The purpose of this study was to determine if Critical Power (CP) and Anaerobic Work Capacity (AWC) could be estimated from a single, all-out test of less than 3-min. Twenty-eight subjects (mean ± SD: age 23.3 ± 3.3 years, body mass 71.6 ± 16 kg) performed an incremental cycle ergometer test to exhaustion to determine peak oxygen consumption rate and heart rate peak. The 3-min all-out test was used to determine the criterion and six estimated values of CP and AWC. The criterion critical power (CP180) and anaerobic work capacity (AWC180) values were determined from the 3-min all-out test and were expressed as 30-s averages (155-180-s). The six estimated CP and AWC values were calculated from 30-s averages at decreasing 10-s intervals from 145 to 170-s (CP170 and AWC170), 135 to 160-s (CP160 and AWC160), 125 to 150-s (CP150 and AWC150), 115 to 140-s (CP140 and AWC140), 105 to 130-s (CP130 and AWC130), and 95 to 120-s (CP120 and AWC120). Mean differences, total error, constant error, standard error of the estimate, and correlations were used to compare the criterion to the estimated CP and AWC values. The results of the present study indicated that 150-s was the shortest test duration that resulted in non-significant differences between the criterion (CP180 and AWC180) and estimated CP (CP150) and AWC (AWC150) values. The subsequent validation analyses showed that there were close agreements for the estimated CP150 and AWC150 versus the criterion (CP180 and AWC180) values. Therefore, the current findings indicated that estimates of CP and AWC were not affected by shortening the test by 30-s. Reducing the length of the test to 2.5 minutes provides a less strenuous, yet valid protocol for estimating CP and AWC
