Assessment of maximal aerobic power and critical power in a single 90-s isokinetic all-out cycling test

The purpose of this study was to establish the validity of a 90-s all-out test for the estimation of maximal oxygen uptake (VO2max) and submaximal aerobic ability as represented by critical power. We hypothesized that the fall in power output by the end of the 90-s all-out test (end power) would represent the exhaustion of anaerobic work capability, and as such, would correspond with the critical power. Sixteen active individuals (mean +/- SD: 30 +/- 6 years; 69.6 +/- 9.9 kg) carried out a series of tests: (i) an incremental ramp test to determine VO2max, (ii) three fixed-work rate trials to exhaustion to determine critical power, and (iii) two 90-s all-out tests to measure end power and peak VO2.. End power (292 +/- 65 W) was related to (r = 0.89) but was significantly higher (p < 0.01) than critical power (264 +/- 50 W). The mean 95% limits of agreement (29 +/- 65 W) were too low to use these variables interchangeably. The peak VO2 in the 90-s trial was significantly lower than the VO2max (3435 +/- 682 ml . min(-1) vs. 3929 +/- 784 ml . min(-1); p<0.01); mean 95% limits of agreement was equal to 495 +/- 440 mL . min(-1). The 90-s all-out test cannot, therefore, assess both VO2max and critical power in adult performers. The duration of all-out exercise required to allow VO2 to attain its maximum is longer than 90 s.