TECHNIQUE ANALYSIS OF THE BACK TOSS ON THE PARALLEL BARS PERFORMED BY ELITE GYMNASTS

  • Spiros G. PRASSAS

Abstract

The back toss (BT), a skill frequently performed by gymnasts on the parallel bars (PB), involves a release-regrasp swing type of motion from a handstand to a handstand position. Mastering the skill is beneficial not only for points awarded to gymnasts by the judges for the skill itself but also for its contribution towards the perfect execution of other PB skills including the most current1 PB dismounts. The purpose of this study was to: I) identify the skill variables best correlating with the scores given to the BTs by qualifying judges, and 2) to identify the differences in technique between the most and least skillful BTs. Seventeen BTs, recorded during the 1990 United States Gymnastics Federation Championships with a NAC 400 HSV camera operating at 200 Hz, were analyzed utilizing the Arid Performance Analysis System (APAS). Two dimensional position data of 4 (for BTs without knee or elbow joint flexion) to 6 (BTs with elbow and/or knee joint flexion) body points were digitally smoothed before being submitted to further analysis. Product moment correlations between mechanical variables and the scores given to the BTs by qualifying judges, indicate that the best predictors of a good score are the shoulder joint angle at regrasp (p = .001), the time the gymnasts were airborne (p = .021), the horizontal velocity of the center of gravity (COG) at release (p = .022), the hip joint angle at release (p = .025), the hip joint angle at release and the minimum hip joint angle (p = .025 and .048, respectively), the normalized maximum height of the COG above the bar (p =.028), the greatest total angular momentum (p = .035), and the shoulder joint angle at release (p = .054). Paired t tests between variables of the most (N=8) and least (N=9) skillful BTs indicate that the discriminating factors are the hip joint angle at release (p = .03), the shoulder joint angle at regrasp (p = .032), time from the smallest hip joint angle to zero degrees of anterior shoulder joint angle (p = .049), and the horizontal velocity of the COG at release (p = .058). Additional factors differentiating the best and worst BTs studied are the time from zero degrees of anterior shoulder joint angle to release (p = .06), and the shoulder joint angle at release (p = .066)
Section
Coaching and Sports Activities