Abstract: This paper studies the effect of different hardness and thickness of ethylene vingl acetate copolymer(EVA) soles on gait stability of the elderly over 60 years old when walking normally and carrying weight. The experimental shoes are customized in Chinese size 38. The hardness is divided into three grades including 48 Shore A, 53 Shore A and 58 shore a, and the thickness is divided into two grades including 2 cm and 3 cm. There are six pairs in total and all shoes are the same except for the hardness and thickness of the sole. The weight-bearing grade is divided into no-load and 15% of body weight. Gait spatio-temporal parameters and dynamic parameters related to stability were measured using a gait analyzer and a three-dimensional dynamometer. The results show that shoes with medium or relatively hard (53 Shore A) and thin (2 cm) soles are beneficial for maintaining the gait stability of the elderly when walking with or without load, while soft and thick soles are not conducive to stability. Weight bearing reduces walking stability, and the stability gap between soles of different hardness and thickness levels becomes larger when carrying weight. The elderly should pay more attention to the choice of soles when walking with shoes with loads, and try to choose shoes with medium or hard soles and thin soles for improved walking stability and reduced risk of falls.

Key words: EVA sole, hardness, thickness, weight bearing, stability