On the reliability and usefulness of methods for grip strength measurement.

The purposes of this investigation were to assess the accuracy of a grip strength measuring instrument, the Grippit, to modify previously developed methods for measuring maximal isometric grip strength (12) and to evaluate the reliability of these methods, with the use of the Grippit. Grip strength during short (maximal voluntary isometric strength, MVC) and sustained (SMVC) contractions was measured. The modifications concerned the definitions of MVC and SMVC, the measuring position, the intervals between trials and sessions, and the recording procedure. The intra-observer reliability study comprised 29 healthy subjects, and the inter-observer study 10 other healthy subjects. The Grippit had very high precision. The intra-observer reliabilities of MVC and SMVC measurements were improved compared to those with the previous methods (12). The inter-observer reliability was very high.