A COMPARISON OF METHODS OF ESTIMATING ANAEROBIC WORK CAPACITY

The hyperbolic relationship between power output (P) and time to exhaustion (t) is described as: (P- theta(PA)) . t = W', where theta(PA) is the power asymptote (or 'critical power'), which theoretically represents the highest sustainable power output, and W' is a constant which represents a limited amount of work which can be performed above theta(PA) (or 'anaerobic capacity'). The purpose of this study was to determine the validity of W' as anaerobic capacity, using maximal oxygen deficit as the criterion measure. Thirteen women (mean (+/- SD) age 23 +/- 2 years, height 1.67 +/- 0.07 m and mass 60.8 +/- 8 kg) and 13 men (mean age 23 +/- 2 years, height 1.74 +/- 0.1 m and mass 71.3 +/- 14 kg) performed two sets of five bouts of high-intensity cycling exercise to exhaustion, each bout on a separate day and at a different relative power. Individual W' were calculated by nonlinear regression of time with power, with time as the dependent variable. Oxygen deficit was determined during each bout, and the mean of the values obtained from the power output which elicited the highest values was used as the criterion for anaerobic capacity. Mean (+/- SE) values for anaerobic capacity for women were 179 +/- 10 J.kg-1 (W') and 177 +/- 10 J-kg-1 (oxygen deficit) and for men, 224 +/- 10 J.kg-1 (W') and 235 +/- 9 J-kg-1 (oxygen deficit). The W' estimates and criterion measures were the same (F1.24 = 0.61, p = 0.44), and there was no method-gender interaction (F1.24 = 0.26, p = 0.62). It is concluded that anaerobic capacity can be estimated accurately by the W' parameter of the power-time relationship during high-intensity exercise.