Electromyographic analysis in elite swimmers with shoulder pain during a functional task

Area of Science:

• Sports Medicine
• Biomechanics
• Exercise Physiology

Background:

• Shoulder pain is a common issue in elite swimmers, potentially linked to altered muscle activation patterns.
• Understanding the electromyography (EMG) of shoulder girdle muscles is crucial for diagnosing and managing this condition.

Purpose of the Study:

• To determine and compare the electromyography (EMG) activity of selected shoulder girdle muscles in elite swimmers experiencing shoulder pain versus those without pain.

Main Methods:

• Surface electromyography (sEMG) signals were collected from seven upper limb muscles in 12 elite swimmers with shoulder pain and 12 pain-free controls.
• Participants performed a standardized task involving marking points within circles.
• Normalized root-mean-square (RMS) values were used to quantify muscular activation.

Main Results:

• Swimmers with shoulder pain exhibited significantly greater activation in the upper trapezius, serratus anterior, and latissimus dorsi muscles compared to controls.
• No significant differences in muscle activation were observed for the middle/lower trapezius, middle deltoid, or sternocleidomastoid muscles between the groups.
• Statistical analysis revealed significant differences (p < 0.05) for the identified muscles, with moderate effect sizes.

Conclusions:

• Altered muscle activation patterns, particularly increased activity in the upper trapezius, serratus anterior, and latissimus dorsi, are associated with shoulder pain in elite swimmers.
• These findings suggest that abnormal muscle recruitment may contribute to the development or exacerbation of shoulder pain in this athletic population.
• Rehabilitation interventions for elite swimmers with shoulder pain should consider and address these specific muscle activation imbalances.