Shoulder muscle imbalance and subacromial impingement syndrome in overhead athletes

Abstract

Subacromial impingement is a frequent and painful condition among athletes, particularly those involved in overhead sports such as baseball and swimming. There are generally two types of subacromial impingement: structural and functional. While structural impingement is caused by a physical loss of area in the subacromial space due to bony growth or inflammation, functional impingement is a relative loss of subacromial space secondary to altered scapulohumeral mechanics resulting from glenohumeral instability and muscle imbalance. The purpose of this review is to describe the role of muscle imbalance in subacromial impingement in order to guide sports physical therapy evaluation and interventions.

Figures

Figure 1.

Janda's Upper Crossed Syndrome. Reprinted, with permission, from Page et al, 2010, Assessment and Treatment of Muscle Imbalance: The Janda Approach (Champaign, IL: Human Kinetics).

Figure 2.

Rotator Cuff / Deltoid Force Couple. Reprinted, with permission, from Page et al, 2010, Assessment and Treatment of Muscle Imbalance: The Janda Approach (Champaign, IL: Human Kinetics).

Figure 3.

Trapezius / Serratus Force Couple.