Differences between clinician- and self-administered shoulder sustained mobilization on scapular and shoulder muscle activity during shoulder abduction: A repeated-measures study on asymptomatic individuals
Background: Sustained glenohumeral postero-lateral glide administered by a clinician is commonly used in the management of patients with shoulder pain. This technique reduced shoulder muscle activity in asymptomatic individuals, but it is unknown whether a self-administered version of the mobilization leads to similar neuromuscular response. This study compared the effect of sustained shoulder mobilizations (performed by a physiotherapist) with self-administered mobilization (with a belt) on activity levels of scapular and glenohumeral shoulder muscles.
Methods: Twenty-two individuals participated in this study, which had a cross-over, repeated measures design. Seven shoulder muscles (upper and lower trapezius, supraspinatus, infraspinatus, posterior deltoid, middle deltoid, and serratus anterior) were monitored using surface electromyography (SEMG) during shoulder abduction performed with a clinician-administered sustained mobilization, and with self-administered sustained mobilization. Muscle activity levels were measured prior, during and after the sustained glide was applied to the shoulder. Mixed-effect models for repeated measures were used for within- and between-condition comparisons.
Results: There was no carry-over effect. Within-condition comparisons suggest that both interventions lead to changes in scapular and shoulder muscle activity levels. No differences between clinician-administered and self-administered mobilizations at intervention and follow-up were found for the monitored muscles, with the exception of upper trapezius.
Conclusions: In young, asymptomatic individuals, self- or clinician-administered sustained mobilizations reduced activity levels of most scapular and shoulder muscles during shoulder abduction. This effect was observed only while the sustained glides were applied to the shoulder. At the immediate follow-up, muscle activity levels were similar to baseline measurements.