Test–retest Reliability and Precision of the Rotterdam Intrinsic Hand Myometer

Purpose: The purpose of this study was to determine the test–retest reliability and precision of Rotterdam Intrinsic Hand Myometer (RIHM) in healthy adults. Methods: Twenty-nine participants originally recruited via convenience sampling at a Midwestern state fair returned approximately 8 days later for retest. An average of three trials for each of the five intrinsic hand strength measurements were collected using the same technique that was used during initial testing. Test–retest reliability was assessed using the intraclass correlation coefficient or ICC_(2,3) and precision was evaluated using the standard error of measurement (SEM), and the minimal detectable change (MDC₉₀)/MDC%. Results: Across all measures of intrinsic strength, the RIHM and its standardized procedures had excellent test–retest reliability. Index finger metacarpophalangeal flexion demonstrated the lowest reliability, and right small finger abduction, left thumb carpometacarpal abduction, and index finger metacarpophalangeal abduction tests had the highest reliability. Precision, as evidenced by SEM and MDC values, was excellent for tests of left index and bilateral small finger abduction strength and acceptable for all other measurements. Conclusions: Test–retest reliability and precision of RIHM across all measurements was excellent. Clinical Relevance: These findings indicate that RIHM is a reliable and precise tool in measuring intrinsic strength of hands of healthy adults, although further research is needed in clinical populations.