The effect of upper extremity rhythmical exercises on core stability muscle activities during standing position

This study identified core muscle activities that were modulated in upper extremity rhythmical exercise during a standing position. Sixteen active male collegiate subjects participated in this study. The subjects performed rhythmical exercises using their dominant arm in a standing position with 4 different foot stances: (a) double-leg stance (DS), (b) ipsilateral single-leg stance (IS), (c) contralateral single-leg stance (CS), and (d) tandem stance. The subjects performed rhythmical exercise with a customized device which included 3 different weights: 1.4 kg, 2.3 kg, and no device (0 kg). The surface electromyography of the external oblique (EO), internal oblique (IO), and lumbar multifidus (LM) muscles were measured during the exercises. The EO muscle activity in the contralateral side of the dominant arm swinging the device during the IS showed the significantly greatest activity (12.4% maximum voluntary isometric contraction [MVIC]) across different stances (P <.05). In contrast, the IO muscle activity in the contralateral side with the CS was significantly greater (16.7% MVIC) than that of the IS (14.2% MVIC) (P <.05). The LM muscle activity in the contralateral side varied with different weight loads (P <.05). Taken together, the unilateral upper extremity rhythmical exercise can enhance the amount of core muscle activity without postural displacement.