The effect of whole body vibration exercise on muscle activation
The effect of whole body vibration exercise (WBV) on muscle activation has recently been a topic for discussion amongst some researchers. Researchers are divided on the safety and effectiveness of WBV. The aim of this study was to investigate the effect of WBV on muscle activation. Healthy university students (N = 11; 25.2 y) participated in the study (five males and six females). The resting electromyogram (EMG) signal was recorded for the: gastrocnemius medial head, rectus abdominis, and erector spinae. Participants then performed two different exercises: standing calf raises and prone bridging, without and with WBV. A Power-Plate Pro 5 vibration platform was used to superimpose WBV on voluntary exercise. The averaged EMG signal was used to describe the average muscle activation. A paired sample t-test was used for analysis. There was no significant difference observed in the EMG of the gastrocnemius and rectus abdominis muscles when WBV was superimposed onto the respective movements (p = 0.193 and 0.125, respectively). However, the EMG of the erector spinae increased significantly by 35.5% (p = 0.005) when WBV was added to the prone bridging. Thus, adding WBV to voluntary exercise led to significant increases in muscle activation of the erector spinae muscles during prone bridging, but there were no significant changes in the muscle activation of the gastrocnemius and rectus abdominis muscles. These findings are attributed to the specific positioning of the participants during WBV as well as to the specific intensity of the WBV stimuli used.
Key words: Whole body vibration, exercise, EMG, muscle activation.