487 MEP176 – Does whole body vibration training improve neuromuscular performance and knee biomechanics during landing in physically active people?

AbstractBackground An effective Anterior Cruciate Ligament (ACL) injury prevention program is needed to reduce the ACL injury risk. Whole body vibration (WBV) is a neuromuscular training method that has been widely used for muscle strengthening and rehabilitation.Objectives 1.) To investigate the effect of a 6-week WBV training on strength performance of quadriceps and hamstring.2.) To investigate its effect on neuromuscular control and knee biomechanics during landing.Design A randomized – controlled trial.Setting Laboratory setting.Participants Ten healthy volunteers without the history of lower limb injury and with tegner score ≥ 6 and aged 18–30 were recruited.Intervention WBV group received 6 weeks of WBV training (30Hz, 4 mm, 3 times/week) in addition to regular exercise. They performed 5 sets of double leg bridges at knee flex 45 ° and 5 sets of squats at knee flex 60 ° with total WBV exposure of 10 minutes each time. Main Outcome Measurements Peak torque of isokinetic muscle strength of quadriceps and hamstring was measured to evaluate strength performance, while knee biomechanics, and electromyographic (EMG) activity during single leg hop and vertical drop landing were measured to quantify neuromuscular control.Result In WBV group, quadriceps peak torque (Nm/Kg) (Pre: 219.08±14.25 vs Post 236.58±16.8, p=0.009), hamstring peak torque (Nm/Kg) (Pre: 97.41±8.88 vs Post: 113.61±9.99, p=0.017), and hamstring-to-quadriceps (H/Q) peak torque ratios (Pre: 43.95±2.15 vs Post: 47.58±2.08, p=0.047) increased significantly after WBV training, whereas there were no significant changes in the control group (p>0.05). There were no significant changes in terms of EMG activity and knee biomechanics in both groups (p>0.05).Conclusion This on-going study shows additional 6-week WBV training significantly increases H/Q peak torque ratios which may reduce the risk of ACL injury. We may propose to incorporate this WBV training into current ACL injury prevention program.View this table:View inline View popup Download powerpoint Abstract 487 Table 1 Physical characteristics of the subjects in the different groups. Values are mean ± SDView this table:View inline View popup Download powerpoint Abstract 487 Table 2 Isokinetic peak torque values of knee extensors (KE), knee flexors (KF) muscles and conventional hamstrings-to-quadriceps (H/Q) torque ratio and work fatigue in the WBV and control groups at pre- and post- training. Values are mean ± SD.* p < 0.05, respective post-training values in WBVView this table:View inline View popup Download powerpoint Abstract 487 Table 3 EMG activity during task before and after in the WBV and Control groups. Values are mean ± SDDownload figure Open in new tab Download powerpoint Abstract 487 Figure 1 Position of double leg bridges at knee flex 45°Download figure Open in new tab Download powerpoint Abstract 487 Figure 2 Position of double leg squat at knee flex 60°