Mechanical modeling in sports motion

Abstract

The present paper provides a broad overview of the three main dynamic models-the rigid body model, the deformation (deformable body) model, and the fluid structure model-that are used when investigating physical exercise and sports techniques from a biomechanical or ergonomic stand- point. The benefits of such models and the precautions that should be taken in their use and inter- pretation are investigated, as are some potential future models. Rigid body system models, among which the mass-spring model and rink-segment model are the most common, have conventionally been the core models in the fields of physical education and sport. This type of model will likely con- tinue to evolve and be applied to various problems. At the same time, it is true that rigid body mod- els are ill-suited to the study of certain techniques. For this reason, deformation and fluid structure models have been developed for use in such research and for problem solving. Analyses using con- ventional physical education and sport models usually describe sporting techniques in detail by cal- culating joint torque based on kinematic data from actual movement coordinates in an inverse dy- namic manner (inputting displacement and outputting force). This has, to date, produced outstand- ing results, providing a “description” of the action taking place. In future, analyses that incorporate direct dynamics (inputting force and outputting displacement) based on elicited force will also be re- quired in conjunction with this descriptive approach. A combination of these two approaches will enable simple “predictions” to be carried out on an appropriate level. The ultimate goal of such pre- dictions will be to optimize the performance of the technique. In future, therefore, it will be impor- tant to perform modeling that incorporates description and prediction, yielding a model for opti- mization of the action. Key