Bergstrom, HC, Housh, TJ, Zuniga, JM, Camic, CL, Traylor, DA, Schmidt, RJ, and Johnson, GO. A new single work bout test to estimate critical power and anaerobic work capacity. J Strength Cond Res 26(3): 656–663, 2012—The purpose of this study was to develop a 3-minute, all-out test protocol using the Monark cycle ergometer for estimating the critical power (CP) and anaerobic work capacity (AWC) with the resistance based on body weight. Twelve moderately trained adults (mean age ± SD = 23.2 ± 3.5 years) performed an incremental cycle ergometer test to exhaustion. The CP and AWC were estimated from the original work limit (Wlim) vs. time limit (Tlim) relationship (CPPT) and a 3-minute all-out test (CP3min) against a fixed resistance and compared with the CP and AWC estimated from the new 3-minute tests on the Monark cycle ergometer (CP3.5% and CP4.5%). The resistance values for the CP3.5% and CP4.5% tests were set at 3.5 and 4.5% of the subject's body weight (kilograms). The results indicated that there were no significant differences (p > 0.05) among mean CP values for CPPT (178 ± 47 W), CP3.5% (173 ± 40 W), and CP4.5% (186 ± 44 W). The mean CP3min (193 ± 54 W), however, was significantly greater than CPPT and CP3.5%. There were no significant differences in AWC for the CPPT (13,412 ± 6,247 J), CP3min (10,895 ± 2,923 J), and CP4.5% (9,842 ± 4,394 J). The AWC values for the CPPT and CP3min, however, were significantly greater than CP3.5% (8,357 ± 2,946 J). The results of this study indicated that CP and AWC could be estimated from a single 3-minute work bout test on the Monark cycle ergometer with the resistance set at 4.5% of the body weight. A single work bout test with the resistance based on the individual's body weight provides a practical and accessible method to estimate CP and AWC.