Contributions to the performance of longswings on rings
thesisposted on 26.09.2012, 13:20 authored by Mark A. Brewin
Rings is one of six disciplines in Men's Artistic Gymnastics. Judging criteria stipulate that a routine must incorporate two swinging elements completed in a motionless handstand. Performing backward and forward longswings in a routine fulfils this requirement. During both types of longswing, gymnasts typically use large angle changes at their hip and shoulder joints and move their arms laterally. Previous studies have ignored these three-dimensional arm movements, possibly neglecting a crucial aspect of technique. Using a computer simulation model this study investigated the contributions of hip and shoulder elevation angle changes and lateral arm movements to the performance of backward and forward longswings. A three-dimensional video and cable tension analysis of several backward and forward longswings performed by two elite gymnasts was conducted. The data provided accurate three-dimensional descriptions of backward and forward longswing techniques and the forces experienced by the gymnasts. In addition, data describing deformations of the rings frame and the extension of the gymnast were determined. A simulation model representing the three-dimensional movements of the rings cables and arms of a gymnast was developed. The model represented the right side of the gymnast and rings apparatus and comprised five segments: rings cable, arm, torso with head, thigh, and shank with foot. Damped linear springs represented the elasticity of the apparatus and gymnast. The model was evaluated against actual backward and forward longswing performances of two elite gymnasts. Actual joint angle time histories describing the gymnasts' techniques, together with subject specific inertia parameters, were used for this procedure. The RMS differences between values estimated by the model and actual values for the orientation of the gymnast and rings cable, the cable tension and the body extension were 4.3°, 2.1°,161N and 0.1 m respectively. The evaluated model was used to determine the contributions of each aspect of technique to the performance of longswings. Hip and shoulder elevation angle changes are important in producing the required rotation of the gymnast in both types of longswing. Without these components of technique the gymnast generated up to 113° less rotation. Lateral arm movements performed during backward longswings resulted in 40% less shoulder elevation torque required to complete the element and a 0.8 bodyweights decrease in peak force experienced at the shoulder joints. When lateral arm movements were omitted during forward longswings the gymnast produced 49° less rotation, and failed to reach the final handstand. This study shows that lateral arm movements make an important contribution to the performance of longswings on rings.
- Sport, Exercise and Health Sciences