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 positions (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.