J Korean Phys Ther.  2023 Dec;35(6):167-176. 10.18857/jkpt.2023.35.6.167.

Comparisons of Shoulder Muscle Activity and Muscle Activity Ratio during Serratus Anterior Exercise between CrossFit Practitioners with/without Shoulder Impingement Syndrome

• Kang E
• Lim C
• Lim H

• KMID: 2552683
• DOI: http://doi.org/10.18857/jkpt.2023.35.6.167

Abstract

Purpose
Due to the high incidence of shoulder injuries, including shoulder impingement syndrome (SIS), among CrossFit practitioners due to frequent overhead movements, serratus anterior exercises are considered crucial for scapular stabilization in both intervention and prevention.
Objective
The objective of this study is to compare the muscle activity and ratios of scapular stabilizing and shoulder girdle muscles between individuals with and without SIS during serratus punch and wall slide exercises, both targeting the serratus anterior muscle, in CrossFit training practitioners.
Methods
Surface electromyography was used to compare the muscle activity and activity ratio of scapular stabilizing muscles and shoulder muscles during serratus punch and wall slide exercises in two groups of 20 CrossFit practitioners: ten with SIS and ten without symptoms.
Results
The group with SIS showed higher activation of the pectoralis major, upper trapezius, and a higher pectoralis major/serratus anterior and upper trapezius/serratus anterior muscle activation ratio during the serratus punch exercise compared to the group without SIS. Similarly, during the wall slide exercise, the group with SIS exhibited higher activation of the upper trapezius and a higher upper trapezius/serratus anterior muscle activation ratio compared to the group without SIS. However, no significant difference in serratus anterior muscle activation was observed between the two groups.
Conclusions
This study highlights the higher activation of the pectoralis major and upper trapezius muscles in CrossFit practitioners with SIS during the serratus anterior exercise, suggesting the importance of minimizing the overactivation of these muscles to prevent impingement syndrome in this population.

Keyword

Crossfit; Shoulder impingement syndrome; Serratus punch exercise; Wall slide exercise