Muscle Activation of Serratus Anterior during Self-Resisted Scapular Protraction with Forward Flexion on Unstable Surface in Sitting Position

Muscle Activation of Serratus Anterior during Self-Resisted Scapular Protraction with Forward Flexion on Unstable Surface in Sitting Position

Background The muscle activation of the serratus anterior (SA) is important for the performance of glenohumeral joint during functional activities. However, little research in comparison of SA muscle activation during self-resisted scapular protraction exercises in forward flexion of shoulder has been reported. Purpose The purpose of this study was to compare muscle activity of SA during three different scapular protraction exercises according to various conditions [Forward flexion with protraction (FFP), FFP with self-resistance (FFPS), FFPS with hand-exerciser (FFPSH)] in healthy individuals in sitting position. Study design Comparative, repeated measures design Methods Twenty subjects were participated. The muscle activity of SA, upper trapezius (UT) and pectoralis major (PM) were measured by using a surface electromyography device. Each subject was asked to perform three different scapular protraction exercises (FFP vs. FFPS vs. FFPSH) in random order. One-way repeated measures analysis of the variance and a Bonferroni post hoc test were used. The level of statistical significance was set at α=0.01. Results The muscle activity of SA and the SA/UT ratio were significantly different among three conditions (FFP vs. FFPS vs. FFPSH) (p<0.01). The muscle activity of SA and the SA/UT ratio during FFPSH were significantly greater compared to those with FFP and FFPS (p<0.01). However, the SA/PM ratio was not significantly different among three conditions (p>0.05). Conclusions FFPSH exercise for facilitation of SA muscle can be recommended.