How "healthy" is circuit resistance training following paraplegia? Kinematic analysis associated with shoulder mechanical impingement risk

The purpose of the study was to determine whether wheelchair-based circuit resistance training (CRT) exercises place the shoulder at risk for mechanical impingement. Using a novel approach, we created a mechanical impingement risk score for each exercise by combining scapular and glenohumeral kinematic and exposure data. In a case series design, 18 individuals (25-76 yr old) with paraplegia and without substantial shoulder pain participated. The mean mechanical impingement risk scores at 45-60 degrees humerothoracic elevation were rank-ordered from lowest to highest risk as per subacromial mechanical impingement risk: overhead press (0.6 +/- 0.5 points), lat pulldown (1.2 +/- 0.5 points), chest press (2.4 +/- 2.8 points), row (2.7 +/- 1.6 points), and rickshaw (3.4 +/- 2.3 points). The mean mechanical impingement risk scores at 105-120 degrees humerothoracic elevation were rank-ordered from lowest to highest risk as per internal mechanical impingement risk: lat pulldown (1.2 +/- 0.5 points) and overhead press (1.3 +/- 0.5 points). In conclusion, mechanical impingement risk scores provided a mechanism to capture risk associated with CRT. The rickshaw had the highest subacromial mechanical risk, whereas the overhead press and lat pulldown had the highest internal mechanical impingement risk. The rickshaw was highlighted as the most concerning exercise because it had the greatest combination of magnitude and exposure corresponding with increased subacromial mechanical impingement risk.