An increasing amount of research is focused on the functional future of subjects with spinal cord injuries. In addition to studies on metabolic responses and wheelchair propulsion techniques, these studies have been aimed at defining and preventing traumatisms in paraplegic wheelchair sportsmen. Two groups of 6 paraplegic sportsmen with different neurological levels (HPS and LPS) and 1 group of 6 valid sportsmen (VS) underwent isokinetic evaluation of muscular power developed by the shoulder. The flexion-abduction / extension-adduction for concentric-concentric contraction were carried out at 3 speeds, 60°/sec, 120°/sec and 210°/sec on the right side and the left side. We studied work and power parameters and completed this analysis by determination of agonist / antagonist ratios for shoulder muscles. The results of the isokinetic evaluation demonstrated that: - wheelchair sportsmen with neurological levels inferior to T 10 (LPS), thus with abdominal muscle and stabilization capacities in the sitting position, showed better and significantly different torque and power (HPS) and valid sportsmen (VS) (p<0.001). - the neurological level had an effect on isokinetic power developed by the scapular belt and also wheelchair propulsion modified the torque produced. The comparaison between HPS and LPS during extension movements showed significant differences in maximal work per repetition (p<0.001), total work (p<0.001) and power (p<0.01). - wheelchair propulsion led to specific development of muscular capacities and power, only for wheelchair sportsmen with balance and stabilization capacities in the sitting position. - for the agonist / antagonist ratio, the three parameters of maximal work per repetition, total work and power, often showed agonist / antagonist ratios between 30% and 40% and even more than 30% in our test conditions. Similar ratios were noted for the 3 groups of subjects, thus representing an imbalance in the agonist muscle masses of the shoulder. This may be one factor in traumatism and pain. We consider that further studies, involving other functional parameters, are necessary to define behavioural capacities and prevention factors relative to wheelchair sports activities.