Influence of neurological levels on muscular power developed by arm and shoulder in wheelchair sportmen

International audienceAn 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

Influence of sports discipline on shoulder rotator cuff balance.

Isokinetic shoulder rotational strength was evaluated in four groups of subjects as follows: 12 nonathletes, 12 runners, 15 tennis players, and 12 baseball players for a total of 51 subjects. The 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 a progression of the ratio related to the sports discipline. The nonathletes and runners had ratios close to those reported for nonathletes (1.3 to 1.5). The tennis players had ratios close to 1.5, whereas the baseball players had ratios from 1.6 to 2.2. The comparison between dominant and nondominant side showed no significant differences in the tennis players and higher values for the dominant side in the nonathletes and runners under certain conditions (180 degrees.s-1 for the nonathletes and 300 degrees.s-1 for the runners). Regarding the baseball players, the ratio was systematically higher for the dominant side. These results raise questions about the influence of sports discipline on the internal/external rotator muscle ratio and indicate the need to establish normative values based on the characteristics of the population under study

Relationship between strength and functional indexes (Rowe and Walch-Duplay scores) after shoulder surgical stabilization by the Latarjet technique.

AbstractIntroductionThe rotator cuff muscles help stabilize the glenohumeral joint. Postoperative recovery of rotator cuff muscle strength appears to be an important factor for optimal joint stabilization and the resumption of professional and/or sports activities.ObjectiveTo study the relationship between internal rotator (IR) and external rotator (ER) muscle strength, shoulder function and the resumption of sports activities (as typically evaluated with functional scores) following surgical stabilization with the Bristow-Latarjet procedure in cases of chronic shoulder instability.Patients and methodsTwenty patients with anterior, post-traumatic, chronic shoulder instability were included prospectively in a cohort study. The Rowe and Walch-Duplay functional scores were rated for the operated shoulder and the isokinetic IR and ER peak torque values were evaluated with a Con-Trex® dynamometer before surgery and then 3, 6 and 21months afterwards. The isokinetic evaluation was performed (at 180°/s, 120°/s and 60°/s) in the seated position, with the arms in 45° of abduction and 30° of antepulsion in the plane of the scapula.ResultsThere were no significant postoperative correlations between shoulder function (as judged by the Rowe and Walch-Duplay scores) and IR or ER muscle strength.ConclusionThis study did not provide evidence for a correlation between IR and ER muscle strength and functional scores after surgical stabilization of the shoulder. However, it is necessary to objectively measure the rotator cuff strength recovery to adequate the strengthening of rotator muscle prior to the resumption of sports activities. Isokinetic strength assessment may thus be a valuable decision support tool for the resumption of sports activities and would complement the functional scores studied here