Kinematic Features of Wheelchair Propulsion of Elite Chinese National Wheelchair Racers

Abstract

PURPOSE: This study was to investigate kinematic features of wheelchair propulsion among elite Chinese wheelchair racers during Training Camp of the 2008 Paralympic Games. METHODS: Seven wheelchair racers in Chinese National Paralympic Team (2 females, 5 males, age 25±4.4, body mass 60.3±4.6kg, training year 9.1±2.4) were filmed from the sagittal and front views by a MaxTraq motion analysis system at 60 Hz while they propelled their own racing wheelchairs at maximal speeds on a training roller. Seven reflective markers were placed on the right ear, acromion, lateral epicondyle of humerus, styloid process of Ulna, 3rd metacarpophalangeal joint, wheel axis and pushim. Film data were digitized and smoothed before the joint angles, and angular and linear velocities of the upper extremity were calculated. RESULTS: The results showed the drive phase time (DT), recovery time (RT) and cycle time (CT) were 0.095±0.013, 0.252±0.103 and 0.347±0.114 seconds, respectively. The hand contact angle, release angle and range on the pushrim were 44.2°±2.9, 207.8°±20.2 and 163.6° ±21.8, respectively. The maximal shoulder, elbow and wrist joint angles were 24.1°±25.2, 142.4°±32.2 and 158.7°±14.2, respectively in the drive phase and 66.6° ±27.1, 157.1° ±27.2 and 194.2°±15.3 in the recovery phase. The maximal angular velocities at the shoulder, elbow and wrist joints were 189.5°/s±98.2, 255°/s±165.4 and 573.6°/s±262.4 in the drive phase and 506.3±210.5, 465.6±210.1 and 590.8±273.6°/s in the recovery phase. The pattern recognition demonstrated that the Chinese wheelchair racers used the circular pattern with high upper arm elevation in the recovery phase. CONCLUSION: The Chinese national wheelchair racers had faster CT (0.347s) with comparison to other national wheelchair racers (approximately 0.500s). With the circular stroke pattern, the Chinese wheelchair racers sequentially increased their angular velocities from the shoulder to elbow, then to wrist in the drive phase. The greater upper arm elevation at the end of recovery phase may facilitate the racing speed production in the drive phase.