Isokinetic shoulder rotator muscles in wheelchair athletes

To assess the influence of wheelchair propulsion and neurological level on isokinetic shoulder rotational strength.

University of Montpellier, France

Data were evaluated in three groups of subjects as follows: 12 nonathletes, 15 tennis players and 21 wheelchair athletes. We then compared 12 high paraplegic athletes (HPA) and nine low paraplegic athletes (LPA) within the group of 21 wheelchair athletes: The isokinetic tests were performed in the seated 45 degrees abducted test position in the scapular plane at 60, 180 and 300 degrees s(-1) for both shoulders. Peak torque and mean power values were gathered and, from these values, the internal/external rotation ratios were calculated.

Intergroup comparison showed an influence of lesion and sport on peak torque at 180 and 300 degrees s(-1) for the internal rotators and significantly higher values of the internal/external ratios in the wheelchair athlete group. For mean power, we observed significant differences under all test conditions and significant differences for ratio only on the dominant side at 180 degrees s(-1) and on the dominant side at 300 degrees s(-1). Comparison of the two groups of paraplegic athletes showed significantly higher values of peak torque and mean power of the external rotators in the LPA for all test conditions.

Neurological level of lesion does not systematically influence the development of internal rotator muscles; in contrast, the participation of the external rotators appears strongly correlated to neurological level. The comparison of the two sides in the two paraplegic groups showed that in two-thirds of the cases the values of the external rotators were significantly higher than those of the internal rotators on the nondominant side for peak torque and mean power. Ratios on the dominant side were systematically higher than on the nondominant side, with significant differences also noted in two-thirds of the cases. These results raise questions about the influence of neurological level and wheelchair propulsion on the muscular adaptations of the shoulder in wheelchair athletes.