Muscle Power Predicts Bone Strength in Division II Athletes

Yingling, VR, Webb, SL, Inouye, C, O, J, and Sherwood, JJ. Muscle power predicts bone strength in Division II athletes. J Strength Cond Res 34(6): 1657-1665, 2020-The relationship between muscle fitness measures and tibial bone strength in collegiate level athletes was investigated. Eighty-six Division II collegiate athletes (mean ± SD: age: [18-29 years], height: 1.71 m [0.09], mass: 66.7 kg [10.5], 56 female: 30 male) participated in this cross-sectional study. Maximum grip strength (GS), 1 repetition maximum leg press, and vertical jump peak power (PP) tests were measured. Cortical area, cortical bone mineral density (cBMD), moment of inertia, and bone strength (polar strength-strain index) were measured using peripheral quantitative computed tomography at 50% tibia length. For each bone strength parameter, a hierarchical multiple regression analysis was performed to examine the contribution of sex and the 3 muscle fitness parameters (muscle power, relative 1 repetition leg extensor strength, and relative GS) to bone parameters. Vertical jump PP explained 54-59% of the variance in bone strength parameters, and relative leg extensor and GS were not predictive of bone strength parameters. Muscle power correlated with bone mass and architecture variables but not cBMD values. Cortical bone mineral density was also not predicted by relative leg extensor strength or relative GS. Muscular fitness assessment, specifically PP calculated from vertical jump height assessments, provides a simple, objective, valid, and reliable measure to identify and monitor bone strength in collegiate athletes.