Overhead Shoulder Position Versus Scapular Retraction Position to Normalize the Electromyographic Signal of the Lower...

Area of Science:

• Orthopedics
• Sports Medicine
• Rehabilitation

Background:

• Shoulder pain is a common condition affecting daily activities.
• Understanding muscle activation patterns is crucial for effective rehabilitation.

Purpose of the Study:

• To compare lower trapezius muscle electromyographic (EMG) response during isometric contractions in overhead versus scapular positions.
• To assess pain levels associated with each position in individuals with and without shoulder pain.

Main Methods:

• Surface EMG monitored lower trapezius activity during maximal voluntary isometric contractions.
• Participants performed contractions in overhead and scapular positions.
• Pain was rated using the visual analog scale (VAS).

Main Results:

• The shoulder pain (SP) group reported higher pain in the overhead position (VAS: SP = 4) compared to the scapular position (VAS: SP = 1.09).
• No significant difference in lower trapezius (LT) muscle excitation was observed between the two positions.
• The non-shoulder pain (nSP) group showed higher LT muscle excitation than the SP group.

Conclusions:

• Scapular positioning is preferable to overhead positioning for normalizing lower trapezius activation in individuals with shoulder pain.
• Exercise modifications can reduce pain and maintain muscle engagement during shoulder rehabilitation.