Asymmetry analysis of the arm segments during the forward handspring on vault

Abstract

Much of the current literature within the biomechanics and coaching of gymnastics assumes that gymnasts present symmetry of the upper body during skills such as the handspring vault, but the body of literature that suggests all athlete’s will exhibit some asymmetries is growing. Six female gymnasts (age 19 years, mean height 1.57 ± 0.06 m, mass 53.58 ± 6.55 kg) completed 16 vaults each in total, across two separate landing conditions. Data was collected for kinematic variables using CODA (CODA, Charnwood Dynamics, Ltd). Zifchock et al.’s Symmetry Angle (θSYM) was selected as the method for quantifying asymmetry, as it is not prone to the artificial inflation that exists in systems such as the Symmetry Index (SI) (Robinson, Herzog, & Nigg, 1987). θSYM was applied to the average joint angles and angular velocities at the instant of vault contact for both landing heights. Asymmetries were tested against intra-limb variability to see if they were greater than the variance that occurred in one limb (Exell, Irwin, Gittoes, & Kerwin, 2012a), which left 56% of θSYM’s calculated from joint angles and 53% of θSYM’s calculated from angular velocity. It was found that all participants displayed significant asymmetries in at least one of the variables, with some participants showing significant values for every variable. No significant difference was found between magnitudes of asymmetry for the two landing heights. Future research should aim to include kinetic variables to augment the validity of the study, and should use an elite sample to reduce the effects of intra-limb variability. An interdisciplinary approach may be beneficial to determine how previous injuries affect the psychology of a performer, which may be a factor in the asymmetries they present.