Critical Power in Laboratory and Field Conditions Using Single-visit Maximal Effort Trials

Abstract

To compare critical power (CP) and the maximum work performed above CP (W') obtained from a single-visit laboratory test with a single-visit field test, 10 trained cyclists (V˙O(2max) 63.2±5.5 mL·min(-1)·kg(-1)) performed a laboratory and a field test. The laboratory test consisted of 3 trials to exhaustion between 2-15 min and the field test comprised 3 maximal efforts of 2, 6 and 12 min, where power output was measured using a mobile power meter. CP and W' were estimated using 3 mathematical models (hyperbolic, linear work-time, linear power -1/time). The agreement between laboratory and field conditions was assessed with the 95% limits of agreement (LoA). CP was not significantly different between laboratory (280±33 W) and field conditions (281±28 W) (P=0.950). W' was significantly higher in laboratory (21.6±7.1 kJ) compared to field conditions (16.3±7.4 kJ) (P=0.013). The bias was -2.8±27 W (95% LoA: -55 to 50 W) and 6.4±5.1 kJ (95% LoA: -3.5 to 16.4 kJ) for CP and W', respectively. No differences between the mathematical models were found for CP and W' (P=0.054-1.000). Although CP was not significantly different between conditions, a high random variation does not support its interchangeable use. The mathematical model used has no influence on estimates of CP and W'.

Reliability of the Single-Visit Field Test of Critical Speed in Trained and Untrained Adolescents

“…For example, in a young adolescent athlete with a CS of 3.17 m·s ) in the trained and untrained participants, respectively. Finally, our study revealed that the distance above critical speed (D′) is less reliable than CS, which is in agreement with previous studies [15,16,24,25]. On average, the CV ranged from 9.3% to 13.6% and the 95% CI from 7.7% to 24.6%, indicating a limited reliability and thus practical relevance.…”

“…An additional explanation for the inconsistency found in untrained athletes might be the order of the prediction trials. While some studies started with the longest trial [15,16], others started with the shortest trial or randomly applied the trials [24,25]. Starting with the shortest trial in the present study, could have affected the untrained athletes due to inexperience with maximal efforts and this in turn might impact consistency.…”

“…On average, the CV ranged from 9.3% to 13.6% and the 95% CI from 7.7% to 24.6%, indicating a limited reliability and thus practical relevance. The reasons for this remain unclear but previous studies excluded residual fatigue, standing start during cycling, duration of the prediction trials and familiarization as possible factors [16,25].…”

Avaliação da velocidade crítica de corrida em pista e esteira: perfis fisiológicos e relações com o desempenho em 3000 metros

“…This difference supported the conclusion that tolerance is lower during exercise in the severe field in cycle ergometer (laboratory), influencing changes in the result of the mathematical model and, therefore, in the CP values (adjustment slope) and W '(adjustment intercept). However, Karsten et al 21 and Triska et al 22 could not confirm the existence of differences between CP values assessed in different contexts. For Karsten et al 21 , even differences observed for t Lim , final [La-] and pedal power during velodrome (3, 7 and 12 min) and laboratory (80, 100 and 105% iVȮ 2 max) were determinant to change the CP value, even analyzing it by different linear adjustments (W-t Lim and W-1/ t Lim ) in velodrome (234.0±24.4 vs. 235.0±24.1 W) and laboratory (234.0 ± 25.5 vs. 236.0 ± 29.1 W).…”

“…For Karsten et al 21 , even differences observed for t Lim , final [La-] and pedal power during velodrome (3, 7 and 12 min) and laboratory (80, 100 and 105% iVȮ 2 max) were determinant to change the CP value, even analyzing it by different linear adjustments (W-t Lim and W-1/ t Lim ) in velodrome (234.0±24.4 vs. 235.0±24.1 W) and laboratory (234.0 ± 25.5 vs. 236.0 ± 29.1 W). In the study by Triska et al 22 , the evaluation of CP in laboratory and field conditions provided similar values (280W vs. 281W, respectively); however, the authors warned against reciprocal use due to the high variability of ~7% (95% CI: -55 to 50W) in the CP evaluation between contexts. In the present study, it was observed that many of the information described for cycling apply to track and treadmill running conditions.…”