Immediate and Short-Term Effect of Scapula Retraction Exercises on Subacromial Space: Do We Have Enough Evidence in Patients With Subacromial Pain?

Context: Limited information exists regarding the immediate and short-term effects of scapula retraction exercises (SREs) on acromiohumeral distance (AHD) in subacromial pain syndrome (SPS). This study's 2 main objectives were to investigate (1) the immediate effect of the SRE on AHD at varying shoulder abduction angles in patients with SPS and healthy controls and (2) the effect of the 8-week SRE program on AHD in patients with SPS.

Design: Cross-sectional and pre-post intervention designs were utilized on this study.

Methods: Twenty-one patients with SPS and age-matched healthy controls were included. First, AHD at 0°, 30°, 45°, 60°, and 90° of active shoulder abductions were recorded during (1) resting upper quadrant posture and (2) while participants were performing SREs. Patients then underwent an 8-week progressive SRE program. AHD measures, pain intensity (visual analog scale), and disability (Shoulder Pain and Disability Index) were recorded at baseline and 8 weeks. AHD were analyzed using mixed-model analyses of variance. Pain and disability were analyzed using paired samples t test.

Results: The immediate effect of the SREs revealed a significant angle-by-exercise-by-group interaction for the AHD values (F3,155 = 3.956, P = .009, ηp2=.175). Pairwise comparisons yielded that the SRE increased AHD values in patients with SPS (P < .05), yet it did not affect healthy controls (P > .05). Besides, the SRE program revealed a significant angle-by-time interaction for the AHD values (F3,054 = 9.476, P < .001, ηp2=.195). AHD increased at all elevation angles, and pain and disability improved over time (P < .05).

Conclusion: SREs immediately affect AHD in patients with SPS but not in healthy populations. Moreover, SREs applied in progressive abduction angles improve pain, functionality, and AHD values in patients with SPS.