Measuring Hand Grip and Pinch Strength

We measured grip strengths of both hands as directed by the Japanese Physical Fitness Test Guidelines¹⁶ with a Smedley-type digital grip dynamometer (Grip-D, Takei Scientific Instruments Co., Ltd., Japan) (Fig. 2A). We adjusted the grip width to place the proximal interphalangeal joint of the index finger approximately at 90° during the grasping of the grip dynamometer. To measure grip strength, we asked the volunteers to lower both arms naturally, taking care not to let the grip dynamometer touch the body or clothing. We measured grip strengths twice, alternating the right and left sides and adopting the higher values for analysis. We measured lateral pinch strength with a pinch dynamometer (MT-100, SAKAI Medical Co., Ltd., Japan) (Fig. 2B). We obtained the measurements with the radial surface between the distal and proximal interphalangeal joints of the index finger and thumb, with the shoulder joint in 0° flexion, abduction, and internal/external rotation, the elbow joint in 90° flexion, and the forearm in the middle position. We obtained two measurements, alternating each side, and adopting the higher value for analysis.Figure 2

Measurement of hand motor performance. (A) Grip strength measurement. (B) Lateral pinch strength measurement. (C) Paper format of the Target Test.