In tennis the wrist is required to be in different degrees of orientation at ball impact depending on the stroke and type of shot being hit. To date, little is known about the interplay between wrist position and grip strength, despite the fact that hitting the ball and firmly holding the racket when the wrist is flexed has been suggested as factor predisposing tennis players to lateral epicondylitis. The aim of this study was to investigate the effect of different wrist positions on isometric grip strength at self-selected grip size. Thirty-seven tennis players performed three isometric contractions at each of the following wrist positions: neutral, extension, flexion, ulnar deviation and radial deviation. Maximal isometric grip force was measured at each wrist position with the use of a hand-held grip dynamometer and then the highest value at each position selected for analysis. Our results are as follows: at neutral the force exerted was 80.2 ± 22.07 (mean ± sd) kg, at wrist extension 56.99 ± 18.40 kg, at wrist flexion 33.96 ± 9.47 kg, at radial deviation 56.26 ± 19.39 kg and at ulnar deviation 56.64 ± 17.60 kg. Our findings show that, compare to the position defined as neutral, the maximum isometric force exerted by the fingers` flexor muscles is significantly affected (lowered) by wrist position.
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