OBJECTIVE. We examined the reliability and validity of the analog and digital models of TKK handgrip dynamometers using calibrated known weights.
METHOD. A total of 6 dynamometers (3 digital and 3 analog; 2 new and 1 old for each model) were used in this study.
RESULTS. Intrainstrument reliability was very high; systematic error for test–retest reliability was ≤|0.3 kg|. The systematic error among different instruments (same model) and between different models (digital vs. analog) ranged between |0.4 kg| and |0.6 kg|. The systematic error between new and old dynamometers ranged from |0.8 kg| to |1 kg|. All dynamometers provided lower values for the same known weights than a SECA scale, with a systematic error ranging from −0.94 to −2.64 kg.
CONCLUSION. This study indicates that clinicians and investigators who provide treatment to address handgrip strength should use the same instrument and model for repeated measures. Distinguishing meaningful change from dynamometer variability is discussed.