Effects of whole body vibration on motor unit recruitment and threshold

One-week quercetin intervention modifies motor unit recruitment patterns before and during resistance exercise in older adults: A randomized controlled trial

We investigated the effects of one-week quercetin ingestion on motor unit (MU) behavior and muscle contractile properties before, during, and after a single session of resistance exercise in older adults. Twenty-four older adults were divided into two groups: those receiving quercetin glycosides (QUE) or placebo (PLA), and they performed a single session of resistance exercise. MU behavior before and during resistance exercise and electrically elicited contraction before and after resistance exercise were measured (Day 1), and the same measurements were conducted again after 7 days of placebo or quercetin glycoside ingestion (Day 8). The MU recruitment threshold (RT) was decreased (p < 0.001, 25.6 ± 10.1 to 23.6 ± 9.5 %MVC) and the exerted force normalized by the MU firing rate (FR) was increased (p = 0.003, 1.13 ± 0.24 to 1.18 ± 0.22 %MVC/pps) from Days 1 to 8, respectively, in QUE but not PLA (p = 0.263, 22.6 ± 11.9 to 21.9 ± 11.6 %MVC; p = 0.713, 1.09 ± 0.20 to 1.10 ± 0.19 %MVC/pps, respectively). On Day 1, a significant correlation between MURT and%change in MUFR from the first to last contractions during the resistance exercise was observed in both groups (QUE: p = 0.009, rs = 0.308; PLA: p < 0.001, rs = 0.403). On Day 8 %change in MUFR was negatively correlated with MURT in QUE (p = 0.044, rs = -0.251), but there was no significant correlation in PLA (p = 0.844). There was no difference in electrically elicited contraction before and after the resistance exercise between QUE and PLA (p < 0.05). These results suggest that one-week quercetin ingestion in older adults lowered MURT and led to greater fatigue in MU with higher RT than with lower RT during resistance training.

Acute effects of caffeine or quercetin ingestion on motor unit firing pattern before and after resistance exercise

The aim of the present study was to investigate the acute effect of caffeine or quercetin ingestion on motor unit firing patterns and muscle contractile properties before and after resistance exercise. High-density surface electromyography (HDs-EMG) during submaximal contractions and electrically elicited torque in knee extensor muscles were measured before (PRE) and 60 min after (POST1) ingestion of caffeine, quercetin glycosides, or placebo, and after resistance exercise (POST2) in ten young males. The Convolution Kernel Compensation technique was used to identify individual motor units of the vastus lateralis muscle for the recorded HDs-EMG. Ingestion of caffeine or quercetin induced significantly greater decreases in recruitment thresholds (RTs) from PRE to POST1 compared with placebo (placebo: 94.8 ± 9.7%, caffeine: 84.5 ± 16.2%, quercetin: 91.9 ± 36.7%), and there were significant negative correlations between the change in RTs (POST1-PRE) and RT at PRE for caffeine (rs = - 0.448, p < 0.001) and quercetin (rs =  - 0.415, p = 0.003), but not placebo (rs =  - 0.109, p = 0.440). Significant positive correlations between the change in firing rates (POST2-POST1) and RT at PRE were noted with placebo (rs = 0.380, p = 0.005) and quercetin (rs = 0.382, p = 0.007), but not caffeine (rs = 0.069, p = 0.606). No significant differences were observed in electrically elicited torque among the three conditions. These results suggest that caffeine or quercetin ingestion alters motor unit firing patterns after resistance exercise in different threshold-dependent manners in males.

Whole-Body Vibration to Improve Physical Function Parameters in Nursing Home Residents Older Than 80 Years: A Systematic Review With Meta-Analysis

OBJECTIVE

Loss of functional independence is more likely in older adults who reside in an institution as a consequence of a decline in muscle mass and a loss of force production capacity. The aim of this review was to assess the effect of whole-body vibration (WBV) interventions on the strength, balance, and mobility of nursing home residents older than 80 years.

METHODS

An electronic search in MEDLINE, Scopus, and CINAHL databases was conducted. Randomized controlled trials that involved nursing home residents older than 80 years, that investigated WBV interventions compared with nonintervention, usual care, or placebo, and that measured physical function outcomes including strength, balance, gait, and mobility were included. Risk of bias was assessed by 2 reviewers using the Physiotherapy Evidence Database scale. The standardized mean differences (SMD) between the experimental and control groups were calculated with a random-effects model for each outcome, and subgroup analysis was conducted for different outcomes.

RESULTS

In total, 2864 articles were identified; of these, 14 randomized controlled trials met the inclusion criteria. The meta-analysis revealed that WBV significantly increased the lower limb muscle strength (SMD = 0.59; 95% CI = 0.16 to 1.03), mobility (SMD = 0.45; 95% CI = 0.10 to 0.81), gait score (SMD = 0.26; 95% CI = 0.01 to 0.51), balance (SMD = 0.41; 95% CI = 0.01 to 0.81), and physical performance (SMD = 1.33; 95% CI = 0.33 to 2.33).

CONCLUSION

WBV may be an effective intervention to improve the strength, balance, mobility, walking ability, and physical performance of older nursing home residents.

IMPACT

WBV presents a safe, accessible alternative for improving health in this vulnerable population, warranting further research and integration into health care practices.

Frequency Transmission of Oscillation from External Whole-Body Vibration Platform to the Larynx

PURPOSE

This study investigates (1) the presence of frequency transmission of oscillation from an external whole-body vibration (WBV) platform to the larynx; and (2) the factors that influence this frequency transmission.

METHODS

Thirty participants (mean age=22.3years) with normal voice were exposed to four frequency-intensity levels of WBV (10 Hz-10%, 10 Hz-20%, 20 Hz-10%, 20 Hz-20%) and were instructed to produce the natural vowel /a/ three times during each WBV setting. The frequency was extracted from the middle 1-second of each electroglottographic (EGG) signal after passing through a Hann band filter with a range of 6-24 Hz. Linear mixed-effects models were applied to determine the factors that influenced the absolute deviation of the frequency transmission.

RESULTS

All participants exhibit an extracted EGG frequency that aligns with the external WBV frequency, deviating by - 0.6 to 1.2 Hz. The absolute deviation of WBV frequency transmission is consistent for both sexes across various WBV settings, except the 10 Hz-10% setting where men tend to exhibit significantly higher deviations (P = 0.018).

CONCLUSION

Oscillations at a specific frequency are transmitted from an external WBV platform to the larynx. This study proposes the use of a "spring" system to investigate the effect of WBV on the larynx, and recommends further research to explore the potential of WBV in managing voice disorders.

Integrative function of proprioceptive system in the acute effects of whole body vibration on the movement performance in young adults

Background

The proprioceptive system coordinates locomotion, but its role in short-term integration and recovery of motor activity in imbalance of motor patterns and body remains debated. The aim of this study is investigating the functional role of proprioceptive system in motor patterns and body balance in healthy young adults.

Methods

70 participants (aged 20.1 ± 0.3) were divided into experimental groups EG1 (n = 30), EG2 (n = 30), control group (CG, n = 10). EG1 performed single WBV session on Power Plate (7 exercises adapted to Functional Movement Screen (FMS). EG2 performed single session of FMS Exercises (FMSE). CG didn't perform any physical activity. All participants performed pre- and post-session of FMS and stabilometric measurements.

Results

FMS total score in EG1 increased by 2.0 ± 0.2 (p0 < 0.001), this was significantly differed (p0 < 0.001) from EG2 and CG. Acute effects of WBV and FMSE on rate of change and standard deviation (SD) of pressure center (COP) were shown in all groups during Static Test (p0 < 0.01). SD increased (p0 < 0.01) in Given Setting Test in EG1 and EG2, and in Romberg Test (p0 < 0.001) in EG1. Length, width and area (p0 < 0.01) of confidence ellipse, containing 95% of the statokinesiogram points, decreased in Static Test in EG1; width and area (p0 < 0.01) decreased in EG2 group. Significant (p0 < 0.01) decrease in Given Setting Test was in EG1, and significant (p0 < 0.01) increase was in Romberg Test (open eyes) in CG. Maximum amplitude of COP oscillations: significantly (p0 < 0.01) decreasing along X and Y axes in EG1 and EG2, and along Y axis in CG during Static Test; along Y axis (p0 < 0.01) in all groups during Given Setting Test. Significant differences were identified (p0 < 0.01) in calculated energy consumption for COP moving during all stabilometric tests. However, inter-group differences in COP after acute WBV and FMSE sessions have not been identified.

Conclusions

Acute WBV session eliminates the deficits in motor patterns which is not the case after acute FMSE session, which, according to our integrative movement tuning hypothesis, is due to high activation of integrative function of proprioceptive system. Efficacy of WBV and FMSE on COP performance indicates a high sensitivity of postural control to different levels of proprioceptive system activity.

The impact of whole-body vibration training and proprioceptive neuromuscular facilitation on biomechanical characteristics of lower extremity during cutting movement in individuals with functional ankle instability: A parallel-group study

BACKGROUND

We compared the effects of whole-body vibration training and proprioceptive neuromuscular facilitation on the biomechanical characteristics of the lower limbs in functional ankle instability patients during cutting movement to ascertain the superior rehabilitation method.

METHODS

Twenty-two male College students with unilateral functional ankle instability volunteered for this study and were randomly divided into whole-body vibration training group and proprioceptive neuromuscular facilitation group. Kinematics data and ground reaction forces were collected using infrared motion capture system and 3-D force plates synchronously during cutting. Repeated measures two-way ANOVA was performed to analyze the data.

FINDINGS

Both training methods reduced the maximum hip abduction angle (p = 0.010, effect size: proprioceptive neuromuscular facilitation = 0.69; whole-body vibration training = 0.20), maximum knee flexion angle (p = 0.008, effect size: proprioceptive neuromuscular facilitation = 0.39, whole-body vibration training = 1.26) and angular velocity (p = 0.014, effect size: proprioceptive neuromuscular facilitation = 0.62, whole-body vibration training = 0.55), maximum ankle inversion angular velocity (p = 0.020, effect size: proprioceptive neuromuscular facilitation = 0.52, whole-body vibration training = 0.81), and knee flexion angle at the time of maximum vertical ground reaction forces (p = 0.018, effect size: proprioceptive neuromuscular facilitation = 0.27, whole-body vibration training = 0.76), and increased the maximum ankle dorsiflexion moment (p = 0.049, effect size: proprioceptive neuromuscular facilitation = -0.52, whole-body vibration training = -0.22). Whole-body vibration training reduced the maximum ground reaction forces value in the mediolateral directions (p = 0.010, effect size = 0.82) during cutting movement.

INTERPRETATION

These findings suggested that the two types of training might increase neuromuscular conduction function around the ankle. After these two types of training, functional ankle instability patients showed a similar risk of injury to the lateral ankle ligaments during cutting.

Effect of Whole-Body Vibration on Balance or Proprioception in Nonspecific Chronic Low Back Pain: A Systematic Review

Objective

This systematic review aimed to investigate the effect of whole-body vibration (WBV) on balance or proprioception for patients with nonspecific chronic low back pain (NSCLBP).

Methods

A comprehensive search was conducted using 5 databases-PubMed, Web of Science, Cochrane Library, Science Direct, and Physiotherapy Evidence Database-from inception to January 2022. Randomized clinical trials that examined the efficacy of WBV on balance or proprioception in patients with NSCLBP were incorporated. The methodological quality of each included study was assessed using the Physiotherapy Evidence Database scale.

Results

Our search strategy yielded 5309 articles, of which 7 published randomized clinical trials (313 patients) met the inclusion criteria. Three of the 4 included studies that investigated balance reported significant improvements after WBV, of which 2 were of high methodological quality. The remaining 3 studies investigating proprioception also showed significant improvements after WBV intervention.

Conclusion

Although some studies seem to provide promising results regarding the efficacy of WBV or WBV combined with exercise in improving balance and proprioception in patients with NSCLBP, at present, no definite conclusions can be drawn due to article heterogeneity and lack of clinical trials.

Whole-Body Vibration Impacts on the Degree of Toe Angle and Its Correlation to the Knee Osteoarthritis Index during Level Walking among Female University Students: A Randomized Controlled Trial

Whole-body vibration (WBV) training is used for ankle rehabilitation as it stimulates muscle spindles to excite tonic vibration reflexes, and improves muscle strength, power, joint proprioception, balance, and flexibility. Thus, this study aims to determine the impact of whole-body vibration on the degree of the toe angle and the correlation between the toe angle and knee osteoarthritis index during level walking among female university students. A randomized controlled trial was conducted with 42 participants divided into two groups. The control group performed only home-based exercise (HBE) after education, and the study group received WBV with HBE. The functional status of participants to predict osteoarthritis was evaluated using the Western Ontario and McMaster osteoarthritis index (WOMAC), where the toe angle degree and WOMAC index were assessed before and six weeks after training. The results showed a significant improvement in the toe-in angle of HBE + WBV compared to the HBE group (p = 0.02), and in HBE + WBV, an improvement of the toe angle showed a 43% decrease in the WOMAC index (p = 0.001). In conclusion, WBV for the ankle and foot training program positively affected the degree of the toe angle, that directly affected the subtalar and ankle joint mechanics. Trial registration in the Pan African Clinical Trial Registry PACTR202304816093190 (registered retrospectively, date of registration: 18 April 2023).

Whole-body vibration reduces hamstrings neuromuscular function in uninjured individuals

OBJECTIVES

Despite the growing use of whole-body vibration (WBV) to enhance quadriceps neuromuscular function, the hamstrings-specific response is unclear among those without neuromuscular impairment, which is important to inform performance-based recommendations. Our objective was to determine the immediate and prolonged effects of WBV on hamstrings and quadriceps neuromuscular function in uninjured individuals.

DESIGN

Crossover.

SETTING

Laboratory.

PARTICIPANTS

Nineteen, recreationally active individuals performed WBV and control exercise protocols, consisting of six 1-min repetitions of isometric squats, on separate days in a randomized order.

MAIN OUTCOME MEASURES

Electromyographic (EMG) amplitude, antagonist-to-agonist co-activation, rate of torque development, and peak torque of the hamstrings and quadriceps were measured pre-, immediately post-, and 20 min post-condition. Percentage change scores were calculated from baseline to each post-measurement.

RESULTS

A condition main effect indicated that WBV reduced agonist semitendinosus EMG amplitudes more than the control (-12.1% vs. -1.5%, p < .001). Antagonist vastus medialis EMG amplitudes were reduced immediately, but not 20 min following WBV (-7.1% vs. 3.5%, p < .001).

CONCLUSIONS

WBV induced an inhibitory effect on medial hamstrings activity during knee flexion contraction in a majority of our sample, yet this response was not uniformly observed and its functional relevance remains unclear in an uninjured population.

High-frequency whole-body vibration activates tonic vibration reflex

Objectives

The aim of this research was to examine whether high-frequency whole-body vibration activates the tonic vibration reflex (TVR).

Patients and methods

The experimental study was conducted with seven volunteers (mean age: 30.8±3.3 years; range, 26 to 35 years) between December 2021 and January 2022. To elicit soleus TVR, high-frequency (100-150 Hz) vibration was applied to the Achilles tendon. High-frequency (100-150 Hz) whole-body vibration and low-frequency (30-40 Hz) whole-body vibration were applied in quiet standing. Whole-body vibration-induced reflexes were recorded from the soleus muscle using surface electromyography. The cumulative average method was used to determine the reflex latencies.

Results

Soleus TVR latency was 35.6±5.9 msec, the latency of the reflex activated by high-frequency whole-body vibration was 34.8±6.2 msec, and the latency of the reflex activated by low-frequency whole-body vibration was 42.8±3.4 msec (F_{(2, 12)}=40.07, p=0.0001, ƞ² =0.87). The low-frequency whole-body vibration-induced reflex latency was significantly longer than high-frequency whole-body vibration-induced reflex latency and TVR latency (p=0.002 and p=0.001, respectively). High-frequency whole-body vibration-induced reflex latency and TVR latency were found to be similar (p=0.526).

Conclusion

This study showed that high-frequency whole-body vibration activates TVR.

Adding Intermittent Vibration to Varied-intensity Work Intervals: No Extra Benefit

Varied-intensity work intervals have been shown to induce higher fractions of maximal oxygen uptake during high-intensity interval training compared with constant-intensity work intervals. We assessed whether varied-intensity work intervals combined with intermittent vibration could further increase cyclists' fraction of maximal oxygen uptake to potentially optimise adaptive stimulus. Thirteen cyclists (V̇O_2max: 69.7±7.1 ml·kg^-1·min^-1) underwent a performance assessment and two high-intensity interval training sessions. Both comprised six 5-minute varied-intensity work intervals within which the work rate was alternated between 100% (3×30-second blocks, with or without vibration) and 77% of maximal aerobic power (always without vibration). Adding vibration to varied-intensity work intervals did not elicit a longer time above ninety percent of maximal oxygen uptake (415±221 versus 399±209 seconds, P=0.69). Heart rate- and perceptual-based training-load metrics were also not affected (all P≥0.59). When considering individual work intervals, no between-condition differences were found (fraction of maximal oxygen uptake, P=0.34; total oxygen uptake, P=0.053; mean minute ventilation, P=0.079; mean heart rate, P=0.88; blood lactate concentration, P=0.53; ratings of perceived exertion, P=0.29). Adding intermittent vibration to varied-intensity work intervals does not increase the fraction of maximal oxygen uptake elicited. Whether intermittent exposure to vibration can enhance cyclists' adaptive stimulus triggered by high-intensity interval training remains to be determined.

The Effects of Vibration Exposure on Lower-Limb Extensor Muscles' Stiffness, Elasticity, and Strength Responses in Untrained Young Individuals: A Randomized Controlled Trial

OBJECTIVES

The whole-body vibration (WBV) effects on muscle strength show inconsistent results. Moreover, there is no study about the WBV effect on stiffness, elasticity, and muscle strength. Therefore, the study aimed to examine the effect of WBV exposure with static squat posture on the stiffness, elasticity, and strength of the lower-limb extensor muscles.

MATERIAL AND METHODS

Forty healthy untrained young adults were divided into WBV and control groups. The experimental group received WBV exposure on 2 nonconsecutive days of the week, for 6 weeks. The MyotonPRO device was used for the assessment of the knee extensor and the ankle dorsiflexors' stiffness and elasticity. Isometric muscle strength was evaluated with a hand-held dynamometer. All measurements were done by the same assessor at baseline, and the following 6 weeks.

RESULTS

Significant group-by-time interactions were found for the elasticity scores of the right (d = 0.84, P = .01) and left (d = 0.77, P = .02) ankle dorsiflexors. Similar to the elasticity measurements, significant group-by-time interactions were observed in the muscle strength scores of the right (d = 0.45, P = .046) and left (d = 1.25, P < .001) ankle dorsiflexors. No significant effects were observed in any of the evaluated muscle stiffness measurements (P > .05), and there was no significant group-by-time interaction in knee-extensor muscle strength and elasticity scores (P > .05).

CONCLUSIONS

The study results indicate that if the ankle dorsiflexor strength and elasticity are desired to be increased, the 6-week WBV exposure in a static squat posture can be used in healthy individuals.

Sensorimotor recalibration of postural control strategies occurs after whole body vibration

Efficient postural control results from an effective interplay between sensory feedbacks integration and muscle modulation and can be affected by ageing and neuromuscular injuries. With this study, we investigated the effect of whole-body vibratory stimulation on postural control strategies employed to maintain an upright posture. We explored both physiological and posturography metrics, through corticomuscular and intramuscular coherence, and muscle networks analyses. The stimulation disrupts balance in the short term, but leads to a greater contribution of cortical activity, necessary to modulate muscle activation via the formation of (new) synergies. We also observed a reconfiguration of muscle recruitment patterns that returned to pre-stimulation levels after few minutes, accompanied by a slight improvement of balance in the anterior-posterior direction. Our results suggest that, in the context of postural control, appropriate mechanical stimulation is capable of triggering a recalibration of the sensorimotor set and might offer new perspectives for motor re-education.

The acute effects of whole-body vibration on motor unit recruitment and discharge properties

Introduction: several studies have reported improved neuromuscular parameters in response to whole-body vibration (WBV). This is likely achieved by modulation of the central nervous system (CNS). Reduced recruitment threshold (RT), which is the % of Maximal Voluntary Force (%MVF) at which a given Motor Unit (MU) is recruited, may be responsible for the force/power improvements observed in several studies. Methods: 14 men (25 ± 2.3 years; BMI = 23.3 ± 1.5 kg m² MVF: 319.82 ± 45.74 N) performed trapezoidal isometric contractions of the tibialis anterior (TA) at 35-50-70 %MVF before and after three conditions: WBV, STAND (standing posture), and CNT (no intervention). The vibration was applied through a platform for targeting the TA. High-density surface electromyography (HDsEMG) recordings and analysis were used to detect changes in the RT and Discharge Rate (DR) of the MUs. Results: Mean motor unit recruitment threshold (MURT) reached 32.04 ± 3.28 %MVF before and 31.2 ± 3.72 %MVF after WBV, with no significant differences between conditions (p > 0.05). Additionally, no significant changes were found in the mean motor unit discharge rate (before WBV: 21.11 ± 2.94 pps; after WBV: 21.19 ± 2.17 pps). Discussion: The present study showed no significant changes in motor unit properties at the base of neuromuscular changes documented in previous studies. Further investigations are needed to understand motor unit responses to different vibration protocols and the chronic effect of vibration exposure on motor control strategies.

Short-term effects of side-alternating Whole-Body Vibration on cognitive function of young adults

Recent research in rodents and humans revealed that Whole-Body Vibration (WBV) is beneficial for cognitive functions. However, the optimal WBV conditions are not established: contrary to vertical WBV, side-alternating WBV was not investigated before. The present study investigated the short-term effects of side-alternating WBV in standing and sitting posture on specific cognitive function of young adults. We used a balanced cross-over design. Sixty healthy young adults (mean age 21.7 ± 2.0 years, 72% female) participated. They were exposed to three bouts of two-minute side-alternating WBV (frequency 27 Hz) and three control conditions in two different sessions. In one session a sitting posture was used and in the other session a standing (semi-squat) posture. After each condition selective attention and inhibition was measured with the incongruent condition of the Stroop Color-Word Interference Test. WBV significantly (p = 0.026) improved selective attention and inhibition in the sitting posture, but not in the standing posture. The sitting posture was perceived as more comfortable, joyous and less exhaustive as compared to the standing posture. This study demonstrated that side-alternating WBV in sitting posture improves selective attention and inhibition in healthy young adults. This indicates that posture moderates the cognitive effect of WBV, although the effects are still small. Future studies should focus on the working mechanisms and further optimization of settings, especially in individuals who are unable to perform active exercise.

Effect of whole-body vibration on neuromuscular activation and explosive power of lower limb: A systematic review and meta-analysis

OBJECTIVE

The review aimed to investigate the effects of whole-body vibration (WBV) on neuromuscular activation and explosive power.

METHODS

Keywords related to whole-body vibration, neuromuscular activation and explosive power were used to search four databases (PubMed, Web of Science, Google Scholar and EBSCO-MEDLINE) for relevant studies published between January 2000 and August 2021. The methodology of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses was used. The eligibility criteria for the meta-analysis were based on PICOST principles. Methodological assessment used the Cochrane scale. Heterogeneity and publication bias were assessed by I2 index and funnel plots, respectively. The WBV training cycle is a random effect model. Publication bias was also assessed based on funnel plots. This study was registered in PROSPERO (CRD42021279439).

RESULTS

A total of 156 participants data in 18 studies met the criteria and were included in the meta-analysis for quantitative synthesis. Results of the meta-analysis showed significant improvements in lower limb neuromuscular activation immediately after WBV compared with the baseline (SMD = 0.51; 95% CI: 0.26, 0.76; p<0.001), and no significant heterogeneity was observed (I2 = 38%, p = 0.07). In addition, the highest increase in lower limb explosive power was observed (SMD = 0.32; 95% CI: 0.11, 0.52; p = 0.002), and no significant heterogeneity (I2 = 0%, p = 0.80) was noted.

CONCLUSIONS

WBV training could improve neuromuscular activation and explosive power of the lower limb. However, due to different vibration conditions, further research should be conducted to determine standardized protocols targeting performance improvement in athletes and healthy personnel experienced in training.

Adding Vibration During Varied-Intensity Work Intervals Increases Time Spent Near Maximal Oxygen Uptake in Well-Trained Cyclists

PURPOSE

Previous research suggests that the percentage of maximal oxygen uptake attained and the time it is sustained close to maximal oxygen uptake (eg, >90%) can serve as a good criterion to judge the effectiveness of a training stimulus. The aim of this study was to investigate the acute effects of adding vibration during varied high-intensity interval training (HIIT) sessions on physiological and neuromuscular responses.

METHODS

Twelve well-trained cyclists completed a counterbalanced crossover protocol, wherein 2 identical varied HIIT cycling sessions were performed with and without intermittent vibration to the lower-intensity workloads of the work intervals (6 × 5-min work intervals and 2.5-min active recovery). Each 5-minute work interval consisted of 3 blocks of 40 seconds performed at 100% of maximal aerobic power interspersed with 60-second workload performed at a lower power output, equal to the lactate threshold plus 20% of the difference between lactate threshold and maximal aerobic power. Oxygen uptake and electromyographic activity of lower and upper limbs were recorded during all 5-minute work intervals.

RESULTS

Adding vibration induced a longer time ≥90% maximal oxygen uptake (11.14 [7.63] vs 8.82 [6.90] min, d = 0.64, P = .048) and an increase in electromyographic activity of lower and upper limbs during the lower-intensity workloads by 20% (16%) and 34% (43%) (d = 1.09 and 0.83; P = .03 and .015), respectively.

CONCLUSION

Adding vibration during a varied HIIT session increases the physiological demand of the cardiovascular and neuromuscular systems, indicating that this approach can be used to optimize the training stimulus of well-trained cyclists.

The immediate effect of a single whole-body vibration session on balance, skin sensation, and pain in patients with type 2 diabetic neuropathy

Purpose

Patients with diabetic neuropathy usually suffer from impaired balance, pain, and decreased sole-foot sensation. The present research was designed to appraise the relic of whole-body vibration (WBV) on balance, pain, and sole-foot sensation in diabetic neuropathy patients.

Methods

Present study was a single-blind randomized controlled clinical trial. Thirty-four patients with type 2 diabetic neuropathy were randomly divided into intervention groups (n=17) and control (n=17). The therapeutic program in the intervention group included standing on the platform of the WBV device, and in the control group included using the device in off mode. Dynamic balance (including overall, anterior-posterior, and medial-lateral stability indices) was measured using Biodex device, functional balance with timed up and go (TUG) test, pain using the visual analog scale (VAS), and sole-foot sensation of both feet with a monofilament. The outcomes were measured in both groups before and after the interventions.

Results

Sixteen people in each group were analyzed. Intra-group comparison showed a significant improvement in the mean pain (P = 0.000), functional balance (P = 0.011), right and left sole-foot sensation (P = 0.001), and overall (P = 0.000), anterior-posterior (P = 0.000) and medial-lateral (P = 0.000) stability indices for the intervention group in post-intervention compared to pre-intervention. However, changes in the control group were not statistically significant. Results of inter-group comparison indicated a significant improvement in all parameters in the intervention group, except for functional balance.

Conclusion

WBV can be effective in reducing pain and improving the sole-foot sensation and dynamic balance.

Acute effects of vibration foam rolling and local vibration during warm-up on athletic performance in tennis players

Athletes are currently fond of vibration foam rollers (VFRs) and commercial portable vibration percussion devices (PVPDs). It is still unknown whether using these devices during warm-up has an immediate impact on athletic performance. A randomized block design was used in this study. The acute effects of VFR and PVPD on tennis players’ athletic performance during warm-up were compared. For the countermovement jump (CMJ), reactive strength index (RSI), and hexagon test (HT), the difference in performance between all interventions was significant (p = 0.007–0.034, η²_p = 0.266–0.364). Only those who received VFR had significantly different CMJ and HT results when compared to the control group (CMJ height = 53.18 ±4.49 cm, p = 0.03, d = 1.26; HT time = 10.73 ±0.4 s, p = 0.03, d = 1.12). Participants’ RSI values were significantly different after VFR (RSI = 2.01 ±0.11 cm·mm^–1, p = 0.012, d = 1.76) and PVPD (RSI = 1.99 ±0.11 cm·mm^–1, p = 0.025, d = 1.52) compared to the control group. Therefore, when using VFR and PVPD as part of warm-up protocols for tennis players of varying skill levels, VFR could have an immediate positive effect on power, reactive strength, and change of direction performance, while PVPD could immediately improve reactive strength performance.

The effect of whole body vibration on sensorimotor deficits in people with chronic ankle instability: A systematic review and meta-analysis

OBJECTIVE

To investigate the effects of whole body vibration on chronic ankle instability-associated sensorimotor deficits in balance, strength, joint position sense and muscle activity.

DATA SOURCES

Electronic databases including Cochrane Library, PubMed, Embase, Web of Science, EBSCO, China National Knowledge Infrastructure and WanFang were searched from database inception up to 31 March 2022.

METHODS

The risk of bias and methodological quality of included studies were assessed using the Cochrane tool and Physiotherapy Evidence Database (PEDro) scale respectively. Standardized mean difference (SMD) and mean differences (MD) with 95% confidence interval (CI) were calculated using the RevMan 5.3 software. Meta-regression was conducted with Stata 16.

RESULTS

Eight studies, with 315 subjects were eventually included in this review with an average PEDro score of 6.1/10. Significant effects of whole body vibration on balance (SMD = 0.61, 95% CI: 0.12 to 1.09, P = 0.01), and on the posterolateral direction (MD = 5.52, 95% CI: 1.02 to 10.01, P = 0.02) and medial direction (MD = 3.90, 95% CI: 0.87 to 6.94, P = 0.01) of the star excursion balance test were found. Whole body vibration significantly improved the peak torque (SMD = 0.36, 95% CI: 0.04 to 0.69, P = 0.03), joint position sense (SMD = 0.60, 95% CI: 0.10 to 1.11, P = 0.02), and muscle activity in tibialis anterior (SMD = 0.46, 95% CI: 0.04 to 0.88, P = 0.03) and gastrocnemius (SMD = 0.68, 95% CI: 0.14 to 1.23, P = 0.01).

CONCLUSIONS

The current evidence supports the use of whole body vibration to improve sensorimotor deficits involving balance, strength, joint position sense, and muscle activity in people with chronic ankle instability.

Characterisation of the transient mechanical response and the electromyographical activation of lower leg muscles in whole body vibration training

The aim of this study is to characterise the transient mechanical response and the neuromuscular activation of lower limb muscles in subjects undergoing Whole Body Vibration (WBV) at different frequencies while holding two static postures, with focus on muscles involved in shaping postural responses. Twenty-five participants underwent WBV at 15, 20, 25 and 30 Hz while in hack squat or on fore feet. Surface electromyography and soft tissue accelerations were collected from Gastrocnemius Lateralis (GL), Soleus (SOL) and Tibialis Anterior (TA) muscles. Estimated displacement at muscle bellies revealed a pattern never highlighted before that differed across frequencies and postures (p < 0.001). After stimulation starts, muscle oscillation peaks, drops and further stabilises, suggesting the occurrence of a neuromuscular activation to reduce the vibration-induced oscillation. The oscillation attenuation at the SOL muscle correlated with its increased activation (rho = 0.29, p < 0.001). Furthermore, only specific WBV settings led to a significant increase in muscle contraction: WBV-induced activation of SOL and GL was maximal in fore-feet (p < 0.05) and in response to higher frequencies (30 Hz vs 15 Hz, p < 0.001). The analysis of the mechanical dynamics of lower leg muscles highlights a resonant response to WBVs, that for the SOL correlates to the increased muscle activation. Despite differing across frequencies and postures, this resonant behaviour seems to discourage the use of dynamic exercises on vibrating platforms. As for the most efficient WBV combination, calf muscle response to WBVs is maximised if those muscles are already pre-contracted and the stimulation frequencies are in the 25–30 Hz range.

The reflex mechanism underlying the neuromuscular effects of whole-body vibration: Is it the tonic vibration reflex?

OBJECTIVES

Whole-body vibration (WBV) is applied to the sole of the foot, whereas local mechanical vibration (LMV) is applied directly to the muscle or tendon. The time required for the mechanical stimulus to reach the muscle belly is longer for WBV. Therefore, the WBV-induced muscular reflex (WBV-IMR) latency may be longer than the tonic vibration reflex (TVR) latency. The aim of this study was to determine whether the difference between WBV-IMR and TVR latencies is due to the distance between the vibration application point and the target muscle.

METHODS

Eight volunteers participated in this study. The soleus reflex response was recorded during WBV, LMVs, and tendon tap. LMVs were applied to the Achilles tendon and sole of the foot. The latencies were calculated using the cumulative averaging technique.

RESULTS

The latency (33.4±2.8 ms) of the soleus reflex induced by the local foot vibration was similar to the soleus TVR latency (30.9±3.2 ms) and T-reflex (32.0±2.4 ms) but significantly shorter than the latency of the soleus WBV-IMR (42.3±3.4 ms) (F_(3,21)=27.46, p=0.0001, partial η²=0.797).

CONCLUSIONS

The present study points out that the neuronal circuitries of TVR and WBV-IMR are different.

Impact of Local Vibration Training on Neuromuscular Activity, Muscle Cell, and Muscle Strength: A Review

This paper presents a review of studies on the effects of local vibration training (LVT) on muscle strength along with the associated changes in neuromuscular and cell dynamic responses. Application of local/direct vibration can significantly change the structural properties of muscle cell and can improve muscle strength. The improvement is largely dependent on vibration parameters such as amplitude and frequency. The results of 20 clinical studies reveal that electromyography (EMG) and maximal voluntary contraction (MVC) vary depending on vibration frequency, and studies using frequencies of 28-30 Hz reported greater increases in muscle activity in terms of EMG (rms) value and MVC data than the studies using higher frequencies. A greater muscle activity can be related to the recruitment of large motor units due to the application of local vibration. A greater increase in EMG (rms) values for biceps and triceps during extension than flexion under LVT suggests that types of muscles and their functions play an important role. Although a number of clinical trials and animal studies have demonstrated positive effects of vibration on muscle, an optimum training protocol has not been established. An attempt is made in this study to investigate the optimal LVT conditions on different muscles through review and analysis of published results in the literature pertaining to the changes in the neuromuscular activity. Directions for future research are discussed with regard to identifying optimal conditions for LVT and better understanding of the mechanisms associated with effects of vibration on muscles.

Arthrogenic Muscle Inhibition: Best Evidence, Mechanisms, and Theory for Treating the Unseen in Clinical Rehabilitation

CONTEXT

Arthrogenic muscle inhibition (AMI) impedes the recovery of muscle function following joint injury, and in a broader sense, acts as a limiting factor in rehabilitation if left untreated. Despite a call to treat the underlying pathophysiology of muscle dysfunction more than three decades ago, the continued widespread observations of post-traumatic muscular impairments are concerning, and suggest that interventions for AMI are not being successfully integrated into clinical practice.

OBJECTIVES

To highlight the clinical relevance of AMI, provide updated evidence for the use of clinically accessible therapeutic adjuncts to treat AMI, and discuss the known or theoretical mechanisms for these interventions.

EVIDENCE ACQUISITION

PubMed and Web of Science electronic databases were searched for articles that investigated the effectiveness or efficacy of interventions to treat outcomes relevant to AMI.

EVIDENCE SYNTHESIS

122 articles that investigated an intervention used to treat AMI among individuals with pathology or simulated pathology were retrieved from 1986 to 2021. Additional articles among uninjured individuals were considered when discussing mechanisms of effect.

CONCLUSION

AMI contributes to the characteristic muscular impairments observed in patients recovering from joint injuries. If left unresolved, AMI impedes short-term recovery and threatens patients' long-term joint health and well-being. Growing evidence supports the use of neuromodulatory strategies to facilitate muscle recovery over the course of rehabilitation. Interventions should be individualized to meet the needs of the patient through shared clinician-patient decision-making. At a minimum, we propose to keep the treatment approach simple by attempting to resolve inflammation, pain, and effusion early following injury.

Ia EPSPs in rat spinal motoneurons are potentiated after a 5-week whole-body vibration

Whole-body vibration (WBV) is often applied as an alternative method for strength training or to prevent muscle force decrease. Previous studies indicated that WBV induced: 1) changes in the contractile parameters predominantly of fast motor units, 2) higher motoneuron excitability, and 3) higher motoneuron firing rates at lower stimulus intensities compared with the control. In this study, we evaluated the influence of WBV on Ia monosynaptic input from muscle spindles because the tonic vibration reflex is responsible for the enhancement of muscle activity observed after WBV. The aim was to answer the question of whether repeated activation of muscle spindles during WBV may result in altered synaptic excitation of motoneurons. WBV was performed on adult male Wistar rats, 5 days per week, for 5 weeks, and each daily session consisted of four 30-s runs of vibration at 50 Hz. Fast-type medial gastrocnemius motoneurons were investigated intracellularly in deeply anesthetized animals in the experimental (n=7, 34 motoneurons) and control (n=7, 32 motoneurons) groups. Monosynaptic Ia EPSPs were evoked by electrical stimulation of afferent fibers from the synergistic lateral gastrocnemius and soleus muscles. Data were analyzed using a mixed linear model. WBV induced an increase of the mean EPSP amplitude by 28% (P=0.025), correlated with the resting membrane potential and input resistance, and a shortening of the mean EPSP rise time by 11% (P=0.012). The potentiation of synaptic excitation of motoneurons indicates that WBV may support rehabilitation or training processes aimed at increasing muscle strength on the basis of increased motoneuronal drive.

Is 20 Hz Whole-Body Vibration Training Better for Older Individuals than 40 Hz?

In recent years, whole-body vibration (WBV) training has been used as a training method in health promotion. This study attempted to use WBV at three different frequencies (20, 30, and 40 Hz) with subjects from different age groups to analyze the activation of the rectus femoris muscle. The subjects included 47 females and 51 males with an average age of 45.1 ± 15.2 years. Results indicated significant differences in subjects from different age groups at 20 Hz WBV. Muscle contraction was greater in the subjects who were older (F_(4,93) = 82.448, p < 0.001). However, at 30 Hz WBV, the difference was not significant (F_(4,93) = 2.373, p = 0.058). At 40 Hz WBV, muscle contraction was less in the older subjects than in the younger subjects (F_(4,93) = 18.025, p < 0.001). The spectrum analysis also indicated that at 40 Hz there was less muscle activity during WBV in the older subjects than in the younger ones. Therefore, age was found to have a significant effect on muscle activation during WBV at different frequencies. If the training is offered to elderly subjects, their neuromuscular responses to 20 Hz WBV will be more suitable than to 40 Hz WBV.

ACUTE EFFECTS OF SLING EXERCISE RECOVERY WITH WHOLE-BODY VIBRATION RESTING MUSCLE FUNCTION AND BLOOD OF LACTATE

The purpose of this study was to investigate an effective recovery method on muscle function and blood of lactate level after maximal isotonic exercise. This study was conducted in 36 adult males. The group was divided into three groups. Sling therapy group (SG, [Formula: see text]), sling therapy group with whole body vibration continuous (SAVG, [Formula: see text]) and sling therapy group with whole body vibration in intermittent (SIVG, [Formula: see text]) were randomly composed. Sling exercise therapy using supine position and whole-body vibration of 10[Formula: see text]Hz, 5[Formula: see text]mm were performed. Lactate level and muscle function during the rest, fatigue and recovery period were measured and then maximal exercise using back extension was performed to induce fatigue. After 15[Formula: see text]min, sling with whole body vibration was conducted in two groups, respectively. Blood lactate was measured a few hours before and after of vibration. Also, muscle function between only sling exercise therapy condition, sling with whole body vibration condition in all time and sling with whole body vibration condition in intermittent time were analyzed. Lactate level was recorded by lactate measurement device. Isokinetic of lumber joint extension and flexion Peak torque/body weight, total work (J), average power (W) and acceleration time (m/s2) were measured using isokinetic dynamometer. The recovery method of sling with whole body vibration showed positive changes in physical characteristics. Isokinetic contraction of peak torque/body weight (N[Formula: see text]m), average power (Watts) and total work (J) were significantly increased in the recovery step for SIVG. Lactate level was significantly decreased for SIVG as compared with SG and SAVG. This study demonstrated that sling exercise therapy with intermittent time whole body vibration could provide a positive effect on the efficient recovery of muscle function and higher reduction of lactate after maximal isotonic exercise.

Efficacy of Transcutaneous Spinal Stimulation versus Whole Body Vibration for Spasticity Reduction in Persons with Spinal Cord Injury

Transcutaneous spinal stimulation (TSS) and whole-body vibration (WBV) each have a robust ability to activate spinal afferents. Both forms of stimulation have been shown to influence spasticity in persons with spinal cord injury (SCI), and may be viable non-pharmacological approaches to spasticity management. In thirty-two individuals with motor-incomplete SCI, we used a randomized crossover design to compare single-session effects of TSS versus WBV on quadriceps spasticity, as measured by the pendulum test. TSS (50 Hz, 400 μs, 15 min) was delivered in supine through a cathode placed over the thoracic spine (T11-T12) and an anode over the abdomen. WBV (50 Hz; eight 45-s bouts) was delivered with the participants standing on a vibration platform. Pendulum test first swing excursion (FSE) was measured at baseline, immediately post-intervention, and 15 and 45 min post-intervention. In the whole-group analysis, there were no between- or within-group differences of TSS and WBV in the change from baseline FSE to any post-intervention timepoints. Significant correlations between baseline FSE and change in FSE were associated with TSS at all timepoints. In the subgroup analysis, participants with more pronounced spasticity showed significant decreases in spasticity immediately post-TSS and 45 min post-TSS. TSS and WBV are feasible physical therapeutic interventions for the reduction of spasticity, with persistent effects.

Deleterious effects of whole-body vibration on the spine: A review of in vivo, ex vivo, and in vitro models

Occupational exposure to whole-body vibration is associated with the development of musculoskeletal, neurological, and other ailments. Low back pain and other spine disorders are prevalent among those exposed to whole-body vibration in occupational and military settings. Although standards for limiting exposure to whole-body vibration have been in place for decades, there is a lack of understanding of whole-body vibration-associated risks among safety and healthcare professionals. Consequently, disorders associated with whole-body vibration exposure remain prevalent in the workforce and military. The relationship between whole-body vibration and low back pain in humans has been established largely through cohort studies, for which vibration inputs that lead to symptoms are rarely, if ever, quantified. This gap in knowledge highlights the need for the development of relevant in vivo, ex vivo, and in vitro models to study such pathologies. The parameters of vibrational stimuli (eg, frequency and direction) play critical roles in such pathologies, but the specific cause-and-effect relationships between whole-body vibration and spinal pathologies remain mostly unknown. This paper provides a summary of whole-body vibration parameters; reviews in vivo, ex vivo, and in vitro models for spinal pathologies resulting from whole-body vibration; and offers suggestions to address the gaps in translating injury biomechanics data to inform clinical practice.

Effects of Whole-Body Vibration and Balance Training on Female Athletes with Chronic Ankle Instability

We explored the effects of 6-week whole-body vibration (WBV) and balance training programs on female athletes with chronic ankle instability (CAI). This randomized controlled study involved female athletes with dominant-leg CAI. The participants were randomly divided into three groups: WBV training (Group A), balance training (Group B), and nontraining (control group; Group C). Groups A and B performed three exercise movements (double-leg stance, one-legged stance, and tandem stance) in 6-week training programs by using a vibration platform and balance ball, respectively. The Star Excursion Balance Test (SEBT), a joint position sense test, and an isokinetic strength test were conducted. In total, 63 female athletes with dominant-leg CAI were divided into three study groups (all n = 21). All of them completed the study. We observed time-by-group interactions in the SEBT (p = 0.001) and isokinetic strength test at 30°/s of concentric contraction (CON) of ankle inversion (p = 0.04). Compared with the control group, participants of the two exercise training programs improved in dynamic balance, active repositioning, and 30°/s of CON and eccentric contraction of the ankle invertor in the SEBT, joint position sense test, and isokinetic strength test, respectively. Furthermore, the effect sizes for the assessed outcomes in Groups A and B ranged from very small to small. Female athletes who participated in 6-week training programs incorporating a vibration platform or balance ball exhibited very small or small effect sizes for CAI in the SEBT, joint position sense test, and isokinetic strength test. No differences were observed in the variables between the two exercise training programs.

Individual Responses to Different Vibration Frequencies Identified by Electromyography and Dynamometry in Different Types of Vibration Application

ABSTRACT

Oliveira, MP, Menzel, H-JK, Cochrane, DJ, Drummond, MD, Demicheli, C, Lage, G, and Couto, BP. Individual responses to different vibration frequencies identified by electromyography and dynamometry in different types of vibration application. J Strength Cond Res 35(6): 1748-1759, 2021-The application of mechanical vibration is a common neuromuscular training technique used in sports training programs to generate acute increases in muscle strength. The principal aim of the study was to compare the individual optimal vibration frequency (IOVF) identified by electromyography (EMG) activity and force production in strength training. Twenty well-trained male volunteers (age: 23.8 ± 3.3 years) performed a familiarization and 2 interventions sessions, which included 5 maximal voluntary contractions (MVCs) of the elbow flexors with a duration of 10 seconds and 5-minute intervals between each MVC. The first MVC was performed without vibration followed by 4 randomized MVCs with application of vibration in the direction of the resultant muscle forces' vector (VDF) or whole-body vibration (WBV) at frequencies of 10, 20, 30, or 40 Hz. The mechanical vibration stimulus was superimposed during the MVC. Individual optimal vibration frequency, as identified by EMG, did not coincide with IOVF identified by force production; low agreement was observed between the vibration frequencies in generating the higher EMG activity, maximal force, and root mean square of force. These findings suggest that the magnitude of the vibratory stimulus response is individualized. Therefore, if the aim is to use acute vibration in conjunction with strength training, a preliminary vibration exposure should be conducted to determine the individualized vibratory stimulus of the subject, so that training effects can be optimized.

The effect of the combination of whole body vibration and shoe with an unstable surface in chronic ankle instability treatment: a randomized clinical trial

Background

Chronic ankle instability (CAI) is a common condition following an ankle sprain. This study investigated the effects of whole body vibration (WBV) and shoe with an unstable surface training on balance, functional performance, strength, joint position sense in people with CAI.

Method

Thirty- four peoples with unilateral CAI were randomly assigned to three groups: WBV group, WBV with shoe with an unstable surface (WBV-S), and no treatment control group (CON). The WBV group received 4 weeks progressive WBV training and the WBV-S group received progressive WBV training with shoe with an unstable surface. Modified star excursion balance test (mSEBT)reach distance, Hop-Test, muscle strength, and joint position sense were measured at baseline and after the 4 weeks; Moreover, the mSEBT and Hop-Test were reassessed again 2 weeks post intervention.

Results

The result showed a significant group-by-time interaction for anterior and posterolateral directions of mSEBT. The reach distance of these directions at post-intervention and follow-up increased significantly compare to pre-intervention in the WBV and WBV-S groups but not significantly change in the CON group. The Hop test in the WBV-S group was significantly more at post-intervention and follow-up compared to pre-intervention. However, no significant changes were observed in WBV and CON groups. No significant changes were observed for mSEBT posteromedial direction, muscles strength, and joint position sense errors.

Conclusion

The 4 weeks WBV and WBV-S interventions could improve balance in peoples with CAI. Improvement in Hop test was only observed in the WBV-S group suggesting the added value of combining WBV and shoe with an unstable surface as an effective therapy compared to WBV training alone. The use of WBV and WBV-S were not associated with significant changes in strength and joint position sense variables over a four-week period.

Trial registration

This work registered in the Iranian Registry of Clinical Trials (IRCT20151118025105N4).

Effects of different vibration frequencies on muscle strength, bone turnover and walking endurance in chronic stroke

This randomized controlled trial aimed to evaluate the effects of different whole body vibration (WBV) frequencies on concentric and eccentric leg muscle strength, bone turnover and walking endurance after stroke. The study involved eighty-four individuals with chronic stroke (mean age = 59.7 years, SD = 6.5) with mild to moderate motor impairment (Fugl-Meyer Assessment lower limb motor score: mean = 24.0, SD = 3.5) randomly assigned to either a 20 Hz or 30 Hz WBV intervention program. Both programs involved 3 training sessions per week for 8 weeks. Isokinetic knee concentric and eccentric extension strength, serum level of cross-linked N-telopeptides of type I collagen (NTx), and walking endurance (6-min walk test; 6MWT) were assessed at baseline and post-intervention. An intention-to-treat analysis revealed a significant time effect for all muscle strength outcomes and NTx, but not for 6MWT. The time-by-group interaction was only significant for the paretic eccentric knee extensor work, with a medium effect size (0.44; 95% CI: 0.01, 0.87). Both WBV protocols were effective in improving leg muscle strength and reducing bone resorption. Comparatively greater improvement in paretic eccentric leg strength was observed for the 30 Hz protocol.

The effects of whole-body vibration on EMG activity of the lower body muscles in supine static bridge position

OBJECTIVES

The purpose of the current study was to firstly examine the effects of different whole-body vibration (WBV) frequencies in the lower-body muscles when applied simultaneously during a bridge exercise. Secondly, determine if there were any sex differences in the lower-body muscles of WBV during the bridge.

METHODS

Seven females and 7 males completed 2 familiarization and 1 test sessions. In the test session participants were randomized to complete one 30 s bout of a bridge exercise for 3 separate conditions followed by 3-min of rest. The 3 conditions (a) No-WBV (without WBV); (b) WBV-30 (30 Hz, low amplitude); (c) WBV-50 (50 Hz, low amplitude) were performed on a WBV platform. Muscle activity of the biceps femoris (BF), semitendinosus (ST), gluteus maximus (Gmax), multifidus muscle (MF) muscles were measured.

RESULTS

Muscle activity was increased with WBV in the BF and ST muscles at WBV-30 and WBV-50 conditions (p<0.05) vs. no-WBV. During No-WBV and WBV-50 conditions, males had a higher biceps femoris activity compared to females for (p<0.05) 45 and 27 %, respectively; however, during all conditions females had a high level of Gmax activity (57%) than males (p<0.05).

CONCLUSION

Additional vibration at 30 and 50 Hz during the bridge exercise could be a useful method to enhance hamstring muscle activity.

Effect of Whole-Body Vibration Exercise on Power Profile and Bone Mineral Density in Postmenopausal Women With Osteoporosis: A Randomized Controlled Trial

OBJECTIVE

The purpose of this study was to investigate the effect of whole-body vibration (WBV) on muscle work and bone mineral density (BMD) of the lumbar vertebrae and femur in postmenopausal women.

METHODS

Forty-three postmenopausal women with low BMD were randomly assigned to WBV and control groups. Both groups received calcium and vitamin D supplementations once daily, while the WBV group additionally received WBV exercise (twice/wk) for 24 successive weeks. Qualisys gait analysis system was used to measure hip power generation by hip extensors (H1S) and flexors (H3S), hip power absorption by hip flexors (H2S), knee power absorption by quadriceps during loading response (K1S) and preswing (K3S), knee power absorption by hamstring (K4S), knee power generation by quadriceps (K2S), ankle power absorption by dorsiflexors (A1S) and plantar flexors (A2S), and ankle power generation by plantar flexors (A3S). Also, dual-energy X-ray absorptiometry was used to measure BMD of the lumbar vertebrae and femur before and after the intervention.

RESULTS

There were significant increases (P < .05) in the hip muscle work (H1S, H2S, and H3S), knee muscle work (K1S, K2S, K3S, and K4S), ankle muscle work (A1S, A2S, and A3S) during gait, and BMD of the lumbar vertebrae and femur of the WBV group. However, there were no significant changes (P > .05) in the control group. The posttreatment values of the hip, knee, and ankle muscle work and BMD of the WBV group were significantly (P < .05) higher than the posttreatment values of the control group.

CONCLUSION

Whole-body vibration training improved the leg muscle work and lumbar and femoral BMD in postmenopausal women with low BMD.

The immediate effect of whole body vibration training on the electromyographic activity of contralateral hand muscles; a randomized controlled trial

Whole Body Vibration (WBV) has been used as a useful adjunct to improve the neuromuscular function of the upper limb. Cross-transfer of strength plays an important role in rehabilitation of unilateral injuries. The present research intended to evaluate the acute effect of low frequency WBV training on cross-transfer of electromyographic activity and hand muscles strength when the measurement was performed on the contralateral limb. This was a randomized crossover trial conducted in a clinical biomechanics laboratory. Twenty-eight healthy participants aging between 20 and 35 years were included who were involved in two sessions with two weeks of rest. The participants were randomly assigned in two groups as follows: 1) active WBV/sham WBV; 2) sham WBV/active WBV. The participants were asked to stand on the vibrating plate and pull its belt in a vibrating mode using their dominant hand. Then, after a two-week rest, they performed the same task in the vibrating mode (35 Hz). Grip strength and electromyography (root mean square) in flexor digitorum profundus (FDP), flexor digitorum superficialis (FDS), extensor carpi radialis (ECR), and extensor carpi ulnaris (ECU) muscles of the contralateral limb were measured before and after exercise in both phases. No significant change was observed in the electrical activity of FDP, FDS, ECR, ECU muscles, and hands' grip strength of the contralateral limb (P > 0.05). WBV (35 Hz) was not able to augment cross-transfer in electromyographic activity and neuromuscular performance of the upper limb. Further studies would help to explore these results for several sessions of WBV on cross-transfer of training.

Combined Effects of Strengthening and Proprioceptive Training on Stability, Balance, and Proprioception Among Subjects with Chronic Ankle Instability in Different Age Groups: Evaluation of Clinical Outcome Measures

BACKGROUND

Lateral ankle sprains are among the common injuries in the physically active population in different age groups and progress to chronic ankle instability (CAI). Accordingly, the current study assesses the effectiveness of strengthening and proprioceptive training programs on proprioception and balance in those suffering from CAI.

DESIGN

Quasi-experimental design.

METHODS

Thirty-six individuals with self-reported CAI were assigned into three groups based on age: group 1 (23 ± 1.84), group 2 (35.80 ± 1.68), group 3 (44.25 ± 4.86), then performed strength and balance exercises for 6 weeks. The study furthermore measured pre- and post-training of joint position sense (JPS), static balance, dynamic balance, chronic ankle instability tool (CAIT) and lower extremity functional scale (LEFS).

RESULTS

Statistical analysis showed significant improvement (P < 0.01) on all outcome measures among all groups. In group 1, mainly the plantar flexion JPS improved to 3.7°, while in group 2 and group 3 the eversion JPS improved to 3.1° and 1.78° (P < 0.01). With reference to static balance with one's eyes closed and eyes open, the improvement in group 1 was 4.46, 11.05 s, group 2 was 2.23, 7.85 s and group 3 was 1.69, 4.68 s. In relation to dynamic balance, the development in group 1 was 5.85 cm, while group 2 was 4.71 cm and group 3 was 2.49 cm. Moreover, both CAIT and LEFS showed significant differences (P < 0.01) after training.

CONCLUSION

This study found that combined strengthening and proprioceptive training effectively improves stability, proprioception, balance, and self-reported functional outcomes.

Individualized Whole-Body Vibration: Neuromuscular, Biochemical, Muscle Damage and Inflammatory Acute Responses

Objective. We aimed to investigate the acute residual hormonal, biochemical, and neuromuscular responses to a single session of individualized whole-body vibration (WBV) while maintaining a half-squat position. Methods. Twenty male sport science students voluntarily participated in the present study and were randomly assigned to an individualized WBV group (with the acceleration load determined for each participant) or an isometric group (ISOM). A double-blind, controlled parallel study design with repeated measures was employed. Results. Testosterone and growth hormone increased significantly over time in the WBV group (P < .05 and P < .01, respectively; effect size [ES] ranged from 1.00 to 1.23), whereas cortisol increased over time in both groups (P < .01; ES ranged from 1.04 and 1.36). Interleukin-6 and creatine kinase increased significantly over time only in the WBV group (P < .05; ES = 1.07). The maximal voluntary contraction decreased significantly over time in the ISOM group (P = .019; ES = 0.42), whereas in the WBV group, the decrease did not reach a significant level (P = .05). The ratio of electromyographic activity and power decreased significantly over time in the WBV group (P < .01; ES ranged from 0.57 to 0.72). Conclusion. Individualized WBV increased serum hormonal concentrations, muscle damage, and inflammation to levels similar to those induced by resistance training and hypertrophy exercises.

Effect of Whole-Body Vibration on the Functional Responses of the Patients with Knee Osteoarthritis by the Electromyographic Profile of the Vastus Lateralis Muscles during the Five-Repetition Chair Stand Test: A Randomized Crossover Trial

Knee osteoarthritis (KOA) can cause functional disability. Neuromuscular function is relevant in the development and progression of KOA. It can be evaluated by the analysis of the surface electromyography (sEMG), which has an important role in the understanding of KOA. Whole-body vibration (WBV) is an intervention suggested to treat KOA. The objective of this work was to verify the effectiveness of WBV on the functionality of lower limbs by the electromyographic profile of the vastus lateralis (VL) muscles during the five-repetition chair stand test (5CST) in patients with KOA. This was a two-period crossover trial study (8-week washout). Nineteen patients with KOA were allocated to the group submitted to WBV (WBVG), with peak-to-peak displacement of 2.5 to 7.5 mm, frequency from 5 to 14 Hz, and acceleration peak from 0.12 to 2.95 g, or to the control group (0 Hz) (2 days per week for 5 weeks). The 5CST and the sEMG of the VL during 5CST were evaluated before and after the interventions. Results: Significant differences in 5CST were evident only in WBVG (p = 0.018), showing a decrease of the execution time. The sEMG profile showed no significative difference. Therefore, only 10 sessions of WBV with comfortable posture can bring about improvement in functionality of KOA patients without alteration of the muscle excitation.

Whole-Body Vibration for Individuals with Reconstructed Anterior Cruciate Ligament: A Systematic Review

Background

ACL ruptures are a prevalent condition, affecting daily living activities, associated with high financial burden.

Objective

To assess the effect of whole-body vibration (WBV) in the rehabilitation of patients with reconstructed anterior cruciate ligament. Methodology. An electronic search in Pubmed, Scopus, Web of Science, and PEDro databases was conducted and randomized controlled trials (RCTs) in humans that analysed the effects of WBV in patients with ACL injury subjected to reconstruction surgery, published in English, Portuguese, Spanish, Italian, or French were included. Records were identified through database search and reference screening by two reviewers, which independently examined titles and abstracts and irrelevant studies were excluded based in eligibility criteria. Relevant full texts were analysed for eligibility, and all relevant studies were included in the systematic review.

Results

Ten studies were included in the systematic review with a mean methodological quality score of 6. Results demonstrate positive effects of WBV in relevant outcomes such as knee function, electromyographic activity, balance, and muscle strength.

Conclusions

WBV demonstrated a positive effect in strength, balance, electromyographic activity, and knee function.

Cross-training effect of chronic whole-body vibration exercise: a randomized controlled study

Purpose: To determine whether unilateral leg whole-body vibration (WBV) strength training induces strength gain in the untrained contralateral leg muscle. The secondary aim was to determine the potential role of spinal neurological mechanisms regarding the effect of WBV exercise on contralateral strength training.Materials and Methods: Forty-two young adult healthy volunteers were randomized into two groups: WBV exercise and Sham control. An isometric semi-squat exercise during WBV was applied regularly through 20 sessions. WBV training was applied to the right leg in the WBV group and the left leg was isolated from vibration. Sham WBV was applied to the right leg of participants in the Control group. Pre- and post-training isokinetic torque and reflex latency of both quadricepses were evaluated.Results: The increase in the strength of right (vibrated) knee extensors was 9.4 ± 10.7% in the WBV group (p = .001) and was 1.2 ± 6.6% in the Control group (p = .724). The left (non-vibrated) extensorsvibrated) knee extensors w4 ± 8.4% in the WBV group (p = .038), whereas it decreased by 1.4 ± 7.0% in the Control (p = .294). The strength gains were significant between the two groups. WBV induced the reflex response of the quadriceps muscle in the vibrated ipsilateral leg and also in the non-vibrated contralateral leg, though with a definite delay. The WBV-induced muscle reflex (WBV-IMR) latency was 22.5 ± 7.7 ms for the vibrated leg and 39.3 ± 14.6 ms for the non-vibrated leg.Conclusions: Chronic WBV training has an effect of the cross-transfer of strength to contralateral homologous muscles. The WBV-induced muscular reflex may have a role in the mechanism of cross-transfer strength.

Effect of Multi-Frequency Whole-Body Vibration on Muscle Activation, Metabolic Cost and Regional Tissue Oxygenation

Prolonged immobilization from a critical illness can result in significant muscle atrophy. Whole-body vibration (WBV) could potentially attenuate the issue of muscle atrophy; however, there exists no device that could potentially provide WBV in supine position that is suitable for critically ill patients. Hence, the purpose of this study was to develop a new wearable suit, called therapeutic vibration device (TVD), that can provide WBV in supine position and test its effects on physiologic markers of physical activity including muscle activation, oxygen consumption (VO₂), and regional hemoglobin oxygen saturation (rSO₂). The prototype TVD delivered multi-frequency WBV axially to 19 healthy participants in supine position for 10 minutes simultaneously at 25 Hz/4.2 g_rms on the feet and 15 Hz/0.7 g_rms on the shoulders. Muscle activation was recorded by electromyography (EMG), VO₂ was measured by indirect calorimetry and rSO₂ was recorded by near-infrared spectroscopy. Recordings were collected from each participant from multiple body locations, on three separate days, at baseline and during the intervention. Acceleration was also recorded to gain insight into transmissibility and coherence. Repeated-measures ANOVA using Bonferroni correction revealed that the muscle activity significantly increased by 4% - 62% (p < 0.05), VO₂ improved by 22.3% (p < 0.05) and rSO₂ increased by 1.4% - 4.5% (p < 0.05) compared to baseline. WBV provided by the TVD is capable of producing physiologic responses consistent with mild physical activity. Such effects could potentially be valuable as an adjunct to physical therapy for early mobilization to prevent atrophy occurring from prolonged immobilization.

Effect of whole-body vibration exercise in the pelvic floor muscles of healthy and unhealthy individuals: a narrative review

The aim of this narrative review was to determine effects of whole body vibration exercises (WBVE) on the pelvic floor muscle (PFM) of healthy and unhealthy individuals. Searches were performed in the databases PubMed, Scopus, Science Direct and PEDRo. The level of evidence and methodological quality of the selected papers were determined. It was included six studies with a total of 189 participants (95.76% women) with ages ranging from 18 to 68 years. It was reported that WBVE: (I) improves the PFMs strength and quality of life (QOL) in individuals with urinary incontinence; (II) does not cause (PFM) fatigue in nulliparous continent women; (III) leads to higher (PFM) activation in subjects with weakened (PFM) and achieves higher pelvic floor (PF) activation than maximum voluntary contraction alone; (IV) in an individual with postprostatectomy stress urinary incontinence (SUI), over a period of 6 weeks after starting treatment, the patient regained continence (usage of 1 safety pad) and (V) has a significant effect on the electromyographic response and additionality and the rating of perceived exertion (RPE) significantly increased with increased frequency of the mechanical vibration. Relevant findings are presented and demonstrated that the WBVE might be highly relevant to the management of clinical disorders of the (PFM). Nevertheless, this intervention must be more understood and known to be used in the management of individuals with impairment of the (PFM) and there is the necessity of more research in this area.

The Acute Effects of Whole-Body Vibration on Fencers' Special Abilities

The purpose of this research was to study the effects of a whole-body vibration (WBV) warm-up for improving fencers' performance on variables derived from a lunge reaction test, the 10-meter sprint, and the countermovement jump. We compared fencer performances at four time intervals: (a) preintervention, (b) immediately postintervention, (c) 1-minute postintervention, and (d) 2-minute postintervention. Study participants were 16 male fencers. The vibration frequency was 30 Hz, and its amplitude was two mm. After each WBV session, participants significantly improved their performance on all measures at both one and two minutes after the intervention. Specifically, lunge reaction tests scores improved by 5.50% and 7.34%, respectively, relative to preintevention testing (p < .01), peak power output improved by 4.94% and 11.52%, respectively (p < .05), and maximum rate of force development improved by 13.41% and 18.38%, respectively (p < .01). Acute WBV (frequency = 30 Hz, peak-to-peak amplitude of two mm) induced neuromuscular activation and improved lunge reaction scores, agility, and power.

Effects of Whole-Body Vibration in Older Adult Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

OBJECTIVES

The aim of this systematic review and meta-analysis was to determine the effects of whole-body vibration training on metabolic abnormalities, mobility, balance and aerobic capacity in older adult patients with type 2 diabetes mellitus.

METHODS

We searched PubMed, Cochrane Library, PEDro, LILACS and SciELO (from the earliest date available to March 2018) for controlled trials that evaluated the effects of whole-body vibration on the health-related outcomes of patients with type 2 diabetes. Two reviewers independently selected the studies and performed statistical analyses of the studies. Weighted mean differences, standard mean differences and 95% confidence intervals (CIs) were calculated.

RESULTS

In total, 7 studies, involving 279 patients who had type 2 diabetes, that compared whole-body vibration with other exercises and/or controls were included. Individual studies suggested that whole-body vibration was associated with improvements in pain levels, blood flow in the legs, glycated hemoglobin levels and fasting blood glucose levels. Whole-body vibration improved mobility weighted mean differences (-.24 seg; 95% CI -2.0, -0.5; n=96); balance standard mean differences (2.34; 95% CI 1.16, 3.5; n=57); and aerobic capacity standard mean differences (0.7; 95% CI 0.2, 1.3; n=59).

CONCLUSIONS

Whole-body vibration could be a useful strategy in the management of the symptoms and disabilities associated with type 2 diabetes; however, it is necessary to perform further studies to reinforce the reported findings.

THE EFFECTS OF WHOLE BODY VIBRATION ON VERTICAL JUMP, POWER, BALANCE, AND AGILITY IN UNTRAINED ADULTS

BACKGROUND

Despite the increased use of whole body vibration among athletes, there is limited literature on its acute effects within heterogeneous populations such as untrained adults or recreational athletes.

HYPOTHESIS/PURPOSE

The purpose of this study was to investigate the acute effects of whole body vibration on vertical jump, power, balance, and agility for untrained males and females. It was hypothesized that there would be an effect on each outcome variable.

STUDY DESIGN

Quasi-experimental, pretest-posttest design.

METHODS

Twenty males and sixteen females, mean age 24.5 years, were assessed for vertical jump height and power as measured by the Myotest accelerometer, balance as measured by the NeuroCom Balance Master System, and agility as measured by a modified T-test. Each session consisted of a five-minute treadmill warm-up, a practice test, a baseline measurement, a two-minute rest period, whole body vibration at 2 mm and 30 Hz for 60 seconds, and a final measurement. Three different counterbalanced testing sessions were separated by a minimum of 48 hours in between sessions to minimize fatigue.

RESULTS

Significant differences existed for both genders for main effect of time for Agility (p = 0.022); end point excursion Left (p = 0.007); and maximum endpoint excursion Left (p = 0.039). Differences for main effect of gender revealed females performed better than males in the following respects: end point excursion Right (p = 0.035); end point excursion Left (p = 0.014); maximum endpoint excursion Right (p = 0.024); and maximum endpoint excursion Left (p = 0.005). Males performed better than females in two respects: Agility (p < 0.0005) and Power (p < 0.0005). A significant interaction was observed between time and gender for vertical jump (p = 0.020). Simple main effects revealed males jumped higher than females during both pre and post intervention, p < 0.0005. Females had a significant decrease in the vertical jump post intervention (p = 0.05).

CONCLUSION

Results indicated that whole body vibration produced significant differences in the main effect of time and agility, and end point and maximum end point excursion Left for both genders, acutely. Females performed better in balance compared to males and poorer in vertical jump, but males performed better in agility and power.

Effect of Horizontal Whole-Body Vibration Training on Trunk and Lower-Extremity Muscle Tone and Activation, Balance, and Gait in a Child with Cerebral Palsy

Patient: Male, 10

Final Diagnosis: Cerebral palsy

Symptoms: Movement disorder

Medication: —

Clinical Procedure: —

Specialty: Rehabilitation