Anti-phase cocontraction practice attenuates in-phase low-frequency oscillations between antagonistic muscles as assessed with phase coherence

Voluntary contraction of skeletal muscles involves common in-phase neural oscillations in low frequencies (around 1–2 Hz) across muscles. The purpose of this study was to determine if anti-phase antagonistic cocontraction practice can attenuate the occurrence of in-phase low-frequency oscillations in antagonistic muscle activity. For this purpose, we determined the probability density function of phase coherence in surface electromyogram (EMG) between antagonistic muscles. Healthy young adults were assigned to one of three intervention groups. They performed an isometric transient and steady cocontraction test with elbow flexors and extensors before and after a session of distinct intervention. In the Cocontraction group, subjects practiced alternating anti-phase isometric cocontraction with the flexors and extensors concurrently. In the Contraction group, subjects practiced alternating isometric contraction levels with flexors or extensors independently. Subjects in the Control group did not perform motor practice. The occurrence of in-phase coherence