Grip d

PP assessment included three tests: HGS, timed up-and-go (TUG) test and walking speed – the latter two assessments were performed at the usual speed. HGS was measured twice in the standing position with the dominant hand using a digital dynamometer (Grip D, T.K.K. 5401, Takei Scientific Instruments). The measurement was recorded at a standing position, with the elbow and wrist in the extended and intermediate positions, respectively. Only the dominant hand was measured twice, and the maximum value was used. TUG measures the time from sitting to walking to a marker 3 m in front of the subject and then turning around and sitting down again. Walking speed was averaged as the 5 m walking test time twice at a comfortable speed. We provided 2-m back and forth sections (acceleration and deceleration sections) on the 5-m gait path.

Maximum grip strength was assessed using a GRIP-D (Takei Scientific Instruments Co., Ltd., Niigata, Japan) [26 (link)]. The participant’s right and left hands were assessed. The width of the dynamometer handle was adjusted according to the individual’s preference. Each participant stood still and upright, looking ahead, and the hand to be tested could not be touched with the thigh or any part of the body. Participants were instructed to perform a maximum effort attempt. During testing, verbal encouragement was given to the participants to obtain their best score. Four measurements were taken, and each one was supposed to last a few seconds [27 (link),28 (link)]. Participants performed the first 2 measurements in a row: one with the dominant hand and the other with the non-dominant hand. Then, one minute of rest was allotted before the 2 measurements were repeated. The highest scores of both hands were recorded in kilograms (kg).

The EWGSOP2 sarcopenia guidelines define muscle quality as ‘referring both to micro‐ and macroscopic changes in muscle architecture and composition, and to muscle function delivered per unit of muscle mass’.⁴ In this study, muscle quality (kg/kg) was calculated by dividing handgrip strength (HGS) (kg) by upper limbs muscle mass (kg) according to previous reports,¹⁷, ³⁵, ³⁶ focusing on ‘muscle function delivered per unit of muscle mass’. HGS was measured using a Smedley spring‐type dynamometer (Grip‐D, Takei Scientific Instruments Co., Ltd., Niigata, Japan), while upper limb muscle mass was determined using BIA.

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.