The effects of ball impact location and grip tightness on the arm, racquet and ball for one-handed tennis backhand groundstrokes


King M. A., Kentel B. B., Mitchell S. R.

Journal of Biomechanics, vol.45, no.6, pp.1048-1052, 2012 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 45 Issue: 6
  • Publication Date: 2012
  • Doi Number: 10.1016/j.jbiomech.2011.12.028
  • Journal Name: Journal of Biomechanics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1048-1052
  • Keywords: Backhand, Grip tightness, Off-centre impacts, Simulation model
  • TED University Affiliated: No

Abstract

A torque-driven, 3D computer simulation model of an arm-racquet system was used to investigate the effects of ball impact location and grip tightness on the arm, racquet and ball during one-handed tennis backhand groundstrokes. The stringbed was represented by nine point masses connected to each other and the racquet frame with elastic springs and three torsional spring-dampers between the hand and the racquet were used to represent grip tightness. For each perturbation of nine impact locations and grip tightness, simulations were run for a 50. ms period starting with ball-racquet impact. Simulations showed that during off-centre impacts below the longitudinal axis of the racquet, the wrist was forced to flex up to 16° more with up to six times more wrist extension torque when compared to a centre impact simulation. Perturbing grip tightness had no substantial effect on centre impact simulations. However, for off-centre impacts (below the longitudinal axis of the racquet) a tight grip condition resulted in a substantial decrease in racquet rotation within the hand (less than 2°) and an increase of 6° in wrist flexion angle when compared to the equivalent simulation with a normal grip. In addition there was approximately 20% more wrist extension torque when compared with equivalent off-centre impact simulation with a normal grip. Consequently off-centre impacts below the longitudinal axis of the racquet may be a substantial contributing factor for tennis elbow injuries with a tight grip aggravating the effect due to high eccentric wrist extension torques and forced wrist flexion. © 2012 Elsevier Ltd.