title: Effects of swing-weight on swing speed and racket power.
abstract: Measurements are presented of the speed at which six different rods could be swung by four male students. Three of the rods had the same mass but their swing-weight (i.e. moment of inertia) differed by large factors. The other three rods had the same swing-weight but different masses. Our primary objective was to quantify the effects of mass and swing-weight on swing speed. The result has a direct bearing on whether baseball, tennis, cricket and golf participants should choose a heavy or light implement to impart maximum speed to a ball. When swinging with maximum effort, swing speed (V) was found to decrease as swing-weight (Io) increased, according to the relation V = C/Ion, where C is a different constant for each participant and n = 0.27 when Io > 0.03 kg x m2. Remarkably similar results were obtained previously with softball bats (where n = 0.25) and golf clubs (where n = 0.26). Swing speed remained approximately constant as swing mass increased (when keeping swing-weight fixed). The implications for racket power are discussed.
authors.affiliation: Physics Department, University of Sydney, Sydney, NSW 2006, Australia. cross@physics.usyd.edu.au
authors.forename: Rod
authors.initials: R
authors.lastname: Cross
authors.forename: Rob
authors.initials: R
authors.lastname: Bower
mesh_terms: D000054:Acceleration; D000328:Adult; D006801:Humans; D008297:Male; D009517:New South Wales; D015865:Racquet Sports / Q000502:physiology*; D016059:Range of Motion, Articular; D019876:Sports Equipment; D013647:Task Performance and Analysis; D034941:Upper Extremity / Q000502:physiology*; D016474:Weight-Bearing