Biomechanical analysis of an exercise program for forces and stresses in the hip joint and femoral neck

Bone remodeling as a response to exercise in human subjects is described in the literature, although most studies treat exercise as a qualitative factor contributing to bone remodeling. Quantitative description requires assessment of the mechanical loads on the bones. This work describes a generalized lower extremity model that uses existing musculoskeletal modeling techniques to quantify mechanical variables in the femoral neck during exercise. An endurance exercise program consisting of walking, jogging, jumping rope, and weight-training was analyzed. Peak femoral neck cortex stresses and strains were high during jogging and squatting, compared to walking, whereas jumping rope and other weight-training exercises produced peak stresses comparable to or lower than walking. Peak stress and strain rates were significantly higher for walking, jumping rope, and jogging than for weight-training. The model should prove useful for any study investigating a quantitative relationship between exercise and bone remodeling.