JOINT MOBILITY AND FORCE APPLICATION DURING THE THRUST PHASE OF THE FRONT HANDSPRING ON FLOOR EXERCISE

Abstract

The purpose of this study was to conduct a kinetic analysis of the front handspring element as performed on floor exercise by young female gymnasts. Force data as well as flexibility measures with respect to the hip, shoulder and trunk were examined for association with front handspring success. In addition, the predictability of force and impulse generation based on flexibility was examined. Twenty-two girls (Mean age = 12.0 yrs and Mean wgt = 40.4 kg) rated as Class-2 and Class-3 gymnasts comprised the subject .group. Data were recorded with a Kistler Instrument force measurement platform. Results revealed peak vertical impact forces (Mean = 709.3 N) on the order of 1.8 times bodyweight and relatively low vertical impulses (Mean = 94.8 N-sec). Lower yet were horizontal generated forces and impulses. Average hand contact time at take off was 0.30 seconds. Except for the independent variable of shoulder angle, variation in normal and shear impulses could not be explained by variation in joint flexibility. Regression analysis revealed that variations in vertical impulse and horizontal impulse could be explained by variation in shoulder joint flexibility (p < 0.05). Examination of performance ratings with flexibility and dynamometric data revealed only two significant relationships (p < 0.05), those for rating and horizontal impulse and for rating and time of contact. Non-significant relationships were found to exist between performance and degree of shoulder, trunk, and hip flexibility. The results suggest that degree of shoulder--but not trunk nor hip-flexibility can be used to predict impulse of force during the front handspring. However, joint flexibility did not associate strongly with performance level.