The influence of impairment type on the biomechanics of the wheelchair tennis serve technique

Recent years have seen a notable growth of wheelchair tennis (WCT), the form of tennis adapted for people with physical impairments. Players are categorised in the Open (impairment restricted to the lower limbs) and Quad (compromised upper body functions, with a minimum of three limbs affected) divisions. WCT serve has received a limited amount of research attention in particular in the biomechanics area. Therefore, this work aimed to understand the biomechanics of the service stroke in elite WCT players and explore the impact of impairment type on serve performance and technique. After a critical review of the ABT literature, the key factors contributing to the execution of a power serve were identified. Consequently, upper body, racket and ball 3D position data were collected to assist the investigation of the serve technique descriptors in WCT. A total of twenty-three British WCT players from different playing standards (elite, development, junior) involved in regular tennis competitions at both national and international levels, were tested over a four-year period. Data from six elite British WCT players of similar training levels, belonging to different classes were used for the purpose of this research. A qualitative exploration of the WCT serve technique demonstrated that most of the factors contributing to a fast first serve in ABT are also common to WCT (Chapter 5). Ball velocity, spin rate, racket forward velocity, were lower in WCT and decreasing in the least functional subjects (Chapter 5). Moreover, thorax and shoulder joints motion showed the most relevant variations between ABT and WCT technique. The impact of the impairment type within each division was further explored (Chapter 6). Results showed that ball and racket kinematics was variable within the Quad class, and thorax twist, shoulder internal rotation, elbow flexion and wrist extension values upon impact were limited compared to the Open class. Moreover, when the injury was restricted to the lower limbs, regardless of impairment type, players could still hit relatively high-speed serves using similar technique. On the contrary, in the Quad division, where the impairment also affects the upper body, serves outcomes and performance were highly dependent on the extent of residual functions. Peak shoulder internal rotation and elbow flexion torques in the Open class, were similar to ABT however, values observed in the Quad division were lower compared to both Open and ABT (Chapter 7). Chapter 8 analysed the differences in ball toss and racket kinematics when serving to different locations within the Open division. Elite Open WCT players were shown to adopt a leftward ball toss with the contact point occurring at different positions according to the directions of the serve (T or Wide). Finally, findings of Chapter 9 showed that elite WCT players, regardless of the division, were able to maintain elevated serve accuracy and technical skills even when experiencing physiological and thermal strain. This is an encouraging finding suggesting the effectiveness of the fitness and technical coaching of the British WCT players at the time of this data collection. Overall, these findings will support coaches and tennis practitioners in expanding their understanding of elite wheelchair tennis serve technical skills. Future studies are recommended to incorporate the multidisciplinary approaches utilised in this latter study to explore the WCT serve in other ecologically valid scenarios.