Degree Name
Master of Science
Graduate Program
Human Sciences
Advisor
Phil Anton
Abstract
Background
The scapula plays a crucial role in overhead throwing mechanics acting as the proximal base for glenohumeral motion and creating optimal force transfer throughout the kinetic chain. Impaired scapular control can be linked to altered shoulder mechanics, lack of mobility, and increased injury risk in athletes whose sport require overhead movements (overhead athletes) (Cools et al., 2015; Kibler et al., 2021). Scapular stabilization programs are often used in rehabilitation and performance settings, despite the fact that the magnitude of their effectiveness on shoulder range of motion and strength outcomes in throwing populations remains unclear. The purpose of this review was to quantitatively assess the effectiveness of scapular-biased interventions on key shoulder performance indicators relevant to overhead athletes.
Methods
A literature search identified studies examining scapular stabilization interventions and their effects on shoulder mobility and strength. Studies were separated via a tiered inclusion criteria focusing on quantitative pre-post intervention outcomes. Effect sizes were calculated using Hedges g and used to analyze primary outcomes of the involved studies. These key results included internal rotation (IR) and external rotation (ER) range of motion and strength/torque. Random-effects pooling was used to blend results across multiple studies (Plummer et al., 2022; Han et al., 2015; Cha et al., 2014; Moezy et al., 2014).
Results
Pooled analysis demonstrated substantial improvements in shoulder mobility and strength following intervention. IR range of motion demonstrated a very large, pooled effect size (g = 1.19), whereas ER ROM showed moderate improvement (g = 0.47). Strength outcomes exhibited large improvements in IR torque (g = 0.97), whereas ER torque adaptations were small and more varied (g = 0.14). Mobility outcomes showed the most consistent improvements across studies, while strength adaptations demonstrated larger variability. This could potentially be due to intervention design and athlete/ individual workload.
Conclusions
Scapular-focused exercise interventions appear to produce meaningful improvements in key shoulder performance indicators among overhead athletes. Increases in glenohumeral mobility and internal rotation strength suggest improved shoulder function and may contribute to more efficient kinetic chain mechanics during throwing. These findings support the use of scapular stabilization programs as a conservative and effective strategy to enhance shoulder function and potentially facilitate athletic performance transfer.