ASYMMETRY ANALYSIS OF THE ARM SEGMENTS DURING FORWARD HANDSPRING ON FLOOR

Abstract

Movement symmetry is assumed during handspring performance on floor and this belief forms an inherent part of coaching and judging recommendations. The aim of this study was to examine kinetic and kinematic asymmetry of the arm segments during the contact phase of a forward’s handspring on the floor exercise in order to provide useful information to coaches. Four female national level gymnasts (age 19.4 ± 1.1 years; mass 55.25 ± 7.75 kg, and stature 1.62 ±0.41 m) executed 15 forward handsprings whilst synchronised kinetic and 3D kinematic data were collected. Kinematic data were collected using automated motion analysis system (CODAmotion, V6.78.2, Charnwood Dynamics Ltd, UK) whilst kinetic data sourced from two piezoelectric force plates (Kistler 5233A, Winterthur, Switzerland) the two systems sampling at 200Hz and 1000Hz respectively. Symmetry was assessed through Zifchock’s et al. (2008) method, symmetry angle (θsym). Tests for normality (Peat and Barton, 2005) were followed by parametric statistics in the form of a t-test to inform where significant (p<0.05) differences. Percentage difference of the symmetry angle between the right and left side were calculated for discreet and continuous variables. Significant kinematic asymmetry was present at the shoulder but not at the distal joints where discreet kinematic variables showed significant differences between the right and left limbs with θSYM values ranging from 0.10% to 105.60%. Kinetic asymmetry was significant for all gymnasts where the direction of asymmetry was relative to the lead leg. It was noted that wrist impacts appeared to have a vertical ground reaction force (VGRF) of approximately 1BW which was found to be a decrease from previous findings by Burt et al. (2007) (range, 1.99 and 3.99 BW). The findings of this study will provide information for coaching gymnastics skills which are usually thought as being absolutely symmetrical. In addition, implications for loading and injury may be uncovered from kinetic asymmetry present at touchdown. Research outcomes may have implications for coaches, biomechanists and clinicians regarding possible injury implications and data collection methods.