The mechanics of the table contact phase of gymnastics vaulting
thesisposted on 2010-06-14, 14:19 authored by Monique I. Jackson
A computer simulation model of the table contact phase of gymnastics vaulting was developed to gain an understanding of the mechanics of this phase of the vault. The model incorporated a gymnast and a vaulting table, and used a novel two-state contact phase representation to simulate the interaction between these two bodies during the table contact phase. The gymnast was modelled in planar form using seven segments, with torque generators acting at the wrist, shoulder, hip and knee joints. The model also allowed for shoulder retraction and protraction, displacement of the glenohumeral joint centre and flexion/extension of the fingers. The table was modelled as a single rigid body that could rotate. The model was personalised to an elite gymnast so that simulation outputs could be compared with the gymnast's performance. Kinematic data of vaulting performances were obtained using a optoelectronic motion capture system. Maximal voluntary joint torques were also measured using an isovelocity dynamometer, and a torque - angle - angular velocity relationship was used to relate joint torques to joint angles and angular velocities. A set of model system parameters was determined using a gymnast-specific angle-driven model by matching four simulations to their respective performances concurrently. The resulting parameters were evaluated using two independent trials, and found to be applicable to handspring entry vaults. The torque-driven model was successfully evaluated, and shown to produce realistic movements, with mean overall differences between simulations and recorded performances of 2.5% and 8.6% for two different handspring entry vaults. The model was applied to further understanding of the mechanics of the table contact phase of gymnastics vaulting. Optimisation showed that there was limited potential (1.3%) for the gymnast to improve performance through technique changes during the table contact phase. However, with additional changes in configuration at table contact post-flight rotation could be increased by 9.8% and post-flight height could be increased by 0.14m. Angular momentum was found to always decrease during the table contact phase of the vault, although the reductions were less when maximising post-flight rotation.
- Sport, Exercise and Health Sciences