The reliability and validity of the Tekdyne hand dynamometer: Part I.

The purpose of this study was to evaluate the reliability of Tekdyne hand dynamometer in a controlled loading environment using the Instron 1331. Test-retest reliability, the intertool reliability of three different Tekdyne hand dynamometers, and the effects of surface area and the configuration of the forces applied to the Tekdyne hand dynamometer were studied. In addition, intertool reliability between a Jamar dynamometer modified with foam padding and the same Jamar dynamometer without padding was calculated to explore this device as an alternative measurement device. Intratool and intertool reliabilities of the three Tekdyne tools were high (ICC = 0.993-10.998, SEM = 0.106-0.045 psi and ICC = 0.995, SEM = 0.080 psi, respectively) when tested on the Instron. Both the surface area and the configuration of the force applied to the Tekdyne dynamometer appeared to influence the output reading of this device. The measurements obtained on the Tekdyne hand dynamometer correlated well with those obtained with the Jamar hand dynamometer when a controlled load was applied (r = 0.988). The Tekdyne hand dynamometer is a reliable tool in a controlled loading environment; however, further study is needed to determine its validity with respect to the Jamar dynamometer for testing human grip strength.