Association of Knee Extensor Muscle Strength and Cardiorespiratory Fitness With Bone Stiffness in Japanese Adults: A Cross-sectional Study.

Knee extensor muscle strength and CRF were associated additively, not synergistically, with bone health. Maintaining high levels of both physical fitness components may improve musculoskeletal health in the cohort. The relationship between physical fitness and bone status should be longitudinally investigated in the future.