Effects of Crutch Handle Size on Hand and Finger Load during Ambulation

Abstract

The objective of this study was to investigate an optimum crutch handle bar diameter that is easy for grasping and leads less efforts by hands, wrists and fingers. Sixteen healthy young adult males walked with a right-leg-support, swing-through gait motion using one pair of standard axillary crutches with six handles having different diameters (25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, measured lengthwise from the center). During the gait, surface electromyography from flexor digitorum superficialis (FDS) and extensor digitorum communis, wrist posture (flexion and extension), the distribution of externally applied pressure on the palm and subjective evaluation were measured. The results showed that the thicker handle conditions (40 mm, 45 mm and 50 mm) led to a lower pressure on the palm. In addition, wrist posture was more extended in thicker handle conditions than in thinner ones. On the other hand, thinner handle conditions (25 mm and 30 mm) resulted in higher FDS activity. The subjective evaluation showed the 35 mm handle diameter was most suitable for grasping. In conclusion, the handle diameter 35～40mm, which is about 19～22％of hand length, is regarded as the optimum handle size of axillary crutches for young adult males.