title: Racquet string tension directly affects force experienced at the elbow: implications for the development of lateral epicondylitis in tennis players.
abstract: BACKGROUND
  Lateral epicondylitis (LE) occurs in almost half of all tennis players. Racket-string tension is considered to be an important factor influencing the development of LE. No literature yet exists that substantiates how string-tension affects force transmission to the elbow, as implicated in LE development. We establish a quantitative relationship between string-tension and elbow loading, analyzing tennis strokes using rackets with varying string-tensions.
  
  
  METHODS
  Twenty recreational tennis players simulated backhand tennis strokes using three rackets strung at tensions of 200 N, 222 N and 245 N. Accelerometers recorded accelerations at the elbow, wrist and racket handle. Average peak acceleration was determined to correlate string-tension with elbow loading.
  
  
  RESULTS
  Statistically significant differences (p < 0.05) were observed when average peak acceleration at the elbow at 200 N string-tension (acceleration of 5.58 m/s(2)) was compared with that at 222 N tension (acceleration of 6.83 m/s(2)) and 245 N tension (acceleration of 7.45 m/s(2)). The 200 N racket induced the least acceleration at the elbow.
  
  
  CONCLUSIONS
  Although parameters determining force transmission to the elbow during a tennis stroke are complex, the present study was able to control these parameters, isolating the effect of string-tension. Lower string-tensions transmit less force to the elbow in backhand strokes. Reducing string-tension should be considered favourably with respect to reducing the risk of developing LE.
authors: Institute of Motion Analysis and Research (IMAR), TORT Centre, Ninewells Hospital and Medical School, University of Dundee, UK.
authors: Badri R
authors: BR
authors: Mohandhas
authors: Institute of Motion Analysis and Research (IMAR), TORT Centre, Ninewells Hospital and Medical School, University of Dundee, UK.
authors: Navnit
authors: N
authors: Makaram
authors: Institute of Motion Analysis and Research (IMAR), TORT Centre, Ninewells Hospital and Medical School, University of Dundee, UK.
authors: Tim S
authors: TS
authors: Drew
authors: Institute of Motion Analysis and Research (IMAR), TORT Centre, Ninewells Hospital and Medical School, University of Dundee, UK.
authors: Weijie
authors: W
authors: Wang
authors: Institute of Motion Analysis and Research (IMAR), TORT Centre, Ninewells Hospital and Medical School, University of Dundee, UK.
authors: Graham P
authors: GP
authors: Arnold
authors: Institute of Motion Analysis and Research (IMAR), TORT Centre, Ninewells Hospital and Medical School, University of Dundee, UK.
authors: Rami J
authors: RJ
authors: Abboud
keywords: biomechanics; elbow; lateral epicondylitis; string-tension; tennis