Acute changes in neuromuscular activity in vertical jump and flexibility after exposure to whole body vibration

This study was aimed to investigate the neuromuscular activity after 10minutes of exposure to a whole body vibration (WBV) session. Twenty male young adults (24.8 +/- 2.5 year olds) were randomized and divided into 2 groups: the vibration group (VG) was exposed to 10minutes of WBV at 35Hz; performed 10minutes of WBV at 35Hz (displacement=5mm; magnitude=5g); the nonvibrated group (NVG) was the placebo group that maintained the same position on the plate but without exposure to any type of vibration. Subjects were evaluated with counter movement jump (CMJ) and muscular flexibility by means of electromyographic (EMG) analysis recorded on the vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), and gastrocnemius lateralis (LG). The 10minutes of WBV showed an increase in muscular flexibility, associated with a decrease of EMG activity in BF (P < 01) and jump height. The latter was associated with a reduction of EMGs activity in BF (P < 01). The control group did not show any significant difference in all considered parameters. These results support the hypothesis that 10minutes of WBV had effects on flexibility and explosive strength performance influencing neuromuscular behavior through inhibitor effects on antagonist muscles more than the stretch reflex activity on agonist muscles.