Transmission of vertical whole body vibration to the human body

Effect of whole-body vibration training on bone mineral density in older adults: a systematic review and meta-analysis

Background

Whole-body vibration (WBV) aims to increase bone mineral density (BMD) using vertical mechanical accelerations from the plantar surface of the feet through the muscles and bones. A vibration platform is used for this purpose. This systematic review (PROSPERO-CRD 42023395390) analysed the effects of WBV training on BMD at anatomical sites most affected by osteoporotic fractures in older adults.

Methodology

Systematic searches were conducted in the databases. Randomized controlled studies quantifying aerial BMD (aBMD) using the dual-energy X-ray absorptiometry method before and after WBV training in adults aged 55 and older were included. Independent reviewers performed methodological quality analysis (TESTEX) and assessed the risk of bias, and the GRADE scale determined the certainty of evidence in the results of the selected studies. The aBMD values from anatomical sites in the femoral neck, total proximal femur, and lumbar spine from WBV training protocols were included in the meta-analysis. The forest plot was generated using the random-effects model, and the effect size was measured by Hedges' g.

Results

Seven studies involving 202 participants were included, with TESTEX = 12.6 (excellent quality) and risk of bias (43% low risk, and 57% some concerns), demonstrating with low heterogeneity, a significant effect of WBV training on total femur aBMD (g = 0.28 (small), p = 0.04). However, in spite of the low heterogeneity, the femoral neck (g = 0.15 (trivial), p = 0.19) and lumbar spine (g = 0.13 (trivial), p = 0.31) regions did not show a significant effect with WBV training.

Conclusions

The results showed with low certainly evidence that WBV training had a statistically significant effect on total femur aBMD but not on femoral neck and lumbar spine.

Low-Intensity Vibration to Reduce Symptoms and Improve Physical Functioning in Cancer Survivors With Chemotherapy-Induced Peripheral Neuropathy: A Pilot Randomized Trial

PURPOSE

Chemotherapy-induced peripheral neuropathy (CIPN) can have deleterious effects on mobility and quality of life in people with cancer. Vibration therapy shows promise as a CIPN intervention but is understudied. We investigated the feasibility and preliminary efficacy of low-intensity vibration (LIV) in cancer survivors with CIPN.

METHODS

We conducted a pilot randomized controlled trial in adult cancer survivors with persistent CIPN symptoms. Participants were randomly assigned to twice-daily LIV sessions (10 min/session; 30 Hz, 0.4 g) for 12 weeks or usual care (UC). We assessed feasibility by accrual, retention, adherence, and adverse event (AE) reporting. We evaluated preliminary efficacy by changes in patient-reported CIPN symptoms (Functional Assessment of Cancer Therapy/Gynecologic Oncology Group Neurotoxicity), pain (Brief Pain Inventory), fatigue (Patient-Reported Outcome Measurement Information System Fatigue), and physical functioning (Late-Life Function and Disability Instrument) and objectively measured physical functioning (chair stand time, gait speed), stability (postural sway), and mobility (Timed-Up-and-Go). Linear regression models were used to generate effect size estimates (Cohen's d).

RESULTS

We accrued 95% of our target sample (n = 38, mean age: 62.6 ± 9.9 years, 89% female, median time since chemotherapy completion: 18 [6-39] months), with 20 participants randomly assigned to LIV and 18 to UC. Trial retention was 97% and mean adherence to LIV was 77% ± 18%. There were no serious AEs. Compared with UC, LIV participants reported greater improvements in sensory neuropathy symptoms (LIV, +1.4 ± 3.3 points; UC, +0.2 ± 2.8 points; Cohen's d = 0.45) and basic lower extremity function (LIV, +5.3 ± 8.5 points; UC, -0.7 ± 9.2 points; Cohen's d = 0.80), with moderate-to-large effect sizes for changes in stability, mobility, and gait (Cohen's d = 0.60-0.66).

CONCLUSION

LIV is safe, feasible, and shows preliminary efficacy for CIPN symptom relief and improving physical functioning in cancer survivors with CIPN.

The efficacy of vibration therapy on lower limbs spasticity in individuals with stroke: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

This study aims to evaluate the efficacy of vibration therapy (VT) in reducing lower limb spasticity and its potential implications for rehabilitation strategies.

METHODS

A comprehensive search was conducted in multiple databases PUBMED, and Web Of Science, EMBASE(Ovid), Cochrane Library, Clinical Trials and Chi CTR up to 1 June, 2024. Meta-analysis was performed using the RevMan 5.4 software to calculate standardized mean differences (SMD) with 95% confidence intervals (CI).

RESULTS

A total of seven RCTs were included in the meta-analysis. The results indicated that VT significantly reduced lower limb spasticity in post-stroke individuals (SMD= -0.65, 95% CI -1.29 to -0.02, p < 0.05). However, subgroup analyses revealed no significant differences in treatment efficacy based on session duration, targeted joints, number of sessions, or vibration frequency.

CONCLUSIONS

Vibration therapy shows potential in reducing lower limb spasticity in stroke survivors. While the overall findings support its effectiveness, the lack of consistent effects across subgroups suggests that future studies should further explore how specific intervention parameters influence outcomes. Well-designed RCTs are warranted to determine optimal VT protocols and to clarify its role within comprehensive rehabilitation programs.

The effects and possible mechanisms of whole-body vibration on cognitive function: A narrative review

Whole-body vibration (WBV) is a physical stimulation method that transmits mechanical oscillations to the entire body through a vibration platform or device. Biokinetic and epidemiologic studies have shown that prolonged exposure to high-intensity WBV increases health risks, primarily to the lumbar spine and the nervous system connected to it. There is currently insufficient evidence to demonstrate a quantitative relationship between vibration exposure and risk of health effects. The positive effects of WBV on increasing muscle strength and improving balance and flexibility are well known, but its effects on cognitive function are more complex, with mixed findings, largely related to vibration conditions, including frequency, amplitude, and duration. Studies have shown that short-term low-frequency WBV may have a positive impact on cognitive function, demonstrates potential rehabilitation benefits in enhancing learning and memory, possibly by promoting neuromuscular coordination and enhancing neural plasticity. However, long term exposure to vibration may lead to chronic stress in nerve tissue, affecting nerve conduction efficiency and potentially interfering with neuroprotective mechanisms, thereby having a negative impact on cognitive ability, even causes symptoms such as cognitive decline, mental fatigue, decreased attention, and drowsiness. This literature review aimed to explore the effects of WBV on cognitive function and further to analyze the possible mechanisms. Based on the analysis of literatures, we came to the conclusion that the impact of WBV on cognitive function depends mainly on the frequency and duration of vibration, short-term low-frequency WBV may have a positive impact on cognitive function, while long term exposure to WBV may lead to cognitive decline, and the mechanisms may be involved in neuroinflammation, oxidative stress, synaptic plasticity, and neurotransmitter changes. This review may provide some theoretical foundations and guidance for the prevention and treatment of WBV induced cognitive impairment.

Upper extremity function and disability recovery with vibration therapy after stroke: a systematic review and meta-analysis of RCTs

BACKGROUND

This study aimed to investigate the therapeutic effects of vibration therapy for improving upper extremity motor impairment, function, and disability recovery in people with stroke.

DESIGN

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. PubMed, EMBASE, the Cochrane Library Database, Physiotherapy Evidence Database (PEDro), China Knowledge Resource Integrated Database, and Google Scholar were searched from inception to May 31, 2024. Randomized controlled trials (RCTs) that evaluated the effects of vibration therapy on upper extremity motor impairment, function, and disability recovery post-stroke were analyzed.

SETTING AND PARTICIPANTS

Participants with a diagnosis of stroke with hemiplegia (or hemiparesis) were recruited.

METHODS

Methodological quality assessment was performed using the PEDro quality score. Upper extremity motor impairment, function, and disability were the primary outcomes. Upper extremity motor impairment was measured using the Fugl-Meyer Assessment scale and other methods. Upper extremity functions were evaluated using the Wolf Motor Function test or other tools assessing manipulative activities. Disability was assessed using the Functional Independence Measure, Barthel index, and other methods.

RESULTS

Overall, 30 RCTs including 1621 people with stroke were selected. Compared with the control, vibration therapy exerted significant effects on upper extremity motor impairment [standardized mean difference (SMD) = 1.19; p < 0.00001)], function (SMD = 0.62; p < 0.00001), and disability recovery (SMD = 1.01; p < 0.00001). The subgroup analysis revealed that focal vibration therapy (SMD = 2.14) had favorable effects on disability recovery compared with whole-body vibration therapy (SMD = 2.0). Interventions lasting 4-8 weeks showed significant improvements in motor impairment (SMD = 1.19), motor function (SMD = 0.57), and disability (SMD = 0.84); additionally, the effects of vibration therapy combined with conventional rehabilitation (SMD = 1.03) were superior to those of vibration therapy alone (SMD = 0.21).

CONCLUSIONS

Vibration therapy may be a reliable rehabilitation program to improve upper extremity motor functions and disabilities. Furthermore, vibration therapy should be performed at the earliest possibility after stroke for at least 4-8 weeks. Trial registration The protocol of this study was registered with PROSPERO (Registration number: CRD42022301119).

Effects of mediolateral whole-body vibration during gait with additional cognitive load

Whole-body vibration (WBV) may increase musculoskeletal disorder risk among workers standing on vibrating surfaces for prolonged periods. Limited studies were conducted to comprehend WBV impact on individuals engaged in dynamic activities. This study explored the effects of different horizontal WBV frequencies on gait parameters, lower limb kinematics, and the cognitive response of healthy subjects. Forty participants walked at constant speed on a treadmill mounted on a horizontal shaker providing harmonic vibration with an amplitude of 1 m/s2 and frequencies 2-10 Hz, with inversely proportional amplitudes. A Psychomotor Vigilance Test measured reaction time while a motion capture system recorded walking kinematics. ANOVA results revealed no significant impact of vibration frequencies on the reaction time. At 2 Hz, alterations in gait spatiotemporal parameters were significant, with reduced stride length, stride time, step length, and stance time and increased step width and cadence. Similarly, gait variability measured by standard deviation and coefficient of variation significantly increased at 2 Hz compared to the other conditions. Comparably, kinematic time series analyzed through statistical parametric mapping showed significant adjustments in different portions of the gait cycle at 2 Hz, including increased hip abduction and flexion, greater knee flexion around the heel strike, and augmented ankle dorsiflexion. Participants exhibited gait kinematic variations, mainly at 2 Hz, where the associated mediolateral displacement was higher, as a plausible strategy to maintain stability and postural control during perturbed locomotion. These findings highlight individuals' complex biomechanical adaptations in response to horizontal WBV, especially at lower frequencies, under dual-task conditions.

Developing and Investigating a Nanovibration Intervention for the Prevention/Reversal of Bone Loss Following Spinal Cord Injury

Osteoporosis disrupts the fine-tuned balance between bone formation and resorption, leading to reductions in bone quantity and quality and ultimately increasing fracture risk. Prevention and treatment of osteoporotic fractures is essential for reductions in mortality, morbidity, and the economic burden, particularly considering the aging global population. Extreme bone loss that mimics time-accelerated osteoporosis develops in the paralyzed limbs following complete spinal cord injury (SCI). In vitro nanoscale vibration (1 kHz, 30 or 90 nm amplitude) has been shown to drive differentiation of mesenchymal stem cells toward osteoblast-like phenotypes, enhancing osteogenesis and inhibiting osteoclastogenesis simultaneously. Here, we develop and characterize a wearable device designed to deliver and monitor continuous nanoamplitude vibration to the hindlimb long bones of rats with complete SCI. We investigate whether a clinically feasible dose of nanovibration (two 2 h/day, 5 days/week for 6 weeks) is effective at reversing the established SCI-induced osteoporosis. Laser interferometry and finite element analysis confirmed transmission of nanovibration into the bone, and microcomputed tomography and serum bone formation and resorption markers assessed effectiveness. The intervention did not reverse SCI-induced osteoporosis. However, serum analysis indicated an elevated concentration of the bone formation marker procollagen type 1 N-terminal propeptide (P1NP) in rats receiving 40 nm amplitude nanovibration, suggesting increased synthesis of type 1 collagen, the major organic component of bone. Therefore, enhanced doses of nanovibrational stimulus may yet prove beneficial in attenuating/reversing osteoporosis, particularly in less severe forms of osteoporosis.

Effect of 10-Week Whole-Body Vibration Training on Falls and Physical Performance in Older Adults: A Blinded, Randomized, Controlled Clinical Trial with 1-Year Follow-Up

Whole-body vibration training (WBV) training has shown positive effects on bone strength, muscle strength, and balance, but the evidence on fall prevention is not yet persuasive. This study aimed to evaluate the effectiveness of WBV training in preventing falls and improving physical performance among older adults at fall risk. The study was an assessor- and participant-blinded, randomized, and controlled 10-week training trial with a 10-month follow-up. One hundred and thirty older adults (mean age 78.5 years, 75% women) were randomly allocated into the WBV group (n = 68) and the low-intensity wellness group (n = 62). Falls were prospectively collected using monthly returned and verified diaries. Physical performance was evaluated at baseline before randomization, after the intervention, and follow-up with established methods. The data were analyzed on an intention-to-treat basis. Negative binomial regression was used to estimate the incidence rate ratios for falls, and Cox regression models were used to calculate the hazard ratios for fallers. Between-group differences in physical performance were estimated by generalized linear mixed models. The retention rate was 93%, and the mean adherence to the WBV training was 88% and 86% to the wellness training. Sixty-eight participants fell at least once, and there were 156 falls in total. In the WBV group, the incidence rate of falls was 1.5 (95% confidence interval 0.9 to 2.5) compared to the wellness group (p = 0.11). The hazard ratio for fallers in the WBV group was 1.29 (0.78 to 2.15) (p = 0.32). There was no between-group difference in physical performance after the training period, but by the end of the follow-up, WBV-related benefits appeared. The chair-rising capacity was maintained in the WBV group, while the benefit disappeared in the wellness group (p = 0.004). Also, the 0.5-point difference in short physical performance battery (SPPB) score favored WBV training (p = 0.009). In conclusion, progressive side-alternating WBV training was feasible and well-tolerated among fall-prone older adults. During the one-year follow-up, WBV training was associated with improved physical performance but did not prevent falls compared to chair-based group exercises.

Effects of Short-Term Hand Tractor Operation on Upper Limb Responses of Users

OBJECTIVES

Continuous exposure to hand-arm vibration integrated with poor posture and forceful movements are known causes of musculoskeletal disorders (MSD). In most related studies, force and vibration levels in experimental research is controlled. This study aims to determine how actual hand tractor field operation can affect the upper limb of users. It intends to characterize upper limb muscle activation applied during actual hand tractor usage. Lastly, it determines the immediate impacts on hand strength and perceived upper limb discomfort after the operation.

METHODS

We recruited 15 farm operators with a mean working experience of 20.1 ± 12.2 years. They were asked to operate a hand tractor on paddy fields for at most 8 minutes. Handle vibration was measured using a tri-axial accelerometer. The total unweighted vibration acceleration was computed and used to represent the handle vibration magnitude. Muscle activation was measured using surface electromyography (sEMG). Six sEMG sensors were attached to the dominant and non-dominant side of the extensor carpi radialis (ECR), bicep, and deltoid. Pre- and post-task hand strength and subjective discomfort rating were also taken.

RESULTS

The total unweighted handle vibration acceleration is 17.45 ± 7.53 m/s2. This exceeds the allowable safe value. Meanwhile, the percentage of maximum voluntary contraction (% MVC) of the muscles ranged from 6% to 14% with the ECR having a significantly higher activation (p < .05) than the bicep and deltoid. The post-task grip strength of the dominant hand was lower than its pre-task value (p < .01) while that of the non-dominant side did not vary significantly. There is a modest trend of higher hand discomfort of the non-dominant side on post-task than pre-task rating (p < .10). Although, overall, the perceived discomfort ranged from none to mild discomfort.

CONCLUSION

In conclusion, the study showed an indication that the effects of vibration on humans are evident even at mild muscle exertion, with the exertion predominantly concentrated on the distal arm area clearly affecting grip strength and hand discomfort. In such cases, future recommendations can revolve around the improvement of the hand tractor handle grip to impose grip comfort and ease.

Intervention Hypothesis for Training with Whole-Body Vibration to Improve Physical Fitness Levels: An Umbrella Review

Whole-body vibration (WBV) is a training modality, and it seems to be a safe and efficient exercise especially to improve different aspects of physical fitness in different populations. The protocols for WBV are still not standardized. The difficulty in comparing the data confuses the real efficacy of this instrument. Consequently, the objective of this umbrella review is to analyze the protocols previously adopted and eventually to propose a standard operating procedure for WBV training. Systematic review and meta-analysis of randomized controlled trials on WBV were searched on the electronic databases PubMed, Web of Science, and Scopus until 18 March 2024. A quality assessment of the studies included has been performed. A total of 20 studies were included in this umbrella review and frequency, magnitude, and amplitude intensity data were recorded. Detailed information about the protocols (static or dynamic exercises, barefoot or with shoes, intensity duration, weekly frequency, and vibration characteristics) was also collected. WBV presents widely different protocols. Consequently, a standard operating procedure has not been proposed for WBV training. A hypothesis of intervention was instead written in which parameters for frequency, amplitude, acceleration, and training mode were proposed.

Effects of intermittent hypoxia and whole-body vibration training on health-related outcomes in older adults

BACKGROUND

Aging is associated with a health impairment and an increase of the vulnerability of the older people. Strength training under intermittent hypoxic conditions has been shown to have therapeutic effects on individual's health.

AIMS

The aim of this study was to investigate the effects of a combined intermittent hypoxia (IH) and whole-body vibration (WBV) training program on health-related outcomes in older people.

METHODS

A total of 60 adults (over the age of 65) voluntarily participated in an intervention that lasted 20 weeks (three 30-min sessions per week). The participants were divided into four experimental groups subjected to different environmental conditions (IH vs normoxia) and exercise (non-exercise vs WBV). Functional fitness, body composition, metabolic parameters, inflammatory biomarkers, and bone turnover were evaluated before and after the intervention. A multifactorial ANOVA with repeated measures was performed to explore differences within and between groups.

RESULTS

The results showed that IH and WBV had a positive synergistic effect on inflammatory parameters (CRP and IL-10), bone formation biomarker (PINP), and body composition (muscle and bone mass).

CONCLUSION

In conclusion, a combined IH and WVB training could be a useful tool to prevent the deterioration of health-related outcomes associated with aging. Clinical trial registration NCT04281264. https://clinicaltrials.gov/ .

The 'Postural Rhythm' of the Ground Reaction Force during Upright Stance and Its Conversion to Body Sway-The Effect of Vision, Support Surface and Adaptation to Repeated Trials

The ground reaction force (GRF) recorded by a platform when a person stands upright lies at the interface between the neural networks controlling stance and the body sway deduced from centre of pressure (CoP) displacement. It can be decomposed into vertical (VGRF) and horizontal (HGRF) vectors. Few studies have addressed the modulation of the GRFs by the sensory conditions and their relationship with body sway. We reconsidered the features of the GRFs oscillations in healthy young subjects (n = 24) standing for 90 s, with the aim of characterising the possible effects of vision, support surface and adaptation to repeated trials, and the correspondence between HGRF and CoP time-series. We compared the frequency spectra of these variables with eyes open or closed on solid support surface (EOS, ECS) and on foam (EOF, ECF). All stance trials were repeated in a sequence of eight. Conditions were randomised across different days. The oscillations of the VGRF, HGRF and CoP differed between each other, as per the dominant frequency of their spectra (around 4 Hz, 0.8 Hz and <0.4 Hz, respectively) featuring a low-pass filter effect from VGRF to HGRF to CoP. GRF frequencies hardly changed as a function of the experimental conditions, including adaptation. CoP frequencies diminished to <0.2 Hz when vision was available on hard support surface. Amplitudes of both GRFs and CoP oscillations decreased in the order ECF > EOF > ECS ≈ EOS. Adaptation had no effect except in ECF condition. Specific rhythms of the GRFs do not transfer to the CoP frequency, whereas the magnitude of the forces acting on the ground ultimately determines body sway. The discrepancies in the time-series of the HGRF and CoP oscillations confirm that the body's oscillation mode cannot be dictated by the inverted pendulum model in any experimental conditions. The findings emphasise the robustness of the VGRF "postural rhythm" and its correspondence with the cortical theta rhythm, shed new insight on current principles of balance control and on understanding of upright stance in healthy and elderly people as well as on injury prevention and rehabilitation.

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.

Efficacy and safety of whole-body vibration therapy for post-stroke spasticity: A systematic review and meta-analysis

BACKGROUND

One of the main objectives of stroke rehabilitation is to alleviate post-stroke spasticity. Over the recent years, many studies have explored the potential benefits of whole-body vibration (WBV) treatment for post-stroke spasticity, but it is still controversial.

OBJECTIVE

The current study aims to assess the efficacy and safety of WBV for post-stroke spasticity and determine the appropriate application situation.

METHODS

From their establishment until August 2022, the following databases were searched: PubMed, Web of Science, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Medline, China National Knowledge Infrastructure (CNKI), and Wanfang. Only randomized controlled trials (RCTs) that were published in either English or Chinese were taken into consideration. We independently filtered the research, gathered the data from the studies, and evaluated the research quality (Cochrane RoB tool) and the overall evidence quality (GRADE). Rev Man 5.4 software was utilized to conduct statistical analysis.

RESULTS

In this analysis, 11 RCTs with 475 patients that reported on the effectiveness of WBV therapy for post-stroke spasticity were taken into account. Compared to the control groups, the results revealed that WBV combined with conventional rehabilitation at a vibration frequency lower than 20 Hz (SMD = -0.58, 95% CI: -0.98 to -0.19, P = 0.004) was more effective in relieving upper (SMD = -0.53, 95% CI: -1.04 to 0.03, P = 0.03) and lower limb spasticity (SMD = -0.21, 95% CI: -0.40 to -0.01, P = 0.04); similarly, it was superior for patients aged under 60 years (SMD = -0.41, 95% CI: -0.66 to -0.17, P = 0.0008) with acute and subacute stroke (SMD = -0.39, 95% CI: -0.68 to -0.09, P = 0.01). The valid vibration for reducing spasticity was found to last for 10 min (SMD = -0.41, 95% CI: -0.75 to -0.07, P = 0.02). None of the included studies revealed any serious adverse impact.

CONCLUSION

Moderate-quality evidence demonstrated when WBV was used as an adjuvant, vibration <20 Hz for 10 min was effective and secure in treating upper and lower limb spasticity in patients with acute and subacute stroke under the age of 60 years.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022293951.

Analysis of Vibration Frequency and Direction for Facilitating Upper-Limb Muscle Activity

We aimed to determine the effect of vibration frequency and direction on upper-limb muscle activation using a handheld vibrator. We recruited 19 healthy participants who were instructed to hold a handheld vibrator in their dominant hand and maintain the elbow at 90° flexion, while vertical and horizontal vibrations were applied with frequencies of 15, 30, 45, and 60 Hz for 60 s each. Surface electromyography (EMG) measured the activities of the flexor digitorum superficialis (FDS), flexor carpi radialis (FCR), extensor carpi ulnaris (ECU), extensor carpi radialis (ECR), biceps, triceps, and deltoid anterior muscles. EMG changes were evaluated as the difference in muscle activity between vibration and no-vibration (0 Hz) conditions. Muscle activity was induced under vibration conditions in both vertical and horizontal (p < 0.05) directions. At 45 Hz, FDS and FCR activities increased during horizontal vibrations, compared with those during vertical vibrations. ECU activity significantly increased under 15-Hz vertical vibrations compared with that during horizontal vibrations. Vibrations from the handheld vibrator significantly induced upper-limb muscle activity. The maximum muscle activations for FDS, ECR, ECU, biceps, and triceps were induced by 45-Hz horizontal vibration. The 60-Hz vertical and 30-Hz horizontal vibrations facilitated maximum muscle activations for the FCR and deltoid anterior, respectively.

Study on the process of intervertebral disc disease by the theory of continuum damage mechanics

BACKGROUND

Recently, more and more people suffer from low back pain triggered by lumbar degenerative disc disease. The mechanical factor is one of the most significant causes of disc degeneration. This study aims to explore the biomechanical responses of the intervertebral disc, and investigate the process of disc injury by the theory of continuum damage mechanics.

METHODS

A finite element model of the L4-L5 lumbar spine was developed and validated. The model not only considered changes in permeability coefficient with strain, but also included physiological factors such as osmotic pressure. Three loading conditions were simulated: (A) static loads, (B) vibration loads, (C) injury process.

FINDINGS

The simulation results revealed that the facet joints shared massive stresses of the intervertebral discs, and prevented excessive lumbar spine movement. However, their asymmetrical position may have led to degeneration. The von Mises stress and pore pressure of annulus fibrosus showed significantly different trends under static loads and vibration loads. The von Mises stress of nucleus pulposus was not sensitive to vibration loads, but its pore pressure was conspicuously influenced by vibration loads. The injury first appeared at the posterior centre, and then, it gradually expanded along the edge of the intervertebral disc. With an increase in the loading steps, the damage rate of the intervertebral disc increased logarithmically.

INTERPRETATION

The variation in the biomechanical performance of the intervertebral disc could be attributed to the periodic movement of internal fluids. This study might be helpful for understanding the mechanism of intervertebral disc degeneration.

The Essential Role of Stathmin in Myoblast C2C12 for Vertical Vibration-Induced Myotube Formation

Vertical vibration (VV) is a type of whole body vibration, which induces muscle contraction through vibration to improve muscle strength and bone density. However, the mechanism of VV on muscle cell myotube formation is still unclear. In the current study, we aim to clarify the mechanism involved in VV's stimulation of myotube formation. In order to identify the molecules regulated by VV, we performed proteomics analysis including 2D electrophoresis combined with MALDI-TOF/TOF Mass. Stathmin was identified as a high potential molecule responding to VV stimulation, and we found that under VV stimulation, the expression of stathmin gene and protein increased in a time-dependent manner. In addition, we also confirmed that the increase of stathmin stimulated by VV is mediated through the PI3K/Akt pathway. Furthermore, stathmin siRNA significantly down-regulated the expression of myogenic regulatory factor (MRF) MyoD, decorin, and type I collagen (Col-I), and down-regulated the cellular process regulators such as FGF7, TGFBr1 and PAK3. Taken together, our results confirm that under the stimulation of VV, PI3K/Akt and stathmin would be activated, as well as the up-regulation of MRFs, such as FGF7, TGFBr1 and PAK3 to initiate myogenesis. It also showed that the response of MRF to VV stimulation was significantly related to stathmin expression, which also confirmed the importance of stathmin in the entire myotube formation process. This study may provide evidence of stathmin as a biological indicator of VV to increase muscle strength.

Biodynamic Responses to Whole-Body Vibration Training: A Systematic Review

In recent years, whole-body vibration (WBV) training has received an increasing interest in the sports and medical fields. However, there has been inconsistency among several studies regarding the effect of WBV training on the human body, which is partly due to the lack of the existence of guidelines for using WBV training machines. To understand the effect of WBV training on the human body and build the needed regulations, it is essential first to understand the biodynamic responses to vibration which represent how vibration is transmitted to and through the human body. The purpose of this study is to systematically review previous studies that measured biodynamic responses when using WBV training machines to highlight inconsistencies in their results and provide possible reasons for them. An extensive literature search was performed on the SCOPUS database to obtain relevant studies. One hundred and fifty-six potentially relevant studies were obtained but after further screening, 23 papers from 2007 to 2020 met inclusion criteria and were included in the study. The papers were analysed with respect to acceleration, transmissibility, interface force, and apparent mass during different vibration settings, body posture, age, and sex. Results and conflicts among studies were highlighted and possible explanations for the inconsistency were provided.

Effect of whole-body vibration on obstacle clearance and stair negotiation time in chronic stroke patients; A randomized controlled trial

OBJECTIVE

To assess the effect of Whole-Body Vibration (WBV) and Routine Physiotherapy (RP) on obstacle crossing and stair negotiation time in chronic stroke patients.

METHODS

The current study was randomized, parallel-group, assessor-blinded, clinical trial conducted in Physiotherapy Department of Lahore General Hospital, involving 64 patients with chronic stroke. Patients were randomly allocated to 2 groups, i.e., the WBV group (n = 32) and the RP group (n = 32). The WBV group was given additional twelve sessions of vibration therapy (amplitude of 3 mm and frequency of 20 Hz), 6 days/week for 2 weeks. The outcome measures were change in score of height and depth of obstacles cleared, i.e., 6, 8, 10 & 12 inches height and 6, 8, 10 & 12 inches depth and stair negotiation time, i.e., Stair-Climb Test. Chi square test, Independent sample t-test and Paired sample t-test were used to analyze the data.

RESULTS

Results show that higher number of patients improved in crossing the maximum height and maximum depth of obstacles in the WBV group but improvement was significant only in height, i.e., (p < 0.05). In the WBV group, Stair Negotiation Time decreased significantly as compared to the RP group, i.e., (p < 0.05).

CONCLUSIONS

The present study concluded that both study groups, i.e., RP and WBV, improved despite better results for the latter. Speed of stair climbing and capacity to cross obstacles improved with the WBV therapy in chronic stroke survivors.

TRIAL REGISTRATION

IRCT, IRCT20190328043131N1. Registered 03 august 2019 - Retrospectively registered, https://www.irct.ir/user/trial/38832/view.

Transmission of whole body vibration - Comparison of three vibration platforms in healthy subjects

The potential of whole body vibration (WBV) to maintain or enhance musculoskeletal strength during ageing is of increasing interest, with both low and high magnitude WBV having been shown to maintain or increase bone mineral density (BMD) at the lumbar spine and femoral neck. The aim of this study was to determine how a range of side alternating and vertical WBV platforms deliver vibration stimuli up through the human body. Motion capture data were collected for 6 healthy adult participants whilst standing on the Galileo 900, Powerplate Pro 5 and Juvent 100 WBV platforms. The side alternating Galileo 900 WBV platform delivered WBV at 5-30 Hz and amplitudes of 0-5 mm. The Powerplate Pro 5 vertical WBV platform delivered WBV at 25 and 30 Hz and amplitude settings of 'Low' and 'High'. The Juvent 1000 vertical WBV platform delivered a stimulus at a frequency between 32 and 37 Hz and amplitude 10 fold lower than either the Galileo or Powerplate, resulting in accelerations of 0.3 g. Motion capture data were recorded using an 8 camera Vicon Nexus system with 21 reflective markers placed at anatomical landmarks between the toe and the forehead. Vibration was expressed as vertical RMS accelerations along the z-axis which were calculated as the square root of the mean of the squared acceleration values in g. The Juvent 1000 did not deliver detectable vertical RMS accelerations above the knees. In contrast, the Powerplate Pro 5 and Galileo 900 delivered vertical RMS accelerations sufficiently to reach the femoral neck and lumbar spine. The maximum vertical RMS accelerations at the anterior superior iliac spine (ASIS) were 1.00 g ±0.30 and 0.85 g ±0.49 for the Powerplate and Galileo respectively. For similar accelerations at the ASIS, the Galileo achieved greater accelerations within the lower limbs, whilst the Powerplate recorded higher accelerations in the thoracic spine at T10. The Powerplate Pro 5 and Galileo 900 deliver vertical RMS accelerations sufficiently to reach the femoral neck and lumbar spine, whereas the Juvent 1000 did not deliver detectable vertical RMS accelerations above the knee. The side alternating Galileo 900 showed greater attenuation of the input accelerations than the vertical vibrations of the Powerplate Pro 5. The platforms differ markedly in the transmission of vibration with strong influences of frequency and amplitude. Researchers need to take account of the differences in transmission between platforms when designing and comparing trials of whole body vibration.

Managing Vibration Training Safety by Using Knee Flexion Angle and Rating Perceived Exertion

Whole-body vibration (WBV) is commonly applied in exercise and rehabilitation and its safety issues have been a major concern. Vibration measured using accelerometers can be used to further analyze the vibration transmissibility. Optimal bending angles and rating of perceived exertion (RPE) evaluations have not been sufficiently explored to mitigate the adverse effect. Therefore, the aims of this study were to investigate the effect of various knee flexion angles on the transmissibility to the head and knee, the RPE during WBV exposure, and the link between the transmissibility to the head and the RPE. Sixteen participants randomly performed static squats with knee flexion angles of 90, 110, 130, and 150 degrees on a WBV platform. Three accelerometers were fixed on the head, knee, and center of the vibration platform to provide data of platform-to-head and platform-to-knee transmissibilities. The results showed that the flexion angle of 110 degrees induced the lowest platform-to-head transmissibility and the lowest RPE (p < 0.01). A positive correlation between RPE and the platform-to-head transmissibility was observed. This study concluded that a knee flexion of about 110 degrees is most appropriate for reducing vibration transmissibility. The reported RPE could be used to reflect the vibration impact to the head.

Whole-Body Vibration Exercise in Different Postures on Handgrip Strength in Healthy Women: A Cross-Over Study

Objective

To compare the effect of Whole-Body Vibration Exercise (WBVE) applied in push-up modified and half-squat positions, on handgrip strength (HS) and on the electromyography registry (EMGrms) of the flexor digitorum superficialis muscle (FDSM) of the dominant hand.

Methods

Nineteen healthy women (age 23.40 ± 4.03 years, bodyweight: 58.89 ± 9.87 kg), performed in a randomized order five different tests: (S1) Control; (S2) Push-up modified; (S3) Push-up placebo; (S4); Half-squatting; (S5) Half-squatting placebo. The HS and the EMGrms were assessed at baseline and immediately after the tests. ANOVA two-way design mixed test, with Tukey post hoc, was used to evaluate the HS, EMGrms and the ratio between EMGrms and HS, i.e., neural ratio (NR). Thus, the lower NR represents the greater neuromuscular modifications. The statistical significance level was set up at p < 0.05.

Results

WBVE on S2 increased HS compared to the stimulus applied to the S4 (p = 0.0001). The increase in HS was associated with a reduction in the EMGrms of the FDSM (p < 0.001) and a lower NR (p < 0.0001), i.e., greater neuromuscular modifications, in the S2 compared to the S4 after the tests.

Conclusion

The distance of the stimulus and the positioning on the vibratory platform influence the maximum muscular strength due to neuromuscular modifications of hands in healthy women.

Surface acceleration transmission during drop landings in humans

The purpose of this study was to quantify the magnitude and frequency content of surface-measured accelerations at each major human body segment from foot to head during impact landings. Twelve males performed two single leg drop landings from each of 0.15 m, 0.30 m, and 0.45 m. Triaxial accelerometers (2000 Hz) were positioned over the: first metatarsophalangeal joint; distal anteromedial tibia; superior to the medial femoral condyle; L5 vertebra; and C6 vertebra. Analysis of acceleration signal power spectral densities revealed two distinct components, 2-14 Hz and 14-58 Hz, which were assumed to correspond to time domain signal joint rotations and elastic wave tissue deformation, respectively. Between each accelerometer position from the metatarsophalangeal joint to the L5 vertebra, signals exhibited decreased peak acceleration, increased time to peak acceleration, and decreased power spectral density integral of both the 2-14 Hz and 14-58 Hz components, with no further attenuation beyond the L5 vertebra. This resulted in peak accelerations close to vital organs of less than 10% of those at the foot. Following landings from greater heights, peak accelerations measured distally were greater, as was attenuation prior to the L5 position. Active and passive mechanisms within the lower limb therefore contribute to progressive attenuation of accelerations, preventing excessive accelerations from reaching the torso and head, even when distal accelerations are large.

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.

Towards reporting guidelines of research using whole-body vibration as training or treatment regimen in human subjects-A Delphi consensus study

BACKGROUND

Whole-body vibration (WBV) is a method utilizing vibrating platforms to expose individuals to mechanical vibration. In its various applications, it has been linked to improved muscular, skeletal, metabolic, or cognitive functioning, quality of life, and physiological parameters such as blood pressure. Most evidence concerning WBV is inconclusive and meta-analytical reviews may not readily produce insights since the research has a risk of misunderstandings of vibration parameters and incomplete reporting occurs. This study aims at laying an empirical foundation for reporting guidelines for human WBV studies to improve the quality of reporting and the currently limited comparability between studies.

METHOD

The Delphi methodology is employed to exploit the integrated knowledge of WBV experts to distil the specific aspects of WBV methodology that should be included in such guidelines. Over three rounds of completing online questionnaires, the expert panel (round 1/2/3: 51/40/37 experts respectively from 17 countries with an average of 19.4 years of WBV research experience) rated candidate items.

RESULTS

A 40-item list was established based on the ratings of the individual items from the expert panel with a large final consensus (94.6%).

CONCLUSION

The final consensus indicates comprehensiveness and valuableness of the list. The results are in line with previous guidelines but expand these extensively. The present results may therefore serve as a foundation for updated guidelines for reporting human WBV studies in order to improve the quality of reporting of WBV studies, improve comparability of studies and facilitate the development of WBV study designs.

Power Absorbed by the Standing Human Body During Whole-Body Vibration Training

Absorbed power (AP) is a biodynamic response that is directly related to the magnitude and duration of vibration. No work has previously investigated the power absorbed by the standing human body during the exposure to vibration training conditions or otherwise. This article reports the power absorbed by the standing human body under whole-body vibration (WBV) training conditions. In this work, the force and acceleration used to calculate the apparent mass by Nawayseh and Hamdan (2019, "Apparent Mass of the Standing Human Body When Using a Whole-Body Vibration Training Machine: Effect of Knee Angle and Input Frequency," J. Biomech., 82, pp. 291-298) were reanalyzed to obtain the AP. The reported acceleration was integrated to obtain the velocity needed to calculate the AP. The effects of bending the knees (knee angles of 180 deg, 165 deg, 150 deg, and 135 deg) and vibration frequency (17-42 Hz) on the power absorbed by 12 standing subjects were investigated. Due to the different vibration magnitudes at different frequencies, the AP was normalized by dividing it by the power spectral density (PSD) of the input acceleration to obtain the normalized AP (NAP). The results showed a dependency of the data on the input frequency as well as the knee angle. A peak in the data was observed between 20 and 24 Hz. Below and above the peak, the AP and NAP tend to increase with more bending of the knees indicating an increase in the damping of the system. This may indicate the need for an optimal knee angle during WBV training to prevent possible injuries especially with prolonged exposure to vibration at high vibration intensities.

The Acute Effects of Different Intensity Whole-Body Vibration Exposure on Muscle Tone and Strength of the Lower Legs, and Hamstring Flexibility: A Pilot Study

CONTEXT

The research on the change in properties of the lower leg muscles by different intensity sinusoidal vertical whole-body vibration (SV-WBV) exposures has not yet been investigated.

OBJECTIVE

The purpose of this study was to determine effect of a 20-minute different intensity SV-WBV application to the ankle plantar flexor and dorsiflexor muscles properties and hamstring flexibility.

DESIGN

Prospective preintervention-postintervention design.

SETTING

Physiotherapy department.

PARTICIPANTS

A total of 50 recreationally active college-aged individuals with no history of a lower leg injury volunteered.

INTERVENTIONS

The SV-WBV was applied throughout the session with an amplitude of 2 to 4 mm and a frequency of 25 Hz in moderate-intensity vibration group and 40 Hz in a vigorous-intensity vibration group.

MAIN OUTCOME MEASURES

The gastrocnemius and tibialis anterior muscle tone was assessed with MyotonPRO, and the strength evaluation was made on the same lower leg muscles using hand-held dynamometer. The sit and reach test was used for the lower leg flexibility evaluation.

RESULTS

The gastrocnemius muscle tone decreased on the right side (d = 0.643, P = .01) and increased on the left (d = 0.593, P = .04) when vigorous-intensity vibration was applied. Bilateral gastrocnemius muscle strength did not change in both groups (P > .05). Without differences between groups, bilateral tibialis anterior muscle strength increased in both groups (P < .01). Bilateral gastrocnemius and tibialis anterior muscle tone did not change in the moderate-intensity vibration group (P > .05). Flexibility increased in both groups (P < .01); however, there was no statistically significant difference between the groups (d = 0.169, P = .55).

CONCLUSIONS

According to study results, if SV-WBV is to be used in hamstring flexibility or ankle dorsiflexor muscle strengthening, both vibration exposures should be preferred. Different vibration programs could be proposed to increase ankle plantar flexor muscle strength in the acute results. Vigorous-intensity vibration exposure is effective in altering ankle plantar flexor muscle tone, but it is important to be aware of the differences between the lower legs.

The Effects of Long-Term 40-Hz Physioacoustic Vibrations on Motor Impairments in Parkinson's Disease: A Double-Blinded Randomized Control Trial

Recent studies have suggested that vibration therapy may have a positive influence in treating motor symptoms of Parkinson’s disease (PD). However, quantitative evidence of the benefits of vibration utilized inconsistent methods of vibration delivery, and to date there have been no studies showing a long-term benefit of 40 Hz vibration in the PD population. The objective of this study was to demonstrate the efficacy of vibration administered via a physioacoustic therapy method (PAT) on motor symptoms of PD over a longer term, completed as a randomized placebo-controlled trial. Overall motor symptom severity measured by the Unified Parkinson’s Disease Rating Scale III showed significant improvements in the treatment group over 12 weeks. Specifically, all aspects of PD, including tremor, rigidity, bradykinesia, and posture and gait measures improved. To our knowledge, this is the first study to quantitatively assess 40-Hz vibration applied using the PAT method for potential long-term therapeutic effects on motor symptoms of PD.

Sensory inflow manipulation induces learning-like phenomena in motor behavior

PURPOSE

Perceptual and goal-directed behaviors may be improved by repetitive sensory stimulations without practice-based training. Focal muscle vibration (f-MV) modulating the spatiotemporal properties of proprioceptive inflow is well-suited to investigate the effectiveness of sensory stimulation in influencing motor outcomes. Thus, in this study, we verified whether optimized f-MV stimulation patterns might affect motor control of upper limb movements.

METHODS

To answer this question, we vibrated the slightly tonically contracted anterior deltoid (AD), posterior deltoid (PD), and pectoralis major muscles in different combinations in forty healthy subjects at a frequency of 100 Hz for 10 min in single or repetitive administrations. We evaluated the vibration effect immediately after f-MV application on upper limb targeted movements tasks, and one week later. We assessed target accuracy, movement mean and peak speed, and normalized Jerk using a 3D optoelectronic motion capture system. Besides, we evaluated AD and PD activity during the tasks using wireless electromyography.

RESULTS

We found that f-MV may induce increases (p < 0.05) in movement accuracy, mean speed and smoothness, and changes (p < 0.05) in the electromyographic activity. The main effects of f-MV occurred overtime after repetitive vibration of the AD and PD muscles.

CONCLUSION

Thus, in healthy subjects, optimized f-MV stimulation patterns might over time affect the motor control of the upper limb movement. This finding implies that f-MV may improve the individual's ability to produce expected motor outcomes and suggests that it may be used to boost motor skills and learning during training and to support functional recovery in rehabilitation.

Acute Effects of Whole-Body Vibration on Peripheral Blood Flow, Vibrotactile Perception and Balance in Older Adults

Background: Non-invasive application of whole-body vibration (WBV) has the potential for inducing improvements in impaired peripheral circulation, cutaneous sensation and balance among older adults. However, relevant studies have frequently applied high magnitudes of vibration and show conflicting and inconclusive results. Therefore, we attempted to ascertain the acute responses in those parameters from exposure of thirty older subjects to WBV of three different magnitudes, defined according to ISO 2631-1 (1997). Methods: Each subject randomly underwent four sessions of intervention (three bouts of 1 min exposure with 1 min between-bout rests): WBV at 15, 20, or 25 Hz with a peak-to-peak displacement of 4 mm, or control condition. Results: Both during and after intervention, dorsal foot skin blood flow increased significantly under 20 and 25 Hz exposure conditions with greater responses under the latter condition, the magnitude of which slightly exceeded the recommended value. Plantar vibrotactile perception showed significant increases after WBV exposure with overall greater responses under higher frequencies of vibration. In contrast, no WBV-induced change in balance was observed. Conclusions: WBV at 20 Hz with a magnitude within the recommended limit can be effective in inducing enhancements in peripheral blood flow; however, the same magnitude of vibration seems insufficient in improving balance among older adults.

Experimental Modal Analysis of an In-situ Clavicle

Clavicle fractures are widespread, and the understanding of their mechanism of occurrence via dynamic loading is important for prevention and design of protection systems. The proposed work will find the natural frequencies and mode shapes of the human clavicles in-situ, by employing experimental modal analysis (EMA) techniques on cadaver clavicles. The clavicle response to impact depends on mechanical energy transmission to the bone and requires an understanding of bone modal characteristics (natural frequencies and mode shapes), as well as the frequency content of the impact force. These dynamic forces include blunt trauma (sport injury or gun stock impact) or falls (i.e. motorcycle accidents) and exhibit a wide frequency spectrum. Clavicle modes are not well understood, and while researchers performed whole body or individual clavicle EMA, no in-situ EMA has been reported. Since an in-situ clavicle features its natural boundary conditions, mode estimation via EMA was more accurate than one performed for an isolated clavicle.The clavicle EMA used instrumented excitation sources (i.e. impact hammer) and sensors (i.e. triaxial accelerometers). The accelerometer responses gathered at several locations along the cadaver clavicle bone and the exciting force was recorded and through time-frequency transformations, the natural frequencies and mode shapes were identified. Mode shape visualization was performed in ModalView software. While material properties of cadaver clavicles may be influenced by embalming, the results, which include natural frequencies, modes and damping constants, would be more relevant than those obtained for isolated clavicles. These results would be used to design protection systems, define global material properties, and calibrate existing analytical models.

Nutritional Support and Physical Modalities for People with Osteoporosis: Current Opinion

Osteoporosis is a vital healthcare issue among elderly people. During the aging process, a gradual loss of bone mass results in osteopenia and osteoporosis. Heritable factors account for 60%-80% of optimal bone mineralization, whereas modifiable factors such as nutrition, weight-bearing exercise, body mass, and hormonal milieu affect the development of osteopenia and osteoporosis in adulthood. Osteoporosis substantially increases the risk of skeletal fractures and further morbidity and mortality. The effective prevention of fractures by reducing the loss of bone mass is the primary goal for physicians treating people with osteoporosis. Other than pharmacologic agents, lifestyle adjustment, nutritional support, fall prevention strategies, exercise, and physical modalities can be used to treat osteoporosis or prevent further osteoporotic fracture. Each of these factors, alone or in combination, can be of benefit to people with osteoporosis and should be implemented following a detailed discussion with patients. This review comprises a systematic survey of the current literature on osteoporosis and its nonpharmacologic and nonsurgical treatment. It provides clinicians and healthcare workers with evidence-based information on the assessment and management of osteoporosis. However, numerous issues regarding osteoporosis and its treatment remain unexplored and warrant future investigation.

Early Post-Operative Intervention of Whole-Body Vibration in Patients After Total Knee Arthroplasty: A Pilot Study

(1) Background: Knee osteoarthritis causes pain, weakness, muscle atrophy, and disability. The application of whole-body vibration in patients with knee osteoarthritis can improve strength, balance, and functional activities. The purpose of the study is to evaluate the effects of early whole-body vibration intervention in patients after total knee arthroplasty. (2) Method: A single-blinded randomized control trial. Fifty-two patients with knee osteoarthritis post total knee replacement from a medical center in southern Taiwan were randomly assigned to either a whole-body vibration group or control group. Main outcome measures included pain severity, leg circumference, knee range of motion, knee extensor strength, a five-times sit to stand test, and a timed up and go test. (3) Results: Immediately post treatment, the patients in the vibration group showed a significant increase in knee extensor strength and improvement in calf swelling compared to the control group. A trend toward decrease in pain severity and improvement in functional performance were observed in both groups without a significant difference between the groups. There was no significant difference in knee range of motion (ROM) and functional performance between the groups. (4) Conclusions: The whole-body vibration intervention in patients early post total knee arthroplasty showed significant immediate effect in increasing knee extensor strength and decreasing calf swelling.

Fatiguing effects of indirect vibration stimulation in upper limb muscles: pre, post and during isometric contractions superimposed on upper limb vibration

Whole-body vibration and upper limb vibration (ULV) continue to gain popularity as exercise intervention for rehabilitation and sports applications. However, the fatiguing effects of indirect vibration stimulation are not yet fully understood. We investigated the effects of ULV stimulation superimposed on fatiguing isometric contractions using a purpose developed upper limb stimulation device. Thirteen healthy volunteers were exposed to both ULV superimposed to fatiguing isometric contractions (V) and isometric contractions alone Control (C). Both Vibration (V) and Control (C) exercises were performed at 80% of the maximum voluntary contractions. The stimulation used was 30 Hz frequency of 0.4 mm amplitude. Surface-electromyographic (EMG) activity of the Biceps Brachii, Triceps Brachii and Flexor Carpi Radialis were measured. EMG amplitude (EMGrms) and mean frequency (MEF) were computed to quantify muscle activity and fatigue levels. All muscles displayed significantly higher reduction in MEFs and a corresponding significant increase in EMGrms with the V than the Control, during fatiguing contractions (p < 0.05). Post vibration, all muscles showed higher levels of MEFs after recovery compared to the control. Our results show that near-maximal isometric fatiguing contractions superimposed on vibration stimulation lead to a higher rate of fatigue development compared to the isometric contraction alone in the upper limb muscles. Results also show higher manifestation of mechanical fatigue post treatment with vibration compared to the control. Vibration superimposed on isometric contraction not only seems to alter the neuromuscular function during fatiguing efforts by inducing higher neuromuscular load but also post vibration treatment.

Effects of Two Different Neuromuscular Training Protocols on Regional Bone Mass in Postmenopausal Women: A Randomized Controlled Trial

Background: Osteoporosis is a condition associated with a greater incidence of fractures, and one of the main health-related concerns in postmenopausal women. To counteract possible reductions in bone properties, physical exercise has been proposed as an effective strategy. Particularly, training interventions with a high osteogenic potential are recommended. Purpose: To analyze the effect of 24 weeks of whole-body vibration and multi-component training on lumbar spine and femoral neck bone mass, and to determine what type of training produces greater adaptations in postmenopausal women. Methods: A total of 38 women completed the study (Clinical Gov database ID: NCT01966562). Participants were randomly assigned to one of the study groups: whole-body vibration group (WBVG), multi-component training group (MTG), or control group (CG). The experimental groups performed a progressive 24-week training (3 sessions/week) program. Bone mineral density (BMD) and bone mineral content (BMC) at the lumbar spine and femoral neck were assessed by Dual-energy X-ray absorptiometry. Results: Significantly and clinically relevant increases in lumbar spine bone mass (BMD: F = 3.29; p = 0.03; +5.15%; BMC: F = 2.90; p = 0.05; +10.58%) were observed in WBVG. MTG showed clinically important pre-post-changes on lumbar spine BMC (+7.78%), although there was no statistical significance (F = 1.97; p = 0.14). At the femoral neck, no statistically significant increases on bone mass were obtained in either training group. No changes were obtained in any variable in the CG. Additionally, no statistically significant differences were found between groups. Conclusion: The results indicated that 24 weeks of supervised WBV and MT may counteract the rapid loss of bone mass after the cessation of menstruation, thus improving postmenopausal women bone health. However, in the absence of statistically significant differences between groups, it is not possible to determine which training protocol produces greater adaptations. Clinical Trial Registration: www.ClinicalTrialsgov, identifier: NCT01966562.

Combating osteoporosis and obesity with exercise: leveraging cell mechanosensitivity

Osteoporosis, a condition of skeletal decline that undermines quality of life, is treated with pharmacological interventions that are associated with poor adherence and adverse effects. Complicating efforts to improve clinical outcomes, the incidence of obesity is increasing, predisposing the population to a range of musculoskeletal complications and metabolic disorders. Pharmacological management of obesity has yet to deliver notable reductions in weight and debilitating complications are rarely avoided. By contrast, exercise shows promise as a non-invasive and non-pharmacological method of regulating both osteoporosis and obesity. The principal components of exercise - mechanical signals - promote bone and muscle anabolism while limiting formation and expansion of fat mass. Mechanical regulation of bone and marrow fat might be achieved by regulating functions of differentiated cells in the skeletal tissue while biasing lineage selection of their common progenitors - mesenchymal stem cells. An inverse relationship between adipocyte versus osteoblast fate selection from stem cells is implicated in clinical conditions such as childhood obesity and increased marrow adiposity in type 2 diabetes mellitus, as well as contributing to skeletal frailty. Understanding how exercise-induced mechanical signals can be used to improve bone quality while decreasing fat mass and metabolic dysfunction should lead to new strategies to treat chronic diseases such as osteoporosis and obesity.

Effects of Whole-Body Vibration Therapy on Distal Tibial Myotendinous Density and Volume: A Randomized Controlled Trial in Postmenopausal Women

Whole‐body vibration (WBV) therapy has been proposed as a therapy to reduce sarcopenia and improve muscle strength. The purpose of this study was to explore whether 12 months of WBV therapy increases myotendinous density and volume of the distal tibia as measured by HR‐pQCT in postmenopausal women in a parallel group, randomized controlled trial with 1:1:1 allocation to three arms. Postmenopausal women (N = 202) with low hip BMD were randomized to 20 min daily of 0.3g 30‐Hz WBV therapy, 0.3g 90‐Hz WBV therapy using the Juvent platform (Juvent, Somerset, NJ, USA), or no WBV. The main outcome measure was myotendinous density (HU) and volume (mm³) at the distal tibia measured at baseline and 12 months with HR‐pQCT. There were no significant effects on myotendinous density or volume at the distal tibia after 12 months of daily 30‐ or 90‐Hz WBV therapy compared with no WBV therapy. Mean change (SD) in myotendinous density from baseline was 4.6 (5.7) HU in the 30‐Hz WBV group, 3.9 (6.1) HU in the 90‐Hz WBV group, and 3.9 (5.4) HU in the control group (p = 0.70). Mean change (SD) in myotendinous volume from baseline was −7 (503) mm³ in the 30‐Hz WBV group, 111 (615) mm³ in the 90‐Hz WBV group, and 35 (615) mm³ in the control group (p = 0.50). In conclusion, WBV therapy at 30‐ or 90‐Hz for 12 months had no significant effects on myotendinous density or volume at the distal tibia as measured by HR‐pQCT in postmenopausal women. © 2018 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Effect of gender on the biodynamic responses to vibration induced by a whole-body vibration training machine

Whole-body vibration training machines are used by both male and female users. However, studies investigating the biodynamic responses to vibration during training have used either mixed-gender subjects or male subjects. No study has investigated the effect of gender on the biodynamic responses under vibration training conditions. The objective of this study is to investigate the effect of gender on the apparent mass and the vibration of the head of standing people during exposure to vibration. A total of 40 subjects (20 females and 20 males) were exposed to vertical vibration at six frequencies in the range 20-45 Hz and vibration acceleration in the range 10.8-20.9 m/s² (peak). The subjects stood on a force platform mounted on the vibrating plate of the machine adopting an upright standing posture with their knees unlocked and their arms straight along their bodies. The vertical acceleration and force at the interface between the vibrating plate and the feet were measured and used to calculate the apparent mass. The accelerations of the head in the x-, y- and z-directions were also measured and used to calculate the transmissibility to the head. The apparent mass of males was found higher than that of females. The transmissibility to the head in all directions was found higher in females than males. The differences in the biodynamic responses between males and females were attributed to the differences in body properties and structure of the two genders. The results of this study imply the need for gender-specific vibration training programmes.

Effects of Whole-Body Vibration on Lumbar-Abdominal Muscles Activation in Healthy Young Adults: A Pilot Study

BACKGROUND This study investigated how whole-body vibration (WBV), exercise, and their interactions influence core muscle activity in healthy young adults. MATERIAL AND METHODS Twenty-three healthy young adults (8 males and 15 females; age: 21.87±2.33 years) participated in the study. The activities of muscle multifidi (MM), rectus abdominis muscle (RM), erector spinae (ES), abdominis obliquus externus (AOE), and abdominis obliquus internus (AOI) were measured through surface electromyography (sEMG) while participants were performing 4 different exercise forms under 3 WBV conditions (condition 1: 5 Hz, 2 mm; condition 2: 10 Hz, 2 mm; and condition 3: 15 Hz, 2 mm) and a no-WBV condition in single experimental sessions. RESULTS The WBV frequency of 15 Hz is the best vibration stimulation for core muscles in all of the exercises (P<0.05). Single bridge is a better exercise for RM and AOE (P<0.05) compared with other exercises, and crunches is the best exercise for MM, AOI, and ES (P<0.05). Significant interaction effect was observed in different frequencies and exercises (P>0.05) except for AOI (F=0.990, P=0.378). CONCLUSIONS High vibration frequencies can lead to enhanced exercise benefits within an appropriate frequency range, and different exercises have diverse effects on various muscles. Single bridge and crunches are appropriate exercise forms for lumbar-abdominal muscles.

Transmissibility of whole-body vibrations and injury risk in alpine skiing

OBJECTIVES

Whole body vibrations in alpine skiing are a potential cause for frequent overuse and acute injuries. Therefore, the aim of the study was to investigate the transmissibility of vibrations from the skis to lower back and head. Attention was addressed to distinguish shocks and transient vibrations from long-lasting vibrations.

DESIGN

Whole body vibrations were analysed in snow-plough swinging, basic swinging, short swinging and carved turns performed by eight highly skilled skiers.

METHODS

Power spectrum densities (PSD), running root-mean-square accelerations (RMS) and transmissibilities were estimated and analysed from 7 accelerometers positioned on skis, pelvis and head.

RESULTS

In the measurements frequency range, vibrations were effectively transmitted from the skis to the pelvis and to the head, with the highest transmissibility occurring at frequencies below 6Hz. The highest transmissibility was observed for short swinging. The running RMS was cyclically increasing and decreasing with turning and shocks. Also, transient vibrations exhibited similar PSDs with considerably higher densities compared to overall PSDs.

CONCLUSIONS

All form of alpine skiing were associated with random, periodic and transient vibrations. Skiing involving skidding was associated with higher vibration levels, higher transmissibilities and more pronounced shocks and transient vibrations compared to carving turns. Frequent skiers should preferably use carving instead of skidding techniques to decrease the risk for low back pain and loss of control.

Transmission of Acceleration From a Synchronous Vibration Exercise Platform to the Head During Dynamic Squats

Many research studies have evaluated the effects of whole-body vibration exercise on muscular strength, standing balance, and bone density, but relatively few reports have evaluated safety issues for vibration exercises. Knee flexion reduces acceleration transmission to the head during static exercise. However, few studies have evaluated dynamic exercises. The purpose of this investigation was to evaluate the transmission of acceleration to the head during dynamic squats. Twelve participants performed dynamic squats (0°-40° of knee flexion) on a synchronous vertical whole-body vibration platform. Platform frequencies from 20 to 50 Hz were tested at a peak-to-peak nominal displacement setting of 1 mm. Transmissibilities from the platform to head varied depending on platform frequency and knee flexion angle. We observed amplification during 20 and 25 Hz platform vibration when knee flexion was <20°. Vibration from exercise platforms can be amplified as it is transmitted through the body to the head during dynamic squats. Similarly, this vibration energy contributes to observed injuries such as retinal detachment. It is recommended that knee flexion angles of at least 20° and vibration frequencies above 30 Hz are used when performing dynamic squat exercises with whole-body vibration.

Lower Body Acceleration and Muscular Responses to Rotational and Vertical Whole-Body Vibration at Different Frequencies and Amplitudes

Aim:

The aim of this study was to characterize acceleration transmission and neuromuscular responses to rotational vibration (RV) and vertical vibration (VV) at different frequencies and amplitudes.

Methods:

Twelve healthy males completed 2 experimental trials (RV vs VV) during which vibration was delivered during either squatting (30°; RV vs VV) or standing (RV only) with 20, 25, and 30 Hz, at 1.5 and 3.0 mm peak-to-peak amplitude. Vibration-induced accelerations were assessed with triaxial accelerometers mounted on the platform and bony landmarks at ankle, knee, and lumbar spine.

Results:

At all frequency/amplitude combinations, accelerations at the ankle were greater during RV (all P < .03) with the greatest difference observed at 30 Hz, 1.5 mm. Transmission of RV was also influenced by body posture (standing vs squatting, P < .03). Irrespective of vibration type, vibration transmission to all skeletal sites was generally greater at higher amplitudes but not at higher frequencies, especially above the ankle joint. Acceleration at the lumbar spine increased with greater vibration amplitude but not frequency and was highest with RV during standing.

Conclusions/Implications:

The transmission of vibration during whole-body vibration (WBV) is dependent on intensity and direction of vibration as well as body posture. For targeted mechanical loading at the lumbar spine, RV of higher amplitude and lower frequency vibration while standing is recommended. These results will assist with the prescription of WBV to achieve desired levels of mechanical loading at specific sites in the human body.