A Dynamic Computer Simulation of Tibial Strains and Joint Forces During Knee Flexion and Extension Exercise

摘要

Exercise is one of the strongest weapons against bone mass loss. It has been shown that daily physical activity can strengthen bones by stimulating it's growth [1]. Up to this moment most of the research resources were focused on assessing experimental measurements of bone strains [2, 3, 4], and gathering information about usefulness of specific exercises in osteoporosis prevention by means of statistics [5, 6, 7]. This paper presents original method to estimate bone strains during physical activity by means of dynamical simulation. Flexible multibody approach has been utilized to compute bone strains during two typical gym exercises: knee flexion, and knee extension performed with different loads. The results of the simulations are strain patterns during the activity, muscle forces and joint forces, which are comparable with in vivo measurements. The proposed method is computationally efficient and can provide valuable information about bone loading during physical activity in a non-invasive way. The limitations of the method and expected developments are also explored. The method is expected to provide a tool for design of gym equipment that could stimulate bone growth, as well as empirical formulas that relate loading for exercises and persons anthropometric data, to maximize the output of the work out.