Coefficients of Restitution of Balls Used in Team Sports for the Visually Impaired

Abstract

This study examined the coefficients of restitution (e) of selected balls used in team sports for the visually impaired: beep baseball and goal ball. Specifically, a basketball was compared to two men's standard goal balls, and a softball was compared to three different types of beep baseballs. The e for all balls was calculated by dropping each ball five times from heights of 6 ft (1.83 m) and 19.25 ft (5.88 m). A Sony reel-to-reel videotape recorder was used to record rebound heights on a background scale for each ball dropped. Reliability tests of the procedures yielded correlation coefficients (r) of 0.996 and 0.998 for the 6 ft (1.83 m) and 19.25 ft (5.88 m) drops, respectively. Two two-factor analysis of variance (ANOVA) tests yielded significant differences across ball type and height of drop for the basketball and goal balls and for the softball and beep baseballs, respectively (p < 0.001). The es for the more recently developed beep baseballs are close to that of the standard softball, indicating a possible danger to visually impaired participants in beep baseball.

Finding the gap: An empirical study of the most effective shots in elite goalball

“…Biomechanical research analysed different shot techniques and their impact on ball speed [ 9 ]. Other studies focussed on physical properties of the ball [ 10 ], physiological load during matches [ 11 ], anthropometric characteristics of top level players [ 12 , 13 ], requirement profiles for goalball coaches [ 14 ], and provided guidance for teaching in schools [ 15 ]. In addition, goalball-specific testing methods were developed for auditory perception [ 16 ] and endurance [ 17 ].…”