Joint position during anterior-posterior glide mobilization: Its effect on glenohumeral abduction range of motion

Objective: To investigate the effect of joint position during an anterior-posterior glide (APG) procedure on the range of motion (ROM) of glenohumeral abduction in cadaver specimens. Design: Mechanical simulation of APG mobilization and abduction torque ROM measurement of the glenohumeral joint with a material testing system. The immediate mechanical efficacy of APG was compared in two groups of specimens at two different joint positions: midrange (n = 5) and end range (n = 6) of glenohumeral abduction. Setting: Biomechanics laboratory. Specimens: Eleven fresh cadaver shoulder specimens (mean age, 66.9 +/- 2.5yrs). Main Outcome Measure: Improvement in glenohumeral abduction torque ROM obtained before and after APG procedure. Results: Glenohumeral abduction improved significantly, as indicated by a significant increase (Kruskal-Wallis statistics, chi(2) = 7.50, p = .006) in the torque ROM of the end range group (mean +/- standard error of the mean, 2.02 degrees +/- .20 degrees) over the midrange group (.64 degrees +/- .08 degrees). A significant difference in the magnitude of peak displacement of the humeral head between midrange (14.44 +/- 3.56mm) and end range (3.19 +/- .81mm) groups was also found (Mann-Whitney test, p < .030), Conclusion: This study demonstrated that APG technique performed at close to the end of the range of abduction is more effective in improving glenohumeral abduction ROM than that performed at the middle of the range of abduction.