Serratus anterior muscle activation during knee push-up plus exercise performed on static stable, static unstable, and oscillating unstable surfaces in healthy subjects.

Objectives: To compare electromyographic (EMG) activity of the serratus anterior (SA) during knee push-up plus exercises according to various surfaces (static stable, static unstable, and oscillating unstable surfaces).

Study Design: Comparative study by repeated measures.

Setting: Yonsei University laboratory.

Participants: In total, 15 healthy male subjects participated.

Main Outcome Measures: The subjects performed knee push-up plus exercises on three different surfaces: static stable, static unstable, and oscillating unstable surfaces. Surface EMG activity of the SA for the peak and average amplitudes were collected from the dominant arm and presented as a percentage of the maximal voluntary contraction. A one-way repeated-measures ANOVA with a Bonferroni post hoc test was performed to compare differences in SA EMG activity according to the surface.

Results: The peak and average amplitudes of SA activity were significantly greater during knee push-up plus on the oscillating unstable surface than on the static stable or static unstable surfaces (p < 0.01). Additionally, there was no significant difference between the stable and static unstable surfaces (p > 0.05).

Conclusions: Knee push-up plus exercise on an oscillating unstable surface activates the SA more than the same exercise on static stable and static unstable surfaces.