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The interest in whole-body vibration (WBV) for the enhancement of neuromuscular performance has received considerable attention. However, scientific evidence supporting the optimal prescription of WBV settings is lacking. This study investigated the acute eff ect of WBV combining high frequency/high peak-to-peak displacement (HH) or low frequency/low peakto- peak displacement (LL) vs. sham intervention (SHAM) on lower limb muscle power and stiffness. A total of 223 volunteers were randomly assigned to either the HH, LL or SHAM group. Countermovement jump (CMJ) height, maximal and average power, maximal and average lower limbs stiff ness obtained during a hopping test were recorded before and after the respective intervention. After the intervention, the HH group showed an increase of 4.64 % in CMJ height (p < 0.001) whereas the values of both the LL and SHAM groups did not change. In addition, maximal and average power of the lower limbs were signifi cantly increased in all groups (p < 0.001; 10.89 % and 12.82 %, respectively) while no eff ect on lower limbs stiff ness was observed. Our data show that high frequency combined with high peak-to-peak displacement is the most optimal WBV setting for CMJ height enhancement. Further investigation should be undertaken to ascertain the eff ectiveness of WBV on lower limbs stiff ness. [ABSTRACT FROM AUTHOR]

Whether a whole body vibration session can enhance muscle voluntary activation remains debated. This pilot study thus investigated the acute effects of an intervention with whole body vibration versus a "sham" intervention on the voluntary activation of knee extensor muscles. Ten healthy subjects volunteered to participate in two interventions, vibration and sham, in randomized order. Knee extensor muscle voluntary activation, contractile properties and maximal voluntary isometric contraction were assessed before and immediately after each intervention. No significant differences were found for any of the variables. After both interventions, muscle activation remained unchanged, whereas maximal voluntary isometric contraction was significantly reduced (p<0.05). In conclusion, the two interventions induced the same adaptations in the knee extensors. These findings can be useful in conceiving whole body vibration protocols, although future research is warranted to address the influence of vibration on neural adaptation. [ABSTRACT FROM AUTHOR]