Purpose: The purpose of the study was the assessment of the effect of cervical spine rotation on the activity of the upper (UT) and lower (LT) trapezius and serratus anterior (SA) muscles during selected shoulder movements.
Methods: The investigation included 33 healthy individuals (mean age ± SD: 22 ± 1.73 years). Bioelectrical activity of the right (R) and left (L) UT, LT, SA muscles was assessed during the following movements: elevation, flexion, abduction in the scapular and right coronal planes of the dominant (right) arm accompanied by three cervical spine positions (neutral, right rotation, left rotation).
Results: RLT EMG activity was higher during right shoulder abduction with right spine rotation vs. that registered during abduction without cervical spine rotation ( p < 0.001). RUT EMG activity during right shoulder abduction was higher when abduction was associated with left cervical spine rotation ( p < 0.01) and lower during right shoulder flexing with right cervical spine rotation, compared to shoulder movements with neutral spine position ( p < 0.001). A higher RSA EMG activity was seen during shoulder flexing ( p < 0.001) and abducting ( p < 0.05) (both in the frontal and scapular plane) when the movement was performed with right cervical spine rotation, compared to RSA activity during shoulder movements without spinal rotation.
Conclusions: The present results suggest that inclusion of appropriate cervical spine rotation during shoulder movements may result in improved activity of the trapezius and serratus anterior.