Simulating whole-body vibration for neonatal patients on a tire-coupled road simulator

Exposure to excessive whole-body vibration is linked to health issues and may result in increased rates of mortality and morbidity in infants. Newborn infants requiring specialized treatment at neonatal intensive care units often require transportation by road ambulance to specialized care centers, exposing the infants to potentially harmful vibration and noise. A standardized Neonatal Patient Transport System (NPTS) has been deployed in Ontario, Canada, that provides life saving equipment to patients and safe operation for the clinical care staff. However, there is evidence that suggests patients may experience a higher amplitude of vibration at certain frequencies when compared with the vehicle vibration. In a multi-year collaborative project, we seek to create a standardized test procedure to evaluate the levels of vibration and the effectiveness of mitigation strategies. Previous studies have looked at laboratory vibration testing of a transport system or transport incubator and were limited to single degree of freedom excitation, neglecting the combined effects of rotational motion. This study considers laboratory testing of a full vehicle and patient transport system on an MTS Model 320 Tire-Coupled Road Simulator. The simulation of road profiles and discrete events on a tire-coupled road simulator allows for the evaluation of the vibration levels of the transport system and the exploration of mitigation strategies in a controlled setting. The tire-coupled simulator can excite six degrees-of-freedom motion of the transport system for vibration evaluation in three orthogonal directions including the contributions of the three rotational degrees of freedom. The vibration data measured on the transport system during the tire-coupled testing are compared to corresponding road test data to assess the accuracy of the vibration environment replication. Three runs of the same drive file were conducted during the laboratory testing, allowing the identification of anomalies and evaluation of the repeatability. The tire-coupled full vehicle testing revealed a high level of accuracy in re-creating the road sections and synthesized random profiles. The simulation of high amplitude discrete events, such as speed hump traverses, were highly repeatable, yet yielded less accurate results with respect to the peak amplitudes at the patient. The resulting accelerations collected at the input to the manikin (sensor located under the mattress) matched well between the real-world and road simulator. The sensors used during testing included series 3741B uni-axial and series 356A01 tri-axial accelerometers by PCB Piezotronics. These results indicate a tire-coupled road simulator can be used to accurately evaluate vibration levels and assess the benefits of future mitigation strategies in a controlled setting with a high level of repeatability.

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/ .

Effects of whole-body vibration exercise on physical function in patients with chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

The current state of knowledge regarding the efficacy of whole-body vibration (WBV) training for individuals with chronic kidney disease (CKD) is limited. To address this gap, the present study seeks to undertake a comprehensive systematic review and meta-analysis of clinical trials to evaluate the impact of WBV on physical function and quality of life outcomes in CKD patients.

METHODS

A systematic search was performed on the PubMed, Embase, Web of Science, and Scopus databases from inception to March 2023 and updated in June 2023. The inclusion criteria comprised randomized controlled studies, quasi-experimental studies, and single-arm trials that evaluated the impact of WBV on physical function, encompassing cardiopulmonary fitness, muscle strength, mobility, and balance, in CKD patients. Adverse events that were included in the study reports were recorded. The pooled evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) method.

RESULTS

Nine studies were identified, of which seven were included in the meta-analysis. The results of the meta-analysis indicated a statistically significant improvement in upper (mean difference: 3.45 kg; 95% confidence interval 1.61 to 5.29) and lower (standardized mean difference: 0.34, 95% confidence interval 0.08 to 0.59) extremity muscle strength in patients with CKD who underwent WBV training compared to baseline (low-level evidence). Furthermore, WBV training favored improved cardiorespiratory fitness, mobility, and balance function, but no statistical difference was observed. The impact of WBV training on quality of life in patients with CKD requires further validation. Notably, only one adverse event (nausea) was reported in the included studies.

CONCLUSIONS

WBV has demonstrated efficacy and feasibility in enhancing muscle strength among patients with CKD. However, further investigation is warranted to determine its potential for improving cardiorespiratory adaptations, mobility, balance function, and quality of life. Additionally, future research should prioritize comprehensive reporting of WBV protocols to establish an optimal training regimen for the CKD population.

Road safety: The influence of vibration frequency on driver drowsiness, reaction time, and driving performance

Driver drowsiness is a factor in at least 20% of serious motor vehicle accidents. Although research has shown that Whole-Body Vibration (WBV) can induce drowsiness in drivers, it is unknown whether particular frequencies are more problematic. The present study systematically investigated the influence of WBV frequency on driver drowsiness. Fifteen participants each undertook six 1-h sessions of simulated driving while being subjected to WBV of either 0 Hz (no vibration), 1-4 Hz, 4-8 Hz, 8-16 Hz, 16-32 Hz or 32-64 Hz. Subjective sleepiness, as measured by the Karolinska Sleepiness Scale (KSS), confirmed that drivers felt drowsier when exposed to the two lowest frequency ranges (1-4 Hz and 4-8 Hz). Reaction time, which measures attention and alertness, was significantly impaired by the two lowest frequency ranges. Objective driving performance measures (Standard Deviation of Lane Position (SDLP), Standard Deviation of (SD) Steering Angle, Time in Unsafe Zone) also showed significant degradation due to exposure to the two lowest frequency ranges. Exposure to 1-4 Hz or 4-8 Hz vibration caused attention to become significantly impaired within 15-20 min and driving performance to be significantly impaired by 30-35 min. The other frequency ranges had little or no effect. These findings point to a need to develop equivalent vibration-induced drowsiness contours that can be adopted as transportation safety standards.

Finite element modelling and biodynamic response prediction of the seated human body exposed to whole-body vibration

Biodynamic modelling of seat-occupant systems can assist in seat comfort design. A finite element (FE) model of the seated human body, including detailed modelling of the lumbar spine, was established to reflect the human response to vibration and biodynamic response of the lumbar spine under whole-body vibration (WBV). The lumbar spine model was established and validated against the in-vitro results and calculated data. The posture of the lumbar spine was adjusted according to the radiological research results, and the adjusted model was combined to establish a FE model of the seated human body. The present seated human model with backrest inclination angles of 10, 20, and 30°, validated by comparing the measured apparent mass and seat-to-lumbar spine transmissibility, was used to calculate the biodynamic response of the lumbar spine with three inclined backrests under WBV. The results showed that the model could characterise the apparent mass, seat-to-lumbar spine transmissibility, and the biodynamic response of the lumbar spine. Practitioner summary: Biodynamic models can represent dynamic characteristics of the human body exposed to vibration and assist in seat comfort design. The three-dimensional FE model of the human body can be used to explore the human response to vibration and the biodynamic response of the lumbar spine under WBV.

Whole-body vibration may not affect bone mineral density and bone turnover in persons with chronic spinal cord injury: A preliminary study

CONTEXT

Spinal-cord injury (SCI) induces bone loss and dramatically increases the risk of fracture.

OBJECTIVES

Determine the effects of whole-body vibration (WBV) on areal bone mineral density (aBMD), whole body composition and bone biological parameters in individuals with chronic-state SCI.

DESIGN

Randomized study.

SETTING

Centre Neurologique PROPARA.

PARTICIPANTS

Fourteen subjects were randomly assigned to a WBV or a control group.

INTERVENTIONS

WBV (20-45 min, 30-45 Hz, 0.5 g) was performed in verticalized persons twice weekly for 6 months.

OUTCOME MEASURES

aBMD was measured by DXA at baseline and 6 months and bone biological parameters at baseline, 1, 3 and 6 months.

RESULTS

No significant aBMD change was found in either the WBV or control group after 6 months of follow-up. Similarly, periostin, sclerostin and bone turnover markers remained relatively stable throughout follow-up and no difference in variation was observed within-group and between groups. Except for whole-body fat mass, which showed a significant decrease in the WBV group compared to controls, no difference in changes was observed, whatever the localization for fat and lean body mass.

CONCLUSIONS

During the chronic phase, aBMD and bone remodeling reach a new steady state. However, the DXA technique and the bone markers, including sclerostin and periostin, both of which reflect bone cell activity influenced by mechanical strain, showed that the bone tissue of individuals with SCI was insensitive to 6 months of WBV training at the study dose. Nevertheless, results of this preliminary study that was underpowered need to be confirmed and other modalities of WBV may be more effective in improving aBMD of this population.

TRIALS REGISTRATION

N°IDRCB:2011-A00224-37.

Combined effects of whole-body vibration and dynamic squats on cardiovascular and salivary biomarker responses in healthy adults

This study aimed to investigate the acute effects of combining whole-body vibration with dynamic squats on cardiovascular and salivary bio-marker responses in healthy adults. A randomized crossover design was conducted with 20 healthy adults. Each participant underwent three exercise sessions, with a 2-week washout period between each session. The sessions consisted of: (1) whole-body vibration (VB) at 25 Hz for 2 minutes, with an amplitude of 2 mm, and 2 minutes of rest between sets, for a total of 5 sets; (2) dynamic squats (SQ) performed 15 times within 2 minutes, with a 2-minute rest between sets, for a total of 5 sets; and (3) a combination of whole-body VB and SQ (VB+SQ). The cardiovascular variables and salivary biomarkers related to exercise intensity were assessed. Only the VB+SQ session significantly decreased the unstimulated salivary flow rate, and caused greater changes in heart rate, systolic blood pressure, mean arterial pressure, rate-pressure product, and heart rate variability compared to VB or SQ alone. Moreover, the VB+SQ session significantly increased the salivary total protein concentration from 0.56±0.05 mg/mL (baseline) to 0.74± 0.06 mg/mL (postexercise condition) and the salivary alpha-amylase activity from 33.83±5.56 U/mL (baseline) to 63.63±12.33 U/mL (postexercise condition) (P<0.05). These changes were recovered at 1-hr postexercise condition. Our findings provide information for designing exercise programs that incorporate VB+SQ to enhance hemodynamic and cardiac autonomic responses in healthy adults and for application during rehabilitation periods.

Effects of the whole-body vibration direction on the cognitive response of standing subjects

This study aims to investigate the effect of whole-body vibration along different axes on the response time (RT) of standing subjects during a customised psychomotor vigilance task (PVT). Twenty-five subjects were exposed to harmonic vibration with amplitude of 0.7 m/s2 RMS and frequencies between 1.5 Hz and 12.5 Hz. ANOVA was used to assess if the difference of RT with and without vibration had a statistical relevance. Results showed that the RT was statistically affected by the vibration only at frequencies below 2 Hz. The vibration at higher frequencies had a minor effect on the RT. The RTs during the vibration exposure was, on average, 15% higher than the RT post exposure. Practitioner summary: This study investigates the effects of whole-body vibration (WBV) along different axes on the response time (RT). We measured the RTs to a psychomotor vigilance task of 25 standing subject exposed to WBV. The cognitive response was statistically affected by the WBV and, on average RT have increased of 15%.

Effects of whole-body vibration on sensorimotor deficits and brain plasticity among people with chronic ankle instability: a study protocol for a single-blind randomized controlled trial

BACKGROUND

Chronic ankle instability (CAI) is a form of musculoskeletal disease that can occur after a lateral ankle sprain, and it is characterized by pain, recurrent ankle sprains, a feeling of "giving way" at the ankle joint, and sensorimotor deficits. There has been increasing evidence to suggest that plastic changes in the brain after the initial injury play an important role in CAI. As one modality to treat CAI, whole-body vibration (WBV) has been found to be beneficial for treating the sensorimotor deficits accompanying CAI, but whether these benefits are associated with brain plasticity remains unknown. Therefore, the current study aims to investigate the effect of WBV on sensorimotor deficits and determine its correlation with plastic changes in the brain.

METHODS

The present study is a single-blind randomized controlled trial. A total of 80 participants with CAI recruited from the university and local communities will be divided into 4 groups: whole-body vibration and balance training (WBVBT), balance training (BT), whole-body vibration (WBV), and control group. Participants will be given the WBV intervention (25-38 Hz, 1.3-2 mm, 3-time per week, 6-week) supervised by a professional therapist. Primary outcome measures are sensorimotor function including strength, balance, proprioception and functional performance. Brain plasticity will be evaluated by corticomotor excitability, inhibition, and representation of muscles, as measured by transcranial magnetic stimulation. Activation of brain areas will be assessed through functional near-infrared spectroscopy. Secondary outcome measures are self-reported functional outcomes involving the Cumberland Ankle Instability Tool and the Foot and Ankle Ability Measure. All tests will be conducted before and after the WBV intervention, and at 2-week follow-up. Per‑protocol and intention-to-treat analysis will be applied if any participants withdraw.

DISCUSSION

This is the first trial to investigate the role of brain plasticity in sensorimotor changes brought by WBV for individuals with CAI. As plastic changes in the brain have been an increasingly important aspect in CAI, the results of the current study can provide insight into the treatment of CAI from the perspective of brain plasticity.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR2300068972); registered on 02 March 2023.

Whole body vibration activates the tonic vibration reflex during voluntary contraction

[Purpose] The beneficial neuromuscular effects of whole-body vibration are explained by the tonic vibration or bone myoregulation reflex. Depending on factors that remain undefined, whole-body vibration may activate the tonic vibration or bone myoregulation reflex. We aimed to examine whether voluntary contraction facilitates activation of the tonic vibration reflex during whole-body vibration. [Participants and Methods] Eleven volunteers were included in this study. Local and whole-body vibrations were applied in a quiet standing (without voluntary contraction) and a semi-squatting (isometric soleus contraction) position. Local vibration was applied to the Achilles tendon. Surface electromyography was obtained from the soleus muscle. The cumulative average method was used to determine soleus reflex latency. [Results] In the quiet standing position, the bone myoregulation reflex latency was 39.9 ± 4.1 milliseconds and the tonic vibration reflex latency was 35.4 ± 3.6 milliseconds. Whole-body vibration application in the semi-squatting position activated the tonic vibration reflex in four participants and the bone myoregulation reflex in seven participants. Local vibration activated the tonic vibration reflex in both positions for all participants. [Conclusion] Simultaneous whole-body vibration application and voluntary contraction may activate the tonic vibration reflex. Determining the spinal mechanisms underlying the whole-body vibration exercises will enable their effective and efficient use in rehabilitation and sports.

Activation function 2 (AF2) domain of estrogen receptor-α regulates mechanotransduction during bone fracture healing in estrogen-competent mice

External mechanostimulation applied by whole-body low-magnitude high-frequency vibration (LMHFV) was demonstrated to cause no or negative effects on fracture healing in estrogen-competent rodents, while in ovariectomized (OVX), estrogen-deficient rodents bone formation after fracture was improved. Using mice with an osteoblast-specific deletion of the estrogen receptor α (ERα), we demonstrated that ERα signaling in osteoblasts is required for both the anabolic and catabolic effects of LMHFV during bone fracture healing in OVX and non-OVX mice, respectively. Because the vibration effects mediated by ERα were strictly dependent on the estrogen status, we hypothesized different roles of ligand-dependent and -independent ERα signaling. To investigate this assumption in the present study, we used mice with a deletion of the C-terminal activation function (AF) domain-2 of the ERα receptor, which mediated ligand-dependent ERα signaling (ERαAF-2⁰). OVX and non-OVX ERαAF-2⁰ animals were subjected to femur osteotomy followed by vibration treatment. We revealed that estrogen-competent mice lacking the AF-2 domain were protected from LMHFV-induced impaired bone regeneration, while the anabolic effects of vibration in OVX mice were not affected by the AF-2 knockout. RNA sequencing further showed that genes involved in Hippo/Yap1-Taz and Wnt signaling were significantly downregulated upon LMHFV in the presence of estrogen in vitro. In conclusion, we demonstrated that the AF-2 domain is crucial for the negative effects of vibration during bone fracture healing in estrogen-competent mice suggesting that the osteoanabolic effects of vibration are rather mediated by ligand-independent ERα signaling.

Mood regulates the physiological response to whole-body vibration at low intensity

In the present study we evaluated the relationship between human vibrational comfort and psychophysiological processes. We exposed twenty-one participants to three levels of whole-body vibration at low intensity inside a full-scale mock-up of a ship cabin. Autonomic Nervous System (ANS) activity, mood and well-being state during each level of vibration exposure were measured. We found that a positive affective state determined greater changes in ANS activity in response to vibration variations compared to a negative affective condition. Furthermore, we found that variations of the vibration intensity did not always determine variations of the comfort experience at physiological and psychological level. The relevance of our findings is a challenge for comfort design research showing a gap between guidelines for comfort design and evidence based on psychophysiological responses to environmental stimulation.

A reliability study on the cumulative averaging method for estimating effective stimulus time in vibration studies

Finding the reflex circuitry responsible for high-frequency vibration-induced muscle contraction takes work. The main challenge is to determine the effective stimulus time (EST) point at which continuous (sinusoidal) stimulation (i.e., vibration) triggers the reflex response. A novel "cumulated averaging method" has been previously proposed for estimating the EST point. In the current study, we aimed to test the reliability of the cumulated average method. We used five different whole-body vibration (WBV) frequencies in two experiments. The consistency between the EST points estimated from the first and second experiments was analysed with the intraclass correlation (ICC) and technical error of measurement (TEM). The ICC coefficient with 95% CI for the EST point estimation was 0.988 (0.950-0.997). The relative TEM was 1.3%. We concluded that the cumulated average method is highly reliable in estimating the effective stimulus time point for high-frequency continuous sinusoidal signals.

Effects of whole-body vibration exercise in patients with chronic kidney disease: a systematic review

PURPOSE

Chronic kidney disease (CKD) is a clinical condition that promotes a decline in the overall health status of individuals affected, including parameters physical, functional, and psychosocial. This systematic review was conducted to assess effects of whole-body vibration exercise (WBVE) in individuals with CKD.

MATERIALS AND METHODS

It was conducted electronic searches in Pubmed, Embase, Scopus, Web of Science databases on May 2021. Records were identified and irrelevant studies were excluded based in eligibility criteria.

RESULTS

Five studies were included with a mean methodological quality score of 9, considered high quality in PEDRo scale. The studies have shown that the WBVE intervention, when applied low intensity was well tolerated, and no adverse effects; was able to improve the motor performance and strength in frail people, which could benefit the prevention of falls events. However, did not improve the quality of life, and the heart rate variability; and not altered cardiorespiratory parameters.

CONCLUSIONS

WBVE intervention promotes a better response in parameters of the motor performance and muscular strength, and interaction bone-muscle. Nevertheless, more studies are needed with this intervention to improve physiological responses, and to understand your recommendation to prevent and reduce the complications and symptoms of the CKD, promoting an active life to these patients.

PROTOCOL STUDY REGISTRATION

PROSPERO (CRD42020203295).IMPLICATIONS FOR REHABILITATIONChronic kidney disease (CKD) is a clinical condition that promotes a decline in the overall health status of individuals affected, including parameters physical, functional, and psychosocial.WBVE program possibility, of good acceptance, efficient as well tolerated by physically deconditioned patients who present difficulty to perform any type of exercise.WBVE protocol can promote changes in the patient with CKD lifestyle and benefits for this population because is an exercise without fatigue, impact, stress, or discomfort.

Biomechanical responses of the human lumbar spine to vertical whole-body vibration in normal and osteoporotic conditions

BACKGROUND

The prevalence of osteoporosis is continuing to escalate with an aging population. However, it remains unclear how biomechanical behavior of the lumbar spine is affected by osteoporosis under whole-body vibration, which is considered a significant risk factor for degenerative spinal disease and is typically present when driving a car. Accordingly, the objective of this study was to compare the spine biomechanical responses to vertical whole-body vibration between normal and osteoporotic conditions.

METHODS

A three-dimensional finite-element model of the normal human lumbar spine-pelvis segment was developed using computed tomographic scans and was validated against experimental data. Osteoporotic condition was simulated by modifying material properties of bone tissues in the normal model. Transient dynamic analyses were conducted on the normal and osteoporotic models to compute deformation and stress in all lumbar motion segments.

FINDINGS

When osteoporosis occurred, vibration amplitudes of the vertebral axial displacement, disc bulge, and disc stress were increased by 32.1-45.4%, 25.7-47.1% and 23.0-42.7%, respectively. In addition, it was found that for both the normal and osteoporotic models, the response values (disc bugle and disc stress) were higher in L4-L5 and L5-S1 intervertebral discs than in other discs.

INTERPRETATION

Osteoporosis deteriorates the effect of whole-body vibration on lumbar spine, and the lower lumbar segments might have a higher likelihood of disc degeneration under whole-body vibration.

The effect of selected rest break activities on reaction time, balance, and perceived discomfort after one hour of simulated occupational whole-body vibration exposure in healthy adults

MATERIALS & METHODS

Eleven healthy adults participated in four 1-hour sessions of ecologically valid WBV exposure followed by one of four 5-minute activities: sitting, walking, 2 min of gaze stabilization exercise (GSE) coupled with 3 min of trunk mobility exercise (GSE + MOBIL), or 2 min of GSE coupled with a 3-minute walk (GSE + WALK). Baseline and post-activity measurements (rating of perceived discomfort, balance and postural sway measurements, 5-minute psychomotor vigilance task test) were submitted to a paired t-test to determine the effect of WBV exposure and activities on physical, cognitive, and sensorimotor systems and to a repeated measures ANOVA to determine any differences across activities.

RESULTS

We observed degradation of the slowest 10% reaction speed outcomes between baseline and post-activity after walking (7.3%, p < 0.05) and sitting (8.6%, p < 0.05) but not after GSE + MOBIL or GSE + WALK activities. Slowest 10% reaction speed after GSE + MOBIL activity was faster than all other activities. The rating of perceived discomfort was higher after SIT and WALK activities. There were no notable differences in balance outcomes.

CONCLUSION

When compared to sitting for 5 min, an activity including GSE and an active component, such as walking or trunk mobility exercises, resulted in maintenance of reaction time after WBV exposure. If confirmed in occupational environments, GSE may provide a simple, rapid, effective, and inexpensive means to protect against decrements in reaction time after WBV exposure.

Increase in serum nerve growth factor but not intervertebral disc degeneration following whole-body vibration in rats

BACKGROUND

Low back pain is a leading cause of disability and is frequently associated with whole-body vibration exposure in industrial workers and military personnel. While the pathophysiological mechanisms by which whole-body vibration causes low back pain have been studied in vivo, there is little data to inform low back pain diagnosis. Using a rat model of repetitive whole-body vibration followed by recovery, our objective was to determine the effects of vibration frequency on hind paw withdrawal threshold, circulating nerve growth factor concentration, and intervertebral disc degeneration.

METHODS

Male Sprague-Dawley rats were vibrated for 30 min at an 8 Hz or 11 Hz frequency every other day for two weeks and then recovered (no vibration) for one week. Von Frey was used to determine hind paw mechanical sensitivity every two days. Serum nerve growth factor concentration was determined every four days. At the three-week endpoint, intervertebral discs were graded histologically for degeneration.

FINDINGS

The nerve growth factor concentration increased threefold in the 8 Hz group and twofold in the 11 Hz group. The nerve growth factor concentration did not return to baseline by the end of the one-week recovery period for the 8 Hz group. Nerve growth factor serum concentration did not coincide with intervertebral disc degeneration, as no differences in degeneration were observed among groups. Mechanical sensitivity generally decreased over time for all groups, suggesting a habituation (desensitization) effect.

INTERPRETATION

This study demonstrates the potential of nerve growth factor as a diagnostic biomarker for low back pain due to whole-body vibration.

Novel methods to detect impacts within whole-body vibration time series data

We present three candidate mathematical models for detecting impacts within time series accelerometer data in the context of whole-body vibration (WBV). In addition to WBV, data included recordings of erector spinae muscle activity and trunk posture collected during use of agricultural machines in a previous study. For each model, we evaluated associations between several mechanical and biomechanical variables at the time of predicted impact onset and the odds of subsequently observing a bilateral response of the erector spinae muscles. For all models, trunk posture at the time of impact onset was strongly associated with an observed bilateral muscle response; these associations were not observed when impacts were randomly assigned. Results provide a framework for describing the number and magnitudes of impacts that may help overcome ambiguities in current exposure metrics, such as the vibration dose value, and highlight the importance of considering posture in the evaluation of occupational WBV exposures. Practitioner summary: Common metrics of exposure to whole-body vibration do not quantify the number or magnitudes of impacts within time series accelerometer data. Three candidate impact detection methods are presented and evaluated using real-world data collected during use of agricultural machines. Results highlight the importance of considering posture when evaluating vibration exposure.

Effects of whole-body vibration at different periods on lumbar vertebrae in female rats

The current study aimed to investigate the effects of whole-body vibration (WBV) before and after ovariectomy on lumbar vertebrae, and to observe whether the positive effects of WBV before and after ovariectomy on lumbar vertebrae in rats could be maintained after vibration stopped. Three-month-old female rats were divided into four groups (n = 45/group): control (CON), ovariectomy (OVA), WBV before ovariectomy (WBV-BO), and WBV after ovariectomy (WBV-AO) groups. For 1-8 weeks, WBV-BO group was subjected to vertical WBV. At the 9th week, the rats in WBV-BO, WBV-AO, and OVA groups were ovariectomized. During 11-18 weeks, WBV-AO group was subjected to vibration. For 19-26 weeks, no intervention was done for rats. The lumbar vertebrae were examined by Micro-CT, compressive test, creep test, and microindentation test. At the 8th week, the displacement of the L1-L2 annulus fibrosus in WBV-BO group was 18% smaller compared with CON group (p<0.05). At the 18th week, the elastic modulus of the L5 vertebral body in WBV-BO and WBV-AO groups was 53% and 57% higher than that in CON group, respectively (p<0.05); the displacement of the L1-L2 annulus fibrosus in WBV-BO group was 25% smaller than those in the other groups (p<0.05). At the 26th week, there was no significant difference in the displacement of the L1-L2 annulus fibrosus between WBV-BO group and other groups (p>0.05); the elastic modulus of the L5 vertebral body had no significant difference between WBV-AO group and CON group (p>0.05). Our results demonstrated that WBV before ovariectomy effectively prevented disc degeneration with significant effects up to 8 weeks after ovariectomy. The vertebral mechanical properties could be significantly improved by WBV after ovariectomy, but the residual effect did not maintain after WBV stopped.

Development and Validation of a Whole Human Body Finite Element Model with Detailed Lumbar Spine

OBJECTIVE

Investigations showed that low back pain of occupational drivers might be closely related to the whole-body vibration. Restricted by ethical concerns, the finite element method had become a viable alternative to invasive human experiments. Many mechanical behaviors of the human spine inside of the human body were unclear; therefore, a human whole-body finite element model might be required to better understand the lumbar behavior under whole-body vibration.

METHODS

In this study, a human whole-body finite element model with a detailed lumbar spine segment was developed. Several validations were performed to ensure the correctness of this model.

RESULTS

The results of anthropometry and geometry validation, static validation, and dynamic validation were presented in this study. The validation results showed that the whole human body model was reasonable and valid by comparing with published data.

CONCLUSIONS

The model developed in this study could reflect the biomechanical response of the human lumbar spine under vibration and could be used in further vibration analysis and offer proposals for protecting human body under whole-body vibration environment.

Biomechanical role of cement augmentation in the vibration characteristics of the osteoporotic lumbar spine after lumbar interbody fusion

Under whole body vibration, how the cement augmentation affects the vibration characteristic of the osteoporotic fusion lumbar spine, complications, and fusion outcomes is unclear. A L1-L5 lumbar spine finite element model was developed to simulate a transforaminal lumbar interbody fusion (TLIF) model with bilateral pedicle screws at L4-L5 level, a polymethylmethacrylate (PMMA) cement-augmented TLIF model (TLIF-PMMA) and an osteoporotic TLIF model. A 40 N sinusoidal vertical load at 5 Hz and a 400 N preload were utilized to simulate a vertical vibration of the human body and the physiological compression caused by muscle contraction and the weight of human body. The results showed that PMMA cement augmentation may produce a stiffer pedicle screw/rod construct and decrease the risk of adjacent segment disease, subsidence, and rod failure under whole-body vibration(WBV). Cement augmentation might restore the disc height and segmental lordosis and decrease the risk of poor outcomes, but it might also increase the risk of cage failure and prolong the period of lumbar fusion under WBV. The findings may provide new insights for performing lumbar interbody fusion in patients affected by osteoporosis of the lumbar spine. Graphical abstract.

The effect of whole-body vibration in osteopenic patients after total knee arthroplasty: a randomized controlled trial

BACKGROUND

Total knee arthroplasty (TKA) is an important treatment for knee osteoarthritis, but the result of whole-body vibration (WBV) in knee function rehabilitation and bone loss with osteopenia was unknown. Therefore, the purpose of this study is to study whether low-frequency, low-amplitude WBV can improve the clinical outcome of knee osteoarthritis.

METHODS

This study was randomized and included 67 osteopenic patients (55-90 years, 85% women) for TKA surgery (control group N = 32, WBV group N = 35). All selected patients after TKA surgery tested clinical results, such as knee function and bone mass in baseline, 3 months after surgery, and 6 months after surgery.

RESULTS

Compared to the control group, the WBV group improved pain scores, thigh circumference, lower limb muscle strength, joint activity, and joint function in 6 months after surgery. WBV intervention also improves bone density in the spine, the microstructure of the radius and tibia, and the bone turnover marker. At 3 months after TKA surgery, the WBV group had no significant effect on knee function and bone loss.

CONCLUSIONS

Whole-body vibration for osteopenic patients with knee arthroplasty showed good therapeutic results in 6 months after TKA surgery, but the long-term therapeutic effect still needs to be further observed.

The neuromuscular responses in patients with Parkinson's disease under different conditions during whole-body vibration training

BACKGROUND

Whole-body vibration (WBV) training can provoke reactive muscle response and thus exert beneficial effects in various neurological patients. This study aimed to investigate the muscles activation and acceleration transmissibility of the lower extremity to try to understand the neuromuscular control in the Parkinson's disease (PD) patients under different conditions of the WBV training, including position and frequency.

METHODS

Sixteen PD patients and sixteen controls were enrolled. Each of them would receive two WBV training sessions with 3 and 20 Hz mechanical vibration in separated days. In each session, they were asked to stand on the WBV machine with straight and then bended knee joint positions, while the vibration stimulation was delivered or not. The electromyographic (EMG) signals and the segmental acceleration from the lower extremity were recorded and processed. The amplitude, co-contraction indexes (CCI), and normalized median frequency slope (NMFS) from the EMG signals, and the acceleration transmissibility were calculated.

RESULTS

The results showed larger rectus femoris (RF) amplitudes under 3 Hz vibration than those in 20 Hz and no vibration conditions; larger tibialis anterior (TA) in 20 Hz than in no vibration; larger gastrocnemius (GAS) in 20 Hz than in 3 Hz and no vibration. These results indicated that different vibration frequencies mainly induced reactive responses in different muscles, by showing higher activation of the knee extensors in 3 Hz and of the lower leg muscles in 20 Hz condition, respectively. Comparing between groups, the PD patients reacted to the WBV stimulation by showing larger muscle activations in hamstring (HAM), TA and GAS, and smaller CCI in thigh than those in the controls. In bended knee, it demonstrated a higher RF amplitude and a steeper NMFS but smaller HAM activations than in straight knee position. The higher acceleration transmissibility was found in the control group, in the straight knee position and in the 3 Hz vibration conditions.

CONCLUSION

The PD patients demonstrated altered neuromuscular control compared with the controls in responding to the WBV stimulations, with generally higher EMG amplitude of lower extremity muscles. For designing WBV strengthening protocol in the PD population, the 3 Hz with straight or flexed knee protocol was recommended to recruit more thigh muscles; the bended knee position with 20 Hz vibration was for the shank muscles.

Does Whole-Body Vibration Training Have a Concurrent Effect on Bone and Muscle Health? A Systematic Review and Meta-Analysis

BACKGROUND

Aging results in musculoskeletal disorders, which are a leading cause of disability worldwide. While conventional nonpharmacological treatments have included interventions such as resistance exercise, there are subgroups of people who may be at risk of exercise-related injuries, for example, falls. Whole-body vibration (WBV) is an intervention that helps improve musculoskeletal function and is viable for those with limited mobility.

OBJECTIVES

Whether WBV has a dual effect on bone and muscle conditions remains unknown. We aim to assess the evidence of the effects of WBV on bone and muscle parameters concurrently in older people.

METHODS

Under Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines, a systematic literature search was performed in MEDLINE, EMBASE, EMCARE, and the Cochrane Central Registry of Controlled Trials. The main outcomes were changes in bone and muscle parameters.

RESULTS

Our meta-analysis showed that WBV does not have significant synergistic effects on measured bone (bone mineral density [BMD] in the hip and lumbar spine) and muscle (lean muscle mass and sit-to-stand time) outcomes, compared to controls (i.e., no WBV included).

CONCLUSION

While there were no significant results, the included studies are limited by small sample size and variable intervention protocols and follow-up periods. Further trials should endeavor to measure both bone and muscle outcomes concurrently with a longer follow-up time. Osteoporosis status in participants must also be considered as it is not yet possible to exclude that WBV may have a significant effect on BMD in people with known osteoporosis. WBV does not appear to simultaneously influence bone and muscle health in older people, and future research is required to establish a regimen that may lead to measurable clinical efficacy.

Whole-body vibration exercise and training increase regional CBF in mild cognitive impairment with enhanced cognitive function

OBJECTIVES

Preclinical and non-medicinal interventions are essential for preventing and treating cognitive decline in patients with mild cognitive impairment (MCI). Whole-body vibration (WBV) exercise is conducted on a platform that generates vertical sinusoidal vibrations, and WBV training may improve regional cerebral blood flow (rCBF) and cognitive function, however, the underlying mechanism remains unclear. The aim of the present study was to investigate whether WBV exercise and a 24-week WBV training protocol increased rCBF and enhanced cognitive function in patients with amnestic MCI (aMCI).

METHODS

[^99mTc]-ECD and SPECT studies were performed on 16 aMCI patients at baseline, during WBV exercise, and on 6 of the 16 patients after 24-week WBV training. To diagnose SPECT images and select the patients, a Z-score mapping approach was used, which revealed pathological hypoperfusion in the parietal association cortex, precuneus and/or posterior cingulate gyrus for MCI at baseline. rCBF was semi-quantitatively measured and underestimation in the high flow range was corrected. Since it is difficult to quantitatively measure rCBF during WBV exercise, the rCBF_ratio was obtained by standardizing with the average of individual mean SPECT counts with correcting underestimation in the high flow range. The rCBF_ratios at baseline and after WBV training were also obtained in a similar manner. Since the changes in rCBF were regarded as corresponding to the changes in rCBF_ratio, the ratios were compared. Cognitive function was also evaluated and compared.

RESULTS

We found that the rCBF_ratio changed with an average range of 11.5% during WBV exercise, and similar changes were observed after 24-week WBV training with a 13.0% change, resulting in improved cognitive function (MoCA-J, P = 0.028). The rCBF_ratio increased in the parietal association cortex and occipital lobes, including the precuneus and posterior cingulate gyrus, at which hypoperfusion was detected at baseline, but decreased in the frontal lobe and anterior cingulate gyrus. The rCBF_ratio increased on the right side of several motion-suppressive nuclei by WBV exercise; the bilateral red nuclei and right medial globus pallidus by WBV training.

CONCLUSION

WBV exercise and training increase rCBF in aMCI patients, and WBV training enhances cognitive function and may increase the cognitive reserve. Further investigation is necessary.

Effects of two 24-week multimodal exercise programs on reaction time, mobility, and dual-task performance in community-dwelling older adults at risk of falling: a randomized controlled trial

Background

Falls in older adults are considered a major public health problem. Declines in cognitive and physical functions, as measured by parameters including reaction time, mobility, and dual-task performance, have been reported to be important risk factors for falls. The aim of this study was to investigate the effects of two multimodal programs on reaction time, mobility, and dual-task performance in community-dwelling older adults at risk of falling.

Methods

In this randomized controlled trial, fifty-one participants (75.4 ± 5.6 years) were allocated into two experimental groups (EGs) (with sessions 3 times per week for 24 weeks), and a control group: EG1 was enrolled in a psychomotor intervention program, EG2 was enrolled in a combined exercise program (psychomotor intervention program + whole-body vibration program), and the control group maintained their usual daily activities. The participants were assessed at baseline, after the intervention, and after a 12-week no-intervention follow-up period.

Results

The comparisons revealed significant improvements in mobility and dual-task performance after the intervention in EG1, while there were improvements in reaction time, mobility, and dual-task performance in EG2 (p ≤ 0.05). The size of the interventions’ clinical effect was medium in EG1 and ranged from medium to large in EG2. The comparisons also showed a reduction in the fall rate in both EGs (EG1: -44.2%; EG2: − 63.0%, p ≤ 0.05) from baseline to post-intervention. The interventions’ effects on reaction time, mobility, and dual-task performance were no longer evident after the 12-week no-intervention follow-up period.

Conclusions

The results suggest that multimodal psychomotor programs were well tolerated by community-dwelling older adults and were effective for fall prevention, as well as for the prevention of cognitive and physical functional decline, particularly if the programs are combined with whole-body vibration exercise. The discontinuation of these programs could lead to the fast reversal of the positive outcomes achieved.

Trial registration

ClinicalTrials.gov Identifier: NCT03446352. Date of registration: February 07, 2018.

Cardiovascular response to whole-body vibration on an automobile seat

The study aim was to determine whether a relationship exists between the cardiovascular response, measured by HR and HRV and the magnitude of whole-body vibration. Cardiovascular response of sixty male participants in four groups, was measured during three states i.e. (1) no vibration, (2) a reference vibration and (3) an alternative vibration. The reference vibration was the same for all groups with the alternative vibrations different for each group. Weighted vertical seat vibration was 0.66 m.s^-2, root-mean-square for the reference and 0.70, 0.73, 0.76, and 0.79 m.s^-2, root-mean-square for the alternative vibrations. Vibrations only differed in magnitude with the difference between alternative vibrations based on relative difference thresholds. Nonparametric tests compared cardiovascular indicators between groups at State 3 adjusted for state of departure i.e. State 2. No significant differences between groups were found for most of the indicators, suggesting no relationship between cardiovascular response and the magnitude of whole-body vibration. Practitioner summary: The cardiovascular response to the magnitude of whole-body vibration on an automobile seat was investigated. Results suggest that no relationship exists between the magnitude and cardiovascular response and that the latter may not be as effective as other objective measures (e.g. acceleration) in evaluating the human's response to whole-body vibration.

Whole-body vibration decreases delayed onset muscle soreness following eccentric exercise in elite hockey players: a randomised controlled trial

BACKGROUND

Delayed onset muscle soreness (DOMS) is a common non-structural muscle injury which can disrupt training and impair performance in elite athletes. Vibration therapy reduces inflammation and improves neuromuscular efficiency, leading to reductions in pain and stiffness, and may be effective for the prevention or treatment of DOMS. However, the effect of whole-body vibration (WBV) used after sport in elite athletes has not been reported.

METHODS

A randomised, controlled trial was performed. Participants were elite (national or international level) hockey players and underwent an eccentric exercise protocol previously shown to produce clinical DOMS. After exercise, one group underwent static stretching with WBV therapy, and the other performed stretching only. Baseline and serial post-exercise pain scores and measurements of quadriceps tightness were obtained.

RESULTS

Eleven participants were recruited into each study arm. There were no significant differences in baseline group characteristics. Participants receiving WBV had significant reductions in both pain (p = 0.04) and quadriceps tightness (p = 0.02) compared with stretching only.

CONCLUSIONS

Post-exercise WBV is effective in elite hockey players to reduce DOMS after eccentric exercise. Elite athletes in multi-sprint sports are at risk of DOMS during training and competition, and its reduction could contribute to reduced injury risk and improved performance. This treatment modality is favourable because it can be incorporated with minimal disruption into the recovery section of existing training regimes. These findings may also be extrapolated to other multi-sprint sports.

Sinus-like versus random vibration: Acute effects on elderly people with a high risk of falling

BACKGROUND

Whole-body vibration (WBV) could be an alternative training method for elderly with a high risk of falling.

RESEARCH QUESTION

What acute effects of sinus-like and random WBV intervention occur in this risk group and how do they differ?

METHODS

This prospective pilot study was performed on two days separated by a one-week wash-out phase. Twelve subjects (10 women and 2 men, age 77.7 ± 5.3; 162.3 ± 7.4 cm; 82.4 ± 15.2 kg; BMI 31.2 ± 5.1 kg/m²) undertook sinus-like WBV intervention. One week later random WBV were performed. This consisted of six intervals each lasting 60 s, with heart and respiratory rates monitored. Feasibility outcomes involved safety and compliance. The primary endpoint was postural control, measured by a static posturography before and after the first interval and complete intervention. Secondary outcomes measured before and after the intervention were a Timed-Up-and-Go-Test (TUGT) and an instrumental gait analysis.

RESULTS

Random WBV intervention showed positive acute effect on postural control (Standard deviation (SD) Ellipse area p = 0.007; SD of the Center of force (CoF) independent from direction p = 0.017; SD of the CoF in the antero-posterior direction p = 0.011). There were no significant acute effects on TUGT or gait analysis (comparison between sinus-like and random WBV: Single Task: ΔVelocity p = 0.373, ΔStep time p = 0.077, ΔStep length p = 0.369, ΔStride length p = 0.408, ΔDouble-support-time p = 0.492; Dual task: ΔVelocity p = 0.580, ΔStep-time p = 0.559, ΔStep length p = 0.626, ΔStride length p = 0.584, ΔDouble-support-time p = 0.550). During sinus-like WBV, heart rate increased significantly from rest 69.7 ± 20.9bpm to max.146.0 ± 24.9bpm (p = 0.025). Respiratory rate increased significantly from 10.0 ± 1.0 to max.32.0 ± 6.0 (p = 0.011) during random WBV. No undesirable side effects were observed.

SIGNIFICANCE

Findings demonstrate that random WBV improves acute functional ability of postural control, but not gait for elderly people with a high risk of falling. Intervention with WBV seems safe and well accepted by participants. Monitoring of heart and respiratory rate offers protection for subjects with heart disease.

Multi-mechanical waves against Alzheimer's disease pathology: a systematic review

Alzheimer’s disease (AD) is the most common cause of dementia, affecting approximately 40 million people worldwide. The ineffectiveness of the available pharmacological treatments against AD has fostered researchers to focus on alternative strategies to overcome this challenge. Mechanical vibrations delivered in different stimulation modes have been associated with marked improvements in cognitive and physical performance in both demented and non-demented elderly. Some of the mechanical-based stimulation modalities in efforts are earlier whole-body vibration, transcranial ultrasound stimulation with microbubble injection, and more recently, auditory stimulation. However, there is a huge variety of treatment specifications, and in many cases, conflicting results are reported. In this review, a search on Scopus, PubMed, and Web of Science databases was performed, resulting in 37 papers . These studies suggest that mechanical vibrations delivered through different stimulation modes are effective in attenuating many parameters of AD pathology including functional connectivity and neuronal circuit integrity deficits in the brains of AD patients, as well as in subjects with cognitive decline and non-demented older adults. Despite the evolving preclinical and clinical evidence on these therapeutic modalities, their translation into clinical practice is not consolidated yet. Thus, this comprehensive and critical systematic review aims to address the most important gaps in the reviewed protocols and propose optimal regimens for future clinical application.

Spatiotemporal gait parameter changes due to exposure to vertical whole-body vibration

BACKGROUND

Vertical whole-body vibration (vWBV) during work, recreation, and transportation can have detrimental effects on physical and mental health. Studies have shown that lateral vibration at low frequencies (<3 Hz) can result in changes to spatiotemporal gait parameters. There are few studies which explore spatiotemporal gait changes due to vertical vibration at higher frequencies (> 3 Hz). This study seeks to assess the effect of vWBV on spatiotemporal gait parameters at a greater range of frequencies (≤ 30 Hz).

METHODS

Stride Frequency (SF), Stride Length (SL), and Center of Pressure velocity (CoPv) was measured in seven male subjects (23 ± 4 years, 1.79 ± 0.05 m, 73.9 ± 9.7 kg) during In-Place Walking and nine male subjects (29 ± 7 years, 1.78 ± 0.07 m, 77.8 ± 9.9 kg; mean ± SD) during Treadmill Walking while exposed to vWBV. Load cells measured ground reaction forces during In-Place Walking and sensorized insoles acquired under-foot pressure during Treadmill Walking. Statistical tests included a one-way repeated-measures ANOVA, post-hoc two way paired T-tests, statistical power (1-β), correlation (R²), and effect size (Cohen's d).

RESULTS

While statistical significance was not found for changes in SF, SL, or Mean CoPv, small to large effects were found in all measured spatiotemporal parameters of both setups. During Treadmill Walking, vWBV was correlated with a decrease in SF (R² = 0.925), an increase in SL (R² = 0.908), and an increase in Mean CoPv (R² = 0.921) and Max CoPv (R² = 0.952) with a significant increase (p < 0.0083) in Max CoPv at frequencies of 8 Hz and higher.

SIGNIFICANCE

Study results demonstrated that vWBV influences spatiotemporal gait parameters at frequencies greater than previously studied.

Long-term Effects of Mechanical Vibration Stimulus on the Bone Formation of Wistar Rats: An Assessment Method Based on X-rays Images

BACKGROUND

Bone is a complex living tissue that adapts itself to the demands of mechanical stimuli such as physical activity and exercise. Whole-body vibration (WBV) is a type of exercise characterized by the transmission of mechanical vibration stimuli produced by a vibrating platform. This study aimed to investigated, in experimental model, the effect of WBV exercise on the bone in different frequencies through X-ray analysis.

MATERIALS AND METHODS

Wistar rats were divided in three groups: control, exposed to WBV of 10 Hz and exposed to WBV of 20 Hz, during 8-weeks. All procedures to obtain the radiographic images were carried out before and after the experiments. The femur linear size and bone density measurements through radiographic images were performed in all animals. A factor of increase for bone density (FIBD) was determined.

RESULTS

No differences were observed in the qualitative comparison between the groups, as well as radiographic bone density before the experiment. However, after the experiment the bone density increased in the rats exposed to WBV of 10 Hz and 20 Hz compared to control group. Also, the FIBD was higher in the groups exposed to WBV in comparison with control.

CONCLUSION

These findings indicate an increase of the bone density dependent of the vibration stimulus frequency. In addition, this increase suggests a possible osteogenic effect to the mechanical vibrations of 10 and 20 Hz.

Finite element modeling and parameter identification of the seated human body exposed to vertical vibration

Developing a biomechanical model which connected with the actual anatomy of the human body is helpful to understand the human response to vibration. A finite element model of the seated human body with 175 cm in stature and 68.6 kg in weight, which consists of seven segments, six joints and soft tissue, was established to reflect apparent mass based on the Hybrid III dummy model. By comparing the body segment mass percentages with previous data, the rationality of mass distribution in this model was verified. The biomechanical parameters play a crucial role in biodynamic modeling, while the joint and soft tissue parameters are difficult to choose due to the wide range of anthropometric parameters. In this study, the root-mean-square error between the calculated and the measured apparent mass was taken as objective function, and the effect of fifteen human parameters on the objective function was analyzed through sensitivity analysis. Then seven parameters with a considerable influence on the objective function were selected as design variables, and four approximate models were established for parameter optimization. Soft tissues and joint parameters of the model were determined by parameter identification, and the finite element model that can reflect vertical in-line and fore-and-aft cross-axis apparent mass of the human body without backrest was developed. The seated human model presented in this paper can also reflect the transmissibility from seat to the first thoracic spine and the main modes of the human body below 10 Hz, which is conducive to express the human response to vibration.

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.

Prediction of complications and fusion outcomes of fused lumbar spine with or without fixation system under whole-body vibration

Lumbar fixator has been widely used, which can stabilize the lumbar spine and improve the fusion outcomes, but also lead to many complications. The effects of the internal fixator on biomechanical properties of the fused lumbar spine have been widely concerned for many years. However, most studies only considered the static loads and did not consider the effect of the fixator on the properties of the human lumbar spine under whole-body vibration (WBV). The purpose of this study is to investigate how the fixation system affects the biomechanical characteristics of the lumbar spine, fusion outcomes, and complications under WBV based on the finite element analysis. A three-dimensional nonlinear osteoligamentous finite element model of the intact L1-sacrum spine with muscles was established. A 5-Hz, 40-N sinusoidal vertical load supplemented with a 400-N preload was applied at L1 to simulate the vibration of the human body. For the adjacent segments, the fixation system may increase the risk of the adjacent segment disease under WBV. For the fused segments, the fixation system may decrease the risk of subsidence and cage failure including fatigue failure under WBV. The fixation system may provide a more stable and suitable environment for vertebral cell growth under WBV and lead to better fusion outcomes. This study reveals insights into the effect of the fixation system on the vibration characteristics of the lumbar and provides new information on the fixation system, fusion outcomes, complications, clinical evaluation, and selection of fixation system.

Favorable Effects of 24-Week Whole-Body Vibration on Glycemic Control and Comprehensive Diabetes Therapy in Elderly Patients with Type 2 Diabetes

BACKGROUND

Elderly patients with type 2 diabetes (T2DM) are vulnerable to treatment-inducible hypoglycemia, falls, and depressive symptoms. Although it is challenging for elderly patients to adhere to regular exercise, its positive effect on functional ability, glycemic control, and mental wellness offers comprehensive diabetes treatment. In the present study, we aimed to investigate a novel exercise approach for the elderly, focusing on whole-body vibration (WBV).

METHODS

This retrospective cohort study was conducted in a primary-care setting at a medical fitness center affiliated with the incorporated medical institution of THY (TOTAL HEALTH YARD). Fourteen (WBV group) and 12 (control group) elderly patients with T2DM undergoing and not undergoing our WBV program, respectively, for > 6 months were analyzed. Primary endpoints were the functional ability changes, evaluated by Timed Up and Go (TUG), Sit-to-Stand test (SST), gait length, and grip test. Secondary endpoints were global glycemic control and questionnaires, namely the Diabetes Treatment Satisfaction Questionnaire (DTSQ) and Geriatric Depression Scale (GDS). All records of exercise adherence and any adverse events were followed.

RESULTS

Significant improvements in TUG and SST were found only in the WBV group [TUG: 7.1 ± 0.9, 7.1 ± 0.8 to 7.0 ± 1.0, 6.6 ± 0.9 (s), P = 0.63, 0.01; SST: 10.4 ± 1.9, 11.3 ± 2.4 to 9.7 ± 2.3, 9.5 ± 2.1 (s), P = 0.62, P < 0.01, control vs. WBV group, respectively]. The WBV group demonstrated significant improvement of hemoglobin A1C levels (7.2 ± 0.8 to 6.9 ± 0.5, P < 0.01) and DTSQ and GDS scores, while the control group did not. There were no hypoglycemic events during the study. The WBV program adherence was 93.3 ± 8.0%.

CONCLUSION

We demonstrated the favorable effect of WBV training on balance, diabetes treatment, and mood. Therefore, WBV training can be proposed as comprehensive therapy in a safe manner and potentially has a positive effect on health-related quality of life in elderly patients with T2DM.

Prediction of the influence of vertical whole-body vibration on biomechanics of spinal segments after lumbar interbody fusion surgery

BACKGROUND

Previous studies have shown that for healthy spine, cyclic loading encountered due to whole-body vibration exposure generated higher responses in spinal tissues than static loading. However, how whole-body vibration affects spine biomechanics after interbody fusion surgery is poorly understood. This study aimed at comparing the effects of vibration loading on spinal segments between postsurgical and healthy lumbar spines.

METHODS

A validated finite element model of healthy human lumbosacral spine was modified to simulate interbody fusion at L4-L5 level considering the statuses immediately after surgery (before bony fusion) and after bony fusion. Biomechanical responses at its adjacent levels for the healthy and fusion models to a sinusoidal axial vibration load of ±40 N and the corresponding static axal loads (-40 N and 40 N) were computed using transient dynamic and static analyses, respectively.

FINDINGS

For both healthy and fusion models, vibration amplitudes of the predicted responses were significantly higher than the corresponding changing amplitudes under static loads. Specifically, the increasing effect of vibration load in disc bulge, disc stress and intradiscal pressure at L3-L4 level reached 255.9%, 215.0% and 224.4% for the healthy model, 157.4%, 177.8% and 171.8% for the fusion model (before bony fusion), 141.9%, 152.6% and 160.1% for the fusion model (after bony fusion).

INTERPRETATION

Although whole-body vibration is still more dangerous for the lumbar spine after interbody fusion surgery than static loading, the sensitivity of adjacent segment in postsurgical spine to vibration loading is decreased compared with healthy spine, especially when reaching to bony fusion.

Efficacy of whole-body vibration on balance control, postural stability, and mobility after thermal burn injuries: A prospective randomized controlled trial

OBJECTIVE

To investigate the additive effects of whole-body vibration (WBV) training to the traditional physical therapy program (TPTP) on balance control, postural stability, and mobility after thermal burn injuries.

DESIGN

A single-blinded, randomized controlled study.

SETTING

Outpatient physical therapy setting.

PARTICIPANTS

Forty participants, 20-45 years old, with deep second-degree thermal burn involving the lower limbs and trunk, with 35%-40% total body service area, were randomly allocated either into the study group or the control group.

INTERVENTION

The study group received WBV plus TPTP while the control group received the TPTP only. Interventions were applied three sessions a week for eight weeks.

OUTCOME MEASURES

Anteroposterior stability index (APSI), mediolateral stability index (MLSI), overall stability index (OSI), timed-up and go (TUG), and Berg balance scale (BBS) were measured at baseline and after eight weeks of interventions.

RESULTS

There were statistically significant differences in APSI, MLSI, OSI, BBS, and TUG in favor of the WBV group after eight weeks of intervention (P < 0.001). After eight weeks of intervention, the mean (SD) for APSI, MLSI, OSI, BBS, and TUG scores were 1.87 ± 0.51, 41.36 ± 0.18, 1.95 ± 0.56, 47.2 ± 6.12, and 8.15 ± 1.05 seconds in the WBV group, and 2.41 ± 0.71, 2.21 ± 0.54, 2.68 ± 0.73, 40.65 ± 4.7, and 10.95 ± 2.44 seconds in the control group, respectively.

CONCLUSIONS

The whole-body vibration training combined with the TPTP was more beneficial in improving APS, MLS, OSI, TUG, and BBS than TPTP alone. It might be considered a useful adjunctive therapy in treating patients with healed wounds with a deep second-degree burn of the trunk and lower limbs.

The effects of whole-body vibration on wound healing in a mouse pressure ulcer model

BACKGROUND

Pressure ulcers are one of the most common complications of immobility resulting from pressure and shear. Whole-body vibration (WBV) has been shown to increase skin blood flow but little information is known about its effect on pressure ulcers. This study investigated the effects of WBV on wound healing in a mouse pressure ulcer model.

METHODS

Two cycles of ischemia-reperfusion were performed by external application of two magnetic plates to dorsal skin to induce stage II pressure ulcers characterized by partial-thickness skin loss with exposed dermis. A total of 32 male ICR mice were randomly and equally divided into untreated control and the WBV groups. Immediately after the completion of 2-cycle ischemia-reperfusion injury, mice in the WBV group participated in a WBV program using a vibrator (frequency 45 Hz, peak acceleration 0.4 g, vertical motion) for 30 min/day and 5 consecutive days/week. At days 7 and 14 post-ulceration, wound closure rate was assessed. Wound tissues were harvested for determination of collagen deposition in Masson's trichrome stained sections, neutrophil infiltration and capillary density in hematoxylin and eosin-stained sections, as well as TNF-α and VEGF levels using ELISA.

RESULTS

TNF-α levels and neutrophil infiltration were significantly decreased in wounds on days 7 and 14 of WBV treatment. Moreover, wound closure rate and collagen deposition were remarkably accelerated on day 14. Tissue VEGF and capillary density were unaffected by WBV at either time point.

CONCLUSIONS

These findings suggest that WBV has the potential to promote the healing process of stage II pressure ulcers, as evidenced by attenuation of wound inflammation and enhancement collagen deposition.

Postural balance effects from exposure to multi-axial whole-body vibration in mining vehicle operation

Twenty participants (18 males and 2 females) completed postural stability assessments before and after 4-h exposure to whole body vibration (WBV) in four experimental conditions: (a) vertical-dominant WBV with vertical passive air suspension, (b) multi-axial WBV with vertical passive air suspension, (c) multi-axial WBV with multi-axial active suspension, and (d) no WBV condition. Center of pressure (COP)-based postural sway measures significantly increased following multi-axial WBV exposure. Increase in COP velocity and displacement following multi-axial WBV was significantly higher than the increase in all the other exposure conditions. However, no significant differences between the WBV conditions were observed in functional limits of stability and anticipatory postural adjustments. While our results show standing balance to be impaired following the multi-axial WBV exposure of off-road mining vehicles, dynamic stability across a broader range of conditions needs to be understood to causally link postural stability decrements to increased fall-risks associated with off-road vehicle operators.

Whole-body vibration promotes lipid mobilization in hypothalamic obesity rat

OBJECTIVES

This study aimed to analyze the effect of whole-body vibration (WBV) on metabolic parameters using the monosodium l-glutamate (MSG) model of obesity.

METHOD

MSG-obese rats that were exposed to WBV on a vibrating platform with 60 Hz frequency, 2 mm amplitude, three times/week, 10 min/day, during eight weeks (from postnatal day (PN) 80 to PN136). Blood glucose, creatine kinases (CK and CK-MB) and lipid profile through plasma and liver levels of lipids and lipoproteins were evaluated. Morphology and oxidative stress of adipose and hepatic tissues were further evaluated.

RESULTS

When performing a WBV exercise, animals showed contrasting metabolic responses. Vibration Control group (CTL-WBV) presented a reduction in CK and liver triacylglycerol, an increase in glucose, lactate, total cholesterol, liver cholesterol, and LDL while MSG Vibration group (MSG-WBV) showed an increase in total triacylglycerol, VLDL, lactate, CK, liver cholesterol, additional liver lipid peroxidation and LDL, total cholesterol and CKMB reduction.

CONCLUSION

Even although the MSG is a model of impacting injury, the metabolic demand of WBV exercise was able to induce mobilization of substrates, highlighting the lipid mobilization in obese animals, it should be used as a metabolic rehabilitation tool in patients with metabolic diseases, such as obesity and diabetes.

Effect of whole-body vibration on abdominal thickness and sitting ability in children with spastic diplegia

Objective

Reduced muscle and bone mass, improper muscle function, and varying degrees of mobility dysfunctions are the main complications of cerebral palsy (CP). Many children with CP also present with poor abdominal muscle activation. Whole-body vibration (WBV) is a unique approach for enhancing strength and motor abilities in several clinical conditions. This study aimed to determine the influence of a 12-week WBV intervention on the thickness of the abdominal muscles and the sitting ability of children with diplegia.

Methods

A total of 30 children with spastic diplegic CP (aged 4–6 years) were randomly divided into two groups (control and experimental). The control group received a selected physical therapy program for 1 h, and the study group received WBV training for 10 min in addition to the same selected program for the control group for 3 times/week over a period of 12 weeks. Thereafter, abdominal muscle thickness and sitting ability were measured using ultrasonography and the Gross Motor Function Measure-88 (GMFM-88, sitting domain).

Results

Post treatment values revealed significant improvement in the measured variables in favour of the experimental group (p < 0.05), as there was improvement in the thickness of the four abdominal muscles compared to the control group (external oblique: F = 38.783; internal oblique: F = 99.547; transverse abdominis: F = 111.557, and rectus abdominis: F = 129.940, p < 0.05). Additionally, the study group showed a significantly greater improvement in GMFM-88 values compared to the control group (F = 129.940, p < 0.05).

Conclusion

WBV can be a viable strategy for improving sitting ability and abdominal muscle thickness among children with spastic diplegia.

Impact of whole-body vibration exercise on physical performance and bone turnover in patients with monoclonal gammopathy of undetermined significance

OBJECTIVE

Monoclonal Gammopathy of Undetermined Significance (MGUS) is a risk factor for reduced physical performance, osteoporosis, and fractures due to compromised musculoskeletal metabolism. In this condition it is unknown whether whole-body vibration (WBV) exercise favorably alters physical performance and bone metabolism.

METHODS

To evaluate the effect of three-months WBV exercise (30 min; 2x/week) including an optional three-month extension on physical performance, bone metabolism and bone mineral density. Endpoints included functional assessments, bone turnover markers and bone mineral density assessed by peripheral quantitative computed tomography of the tibia.

RESULTS

Fifteen MGUS patients (median age 62.0, nine female) completed the first three months of which ten completed the three-month extension. Measures of physical functioning including chair rise test, timed up and go and 6-minute walk test improved (p = 0.007; p = 0.009; p = 0.005) after three and six months of WBV exercise. Total tibial bone mineral density remained unaltered (p > 0.05). WBV exercise tended to increase levels of sclerostin (p = 0.093) with a transient increase in osteoclast resorption markers (N-terminal telopeptide of collagen type 1, tartrate resistant acid phosphatase 5b) after three months while Dickkopf-1 (p = 0.093), procollagen I N-terminal propeptide (p = 0.074) and total alkaline phosphatase (p = 0.016) appeared to decline. No exercise-related adverse events were reported.

CONCLUSION

WBV exercise in MGUS patients improves indicators of physical performance. Observed trends in bone turnover markers and changes in distal tibial bone mineral density may indicate a regulatory effect of WBV exercise on bone metabolism and warrants further evaluation by large scale studies.

Whole-body vibration associated with underground coal mining equipment in Australia

Environmental and logistical difficulties associated with obtaining whole-body vibration measurements from mobile equipment during operation in underground coal mines have hampered attempts to assess the potential vibration exposures associated with the use of such equipment. An alternative measurement technique was used to gather data from mobile equipment during normal operation at three low-methane coal mines and to estimate the possible magnitude of benefit of three control measures. 188 long duration measurements were obtained from shuttle cars (N = 142, median measurement duration = 3.2 h); personnel transport (N = 24, median measurement duration = 2.4 h); and materials transport vehicles (N = 22, median measurement duration = 1.8 h). Whole-body vibration amplitudes either within or exceeding the ISO health guidance caution zone were consistently measured. In particular, shuttle cars demonstrated whole-body vibration amplitudes which frequently exceeded the health guidance caution zone. The potential effects of roadway maintenance, decreased vehicle speed, and shuttle car seat replacement were found to be practically meaningful.

Thunder road - whole-body vibration during road cycling, and the effect of different seatpost designs to minimise it

Exposure to whole-body vibration (WBV) increases the risk of low back pain, spinal degeneration, and injury. Cycling can expose participants to WBV, but there are limited data available. This preliminary study quantified WBV in road cyclists in accordance with ISO 2631-1, and determined the efficacy of two seatposts designed to minimise vibration, compared to an aluminium alloy seatpost. Sensors were used to measure the root-mean-squared acceleration (a_rms), frequency-weighted a_rms based on an eight-hour reference period (A(8)), vibration dose value (VDV), and transmissibility. Exposures were also calculated using the root-sum-of-squares of the frequency-weighted a_rms in all three axes (A(8)_rss and VDV_rss). The mean±95% confidence interval A(8)_rss and VDV_rss across all tests was 0.58 ± 0.07 ms^-2 and 37.19 ± 4.70 ms^-1.75 respectively at the saddle, if and 0.49 ± 0.06 ms^-2 and 24.31 ± 2.89 ms^-1.75 respectively at the lumbar position. Occupational limits were exceeded with all seatposts, and there were no significant differences between them (p > 0.227). Road cycling results in substantial WBV, and there was no evidence that the seatposts designed to minimise vibrations successfully do so. Further research into the effect of cycling conditions and equipment on WBV would be valuable to both the research and cycling communities.

The combined effect of parathyroid hormone (1-34) and whole-body vibration exercise on physical performance in OSteoporotic women (PaVOS study): a secondary analysis from a randomised controlled trial

Background

The aim of this study was to investigate the effect on physical performance of combining whole-body vibration exercise (WBV) with parathyroid hormone 1-34 (teriparatide) compared to teriparatide alone.

Methods

A secondary analysis from a RCT where postmenopausal women with severe osteoporosis were randomised to WBV plus teriparatide (intervention) or teriparatide alone (control). WBV was applied three times/week (6x1min WBV:1 min rest, (peak acceleration 3.6 g)) for twelve months. Both groups received teriparatide 20 μg s.c./day. The primary endpoint (bone mineral density) is reported elsewhere. Physical performance measures (Short Physical Performance Battery (SPPB), Timed-Up-and-Go (TUG), leg extension power, and grip strength) were obtained at baseline, three-, six-, and twelve months, lean mass at baseline and twelve months. Data were analysed with mixed linear regression model or robust cluster regression in an intention to treat analysis.

Results

Thirty-five women aged (mean ± SD) 69 ± 7) years were recruited of which thirty-two (91%) completed the twelve months follow-up (WBV + teriparatide = 15, teriparatide = 17). SPPB score (mean ± SD) improved significantly at three months in the WBV + teriparatide group from 9.13 ± 2.03 to 10.35 ± 1.69 (p = 0.014) with a statistical trend towards a between-group change in favor of the WBV + teriparatide group (0.86 [95%CI(- 0.05,1.77), p = 0.065]). Both groups improved in leg extension power during the study period whereas no changes were seen in TUG, grip strength, or lean mass in either group. No statistical significant between-group differences were observed.

Conclusion

WBV may improve some short-term aspects of physical performance in severely osteoporotic postmenopausal women who are receiving teriparatide treatment.

Trial Registration

ClinicalTrials.gov, ID:NCT02563353.

Immediate Effects of Local Vibration and Whole-body Vibration on Postural Control in Patients with Ataxia: an Assessor-Blind, Cross-over randomized trial

Vibration interventions are used in neurorehabilitation to improve postural control in recent years. Little is known about the immediate effects of vibration interventions on postural control in patients with ataxia. The aim of this study is to investigate and compare the immediate effects of local vibration (LV) and whole-body vibration (WBV) on postural control in patients with ataxia. This study was designed as cross-over, single blind randomized clinical trial. Twenty-one patients with ataxia met the inclusion criteria. LV (frequency, 80 Hz; amplitude, 1 mm) and WBV (30 Hz, 2 mm) were applied to all patients. There was a 1-week washout time between interventions. Each patient was assessed 3 times: pre-intervention and 1 and 60 min post-intervention. The assessor was blinded to the interventions. Outcome measures were limits of stability (LoS), and postural sways (Bertec Balance Check Screener), gait parameters (GAITRite), and static balance (one-leg stance test). Twenty patients completed both interventions. The mean patient age was 39.43 ± 9.67 years. LV increased the left-LoS post-vibration (1 and 60 min post) more than WBV did (p ˂ 0.05). LV increased the LoS stability score and the base of support at 1 min post-vibration, while WBV decreased them (p ˂ 0.05). This study demonstrated different immediate effects of a single session of LV versus WBV and showed that LV has better effects on postural control in patients with ataxia. ClinicalTrials.gov. nr NCT04183647.

Difference thresholds for a vehicle on a 4-poster test rig

Improving vibration-induced discomfort often requires a reduction in the vibration experienced by vehicle occupants. Simulation software and test equipment are able to measure changes in vibration that are too small for humans to perceive. It is therefore important to know how large the change in vibration should be, i.e. the difference threshold, for occupants to perceive an improvement in comfort. This study estimates difference thresholds for ten automotive engineers seated in a vehicle on a 4-poster test rig. Participants were exposed to multi-axis vibration. Component ride values were calculated by applying BS 6841 frequency weightings and multiplication factors to seat accelerations in the six directions. Difference thresholds were estimated for two road profiles using the vertical component ride value and combined point ride value (i.e. the root-sums-of-squares of the six component ride values). The two road profiles had different magnitudes, but the same spectral shape, resulting in median vertical component ride values of 0.58 and 1.01 m.s.^-2, root-mean-square. An up-down transformed response rule was used with a three-down-one-up response grouping to estimate difference thresholds at a 79.4% probability level. The median relative difference threshold for the two roads was 10.13% and 8.58% considering the vertical component ride value, and 10.99% and 9.24% considering the combined point ride value. No statistically significant difference was found between the medians of the relative difference threshold over the two roads considering either of the two ride values (p-value = 0.995 in both instances), suggesting that Weber's law holds.

Apparent mass of the seated human body during vertical vibration in the frequency range 2-100 Hz

We studied the apparent mass during vertical whole-body vibration in the frequency range 2-100 Hz at four magnitudes (sinusoidal sweep signals, 1.0, 1.5, 2.0 and 2.5 ms^-2 r.m.s.) in 12 males and 12 females with upright and relaxed sitting postures. The first two peaks of apparent mass decreased with increasing vibration magnitude with both postures. The non-linearity characteristics became obscured at the two largest magnitudes and were less transparent with relaxed sitting posture. The peak frequencies and the normalised apparent masses were similar between males and females with both postures. The standardised three degrees-of-freedom parametric model with modified parameters was proposed to predict well the apparent mass of seated human body during vertical vibration in the frequency range 2-100 Hz and in the magnitude range 1.0-2.5 ms^-2 r.m.s. Practitioner summary: This study shows the frequency-dependence and magnitude-dependence of biodynamic responses in the frequency range of 2-100 Hz. The magnitude of apparent mass at frequencies above 20 Hz may not be negligible. The proposed 3 DOF model with modified parameters would help with understanding and developing the human-seat system. Abbreviations: WBV: whole-body vibration; DOF: degrees-of-freedom; CMIFs: complex mode indicator functions.

Localised apparent masses over the interface between a seated human body and a soft seat during vertical whole-body vibration

Vibration transmission through vehicle seats is usually predicted using the biodynamics of the seated human body measured with a rigid seat, however how coupling between the body and the seat would affect the biodynamics of the body is not considered. This study investigated how dynamic forces distributed over a soft seat compared to that over a rigid seat wtih vertical vibration excitation. Fourteen male subjects sitting on a rigid seat and on foam cushions of two different thickness with four different heights of footrest were exposed to vertical whole-body vibration between 0.5 and 20 Hz at 0.5 ms^-2 r.m.s. Dynamic forces were measured beneath the ischial tuberosities, the middle thighs, and the front thighs and the transmissibility of the cushion was measured to the three locations. The resonance in the transmissibility of the cushion was found around 4 Hz to the ischial tuberosities but around 6-8 Hz to the front thighs. Differences between the apparent mass measured with the cushioned seat and the rigid seat decreased with increasing height of footrest. A multi-body dynamic model that can predict the dynamic forces beneath the ischial tuberosities and thighs was applied to identify the cause for the differences. It was suggested the differences can be caused by the variations in vibration over the surface of soft seats, especially when the contact area beneath the thighs was large, and by changes in the effective stiffness and damping of the human body when the contact area beneath the thighs was reduced.