Anterior Glenohumeral Impingement: Mechanisms, Risks, and Corrective Strategies

Shoulder pain is not a spontaneous event—it is often the cumulative result of repetitive stress, imbalance, and insufficient stabilization over time. One of the most common shoulder conditions observed in aquatic athletes and general population clients is anterior glenohumeral impingement, characterized by compression of the anterior structures of the shoulder during forward or overhead movement. Whether seen in swimmers, water polo players, or professionals who spend prolonged periods seated in front of a screen, the biomechanics are similar. Chronic postural distortion, muscular imbalance, and fatigue alter joint positioning, resulting in pain, performance decline, and potential injury.

Understanding Anterior Glenohumeral Impingement

Anterior glenohumeral impingement occurs when the soft tissue structures at the front of the shoulder—most commonly the long head of the biceps tendon, rotator cuff tendons, or joint capsule—are compressed against surrounding structures during active movement (Kibler et al., 2013). This typically manifests as pinching, aching, or weakness when raising the arm overhead or moving into forward flexion. Athletes often report trying to “warm through it,” yet the discomfort persists or gradually worsens, particularly during high-volume overhead training or extended bouts of work-related postures (Ludewig & Reynolds, 2009).

Primary Contributing Factors

Three key contributors drive this condition:

1. Muscular Imbalances:Overdevelopment or tightness in the pectoralis major/minor, latissimus dorsi, and anterior deltoid relative to the posterior rotator cuff and scapular stabilizers can cause anterior translation of the humeral head (Cools et al., 2015). When the posterior musculature lacks the strength or endurance to maintain optimal alignment, anterior shoulder structures are exposed to excessive stress.

2. Postural Distortions:Forward head posture and thoracic kyphosis limit scapular upward rotation and posterior tilt, decreasing subacromial space. Prolonged periods of sedentary work exacerbate this distortion, especially in individuals who do not actively offset these positions through mobility or strength training (Kebaetse et al., 1999).

3. Overuse and Fatigue:High-volume, repetitive motion leads to muscular fatigue and altered neuromuscular control, which reduces the shoulder’s ability to maintain stable mechanics (Escamilla & Andrews, 2009). As compensation occurs, movement shifts anteriorly, increasing joint irritation. In overhead athletes, this often coincides with competition phases or intensified training periods.

Specific Risk in Aquatic Athletes

Water polo players and swimmers experience significant repetitive overhead loading. During shooting, passing, and eggbeater-to-shot transitions in water polo, athletes generate high-velocity arm movements without the benefit of stable ground support. This places increased reliance on shoulder stabilizers and core musculature to maintain alignment (Wheeler et al., 2013). In swimmers, particularly during freestyle, butterfly, and backstroke, cyclic internal rotation and pull patterning create substantial anterior capsule stress, especially when posterior strength or mobility is limited (Pink & Tibone, 2000). Long training cycles and tournament weekends further heighten fatigue-based compensation.

Relevance to General Population Clients

This condition is not limited to competitive athletes. Many general population clients display similar dysfunction due to prolonged sitting, rounded shoulders, and persistent forward head posture. When individuals with existing postural deviations perform overhead movements or resistance training without proper correctional strategies, the likelihood of anterior shoulder irritation increases significantly (Ludewig & Cook, 2000). This often results in chronic discomfort, reduced functional capacity, and limitations during exercise or daily tasks.

Common Consequences if Left Untreated

If unmanaged, anterior impingement can progress into more serious conditions, including labral irritation or tearing, rotator cuff tendinopathy, biceps tendinopathy, long-term glenohumeral instability, and loss of overhead power generation (Wilk et al., 2011). Athletes frequently experience reduced shot velocity, decreased stroke efficiency, and an inability to maintain performance under fatigue. General population clients often report difficulty with reaching motions, sleep disruption, and decreased physical activity, further perpetuating postural imbalance.

Corrective Exercise Strategies

An evidence-based corrective approach addresses three core principles:

1. Restore Mobility to the Anterior Shoulder and Thoracic Spine:Improving tissue extensibility across the anterior shoulder and restoring thoracic extension enhances glenohumeral mechanics and available range of motion (McClure et al., 2006).

2. Strengthen Posterior Chain and Scapular Stabilizers:Training the posterior rotator cuff, mid and lower trapezius, and rhomboids improves humeral head positioning and reduces anterior shear forces (Cools et al., 2015).

3. Develop Shoulder and Scapular Stability Under Load:Dynamic stability training enhances the shoulder’s ability to withstand high-velocity or high-force demands, particularly in overhead athletic environments (Escamilla & Andrews, 2009).

The purpose extends beyond resolving pain; the true goal is optimizing function. When properly addressed, athletes regain power and mechanical efficiency, while general population clients improve posture, movement quality, and long-term shoulder health.

Conclusion

Anterior glenohumeral impingement is a predictable condition resulting from identifiable mechanical breakdowns. Fortunately, because the pattern is predictable, the solution is equally systematic. By restoring mobility, addressing muscular imbalances, and implementing stability-focused training, shoulder mechanics improve, reducing pain and enhancing long-term performance and durability.

Athletes can expect cleaner strokes, more powerful shots, and greater longevity in sport. General population clients often experience improved posture, decreased discomfort, and greater movement confidence. Shoulder pain is not an inevitability—it is an indicator that training must become more intentional.

If you are experiencing shoulder discomfort or wish to optimize performance and prevent future injury, I offer individualized corrective and performance-based programs specific to both high-level athletes and clients with occupational stress patterns. Early intervention is the most effective strategy.

References

• Cools, A. M., et al. (2015). Rehabilitation of scapular dyskinesis: From expert-based opinions to evidence-based practice. British Journal of Sports Medicine.

• Escamilla, R. F., & Andrews, J. R. (2009). Shoulder muscle recruitment patterns and related biomechanics during upper extremity sports. Sports Medicine.

• Kebaetse, M., et al. (1999). Effect of sitting posture on shoulder and thoracic positions. Manual Therapy.

• Kibler, W. B., et al. (2013). The role of the scapula in athletic shoulder function. American Journal of Sports Medicine.

• Ludewig, P. M., & Reynolds, J. F. (2009). The association of posture with shoulder pain. Manual Therapy.

• Ludewig, P. M., & Cook, T. M. (2000). Altered scapular kinematics in individuals with shoulder impingement. Physical Therapy.

• McClure, P. W., et al. (2006). Clinical assessment of scapular positioning. Journal of Orthopaedic & Sports Physical Therapy.

• Pink, M. M., & Tibone, J. E. (2000). The painful shoulder in the swimming athlete. Orthopedic Clinics of North America.

• Wheeler, K. W., et al. (2013). Biomechanics and injury prevention in water polo. Journal of Strength and Conditioning Research.

• Wilk, K. E., et al. (2011). Current concepts in the rehabilitation of the overhead throwing athlete. American Journal of Sports Medicine.