BIOMECHANICAL ANALYSIS OF RELATIONSHIP BETWEEN BICYCLE DIMENSIONS & THE RIDERS' WRIST AND SHOULDER INJURIES

Abstract

The bicycle is the most popular vehicle for transportation in China. Almost every adult and many children ride them to offices or schools. Because of inappropriate selection and design of the bicycles, many chronic injuries of the wrist and shoulder joints are incurred. It is believed that the height between the bicycle bar and saddle (HBS) has an influence on these injuries. In this paper, according to the HBS, the subjects were divided into 3 groups: bicycle group 1 (HG I), HBS is less than 5 cm; BG2, HBS is between 5 and 20 cm; BG 3, HBS is larger than 20 cm. Sixty subjects (30 males and 30 females) were divided into the 3 groups based on the heights of the bicycle seat, group 1 (SG 1) being the shortest and 3(SG 3) the tallest. A special transducer was attached to the bar and then to a computer (z80). Because part of the body weight was transferred by the upper limbs and then supported by the bar, the forces applied on the wrists and shoulders were acquired directly. During this research study, the subjects were required to ride all bicycles with varying seat heights. Results demonstrated that for all of the SGA, the less the HBS, the larger the force. With the changes in BG, the force in different SG changes in a similar way. In BG1 (HBS was less), the SG 3 produced the greatest force and SG 1 the smallest. In BG 3, the force changed slightly from the results for the different SGs. It is suggested that the bicycle with the largest HBS (BG 3) was appropriate for all riders, especially the women. The bicycle for the tall subjects with the least HBS (BG 1) should be avoided. So avoiding chronic injuries of the wrist and shoulder is very important and necessary.