Influence of muscle activation of posterior oblique sling in different hip positions among three different shoulder movements in overhead athletes: an observational study

Introduction
Overhead movement demands optimal pelvic and scapular stability and alignment for efficient energy transfer during shoulder movements. Throughout a game, hyperactivity of the pelvic and scapular musculature might affect performance. As a result, we can establish goals for muscle strength and injury prevention. To study the muscles activation of posterior oblique sling muscles (POS) in different hip positions (Standing, Sitting and Lunge) with three different shoulder movements (flexion, extension & abduction) among sports population.

Material and methods
Muscle activation was recorded by surface electromyography [EMG: Noraxon-USA (MR3 3.8.30)] in 38 male athletes of different sports [cricket (bowlers)-10; baseball-9; volleyball-9; control group (recreational overhead)-10]. Maximum voluntary isometric contraction (MVIC) were collected in order to compare muscular activation. Every player performed shoulder flexion, abduction and extension in standing, sitting and lunge positions.

Results
Significant differences in muscle activity were noted using 3-way ANOVA and Bonferroni post hoc test. The result of study showed statistically significant interactions between individually group, position & muscle with shoulder movements (p = .000) and pairwise comparison between subjects were showed significance difference (p= <. 05).

Conclusions
All hip position changes may be beneficial in scapular rehabilitation training because more muscles are recruited, however in shoulder extension motions, posterior oblique sling muscles are activated more than abduction muscles. While sitting, the serratus anterior is the most active muscle, than the lower trapezius, latissimus dorsi, and gluteus maximus.