title: Comparison of ball-and-racquet impact force between two tennis backhand stroke techniqes.
abstract: METHODS
  A mixed design for kinetic comparison of 2 types of one-handed backhand strokes and 2 skill levels in tennis.
  
  
  OBJECTIVE
  To develop and evaluate a model to estimate the impact force on the racquet during tennis stroke, and to compare the peak impact force between one-handed backhand stroke with a long backswing and one-handed backhand stroke with a short backswing and between the beginning and advanced players.
  
  
  BACKGROUND
  A one-handed backhand stroke is commonly used in tennis and may be associated with many upper extremity over-use injuries. An understanding of kinetics of the backhand stroke is essential for understanding injury mechanisms and prevention.
  
  
  METHODS
  Five male advanced tennis players and 4 male and 1 female beginning tennis players participated. Mean age was 32.2 +/- 7.0 years. Each subject was instructed to use the 2 types of one-handed backhand strokes to hit balls from a tennis ball machine. Three-dimensional coordinates of critical body and racquet landmarks were obtained. A mathematical model was developed to estimate the contact duration and the peak impact force during a stroke.
  
  
  RESULTS
  The estimated peak impact forces were reproducible and comparable to those reported in the literature from direct measurements. A one-handed backhand stroke with a short backswing had a significantly shorter contact duration (0.008 +/- 0.003 seconds) and a greater peak resultant impact force (330.0 +/- 140.7) than that with a long backswing (0.016 +/- 0.004 seconds and 180.8 +/- 49.1 N). Skill level did not significantly affect the peak resultant impact force.
  
  
  CONCLUSIONS
  A long backswing in a one-handed backhand stroke may reduce the load on the upper extremity and may assist in reducing the risks of tennis-related upper extremity over-use injuries.
authors.affiliation: Center for Human Movement Science, Division of Physical Therapy, University of North Carolina at Chapel Hill, 27599-7135, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Wu
authors.forename: M T
authors.initials: MT
authors.lastname: Gross
authors.forename: W E
authors.initials: WE
authors.lastname: Prentice
authors.forename: B
authors.initials: B
authors.lastname: Yu
mesh_terms: D000328:Adult; D012090:Cumulative Trauma Disorders / Q000209:etiology*; D005260:Female; D006225:Hand / Q000503:physiopathology*; D006801:Humans; D008297:Male; D015865:Racquet Sports / Q000293:injuries*; D012016:Reference Values; D013715:Tennis / Q000293:injuries*