Brief report - Effect of wrist positioning on the repeatability and strength of power grip

Objective. This study tested the between-day repeatability and effect of wrist positioning on grip strength measurement. Method. Thirty healthy men 20 years to 69 years of age were tested twice, 1 week apart, in six wrist positions. Results. The findings showed good repeatability for grip strength, with the intraclass correlation coefficient [ICC(1, 3)] ranging from .9043 to .9663. Significant differences were found in grip strength among the six position (p < .001), with grip strength measured at 15<degrees> or 30 degrees of wrist extension (EXT) and 0 degrees ulnar deviation (UD) significantly greater than that of 0 degrees UD and 0 degrees EXT or 15 degrees UD with or without EXT. This finding suggests the clinical importance of standardizing the testing position for grip strength measurement. Conclusion. The high repeatability of the tests supports the use of the grip strength measurement to evaluate treatment progress.