Critical Power Concept: Males vs. Females and the Impact of Muscle Fiber Composition

International Journal of Exercise Science 12(4): 277-286, 2019. CP describes the highest metabolic rate resulting in complete oxidative energy provision (steady state). Between the heavy and severe domain of exercise, CP will be surpassed, and the finite work capacity known as W\u27 will be used up. The purpose of the study is to test CP and W’ and its relationship in males and females, while assessing type I and II muscle fiber distribution in the leg. A 3 MT and isokinetic leg dynamometer muscle fiber typing protocol of 25 consecutive leg extensions were completed. W\u27 for the sample (n = 17) was 8381.64 ± 4556.72 joules [males (n = 9): 12086.22 ± 1851.39 joules; females (n = 8): 4214.00 ± 2459.07 joules]. Type II muscle fiber for the sample was 24.48% ± 12.92% (males: 20.83 ± 13.18%; females: 28.59 ± 12.10%). W\u27 was not significantly correlated to type II muscle fibers (r = -0.070, p = 0.790) but was significantly related when controlling for gender (r = 0.579, p = 0.024). W’ was correlated to Wpeak and BMI in the sample; when controlling for gender, it was correlated to Wpeak, Type I and Type II muscle fiber percentage and CP. Compared to females, males had higher W’ (p \u3c 0.001) and CP (p = 0.004). W’ was not correlated to type II muscle fibers but was when controlling for gender. Males were demonstrated to have significantly higher W’, CP, Wpeak and BMI compared to females suggesting potential muscle cross sectional area influences W’ and CP when comparing genders