Modeling Friction to Incorporate Sliding and Stiction: Application to the Contact Phase of Gymnastics Vaulting

When a gymnast contacts the vaulting table the hands initially slide in the direction tangential to the table surface and then remain stationary. The force resisting the motion in the tangential direction is friction: dynamic friction when the hands are moving and static friction (stiction) when the hands are stationary. An angle-driven simulation model of the table contact phase of gymnastics vaulting was developed. The model incorporated a seven-segment gymnast and a vaulting table, and used a novel two-state contact phase implementation to simulate the frictional forces between the two bodies during the table contact phase. The model was personalized to an elite gymnast so that simulation outputs could be compared with the gymnast’s performance. A set of model system parameters was determined by concurrently matching four simulations to their respective performances. The resulting parameters were evaluated using two independent trials and were found to be applicable to handspring entry vaults. The simulation model replicated the key features of the table contact phase. In particular the motion of the hands was representative of the actual performances.