is preliminary, the proposition of a concurring physiological model to the current CP model is a plausible inference. Here we propose that SmO2 steady-state representing CP as critical oxygenation or CO. And the tissue oxygen reserve above CO would then be identified as O’. This new CO model could fill in the physiological gap between the highly predictive CP model and at times its inability to track human physiology consistently. For simplicity's sake, this would include acute changes in physiology as a result of changing climate or elevation with travel, which can affect performance. These types of acute fluctuations, but not limited to, would be manageable when applying a CO model in conjunction with the CP model. Further, modeling is needed to investigate the true potential of NIRS to model CP, with a focus on repeatability, recovery, and systemic vs local workloads.
... It is appropriate to provide strong verbal encouragement throughout the test. Subjects are not informed of the work rates or their performance on any of the tests [14,21,33]. ...
... Testing provides a metabolic signal to the mitochondria to elevate respiration so that VO 2 increases rapidly to VO 2max and remains there as power falls to CP with W' being completely utilized. This provides an additional cost of O 2 corresponding to a major loss of efficiency, which is similar to the development of the slow component of oxygen uptake during a constant work rate throughout severe intensity exercise leading to exhaustion [33,35]. After the complete depletion of W', this results in PO being maintained from only aerobic metabolism. ...
... A limitation of the present protocol is that a CP validation test is not usually included to ensure that a physiological steady state had been established [37]. However, this is a common limitation within the literature, and it should also be noted that the original research by Vanhatalo et al. [33] on the 3MT did not include a CP validation test [29]. ...
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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.
... The requirement for multiple time-to-task failure severeintensity trials led to development of the three-minute all-out test (3MT) for identification of the MMSS (Burnley et al. 2006;Vanhatalo et al. 2007). In the 3MT, an athlete works all-out for three minutes without pacing, depleting W′ in the initial part of the test to ensure the work output is eventually limited to the critical power. ...
... Accordingly, average power output during the final 30 s is used to estimate critical power, and the total work performed above the end-test power is used to estimate W′. The 3MT was designed for use on an electromagnetically braked laboratory ergometer in a linear mode, where power output is the product of the linear factor (flywheel resistance) and the square of the cadence; the linear factor is typically applied, such that the power output achieved at the individual cyclist's preferred cadence is the gas exchange threshold power output (GET) plus 50% of the interval between GET and V O 2 peak (Burnley et al. 2006;Vanhatalo et al. 2007Vanhatalo et al. , 2008a. The athlete is also supervised and verbally encouraged by a team of researchers, and blinded to power output and time (Burnley et al. 2006;Vanhatalo et al. 2007Vanhatalo et al. , 2008a. ...
... The 3MT was designed for use on an electromagnetically braked laboratory ergometer in a linear mode, where power output is the product of the linear factor (flywheel resistance) and the square of the cadence; the linear factor is typically applied, such that the power output achieved at the individual cyclist's preferred cadence is the gas exchange threshold power output (GET) plus 50% of the interval between GET and V O 2 peak (Burnley et al. 2006;Vanhatalo et al. 2007Vanhatalo et al. , 2008a. The athlete is also supervised and verbally encouraged by a team of researchers, and blinded to power output and time (Burnley et al. 2006;Vanhatalo et al. 2007Vanhatalo et al. , 2008a. The 3MT performed in this manner has been shown to produce valid (Burnley et al. 2006;Vanhatalo et al. 2007Vanhatalo et al. , 2016 and reliable (Burnley et al. 2006;Johnson et al. 2011) estimates of MMSS and W′ in trained populations. ...
Article
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Purpose: The three-minute all-out test (3MT), when performed on a laboratory ergometer in a linear mode, can be used to estimate the heavy-severe-intensity transition, or maximum metabolic steady state (MMSS), using the end-test power output. As the 3MT only requires accurate measurement of power output and time, it is possible the 3MT could be used in remote settings using personal equipment without supervision for quantification of MMSS. Methods: The aim of the present investigation was to determine the reliability and validity of remotely performed 3MTs (3MTR) for estimation of MMSS. Accordingly, 53 trained cyclists and triathletes were recruited to perform one familiarisation and two experimental 3MTR trials to determine its reliability. A sub-group (N = 10) was recruited to perform three-to-five 30 min laboratory-based constant-work rate trials following completion of one familiarisation and two experimental 3MTR trials. Expired gases were collected throughout constant-work rate trials and blood lactate concentration was measured at 10 and 30 min to determine the highest power output at which steady-state [Formula: see text] (MMSS-[Formula: see text]) and blood lactate (MMSS-[La-]) were achieved. Results: The 3MTR end-test power (EPremote) was reliable (coefficient of variation, 4.5% [95% confidence limits, 3.7, 5.5%]), but overestimated MMSS (EPremote, 283 ± 51 W; MMSS-[Formula: see text], 241 ± 46 W, P = 0.0003; MMSS-[La-], 237 ± 47 W, P = 0.0003). This may have been due to failure to deplete the finite work capacity above MMSS during the 3MTR. Conclusion: These results suggest that the 3MTR should not be used to estimate MMSS in endurance-trained cyclists.
... Instead, exercise intensity domains have been recommended 7 and shown to trigger targeted adaptations. 8 Among several possibilities, [9][10][11][12] critical power/speed (CP/CS) [11][12][13][14] can be used, which is described as the highest power/speed output at which metabolic homeostasis is achieved, 15 and may be considered the most important fatigue threshold in exercise physiology. 16 The CP/CS is considered a better individualization method for training, provides a useful insight in the best possible performance for a given work/distance and power/speed for athletes, 17 and permits the separation of heavy from severe intensity domains. ...
... Instead, exercise intensity domains have been recommended 7 and shown to trigger targeted adaptations. 8 Among several possibilities, [9][10][11][12] critical power/speed (CP/CS) [11][12][13][14] can be used, which is described as the highest power/speed output at which metabolic homeostasis is achieved, 15 and may be considered the most important fatigue threshold in exercise physiology. 16 The CP/CS is considered a better individualization method for training, provides a useful insight in the best possible performance for a given work/distance and power/speed for athletes, 17 and permits the separation of heavy from severe intensity domains. ...
Article
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Purpose: Intensity domains are recommended when prescribing exercise, and critical power/speed (CP/CS) was designated the "gold standard" when determining maximal metabolic steady state. CS is the running analog of CP for cycle ergometry. However, a CP for running could be useful for controlling intensity when training in any type of condition. Therefore, this study aimed to estimate external, internal, and total CP (CPext, CPint, and CPtot), obtained based on running power calculations, and verified whether they occurred at the same percentage of peak oxygen uptake as the usual CS. Furthermore, this study examined whether selecting strides at the start, half, or end of the exhaustive runs to calculate running power influenced the estimation of the 3 CPs. Methods: Thirteen male runners performed a maximal incremental aerobic test and 4 exhaustive runs (90%, 100%, 110%, 120% peak speed) on a treadmill. The estimations of CS and CPs were obtained using a 3-parameter mathematical model fitted using weighted least square. Results: CS was estimated at 4.3 m/s while the estimates of CPext, CPint, and CPtot were 5.2, 2.6, and 7.8 W/kg, respectively. The corresponding V˙O2 for CS was 82.5 percentage of peak oxygen uptake and 81.3, 79.7, and 80.6 percentage of peak oxygen uptake for CPext, CPint, and CPtot, respectively. No systematic bias was reported when comparing CS and CPext, as well as the 3 different CPs, whereas systematic biases of 2.8% and 1.8% were obtained for the comparison among CS and CPint and CPtot, respectively. Nonetheless, the V˙O2 for CS and CPs were not statistically different (P = .09). Besides, no effect of the time stride selection for CPs as well as their resulting V˙O2 was obtained (P ≥ .44). Conclusions: The systematic biases among V˙O2 at CS and CPint and CPtot were not clinically relevant. Therefore, CS and CPs closely represent the same fatigue threshold in running. The knowledge of CP in running might prove to be useful for both athletes and coaches, especially when combined with instantaneous running power. Indeed, this combination might help athletes controlling their targeted training intensity and coaches prescribing a training session in any type of condition.
... Studies have used a single 3-min all-out test (3MT) as an alternative approach for determining CP, which is referred to as end-test power (EP) [9]. Previous studies have indicated that 3MT has a good test-retest reliability [10,11] and is a valid protocol for estimation of CP or CV [12,13]. ...
... Maximal effort was considered when three of the following four criteria were achieved [10]: (1) respiratory exchange ratio > 1.2; (2) heart rate > 90% of the age-predicted maximum; (3) a plateau in VO2 defined as no expected increase higher than 150 mL·min −1 , despite an increase in power output; and (4) RPE > 17. After the IETs, we exported the VO2 data with average values of 10 and 30 s, and used them as indicators for calculating VT and the maximal oxygen uptake (VO2max), respectively [11]. ...
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The aim of this study was to investigate the effects of heat on the validity of end-test power (EP) derived from a 3-min all-out test (3MT), which is considered as an alternative method for determining the conventional critical power. Twelve male cyclists were required to perform incremental exercise tests (IET) and 3MTs in both high temperature (HT; 35 °C) and thermoneutral temperature (NT; 22 °C) environments. Maximal oxygen uptake (VO2max), and first and second ventilatory thresholds (VT1 and VT2, respectively) against the power output (wVO2max, wVT1, and wVT2) were measured during IETs. EP was recorded during the 3MTs. A significant correlation was observed between wVT2 and EP under NT (r = 0.674, p < 0.05) and under HT (r = 0.672, p < 0.05). However, wVO2max, wVT1, wVT2, and EP were significantly higher in NT than in HT (p < 0.05). In conclusion, although the physiological stress induced by HT might impair exercise performance, the EP derived from 3MT can validly estimate wVT2 under HT conditions.
... While methods to measure CP (or CS) during e.g. cycling or running using a single laboratory visit have been developed (Vanhatalo et al. 2007;Pettitt et al. 2012;Murgatroyd et al. 2014), these approaches depend upon a sustained maximal effort. Effort-independent methods for measurement of physiological thresholds add construct validity to, and reduce potential variability of, the measured variable, because they do not rely on participant perceptions and are likely preferable for testing vulnerable populations, such as the elderly or patients. ...
... The curvilinear profile of the power (P)-duration (t) relationship (and its parameters CP, W ʹ, Fig. 11; Monod & Scherrer, 1965) defines exercise tolerance for locomotory activity across all species examined including amphibia (salamander, Full, 1986;rodentia, mouse, Billat et al. 2005, andrat, Copp et al. 2010;and equid, horse, Lauderdale & Hinchcliff, 1999). This is also true for alternative muscle contraction paradigms such as isometric (Monod & Scherrer, 1965) and isotonic Burnley, 2009) (see also Briggs (1920) for an early identification of the 'fatigue threshold' (Zoladz & Grassi, 2020)) as well as disparate exercise modalities in humans, specifically, running (Hughson et al. 1984;Fukuba & Whipp, 1999;Fukuba et al. 2003;Broxterman et al. 2013), cycling (Poole et al. 1988(Poole et al. , 1990Hill, 1993;Neder et al. 2000a,b ;Pringle & Jones, 2002;Hill, 2004;Vanhatalo et al. 2007), swimming (Wakayoshi et al. 1993) and rowing (Hill et al. 2003). Consequently, the hyperbolic P-t relationship is highly conserved with its mechanistic underpinnings and close coherence with systemic responses (V O 2 , blood [La − ]) and muscle metabolism supporting its deterministic role in defining exercise performance. ...
Article
The anaerobic threshold (AT) remains a widely recognized, and contentious, concept in exercise physiology and medicine. As conceived by Karlman Wasserman, the AT coalesced the increase of blood lactate concentration ([La- ]), during a progressive exercise test, with an excess pulmonary carbon dioxide output ( V ̇ C O 2 ). Its principal tenets were: limiting oxygen (O2 ) delivery to exercising muscle→increased glycolysis, La- and H+ production→decreased muscle and blood pH→with increased H+ buffered by blood [HCO3- ]→increased CO2 release from blood→increased V ̇ C O 2 and pulmonary ventilation. This schema stimulated scientific scrutiny which challenged the fundamental premise that muscle anoxia was requisite for increased muscle and blood [La- ]. It is now recognized that insufficient O2 is not the primary basis for lactataemia. Increased production and utilization of La- represent the response to increased glycolytic flux elicited by increasing work rate, and determine the oxygen uptake ( V ̇ O 2 ) at which La- accumulates in the arterial blood (the lactate threshold; LT). However, the threshold for a sustained non-oxidative contribution to exercise energetics is the critical power, which occurs at a metabolic rate often far above the LT and separates heavy from very heavy/severe-intensity exercise. Lactate is now appreciated as a crucial energy source, major gluconeogenic precursor and signalling molecule but there is no ipso facto evidence for muscle dysoxia or anoxia. Non-invasive estimation of LT using the gas exchange threshold (non-linear increase of V ̇ C O 2 versus V ̇ O 2 ) remains important in exercise training and in the clinic, but its conceptual basis should now be understood in light of lactate shuttle biology.
... The 3MT is short in duration and has demonstrated to be both a reliable and valid test for the measurement of critical speed (CS) and the finite capacity of running speeds above CS, D prime (D') [30,31]. Critical speed has demonstrated a relationship to both fractional and maximal threshold values [18,[32][33][34][35]. A relationship exists between CS and MLSS [32], although CS may be a more sensitive and reliable fractional threshold measurement of the upper limit of the heavy exercise intensity domain [18,33]. ...
... Critical speed has demonstrated a relationship to both fractional and maximal threshold values [18,[32][33][34][35]. A relationship exists between CS and MLSS [32], although CS may be a more sensitive and reliable fractional threshold measurement of the upper limit of the heavy exercise intensity domain [18,33]. Evidence also suggests that CS and VO 2max are positively correlated, meaning that those with a higher VO 2max also have a greater CS value [34,35]. ...
Article
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Maximal oxygen uptake (VO2max) and critical speed (CS) are key fatigue-related measurements that demonstrate a relationship to one another and are indicative of athletic endurance performance. This is especially true for those that participate in competitive fitness events. However, the accessibility to a metabolic analyzer to accurately measure VO2max is expensive and time intensive, whereas CS may be measured in the field using a 3 min all-out test (3MT). Therefore, the purpose of this study was to examine the relationship between VO2max and CS in high-intensity functional training (HIFT) athletes. Twenty-five male and female (age: 27.6 ± 4.5 years; height: 174.5 ± 18.3 cm; weight: 77.4 ± 14.8 kg; body fat: 15.7 ± 6.5%) HIFT athletes performed a 3MT as well as a graded exercise test with 48 h between measurements. True VO2max was determined using a square-wave supramaximal verification phase and CS was measured as the average speed of the last 30 s of the 3MT. A statistically significant and positive correlation was observed between relative VO2max and CS values (r = 0.819, p < 0.001). Based on the significant correlation, a linear regression analysis was completed, including sex, in order to develop a VO2max prediction equation (VO2max (mL/kg/min) = 8.449(CS) + 4.387(F = 0, M = 1) + 14.683; standard error of the estimate = 3.34 mL/kg/min). Observed (47.71 ± 6.54 mL/kg/min) and predicted (47.71 ± 5.7 mL/kg/min) VO2max values were compared using a dependent t-test and no significant difference was displayed between the observed and predicted values (p = 1.000). The typical error, coefficient of variation, and intraclass correlation coefficient were 2.26 mL/kg/min, 4.90%, and 0.864, respectively. The positive and significant relationship between VO2max and CS suggests that the 3MT may be a practical alternative to predicting maximal oxygen uptake when time and access to a metabolic analyzer is limited.
... The 3-min all-out cycling test (3MT) permits valid and reliable determination of CP and Wʹ (27,28). During this test external power output declines with time to attain a nadir during the final 30 s of the test (end test power, EP) that approximates CP, with the work completed above EP (WEP) being equivalent to Wʹ (27,28). ...
... The 3-min all-out cycling test (3MT) permits valid and reliable determination of CP and Wʹ (27,28). During this test external power output declines with time to attain a nadir during the final 30 s of the test (end test power, EP) that approximates CP, with the work completed above EP (WEP) being equivalent to Wʹ (27,28). Performing two 3MTs, separated by a brief recovery interval (1-min), provides the opportunity to: 1) assess the accuracy of the Wʹ BAL models to predict Wʹ REC following exercise which completely utilises Wʹ at its fastest possible rate; ...
Article
Purpose: This study aimed to: 1) examine the accuracy with which W' reconstitution (W'REC) is estimated by the W' balance (W'BAL) models following a 3-min all-out test (3MT); 2) determine the effects of a 3MT on the power-duration relationship, and; 3) assess whether accounting for changes in the power-duration relationship during exercise improved estimates of W'REC. Methods: The power-duration relationship and the actual and estimated W'REC was determined for 12 datasets extracted from our laboratory database where participants had completed two 3MT separated by 1-min recovery (i.e., control, C-3MT and fatigued, F-3MT). Results: Actual W'REC (6.3 ± 1.4 kJ) was significantly overestimated by the W'BAL·ODE (9.8 ± 1.3 kJ; P < 0.001) and the W'BAL·MORTON (16.9 ± 2.6 kJ; P < 0.001) models, but was not significantly different to the estimate provided by the W'BAL·INT (7.5 ± 1.5 kJ; P > 0.05) model. End power (EP) was 7% lower in the F-3MT (263 ± 40 W) compared to the C-3MT (282 ± 44 W; P < 0.001), and work done above EP (WEP) was 61% lower in the F-3MT (6.3 ± 1.4 kJ) compared to the C-3MT (16.9 ± 3.2 kJ). The size of the error in the estimated W'REC was correlated with the reduction in WEP for the W'BAL·INT and W'BAL·ODE models (both r > -0.74, P < 0.01) but not the W'BAL·MORTON model (r = -0.18, P > 0.05). Accounting for the changes in the power-duration relationship improved the accuracy of the W'BAL·ODE and W'BAL·MORTON, but they remained significantly different to actual W'REC. Conclusions: These findings demonstrate that the power-duration relationship is altered following a 3MT, and accounting for these changes improves the accuracy of the W'BAL·ODE and the W'BAL·MORTON, but not W'BAL·INT models. These results have important implications for the design and use of mathematical models describing the energetics of exercise performance.
... Davide Malatesta and Fabio Borrani authors contributed equally to this work. be defined based on the oxygen uptake kinetics (Whipp and Mahler 1980), maximum lactate steady-state (Iannetta et al. 2018), ventilatory threshold (Wasserman et al. 1973), or CP/ CS (Vanhatalo et al. 2007;Jones et al. 2019). ...
Article
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Purpose Intensity domains are recommended when prescribing exercise. The distinction between heavy and severe domains is made by the critical speed (CS), therefore requiring a mathematically accurate estimation of CS. The different model variants (distance versus time, running speed versus time, time versus running speed, and distance versus running speed) are mathematically equivalent. Nevertheless, error minimization along the correct axis is important to estimate CS and the distance that can be run above CS ( d′ ). We hypothesized that comparing statistically appropriate fitting procedures, which minimize the error along the axis corresponding to the properly identified dependent variable, should provide similar estimations of CS and d ′ but that different estimations should be obtained when comparing statistically appropriate and inappropriate fitting procedure. Methods Sixteen male runners performed a maximal incremental aerobic test and four exhaustive runs at 90, 100, 110, and 120% of their peak speed on a treadmill. Several fitting procedures (a combination of a two-parameter model variant and regression analysis: weighted least square) were used to estimate CS and d ′. Results Systematic biases ( P < 0.001) were observed between each pair of fitting procedures for CS and d ′, even when comparing two statistically appropriate fitting procedures, though negligible, thus corroborating the hypothesis. Conclusion The differences suggest that a statistically appropriate fitting procedure should be chosen beforehand by the researcher. This is also important for coaches that need to prescribe training sessions to their athletes based on exercise intensity, and their choice should be maintained over the running seasons.
... In the present study, the speed measured at the last 5 min of the T10 retest occurred at approximately 51% Δ (range: 25-78% Δ). Previous research reported that CS occurred at 41% Δ (Pringle & Jones, 2002), and CP occurred at 46% Δ (Poole et al., 1988;Vanhatalo et al., 2007), and at 43% Δ (range: 28-65% Δ) of the end-test power (Burnley et al., 2006). Therefore, although the literature suggests that the CS occurs at approximately 50% Δ, the gas exchange individual responses at this exercise intensity may vary considerably (Smith & Jones, 2001), as CS is located considerably above the GET in not highly trained individuals. ...
... Morel et al. [2019], for example, showed that the asymptote of MVIC torque during an isokinetic all-out test depends on the contraction velocity. Intriguingly, during all-out tests, the time course of power bears strong resemblance with the time course of torque (see, for example, Figure 1 in Vanhatalo et al. [2007]). This might indicate a possible application of the model in power-measured exercises. ...
Thesis
In this thesis, we present a novel mathematical model-based approach to optimize loading schemes of isometric resistance training (RT) sessions for different training goals. To this end, we develop a nonlinear ordinary differential equation model of the time course of maximum voluntary isometric (MVIC) force under external isometric loading. To validate the model, we set up multi-experiment parameter estimation problems using a comprehensive dataset from the literature. We solve these problems numerically via direct multiple shooting and the generalized Gauss-Newton method. Moreover, we use the proposed model to examine hypotheses about fatigue and recovery of MVIC force. Then, we mathematically formulate key performance indicators and optimality criteria for loading schemes of isometric RT sessions identified in sports science and incorporate these into multi-stage optimal control problems. We solve these problems numerically via direct multiple shooting and structure-exploiting sequential quadratic programming. We discuss the results from a numerical and sports scientific point of view. Based on the proposed model, we additionally formulate the estimation of critical torque as a nonlinear program. This allows us to reduce the experimental effort compared to conventional testing when estimating these quantities. Furthermore, we formulate multi-stage optimum experimental design problems to reduce the statistical uncertainty of the parameter estimates when calibrating the model. We solve these problems numerically via direct single shooting and sequential quadratic programming. We discuss the solutions from a numerical and physiological point of view. For our approach, a small amount of data obtained in a single testing session is sufficient. Our approach can be extended to more elaborate physiological models and other forms of resistance training once suitable models become available.
... Instead, a model considering exercise intensity domains for exercise prescription has been recommended (Iannetta et al., 2020). Parameters such as oxygen uptake kinetics (Whipp and Mahler, 1980), ventilatory threshold (VT) (Wasserman et al., 1973), maximum lactate steady-state (Iannetta et al., 2018), and CP/CS (Vanhatalo et al., 2007;Constantini et al., 2014;Jones et al., 2019) can be used to define these various intensity domains. ...
Article
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An accurate estimation of critical speed (CS) is important to accurately define the boundary between heavy and severe intensity domains when prescribing exercise. Hence, our aim was to compare CS estimates obtained by statistically appropriate fitting procedures, i.e., regression analyses that correctly consider the dependent variables of the underlying models. A second aim was to determine the correlations between estimated CS and aerobic fitness parameters, i.e., ventilatory threshold, respiratory compensation point, and maximal rate of oxygen uptake. Sixteen male runners performed a maximal incremental aerobic test and four exhaustive runs at 90, 100, 110, and 120% of the peak speed of the incremental test on a treadmill. Then, two mathematically equivalent formulations (time as function of running speed and distance as function of running speed) of three different mathematical models (two-parameter, three-parameter, and three-parameter exponential) were employed to estimate CS, the distance that can be run above CS ( d′ ), and if applicable, the maximal instantaneous running speed ( s max ). A significant effect of the mathematical model was observed when estimating CS, d′ , and s max ( P < 0.001), but there was no effect of the fitting procedure ( P > 0.77). The three-parameter model had the best fit quality (smallest Akaike information criterion) of the CS estimates but the highest 90% confidence intervals and combined standard error of estimates (%SEE). The 90% CI and %SEE were similar when comparing the two fitting procedures for a given model. High and very high correlations were obtained between CS and aerobic fitness parameters for the three different models ( r ≥ 0.77) as well as reasonably small SEE (SEE ≤ 6.8%). However, our results showed no further support for selecting the best mathematical model to estimate critical speed. Nonetheless, we suggest coaches choosing a mathematical model beforehand to define intensity domains and maintaining it over the running seasons.
... After compiling the results, researchers found subjects in the caffeine group had a higher work end power than the placebo group (increase of 10.7% p < 0.05). End power is a measurement that can be used to calculate critical power through critical power models [10]. These results may be due central nervous system stimulation by caffeine and lowered sensitivity to pain which may be responsible for enhanced fatigue resistance. ...
Article
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Hypothesis: The intake of caffeine can increase physical performance during athletic activity Methods: A search for primary sources was done using PubMed with MeSH terms. The search was limited to randomized controlled trials that were published between 2015 and 2020. After application of inclusion and exclusion criteria, seven articles were selected for this literature review. Results: Of the seven randomized controlled trials selected, six demonstrated caffeine ingestion led to a statistically significant increase in physical performance. One of the randomized controlled trials found no statistically significant relationship between caffeine and run timings. Major findings and results of the studies were stated and contrasted against each other. Conclusion: With regards to the results of the selected studies, caffeine was shown to have ergogenic activity and was able to increase physical performance during exercise and sporting competition through multiple mechanisms. Further research should be done with greater sample sizes to determine the effect of rate of metabolism on caffeine activity and to compare caffeine responders and non-responders.
... A limitation of traditional CP testing is that it requires several constant load tests and is timeconsuming. A 3-minute all-out test has been validated for assessment of CP and W' to overcome this (Vanhatalo et al., 2007). However, to verify it is a true CP measurement, oxygen uptake is ideally measured and strong encouragement is needed during the all-out test. ...
Article
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Functional Threshold Power (FTP) in cycling is increasingly used in exercise prescription, particularly with the rise in use of home trainers and virtual exercise platforms. FTP testing does not require biological sampling and is considered a more practical test than others. This scoping review investigated what is known about the 20-minute FTP (FTP²⁰) test. A three-step search strategy was used to identify studies in relevant databases (PubMed, CINAHL, SportDiscus, Google Scholar, Web of Science) and grey literature. Data were extracted and common themes identified which allowed for descriptive analysis and thematic summary. Fifteen studies were included. The primary focus fitted broadly into four themes: reliability, association with other physiological markers, other power-related concepts and performance prediction. The FTP²⁰ test was reported as a reliable test. Studies investigating the relationship of FTP²⁰ with other physiological markers and power-related concepts reported large limits of agreement suggesting parameters cannot be used interchangeably. Some findings indicate that FTP²⁰ may be useful in performance prediction. The majority of studies involved trained male cyclists. Overall, existing literature on the FTP²⁰ test is limited. Further investigation is needed to provide physiological justification for FTP²⁰ and inform use in exercise prescription in a range of populations.
... Critical power is then determined as the slope of the work-time relationship, whereas W' is determined from the y-intercept [7]. More recently, though, investigators have introduced a 3-minute all-out exercise test, known as the 3MT, that has enabled the determination of critical power and W' from a single exercise bout [12,13]. The idea behind the 3-minute all-out test is that when a subject exerts themselves fully and expends W' wholly, their power output equals their critical power [10]. ...
Article
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The relationship between power output and exercise tolerance is well described by a hyperbolic equation, establishing the critical power (CP) and the curvature constant (W'). Critical power represents the greatest metabolic rate that results in 'wholly-oxidative' energy provision. Wholly-oxidative considers the active organism in toto and means that energy supply through substrate-level phosphorylation reaches a steady-state, indicated by a lack of progressive intramuscular phosphocreatine breakdown. W' was initially described as an anaerobic work capacity but has subsequently been shown to be associated with the depletion of intramuscular energy stores as well as to be sensitive to alterations in oxygen delivery. Taken together, these two findings are consistent with the hypothesis that muscle oxygen saturation (SmO2), as measured by near-infrared spectroscopy (NIRS), is a viable means of estimating the power-duration relationship, and subsequently, time to exhaustion at a fixed pace.
... After compiling the results, researchers found subjects in the caffeine group had a higher work end power than the placebo group (increase of 10.7% p < 0.05). End power is a measurement that can be used to calculate critical power through critical power models [10]. ...
... Similarly to CP, FTP is not determined using a physiological test rather using a percentage of mean mechanical power output maintained over a 20-min time-trial (1). ventilatory threshold (Tvent) to percentages of the difference data between power at Tvent and maximum power (Pmax) attained during a VO2max test (4,23). There are multiple equations that can then be applied to this data to estimate CP, with varying results (9). ...
Article
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International Journal of Exercise Science 14(4): 45-59, 2021. The purpose of this investigation was to determine whether Critical Power (CP) and Functional Threshold Power (FTP) can be used interchangeably for a highly-trained group of cyclists and triathletes. CP was ascertained using multiple fixed load trials and FTP determined from a single cycling trial. Three different models for the determination of CP were initially addressed, one hyperbolic (Hmodel) and two linear (Jmodel and Imodel). The Jmodel was identified as most appropriate for a comparison with FTP. The Jmodel and FTP were not found to be interchangeable as ANOVA detected significant differences (282 ± 53 vs. 266 ± 55 W, p < 0.001) between these indices and the associated Bland-Altman 95% limits of agreement exceeded those set a priori. As the Jmodel was found to be consistently higher than FTP, a correction factor was posited to anticipate CP from FTP in this homogenous group of athletes using the mean bias (16 W). An alternate method for assessing CP trial intensities using Dmax as a proxy for ventilatory threshold is also proposed. The concept of both CP and FTP representing a maximal metabolic steady-state requires further investigation as the mechanical power at CP was significantly greater than at FTP.
... The 3-min all out test has also been proposed as a more time efficient way to derive CP and W′ (Vanhatalo et al. 2007(Vanhatalo et al. , 2008. The principal assumption in this test is that W′ or more accurately WEP (work above end test power) as it is known in this test, is fully depleted within the first 150 s and therefore during the last 30 s only CP (end test power) can be sustained. ...
Article
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Emerging trends in technological innovations, data analysis and practical applications have facilitated the measurement of cycling power output in the field, leading to improvements in training prescription, performance testing and race analysis. This review aimed to critically reflect on power profiling strategies in association with the power-duration relationship in cycling, to provide an updated view for applied researchers and practitioners. The authors elaborate on measuring power output followed by an outline of the methodological approaches to power profiling. Moreover, the deriving a power-duration relationship section presents existing concepts of power-duration models alongside exercise intensity domains. Combining laboratory and field testing discusses how traditional laboratory and field testing can be combined to inform and individualize the power profiling approach. Deriving the parameters of power-duration modelling suggests how these measures can be obtained from laboratory and field testing, including criteria for ensuring a high ecological validity (e.g. rider specialization, race demands). It is recommended that field testing should always be conducted in accordance with pre-established guidelines from the existing literature (e.g. set number of prediction trials, inter-trial recovery, road gradient and data analysis). It is also recommended to avoid single effort prediction trials, such as functional threshold power. Power-duration parameter estimates can be derived from the 2 parameter linear or non-linear critical power model: P ( t ) = W ′/ t + CP ( W ′—work capacity above CP; t —time). Structured field testing should be included to obtain an accurate fingerprint of a cyclist’s power profile.
... After compiling the results, researchers found subjects in the caffeine group had a higher work end power than the placebo group (increase of 10.7% p < 0.05). End power is a measurement that can be used to calculate critical power through critical power models (Vanhatalo et al., 2007). These results may be due central nervous system stimulation by caffeine and lowered sensitivity to pain which may be responsible for enhanced fatigue resistance. ...
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Hypothesis:The intake of caffeine can increase physical performance during athletic activity Methods:A search for primary sources was done using PubMed with MeSH terms. The search was limited to randomized controlled trials that were published between 2015 and 2020. After application of inclusion and exclusion criteria, seven articles were selected for this literature review. Results:Of the seven randomized controlled trials selected, six demonstrated caffeine ingestion led to a statistically significant increase in physical performance. One of the randomized controlled trials found no statistically significant relationship between caffeine and run timings. The level set for statistical significance for this literature review was set to p < 0.05.Conclusion: With regards to the results of the selected studies, caffeine was shown to have ergogenic activity and was able to increase physical performance during exercise and sporting competition through multiple mechanisms. Further research should be done with greater sample sizes to determine the effect of rate of metabolism on caffeine activity and to compare caffeine responders and non-responders.
... Clark and colleagues performed a series of studies on the effect of previous exercise in the heavy intensity domain on critical power, the boundary between the heavy and the severe intensity domain (Clark et al., 2018;Clark, Vanhatalo, Thompson, Joseph, et al., 2019;. They showed that the power at the end of a 3-min all out test, which is a measure of critical power (Vanhatalo et al., 2007) was decreased after two hours of exercise in the heavy intensity domain (Clark et al., 2018). The same group then replicated the result that the magnitude of change in critical power was not correlated to changes in muscle glycogen , but critical power did not change if CHO were ingesting during the 2 h fatiguing task, and it was not reduced after only 40 or 80 min (Clark, Vanhatalo, Thompson, Joseph, et al., 2019). ...
Thesis
The objectives of this thesis were to investigate the performance determinants of trail running, and to evaluate the changes in running economy following prolonged endurance running exercise. First, we tested elite road and trail runners for differences in performance factors. Our results showed that elite trail runners are stronger than road runners, but they have greater cost of running when running on flat ground. In the second study, we evaluated the performance factors that predicted performance in trail running races of different distances, ranging from 40 to 170 km. We found that maximal aerobic capacity was a determinant factor of performance for races up to 100 km. Performance in shorter races, up to approximately 55 km, was also predicted by lipid utilization at slow speed, while performance in the 100 km race was also predicted by maximal strength and body fat percentage. The most important factors of performance for races longer than 100 km are still debated. We also tested the effects of trail running race distance on cost of locomotion, finding that cost of running increased after races up to 55 km, but not after races of 100-170 km. Finally, we tested the. effects of two different exercise modalities, cycling and running, on cost of locomotion, after 3 hours of intensity-matched exercise. Cost of locomotion increased more following cycling than running, and the change in cost of locomotion was related to changes in cadence and loss of force production capacity.
... In the present study, the speed measured at the last 5 min of the T10 retest occurred at approximately 51% Δ (range: 25-78% Δ). Previous research reported that CS occurred at 41% Δ (Pringle & Jones, 2002), and CP occurred at 46% Δ (Poole et al., 1988;Vanhatalo et al., 2007), and at 43% Δ (range: 28-65% Δ) of the end-test power (Burnley et al., 2006). Therefore, although the literature suggests that the CS occurs at approximately 50% Δ, the gas exchange individual responses at this exercise intensity may vary considerably (Smith & Jones, 2001), as CS is located considerably above the GET in not highly trained individuals. ...
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We assessed the reliability and validity of a 10-min submaximal treadmill test (T10) to predict critical speed (CS). Forty-two runners completed a familiarization trial plus two experimental trials (T10 test and T10 retest). Reliability between the T10 test and T10 retest was assessed using coefficient of variation (CoV), limits of agreement (LoA) and intraclass correlation (ICC). For validity, the speed from the T10 retest was compared with the CS determined from 3 runs on separate days on a running track over 1200, 2400, and 3600 m (field test). Reliability between the T10 test and T10 retest showed a CoV of 3.4%, LoA of 0.05 ± 0.39 m.s−1, and an ICC of 0.93. Validity showed that speed (m.s−1) (T10 retest: 3.86 ± 0.51; field test: 3.88 ± 0.55) did not differ between trials. The T10 retest was highly correlated with the field test, r = 0.93, and the standard error for the estimate of CS using the T10 retest was 0.06 m.s−1, and the LoA was 0.02 ± 0.40 m.s−1. A submaximal 10-min treadmill test (T10) provides a practical and accessible method to estimate CS.
... %V � O 2 max and %[La -] max were calculated as the highest 30s average achieved during the 3AOT and T lim tests, relative to and [La -] max reached in INC test in both hypoxia and normoxia conditions. In the 3AOT test, CP was calculated as the average power output for the final 30s of the test, and W' was calculated as the power-time integral above end power [24]. ...
Article
We investigated the effects of hypoxia on matched-severe intensity exercise and on the parameters of the power-duration relationship. Fifteen trained subjects performed in both normoxia and normobaric hypoxia (FiO2=0.13, ~3000 m) a maximal incremental test, a 3 min all-out test (3AOT) and a transition from rest to an exercise performed to exhaustion (Tlim) at the same relative intensity (80%∆). Respiratory and pulmonary gas-exchange variables were continuously measured (K5, Cosmed, Italy). Tlim test’s V̇O2 kinetics was calculated using a two-component exponential model. V̇O2max (44.1±5.1 vs. 58.7±6.4 ml.kg-1.min-1, p<0.001) was decreased in hypoxia. In Tlim, time-to-exhaustion sustained was similar (454±130 vs. 484±169 s) despite that V̇O2 kinetics was slower (τ1: 31.1±5.8 vs. 21.6±4.7 s, p<0.001) and the amplitude of the V̇O2 slow component lower (12.4±5.4 vs. 20.2±5.7 ml.kg-1.min-1, p<0.05) in hypoxia. CP was reduced (225±35 vs. 270±49 W, p<0.001) but W’ was unchanged (11.3±2.9 vs. 11.4±2.7 kJ) in hypoxia. The changes in CP/V̇O2max were positively correlated with changes in W’ (r = 0.58, p<0.05). The lower oxygen availability had an impact on aerobic related physiological parameters, but exercise tolerance is similar between hypoxia and normoxia when the relative intensity is matched despite a slower V̇O2 kinetics in hypoxia.
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We examined the application of a land-based swimming ergometer 3-min all-out test to determine physiological predictors of swimming performance. Fourteen young elite swimmers participated (males: n=6; females: n=8). The swimmers completed two 3-min upper-body all-out tests on a swimming ergometer. Additionally, the swimmers completed freestyle swim races ranging from 50 m to 1500 m. High test-retest reproducibility (r=0.98 and coefficient of variation values <7.5%) was evident for ergometer derived peak, mean and critical power. Very strong correlations (r>0.87, p<0.001) were obtained between the 200-, 400-, 800- and 1500-m swimming performances and derived critical speed. Moreover, correlations were found between peak force and peak power and 50-m performance, in addition to critical power and performance for all distances. The critical speed was the dominant predictor of 200- to 1500-m performances (r=0.84−0.99). In conclusion, the land-based 3-min all-out swimming ergometer test is reliable and valid in predicting swimming performance in competitive swimmers and evaluates important physiological components in swimmers independent of technical abilities.
Article
Introduction: The ergogenic effects of respiratory alkalosis induced by prior voluntary hyperventilation (VH) are controversial. This study examined the effects of prior VH on derived parameters from the 3-min all-out cycling test (3MT). Methods: Eleven men ([Combining Dot Above]V˙O2max = 46 ± 8 mL⋅kg-1⋅min-1) performed a 3MT preceded by 15-min of rest (CONT) or voluntary hyperventilation (V˙E = 38 ± 5 L⋅min-1) with PETCO2 reduced to 21 ± 1 mmHg (HYP). End-test power (EP; synonymous with critical power) was calculated as the mean power output over the last 30-s of the 3MT, and the work done above EP (WEP; synonymous with W') was calculated as the power-time integral above EP. Results: At the start of the 3MT, capillary blood PCO2 and [H+] were lower in HYP (25.2 ± 3.0 mmHg, 27.1 ± 2.6 nmol⋅L-1) than CONT (43.2 ± 2.0 mmHg, 40.0 ± 1.5 nmol⋅L-1) (P < 0.001). At the end of the 3MT, blood PCO2 was still lower in HYP (35.7 ± 5.4 mmHg) than CONT (40.6 ± 5.0 mmHg) (P < 0.001). WEP was 10% higher in HYP (19.4 ± 7.0 kJ) than CONT (17.6 ± 6.4 kJ) (P = 0.006), whereas EP was 5% lower in HYP (246 ± 69 W) than CONT (260 ± 74 W) (P = 0.007). The ΔWEP (J·kg-1) between CONT and HYP correlated positively with the PCO2 immediately before the 3MT in HYP (r = 0.77, P = 0.006). Conclusion: These findings suggest that acid-base changes elicited by prior voluntary hyperventilation increase WEP but decrease EP during the all-out 3MT.
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Acute foam rolling protocols may increase range of motion without a negative impact on muscle performance. The main purpose of the present study was to investigate the acute effects of foam rolling on cycling performance (mean power and maximal power), affect and perceived exertion. A secondary aim was to assess the effect of foam rolling on post-exercise muscle soreness. In a random order, ten recreationally trained cyclists (age: 26 ± 5 years; height 1.76 ± 0.06 m; total body mass 78.3 ± 19.8 kg; cycling experience: 5.6 ± 5.3 years; 4.1 ± 1.3 cycling sessions per week and 1.4 ± 1.4 strength sessions per week) were submitted to the following experimental conditions (separated by one week) before performing a three-minute all-out cycling test: foam rolling or control. During foam rolling protocol, participants were instructed to roll back and forth on one leg and to place the opposite leg crossed over, from the proximal to the distal portion of the rectus femoris and vastus lateralis during one set of sixty seconds for each muscle group. Feeling scale (10 min pre and post-test), CR-10 scale of perceived exertion (10 min post-test), pressure pain threshold (pre and 24 h post-test) and mean/maximal power were assessed. No significant differences were observed between conditions for mean and maximal power, affect, perceived exertion, and pressure pain threshold (all p>0.05). In conclusion, a pre-exercise acute session of self-myofascial release does not improve performance and post-exercise muscle soreness of recreationally trained cyclists.
Article
We tested the hypothesis that during whole body exercise, the balance between muscle O 2 supply and metabolic demand may elucidate intensity domains, reveal a critical metabolic rate, and predict time to exhaustion. Seventeen active, healthy volunteers (12 male, 5 female; 32±2 years) participated in two distinct protocols. Study 1 (N=7) consisted of constant work rate cycling in the moderate, heavy, and severe exercise intensity domains with concurrent measures of pulmonary VO 2 and local %SmO 2 (via NIRS) on quadriceps and forearm sites. Average %SmO 2 at both sites displayed a domain dependent response (P<0.05). A negative %SmO 2 slope was evident during severe domain exercise but was positive during exercise below critical power (CP) at both muscle sites. In study 2 (N=10), quadriceps and forearm site %SmO 2 was measured during 3 continuous running trials to exhaustion and 3 intermittent intensity (ratio = 60s severe: 30s lower intensity) trials to exhaustion. Intensity dependent negative %SmO 2 slopes were observed for all trials (P<0.05), and predicted zero slope at critical velocity. %SmO 2 accurately predicted depletion and repletion of %D´ balance on a second-by-second basis (R ² = 0.99, P<0.05; both sites). Time to exhaustion predictions during continuous and intermittent exercise were either not different or better with %SmO 2 (SEE < 20.52sec for quad, < 44.03sec for forearm) vs running velocity (SEE < 65.76sec). Muscle O 2 balance provides a dynamic physiological delineation between sustainable and unsustainable exercise (consistent with a 'critical metabolic rate'), and predicts real time depletion and repletion of finite work capacity and time to exhaustion.
Article
We evaluated the reliability of an over-ground running three-minute all-out test (3MT) and compared this to traditional multiple-visit testing to determine the critical speed (CS) and distance >CS (D´). Using a novel energetics model during the 3MT, critical power (CP) and work >CP (W´) were also evaluated for reliability and compared to the multiple-visit tests. Over-ground running speed was measured using Global Positioning Systems during fixed-speed trials on a 400 m track to exhaustion, at four intensities corresponding to: i) maximal oxygen uptake (O2max) (Vmax), ii) 110% O2max (110%Vmax), iii) Δ70% (i.e. 70% of the difference between gas exchange threshold and Vmax) and iv) Δ85%. The participants subsequently performed the 3MT across two days to determine its reliability. There were no differences between the multiple-visit testing and the 3MT for CS (P = 0.328) and D´ (P = 0.919); however, CP (P = 0.02) and W´ (P < 0.001) were higher in the 3MT. The reliability of the 3MT was stable (P > 0.05) between trials for all variables, with coefficient of variation ranging from 2.0 to 8.1%. The current over-ground energetics model can reliably estimate CP and W´ based on GPS speed data during the 3MT, which supports its use for most athletic training and monitoring purposes. The reliability of the over-ground running 3MT for power- and speed-related indices was sufficient to detect typical training adaptations; however, it may overestimate CP (∼ 25 W) and W´ (∼ 7 kJ) compared to multiple-visit tests.
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New findings: What is the central question of this study? Does muscle size, maximal force and exercise intensity influence the recovery time constant for the finite impulse above critical torque (τIET')? What is the main finding and its importance? This study showed that muscle size and maximal strength have different influences on the parameters of the hyperbolic torque - Tlim relationship. Greater muscle size and maximal strength, as well as exercise at an intensity of 60% MVC, prolong τIET' during intermittent isometric exercise. Abstract: Muscle perfusion and O2 delivery limitations through muscle force generation appear to play a major role in defining the hyperbolic torque - Tlim relationship. Therefore, we aimed to determine the influence of muscle size and maximal strength on the recovery time constant for the finite impulse above critical torque (τIET'). Ten men participated in the study and performed intermittent isometric tests until task-failure (Tlim ) for the knee-extensors (KE 35% and 60% MVC) and plantar flexors (PF 60% MVC). The τIET' was determined for each of these Tlim tests using the IET'BAL model. The IET' (9738 ± 3080 vs 2959 ± 1289 N · m · s) and ET (84.5 ± 7.1 vs 74.3 ± 12.7 N · m) were significantly lower for PF compared to KE (P < 0.05). Exercise tolerance (Tlim ) was significantly longer for PF (239 ± 81 s) than KE (150 ± 55 s) at 60% MVC, and significantly longer for KE at 35% MVC (641 ± 158 s) than 60% MVC. The τIET' was significantly faster at 35% MVC (641± 177 s) than 60% MVC (1840 ± 354 s) for KE, both of which were significantly slower than PF 60% MVC (317 ± 102 s). This study showed that τIET' during intermittent isometric exercise is slower with greater muscle size and maximal strength. This article is protected by copyright. All rights reserved.
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Predicted critical power (CP) varies up to 5-20% depending on the preferredmathematical model and different time to exhaustion intervals. Those differentiationrates related to CP estimations cause some contradictory results. The aim of this studywas to evaluate the relationship between CP predictions obtained from three differentexhaustion approaches (short: 2-10 minutes; medium: 2-15 minutes; long: 2-20minutes) using five mathematical models (linear total work (CP1), linear 1/time (CP2),nonlinear 2-parameter (CP3), nonlinear 3-parameter (CP4) and exponential (CP5)), andother indices such as maximal lactate steady-state (MLSS), ventilatory threshold (VT),respiratory compensation point (RCP) and critical threshold (CT). 10 well trained malecyclists voluntarily participated in the study. VT and RCP levels of the athletes weredetermined by incremental ramp tests. Constant work rate exercises were applied ondifferent days to determine maximal oxygen uptake, peak power output, MLSS, CT andCP. Obtained data were tested by validity analysis. As mathematical models andexhaustion intervals changed, the CP predictions varied up to 20%. Except the CP4,other CP estimations were higher than the work rates corresponding to the MLSS andVT (p<0.05). The CP5, which was estimated by short exhaustion interval, correspondedto the work rates belonging to the CT and RCP (p>0.05; standard error of estimate ~4%and r>0.95). Regardless of the preferred exhaustion interval, CP predictions obtainedfrom the other mathematical models were insufficient to estimate any of anaerobicthreshold indices (p<0.05). As a result, the CP5 estimated by short exhaustion intervalcan be used to predict the work rates corresponded to the CT and RCP. It was notappropriate to estimate the other threshold intensities by the CP. Keywords: Critical threshold, Critical power, Maximal lactate steady-state, Respiratorycompensation point, Ventilatory threshold PDFAvailable from: https://www.researchgate.net/publication/354819716_Farkli_Tukenme_Araliklari_ve_Matematiksel_Model_Kullaniminin_Kritik_Guc_Tahminlerine_Etkisi [accessed May 04 2022].
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Critical power (CP) delineates the heavy and severe exercise intensity domains, and sustained work rates above CP result in an inexorable progression of oxygen uptake to a maximal value and, subsequently, the limit of exercise tolerance. The finite work capacity above CP, W′, is defined by the curvature constant of the power-duration relationship. Heavy or severe exercise in a hot environment generates additional challenges related to the rise in body core temperature (T c ) that may impact CP and W′. The purpose of this study was to determine the effect of elevated T c on CP and W′. CP and W′ were estimated by end-test power (EP; mean of final 30s) and work above end-test power (WEP), respectively, from 3-min "all-out" tests performed on a cycle ergometer. Volunteers (n = 8, 4 female) performed the 3-min tests during a familiarization visit and two experimental visits (Thermoneutral vs Hot, randomized crossover design). Before experimental 3-min tests, subjects were immersed in water (Thermoneutral: 36°C for 30 min; Hot: 40.5°C until T c was ≥ 38.5°C). Mean T c was significantly greater in Hot compared to Thermoneutral (38.5±0.0°C vs. 37.4±0.2°C; mean±SD, P<0.01). All 3-min tests were performed in an environmental chamber (Thermoneutral: 18°C, 45% RH; Hot: 38°C, 40% RH). EP was similar between Thermoneutral (239 ± 57W) and Hot (234 ± 66W; P = 0.55). WEP was similar between Thermoneutral (10.9 ± 3.0 kJ) and Hot (9.3 ± 3.6; P = 0.19). These results suggest that elevated T c has no significant impact on EP or WEP.
Thesis
Purpose: The authors compared the effects of active preconditioning with local and systemic hypoxia during submaximal cycling. Methods: On separate visits, 14 active participants completed 4 trials. Each visit was composed of 1 preconditioning phase followed, after 40 minutes of rest, by 3 × 6-minute cycling bouts (intensity = 85% of critical power; rest = 6 min). The preconditioning phase consisted of 4 × 5-minute cycling bouts at 1.5 W·kg-1 (rest = 5 min) in 4 conditions: control (no occlusion and normoxia), blood flow restriction (60% of total occlusion), HYP (systemic hypoxia; inspired fraction of oxygen = 13.6%), and blood flow restriction + HYP (local and systemic hypoxia combined). Results: During the preconditioning phase, there were main effects of both systemic (all P < .014) and local hypoxia (all P ≤ .001) on heart rate, arterial oxygen saturation, leg discomfort, difficulty of breathing, and blood lactate concentration. Cardiorespiratory variables, gross efficiency, energy cost, and energy expenditure during the last minute of 6-minute cycling bouts did not differ between conditions (all P > .105). Conclusion: Local and systemic hypoxic stimuli, or a combination of both, during active preconditioning did not improve physiological responses such as cycling efficiency during subsequent submaximal cycling.
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Background In cycling, performance can change with the adaptation of the bicycle to the individual, as well as the physiological characteristics of the individual. Aim The aim of the present study was to determine the effects of exercise training and bike fitting on cycling performance in recreational cyclists. Methods A total of 16 recreational cyclists were included in the present study. Individuals were divided into 2 groups as intervention and control groups with a simple random method. To the intervention group, exercise training for 3 days a week for 8 weeks and bike fitting was applied with video analysis method. On the other hand, to the control group, only bike fitting was applied with video analysis method. Cycling performance was evaluated with Functional Threshold Power Test (FTP), Lactate Threshold Heart Rate (LTHR), 10 Mile Time Trial Test (10 Mile TT), and critical powertest. Evaluations were made twice, before and after the training. Results After 8 weeks of training, significant differences were found in FTP (p = 0.008), LTHR (p = 0.044), 10 Mile TT (p = 0.038), and critical power (p = 0.008) tests in intervention group, and in FTP (p = 0.028) in control group. When the cycling performances of the groups were compared, only LTHR results were found to decrease in favor of intervention group (p = 0.017). Conclusion The exercise program developed for recreational cyclists and individual adaptations for bicycle ergonomics are important in terms of increasing cycling performance. We believe that strength training provided along with bike fittng in cyclists will be beneficial particularly in reducing fatigue.
Purpose: The critical power (CP) concept has been extended from cycling to the running field with the development of wearable monitoring tools. Particularly, the Stryd running power meter and its 9/3-minute CP test is very popular in the running community. Locating this mechanical threshold according to the physiological landmarks would help to define each boundary and intensity domain in the running field. Thus, this study aimed to determine the CP location concerning anaerobic threshold, respiratory compensation point (RCP), and maximum oxygen uptake (VO2max). Method: A group of 15 high-caliber athletes performed the 9/3-minute Stryd CP test and a graded exercise test in 2 different testing sessions. Results: Anaerobic threshold, RCP, and CP were located at 73% (5.41%), 86.82% (3.85%), and 88.71% (5.84%) of VO2max, respectively, with a VO2max of 66.3 (7.20) mL/kg/min. No significant differences were obtained between CP and RCP in any of its units (ie, in watts per kilogram and milliliters per kilogram per minute; P ≥ .184). Conclusions: CP and RCP represent the same boundary in high-caliber athletes. These results suggest that coaches and athletes can determine the metabolic perturbance threshold that CP and RCP represent in an easy and accessible way.
Article
Purpose Current aerobic fitness testing during ISS flight does not assess either critical power (CP) or work capacity above CP (W′). Both CP and W′ have been demonstrated to be highly related to time of performance during ground analogues of lunar or planetary work tasks. This study was conducted to determine if CP measures differ between trials performed without (Control) and with (WMD) metabolic gas exchange data collection during 3-min supramaximal cycle ergometer tests. A secondary aim was to determine if peak oxygen consumption (VO2peak) can be ascertained from a 3-min CP test. Methods Subjects (n = 19: 11 M, 8 F) were young and healthy (VO2peak 34.7 ± 7.7 ml/kg/min). Each completed four cycle trials: a ramp test to determine VO2peak, a familiarization trial of the 3-min CP test, and two additional CP tests (control and WMD). Critical power (watts) was calculated as the mean power during the last 30 s of the CP tests. W′ was calculated as the power-time integral above CP. Results No differences (P = 0.11) were found for CP watts between the WMD trial and control conditions (172 ± 46 W, 169 ± 49 W, respectively). Similarly, no differences were found for W’ (11.3 ± 5.4 WMD, 11.7 ± 4.4 kJ control, P = 0.61) and peak watts (627 ± 326 W WMD, 636 ± 335 W control, P = 0.84). No differences (P = 0.23) were observed between VO2peak measured during the CP test (2517 ± 576 ml/min) and that of the initial ramp test (2564 ± 550 ml/min). Conclusions CP, peak watts, and W’ values were not influenced by gas exchange measurement performed during CP tests. It also appears that VO2peak can be attained using the 3-min protocol. Consideration should be given towards CP testing on ISS and future missions.
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The tolerable work duration (t) for high-intensity cycling is well described as a hyperbolic function of power (W): W = (W'.t-1) + Wa, where Wa is the upper limit for sustainable power (lying between maximum W and the threshold for sustained blood [lactate] increase, theta lac), and W' is a constant which defines the amount of work which can be performed greater than Wa. As training increases the tolerable duration of high-intensity cycling, we explored whether this reflected an alteration of Wa, W' or both. Before and after a 7-week regimen of intense interval cycle-training by healthy males, we estimated ( ) theta lac and determined maximum O2 uptake (mu VO2); Wa; W'; and the temporal profiles of pulmonary gas exchange, blood gas, acid-base and metabolic response to constant-load cycling at and above Wa. Although training increased theta lac (24%), mu VO2 (15%) and Wa (15%), W' was unaffected. For exercise at Wa, a steady state was attained for VO2, [lactate] and pH both pre- and post-training, despite blood [norepinephrine] and [epinephrine] ([NE], [E]) and rectal temperature continuing to rise. For exercise greater than Wa, there was a progressive increase in VO2 (resulting in mu VO2 at fatigue), [lactate], [NE], [E] and rectal temperature, and a progressive decrease for pH. We conclude that the increased endurance capacity for high-intensity exercise following training reflects an increased W asymptote of the W-t relationship with no effect on its curvature; consequently, there is no appreciable change in the amount of work which can be performed above Wa.(ABSTRACT TRUNCATED AT 250 WORDS)
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For high-intensity cycling, power (P) can be well described as a hyperbolic function of tolerable work duration (t): P=(W'/t) + PLL W' is a constant and PLL is the lower limit (asymptote) for P which is shown to occur at an O2 uptake ([Vdot]O2) lying above the estimated threshold for sustained blood [lactate] increase (ΘIac) but below the maximum [Vdot]O2 ([Vdot]O2max) obtained during incremental cycling. This relation suggests that, above PLL, only a certain amount of work (W') can be accomplished regardless of its rate of performance, with [Vdot]O2 max being attained at fatigue. Hence, PLL defines a point of discontinuity in the [Vdot]O2-P relation for supra-ΘIac exercise. In order to determine the factors responsible for the continued increase in [Vdot]O2 (to the maximum fatiguing value) at power outputs >PLL, we documented the temporal profiles of metabolic (rectal temperature; blood [lactate], [pyruvate], [norepinephrine], [epinephrine]) and respiratory ([Vdot]E; [Vdot]O2; [Vdot]CO2; blood pH, PCO2, [HCO3 ]) responses to constant-load cycling in eight healthy males at PLL (24 min) and slightly above PLL (to exhaustion, i.e. < 24 min). [Vdot]O2 manifested a delayed steady state at PLL, despite catecholamine levels and core temperature continuing to increase throughout; blood [lactate] and pH plateaued, however. In contrast, [Vdot]O2 continued to increase slowly for the duration of the exercise > PLL and attained [Vdot]O2max. The response patterns at PLL, and > PLL suggest that the slow phase of the [Vdot]O2 response is best correlated with the temporal profile of blood [lactate], and hence the site and route of metabolism of this variable may play a major role in the [Vdot]O2 kinetics for high-intensity exercise.
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In cycle exercise, it has been suggested that critical power, maximal lactate steady state, and lactate turnpoint all demarcate the transition between the heavy exercise domain (in which blood lactate is elevated above resting values but remains stable over time) and the very heavy exercise domain (in which blood lactate increases continuously throughout constant-intensity exercise). The purpose of the present study was to assess the level of agreement between critical velocity (CV), maximal lactate steady-state velocity (MLSSV), and lactate turnpoint velocity (LTPV) during treadmill running. Eight male subjects [mean (SD) age 28 (5) years, body mass 71.2 (8.0) kg, maximum oxygen uptake 54.9 (3.2) ml.kg(-1).min(-1)) performed an incremental treadmill test for the determination of LTPV (defined as a sudden and sustained increase in blood lactate concentration ([La]) at approximately equals 2.0-5.0 mM). The subjects returned to the laboratory on eight or nine occasions for the determination of CV and MLSSV. The CV was determined from four treadmill runs at velocities that were chosen to result in exhaustion within 2-12 min. The MLSSV was determined from four or five treadmill runs of up to 30 min duration and defined as the highest velocity at which blood [La] increased by no more than 1.0 mM after between 10 and 30 min of exercise. Analysis of variance revealed no significant differences between [mean (SD)] CV [14.4 (1.1) km.h(-1)], MLSSV [13.8 (1.1) km.h(-1)] and LTPV [13.7 (0.6) km.h(-1)]. However, the bias +/-95% limits of agreement for comparisons between CV and MLSSV [0.6 (2.2) km.h(-1)], CV and LTPV [0.7 (2.7) km.h(-1)], and MLSSV and LTPV [0.1 (1.8) km.h(-1)] suggest that the extent of disagreement is too great to allow one variable to be estimated accurately from another in individual subjects. Direct determination of MLSSV is necessary if precision is required in experimental studies.
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The severe exercise intensity domain may be defined as that range of work rates over which .VO(2max) can be elicited during constant-load exercise. The purpose of this study was to help characterize the .VO(2) response within this domain. Eleven participants performed cycle ergometer exercise tests to fatigue at several discrete work rates between 95% and 135% of the maximum power (P(max)) achieved during an incremental exercise test. As previously demonstrated, the relationship between power and time to fatigue was hyperbolic. The asymptote of power (critical power, P(critical)) was 198 +/- 44 W. The rapidity of the .VO(2) response increased systematically at higher work rates such that the relationship between power and time to .VO(2max) was also well fit by a hyperbola. The power asymptote of this relationship (196 +/- 42 W) was not different from P(critical)(P > 0.05). The two hyperbolic relationships converged at 342 +/- 70 W (136% P(max)). These data suggest that, for this population of male and female university students, the upper boundary of the severe exercise intensity domain is approximately 136% P(max). This upper boundary is the highest work rate for which exercise duration is prolonged sufficiently (in this study, 136 +/- 17 s) to allow .VO(2) to rise to its maximal value. The lower boundary for severe exercise is just above P(critical), which is the highest work rate that is sustainable for a prolonged duration and that will not elicit .VO(2max).
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The curvature of the power–time (P–t) relationship (W′) has been suggested to be constant when exercising above critical power (CP) and to represent the anaerobic work capacity (AWC). The aim of this study was to compare W′ to (1) the total amount of work performed above CP (W 90s′) and (2) the AWC, both determined from a 90s all-out fixed cadence test. Fourteen participants (age 30.5±6.5 years; body mass 67.8±10.3 kg), following an incremental VO2max ramp protocol, performed three constant load exhaustion tests set at 103±3, 97±3 and 90±2% P-VO2max to calculate W′ from the P–t relationship. Two 90s all-out efforts were also undertaken to determine W 90s′ (power output—time integral above CP) and AWC (power output—time integral above the power output expected from the measured VO2). W′ (13.6±1.3 kJ) and W 90s′ (13.9±1.1 kJ; P=0.96) were not significantly different but were lower than AWC (15.9±1.2 kJ) by 24% (P=0.03) and 17%, respectively (P=0.04). All these variables were correlated (P<0.001) but great extents of disagreement were reported (0.2±6.4 kJ between W′ and W 90s′, 2.3±7.2 kJ between W′ and AWC, and 2.1±4.3 kJ between W 90s′ and AWC). The underestimation of AWC from both W′ and W 90s′ can be explained by the aerobic inertia not taking into consideration when determining the two latter variables. The low extents of agreement between W′, W 90s′ and AWC mean the terms should not be used interchangeably.
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The aims of this study were to determine the most appropriate duration for the measurement of the maximal accumulated O2 deficit (MAOD), which is analogous to the anaerobic capacity, to ascertain the effects of mass, fat free mass (FFM), leg volume (V leg) and lower body volume (V 1b) on anaerobic test performance, to examine the reproducibility for peak power output ($$\dot W_{{\text{peak}}}$$) or maximal anaerobic power using an air-braked cycle ergometer and to produce approximations for the percentages of aerobic and anaerobic metabolism during exercise of short duration but high intensity. A group of 12 endurance trained cyclists [mean age 25.1 (SD 4.6) years; mean body mass 73.43 (SD 7.12) kg; mean maximal oxygen consumption 5.12 (SD 0.35) l·min−1; mean body fat 12.5 (SD 4.1) %] accordingly performed four counterbalanced treatments of 45, 60, 75 and 90 s of maximal cycling on an air-braked ergometer. The mean O2 deficit of 3.52 l for the 45-s treatment was significantly less (P < 0.01) than those for the 60 (3.75 l), 75 (3.80 l) and 90-s (3.75 l) treatments. These data therefore indicate that in predominantly aerobically trained subjects the O2 deficit attains a plateau after 60 s of maximal cycling on an air-braked ergometer. Statistically significant interclass correlation coefficients (P
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The basis of the critical power concept is that there is a hyperbolic relationship between power output and the time that the power output can be sustained. The relationship can be described based on the results of a series of 3 to 7 or more timed all-out predicting trials. Theoretically, the power asymptote of the relationship, CP (critical power), can be sustained without fatigue; in fact, exhaustion occurs after about 30 to 60 minutes of exercise at CP. Nevertheless, CP is related to the fatigue threshold, the ventilatory and lactate thresholds, and maximum oxygen uptake (VO2max), and it provides a measure of aerobic fitness. The second parameter of the relationship, AWC (anaerobic work capacity), is related to work performed in a 30-second Wingate test, work in intermittent high-intensity exercise, and oxygen deficit, and it provides a measure of anaerobic capacity. The accuracy of the parameter estimates may be enhanced by careful selection of the power outputs for the predicting trials and by performing a greater number of trials. These parameters provide fitness measures which are mode-specific, combine energy production and mechanical efficiency in 1 variable, and do not require the use of expensive equipment or invasive procedures. However, the attractiveness of the critical power concept diminishes if too many predicting trials are required for generation of parameter estimates with a reasonable degree of accuracy.
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The hyperbolic relationship between power output (P) and time to exhaustion (t) is described as t = W'/(P-theta PA). The purpose of this study was to determine the stability of estimations of estimates of theta PA and W', said to reflect maximal sustainable power and anaerobic capacity, respectively. Thirteen women and 13 men performed five bouts of cycling exercise to exhaustion. Individual theta PA and W' were calculated from the results of these five bouts (Trial 1). These procedures were repeated (Trial 2). For both sexes, Trial 2 estimates of theta PA were 5 to 6% higher than Trial 1 estimates, but they were highly correlated. Mean W' estimates were the same in Trials 1 and 2, with higher trial-to-trial correlations in the men than in the women.
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