BIOMECHANICAL EFFECT OF TESTING POSITIONS ON HAND GRIP STRENGTH

Hand grip strength (HGS) is a useful functional measure of the integrity of the upper extremities, however, many studies have examined it from selected positions (i.e., supine, sitting, standing), with no emphasis on other derived positions that are used in clinical setting. This study’s objective was to evaluate HGS in different body positions that are used in clinical setting by using a standard protocol. The study sample was a convenience sample of 40 healthy male participants with no history of psychiatric, neurological, or upper extremity orthopedic dysfunction. Grip strength in the dominant hand was measured with a Jamar Plus+ digital hand dynamometer in five positions: Supine, prone, side-lying, sitting, and standing. The HGS value in prone position was significantly lower than in standing position (p=0.043) and sitting position (p=0.013). However, no statistically significant difference was found in HGS among the supine, prone, and side-lying positions. Grip strength was moderately correlated with age (r=0.643). This study provides useful evaluation for grip strength in different positions. In identical upper extremity positions, grip strength varies between different body positions. Grip strength is equivalent when tested from the supine, side-lying, or prone positions, thus the position can be adjusted according to the patient’s condition. Finally, age is an important determinant of hand grip evaluation, particularly when standing position is used.