Differences in EMG activity during exercises targeting the scapulothoracic region: a preliminary study

Abstract

Surface electromyographic response of the middle, lower serratus anterior, and the upper trapezius muscles was investigated within a number of exercises. In total, 16 healthy, physically active volunteers completed three individual trials consisting of arm elevation above 120°, diagonal elevation, dynamic hug, dynamic hug plus, and push-up plus while surface electromyography was used to record muscle activity in the lower and middle serratus anterior (LSA, MSA) and upper trapezius (UT) muscles. The dynamic hug plus exercise caused significant increases in the activity of the MSA compared with the other exercises (P < 0.05). The diagonal elevation, dynamic hug plus, and push up plus showed significantly higher activation in the LSA compared with the arm elevation above 120° and the dynamic hug (P < 0.05). The activation of the UT and the UT/MSA and UT/LSA ratios in both the arm elevation and diagonal shoulder flexion exercises was significantly higher than that for the dynamic hug, dynamic hug plus, and push-up plus exercises (P < 0.05). The present study showed that the dynamic hug plus exercise could be used for activating MSA and LSA. Selective activation of the LSA and MSA is better achieved with exercises that include a scapular protraction component.

Keywords: Electromyography; Scapulae; Scapulothoracic musculature; Selective activation.