Effect of Vibration Training in Maximal Effort (70% 1RM) Dynamic Bicep Curls
To examine (i) the acute effect of direct vibration on neuromuscular performance with a maximal-effort dynamic resistance exercise and (ii) the acute residual effect of direct vibration training both with and without the resistance exercise.
Fourteen subjects were exposed to four training conditions in random order: exercise with vibration (E + V); exercise with sham vibration (E + SV); no exercise with vibration (NE + V); and no exercise with sham vibration (NE + SV). The exercise comprised three sets of maximal-effort bicep curls with a load of 70% 1RM. A portable vibrator was strapped onto the skin over the bicep tendon to apply vibration with an amplitude and frequency of 1.2 mm and 65 Hz. Elbow joint angle and bicep EMG were measured both during training and in pre- and posttraining tests. Angular velocity, moment, power, and bicep root mean squared value of EMG (EMG(rms)) and mean power frequency of EMG (EMG(mpf)) were determined for the concentric phase. Interday reliability ranged from 0.69 to 0.99.
During training (acute effect) vibration did not enhance mean angular velocity (1.5 vs 1.5 rad.s(-1), P = 0.86), peak angular velocity (2.7 vs 2.7 rad.s(-1), P = 0.90), mean moment (27.3 vs 27.4 N.m, P = 0.83), peak moment (39.8 vs 39.4 N.m, P = 0.53), mean power (40.3 vs 41.1 W, P = 0.72), peak power (91.9 vs 90.2 W, P = 0.77), or bicep EMG(rms) (73.9 vs 71.9, P = 0.78). Similarly, after training (acute residual effect) there was no enhancement from vibration in the mechanical and EMG output when the muscle was trained or was rested (P > 0.05).
These findings suggest that direct vibration, with an amplitude of 1.2 mm and frequency of 65 Hz, applied to the bicep muscle tendon, does not enhance neuromuscular performance in maximal-effort contractions during or immediately after training.
Available from: Derek N Pamukoff
- "Therefore, a higher WBV frequency may be required to elicit the same response as a lower LMV frequency applied directly to the quadriceps. Studies suggest that LMV at 60–65 Hz at 1–2 mm amplitude does not improve muscle function (Luo et al., 2008; Moran et al., 2007). Luo et al. (2008) suggested that this frequency range may be too high to stimulate neuromuscular output. "
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Vibratory stimuli enhance muscle activity and may be used for rehabilitation and performance enhancement. Efficacy of vibration varies with the frequency of stimulation, but the optimal frequency is unclear. The purpose of this study was to examine the effects of 30Hz and 60Hz local muscle vibration (LMV) on quadriceps function.
20 healthy volunteers (age=20.4±1.4 years, mass=68.1±11.0 kg, height=170.1±8.8 cm, males=9) participated. Isometric knee extensor peak torque (PT), rate of torque development (RTD), and electromyography (EMG) of the quadriceps were assessed followed by one of the three LMV treatments (30Hz, 60Hz, control) applied under voluntary contraction, and again immediately, 5, 15, and 30 minutes post-treatment in three counterbalanced sessions. Dependent variables were analyzed using condition by time repeated-measures ANOVA.
The condition x time interaction was significant for EMG amplitude (p=0.001), but not for PT (p=0.324) or RTD (p=0.425). The increase in EMG amplitude following 30Hz LMV was significantly greater than 60Hz LMV and control.
These findings suggest that 30Hz LMV may elicit an improvement in quadriceps activation and could be used to treat quadriceps dysfunction resulting from knee pathologies.
Journal of Electromyography and Kinesiology 12/2014; DOI:10.1016/j.jelekin.2014.07.014 · 1.65 Impact Factor
Available from: Chiang Liu
- "Furthermore, not all WBV training was effective, and the effects differed when using different equipment and methods (Giminiani et al., 2009; Luo et al., 2008). Consequently, WBV training was also combined with other training methods, such as conventional weight training (Ronnestad, 2004), upper limb muscle training (Moran et al., 2007) or isometric training together with vibration stimuli (Mischi and Cardinale, 2009). The results showed that the combined WBV training was more effective than the isolated training methods (Delecluse et al., 2003). "
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ABSTRACT: The aim of this study was to determine whether performing Tai Chi Chuan on a customized vibration platform could enhance balance control and lower extremity muscle power more efficiently than Tai Chi Chuan alone in an untrained young population. Forty-eight healthy young adults were randomly assigned to the following three groups: a Tai Chi Chuan combined with vibration training group (TCV), a Tai Chi Chuan group (TCC) or a control group. The TCV group underwent 30 minutes of a reformed Tai Chi Chuan program on a customized vibration platform (32 Hz, 1 mm) three times a week for eight weeks, whereas the TCC group was trained without vibration stimuli. A force platform was used to measure the moving area of a static single leg stance and the heights of two consecutive countermovement jumps. The activation of the knee extensor and flexor was also measured synchronously by surface electromyography in all tests. The results showed that the moving area in the TCV group was significantly decreased by 15.3%. The second jump height in the TCV group was significantly increased by 8.14%, and the activation of the knee extensor/flexor was significantly decreased in the first jump. In conclusion, Tai Chi Chuan combined with vibration training can more efficiently improve balance control, and the positive training effect on the lower extremity muscle power induced by vibration stimuli still remains significant because there is no cross-interaction between the two different types of training methods. Key pointsEight weeks of Tai Chi Chuan combined with vibration training can more efficiently improve balance control for an untrained young population.The positive training effect on the lower extremity muscle power induced by vibration stimuli during Tai Chi Chuan movements still remains significant because of SSC mechanism.Combining Tai Chi Chuan with vibration training is more efficient and does not decrease the overall training effects due to a cross-interaction of each other.
Journal of sports science & medicine 10/2013; 12(1):19-26. · 1.03 Impact Factor
Available from: jssm.org
- "However, the range of amplitude, which caused augmentation, occurred between 25-150 µm (Bishop 1974). Moran et al. (2007) argued that higher vibration amplitudes may only benefit sub-maximal contractions and proposed that in maximal voluntary contractions the Ia afferent discharge may reach a saturation threshold, where vibration is unable to cause further increases in Ia afferent inflow. Supporting evidence is based on observations that state, vibration can only increase maximal isometric contraction force and EMG activity when fatigue is present in the intrafusal fibres (Bongiovanni and Hagbarth, 1990) or when α-fibre are blocked (Hagbarth et al., 1986). "
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ABSTRACT: There is strong evidence to suggest that acute indirect vibration acts on muscle to enhance force, power, flexibility, balance and proprioception suggesting neural enhancement. Nevertheless, the neural mechanism(s) of vibration and its potentiating effect have received little attention. One proposal suggests that spinal reflexes enhance muscle contraction through a reflex activity known as tonic vibration stretch reflex (TVR), which increases muscle activation. However, TVR is based on direct, brief, and high frequency vibration (>100 Hz) which differs to indirect vibration, which is applied to the whole body or body parts at lower vibration frequency (5-45 Hz). Likewise, muscle tuning and neuromuscular aspects are other candidate mechanisms used to explain the vibration phenomenon. But there is much debate in terms of identifying which neural mechanism(s) are responsible for acute vibration; due to a number of studies using various vibration testing protocols. These protocols include: different methods of application, vibration variables, training duration, exercise types and a range of population groups. Therefore, the neural mechanism of acute vibration remain equivocal, but spinal reflexes, muscle tuning and neuromuscular aspects are all viable factors that may contribute in different ways to increasing muscular performance. Additional research is encouraged to determine which neural mechanism(s) and their contributions are responsible for acute vibration. Testing variables and vibration applications need to be standardised before reaching a consensus on which neural mechanism(s) occur during and post-vibration. Key pointsThere is strong evidence to suggest that acute indirect vibration acts on muscle to enhance force, power, flexibility, balance and proprioception, but little attention has been given to the neural mechanism(s) of acute indirect vibration.Current findings suggest that acute vibration exposure may cause a neural response, but there is little consensus on identifying which neural mechanism(s) are specifically responsible. This is due to a number of studies using various vibration testing protocols (i.e.varying frequencies, amplitudes, durations, and methods of application).Spinal reflexes, muscle tuning and neuromuscular aspects and central motor command are all viable neuromechanical factors that may contribute at different stages to transiently increasing muscular performance.Additional research is encouraged to determine when (pre, during and post) the different neural mechanism(s) respond to direct and indirect vibration stimuli.
Journal of sports science & medicine 01/2011; 10(1):19-30. · 1.03 Impact Factor
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