Whole Body Vibration Does not Enhance Muscle Activation

Abstract

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.

Optimal whole-body vibration settings for muscle strength and power enhancement in human knee extensors

“…Although they cannot specifically be attributed to any particular group (i.e., time effect), significant improvements in Pts and Ptd were observed after the training period. This result is consistent with previous reports of isometric training of the same muscle group (Rich and Cafarelli, 2000;Maffiuletti and Martin, 2001) and with an acute WBV study (Colson et al, 2009). The potentiation of Pts was associated with an increase in the maximal rates of both twitch development (+dPt/dt) and relaxation (ÀdPt/ dt).…”

“…This result is consistent with two prior studies which reported that knee extensor muscle activation, determined by a superimposed tetanic train on maximal voluntary contraction, was not changed after 2 and 11 weeks of WBV training (de Ruiter et al, 2003a,b). In addition, recent acute WBV studies have demonstrated that voluntary muscle activation of the knee extensor muscles did not change (Colson et al, 2009) or even decreased (Jordan et al, 2010) after a single WBV session. Even though the reliability of the twitch interpolation technique can be questioned because of the recent reports on animal fibers suggesting that intracellular mechanisms can also account for the increase in torque during the superimposed twitch (Place et al, 2008), we quantified muscle activation by normalizing the superimposed twitch onto the post-contraction potentiated twitch, which was recently recommended as the most valid method at high levels of contraction (Folland and Williams, 2007).…”

“…These authors reported that WBV training did not improve voluntary muscle activation. In addition, although a recent study showed that a single WBV session induced central nervous system plasticity, which supports the possibility of neural adaptations in the tibialis anterior muscle (Mileva et al, 2009), two other acute WBV studies reported unchanged (Colson et al, 2009) or depressed (Jordan et al, 2010) voluntary muscle activation of the knee extensors. Therefore, the likelihood of neural adaptations of the knee extensor muscle after multiple sessions of WBV remains low.…”

“…Therefore, the likelihood of neural adaptations of the knee extensor muscle after multiple sessions of WBV remains low. In contrast, it is noteworthy that the electrically evoked single-twitch strength of the knee extensors was improved after both acute WBV and sham sessions (Colson et al, 2009). Then, the precise mechanisms underlying the beneficial effects of WBV training programs on muscle strength and power have yet to be determined.…”

Evaluation of a Six-Week Whole-Body Vibration Intervention on Neuromuscular Performance in Older Adults

“…In the current literature, there are some studies reporting no or less effects of WBV intervention (10,11,44). These discrepancies between previous study outcomes in younger and older men arose from the different training procedures used regarding the exercise parameters (side-alternating or synchronous vibration platform device, training period, number of sessions, duration of WBV, and volume of WBV exercises), and the vibration load determined by vibration frequency, vibration amplitude, and joint angle.…”