Background: Passive or therapist-assisted stretching, followed by scapular stabilization exercises, has been shown to be effective. However, most previous studies have focused on stretching individual muscles or specific movement directions, often neglecting the role of active scapular stretching. Objects: This study aimed to compare changes in the muscle activity of the lower trapezius (LT), serratus anterior (SA), and upper trapezius (UT), as well as the scapular posterior tilt (SPT) angle before and after scapular circle (SC) stretching during SPT exercise. Methods: Twenty participants were recruited for this study. Electromyography electrodes were attached to the LT, SA, and UT. Muscle activity and the posterior scapular tilt angle were measured while performing the SPT exercises. After the SC stretch, the measurements were repeated in the same manner. The LT, SA, and UT electromyography activities and SPT angles were analyzed using paired t-tests. Results: LT activity was significantly higher in the SC stretch plus SPT exercise compared with in the SPT exercise alone (p = 0.018). There were no significant differences in SA activity between the SPT and SC stretch plus SPT exercise conditions (p = 0.812). UT activity significantly increased in the SC stretch plus SPT exercise compared with that in the SPT exercise (p = 0.001). The SPT angle was significantly enhanced during SPT exercise after the SC stretching compared to that without SC stretching (p = 0.009). The RSP improved by 2.32% compared to the initial posture when only the SPT was performed, and improved by 9.95% when the SPT was performed after the SC stretching. Conclusion: These results suggest that performing SC stretching prior to SPT exercise may effectively improve scapular alignment and posture, even when UT activation increases more than of the LT. Elevated UT activity highlights the need to address muscular balance in corrective exercise design.

Background: The purpose of this study was to compare gluteus medius (Gmed) and quadratus lumborum (QL) muscle activities and the Gmed/QL activity ratio, during five hip abduction exercises in individuals with Gmed weakness. Objects: Nineteen participants with clinically identified Gmed weakness performed five hip abduction exercises: side-lying hip abduction (SHA), side-bridge (SB), SB using sling (SB-sling), SB with hip abduction (SB-HA), and SB-HA using sling (SB-HA-sling). Surface electromyography recorded Gmed and QL, normalized to %maximum voluntary isometric contraction (%MVIC). A repeated-measures ANOVA was used to assess differences across conditions. Results: Significant differences were found in Gmed (F = 68.980, p = 0.001) and QL (F = 10.676, p = 0.001) activation across exercises. Gmed activity was highest in SB-HA (61.77 ± 14.46 %MVIC), while SHA produced the highest Gmed/QL activity ratio (1.70 ± 0.26), indicating more selective Gmed activation. SB and SB-sling showed lower Gmed activity and higher QL activation. SB-HA-sling resulted in moderate Gmed activation without significantly increasing QL activation. Conclusion: The SB-HA exercise is effective for co-activating Gmed and QL, while SHA and SB-HA-sling are better suited for selectively targeting Gmed with minimal QL compensation. These findings support exercise selection based on specific rehabilitation goals.