Evaluation of instruments for measuring grip strength.

Three instruments for measuring grip strength: the steel spring dynamometer, the Martin Vigorimeter and the My-Gripper, were tested in a universal testing machine to evaluate the linearity of the readings. Furthermore, a clinical study including 100 normal probands evaluated the applicability of these instruments. It was concluded that the steel spring dynamometer was not suitable for clinical use, due to its lack of precision. The Martin Vigorimeter and the My-Gripper were both very precise instruments. The My-Gripper seems to be preferable for clinical use because it is cheap and easy to handle. Also, the instrument can accumulate the results of several trials, facilitating the calculation of average grip strength. A nomogram showing the relationship between the dominant and the non-dominant hand is given.