High agreement between laboratory and field estimates of critical power in cycling

The purpose of this study was to investigate the level of agreement between field-based and laboratory-based estimates of critical power (CP) in cycling. Subjects were fourteen trained cyclists (age 40 ± 7 yrs; body mass 70.2 ± 6.5 kg; V& O2 max 3.8 ± 0.48 L·min-1). Laboratory-based CP was estimated from three constant work-rate tests performed on a cycle ergometer at 80%, 100% and 105% of maximal aerobic power (MAP). Field-based CP was estimated from three all-out tests performed on an outdoor velodrome over fixed durations of 3, 7 and 12 minutes. Using the linear work limit (W ) versus time limit (T ) relation and the inverse time (1/t) versus power (P) models, field-based CP1 and CP2 values did not significantly differ from laboratory-based values (234 ± 24.4W vs. 234 ± 25.5W (CP1); P < 0.001, r2 = 0.95; limits of agreement [LOA], −10.98 to 10.8 W and 236 ± 29.1W vs. 235 ± 24.1W (CP2); P < 0.001, r2 = 0.95 [LOA], -13.88 to 17.3 W. Data suggest that employing all-out field tests lasting 3, 7 and 12 minutes has potential utility in the estimation of CP.