Low-intensity Whole-body Vibration Research Articles

Discretizing low-intensity whole-body vibration into bouts with short rest intervals promotes bone defect repair in osteoporotic mice.

Continuous administration of low-intensity whole-body vibration (WBV) gradually diminishes bone mechanosensitivity over time, leading to a weakening of its osteogenic effect. We investigated whether discretizing WBV into bouts with short rest intervals was effective in enhancing osteoporotic bone repair. Ten-week-old female mice were ovariectomized and underwent drill-hole defect surgery (Day 0) on the right tibial diaphysis at 11 weeks of age. The mice underwent one of three regimens starting from Day1 for 5 days/week: continuous WBV at 45 Hz and 0.3 g for 7.5 min/day (cWBV); 3-sbouts of WBV at 45 Hz, 0.3 g followed by 9-srest intervals, repeated for 30 min/day (repeated bouts of whole-body vibration with short rest intervals[rWBV]); or a sham treatment. Both the cWBV and rWBV groups received a total of 20,250 vibration cycles per day. On either Day 7 or 14 posteuthanasia (n = 6/group/timepoint), the bone and angiogenic vasculature in the defect were computed tomographyimaged using synchrotron light. By Day 14, the bone repair was most advanced in the rWBV group, showing a higher bone volume fraction and a more uniform mineral distribution compared with the sham group. The cWBV group exhibited an intermediate level of bone repair between the sham and rWBV groups. The rWBV group had a decrease in large-sized angiogenic vessels, while the cWBV group showed an increase in such vessels. In conclusion, osteoporotic bone repair was enhanced by WBV bouts with short rest intervals, which may potentially be attributed to the improved mechanosensitivity of osteogenic cells and alterations in angiogenic vasculature.

The effect of low-intensity whole-body vibration with or without high-intensity resistance and impact training on risk factors for proximal femur fragility fracture in postmenopausal women with low bone mass: study protocol for the VIBMOR randomized controlled trial

BackgroundThe prevailing medical opinion is that medication is the primary (some might argue, only) effective intervention for osteoporosis. It is nevertheless recognized that osteoporosis medications are not universally effective, tolerated, or acceptable to patients. Mechanical loading, such as vibration and exercise, can also be osteogenic but the degree, relative efficacy, and combined effect is unknown. The purpose of the VIBMOR trial is to determine the efficacy of low-intensity whole-body vibration (LIV), bone-targeted, high-intensity resistance and impact training (HiRIT), or the combination of LIV and HiRIT on risk factors for hip fracture in postmenopausal women with osteopenia and osteoporosis.MethodsPostmenopausal women with low areal bone mineral density (aBMD) at the proximal femur and/or lumbar spine, with or without a history of fragility fracture, and either on or off osteoporosis medications will be recruited. Eligible participants will be randomly allocated to one of four trial arms for 9 months: LIV, HiRIT, LIV + HiRIT, or control (low-intensity, home-based exercise). Allocation will be block-randomized, stratified by use of osteoporosis medications. Testing will be performed at three time points: baseline (T0), post-intervention (T1; 9 months), and 1 year thereafter (T2; 21 months) to examine detraining effects. The primary outcome measure will be total hip aBMD determined by dual-energy X-ray absorptiometry (DXA). Secondary outcomes will include aBMD at other regions, anthropometrics, and other indices of bone strength, body composition, physical function, kyphosis, muscle strength and power, balance, falls, and intervention compliance. Exploratory outcomes include bone turnover markers, pelvic floor health, quality of life, physical activity enjoyment, adverse events, and fracture. An economic evaluation will also be conducted.DiscussionNo previous studies have compared the effect of LIV alone or in combination with bone-targeted HiRIT (with or without osteoporosis medications) on risk factors for hip fracture in postmenopausal women with low bone mass. Should either, both, or combined mechanical interventions be safe and efficacious, alternative therapeutic avenues will be available to individuals at elevated risk of fragility fracture who are unresponsive to or unwilling or unable to take osteoporosis medications.Trial registrationAustralian New Zealand Clinical Trials Registry (www. anzctr.org.au) (Trial number ANZCTR12615000848505, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id = 368962); date of registration 14/08/2015 (prospectively registered). Universal Trial Number: U1111-1172-3652.

Low-Intensity Whole-Body Vibration: A Useful Adjuvant in Managing Obesity? A Pilot Study

The use of whole-body vibration (WBV) for therapeutic purposes is far from being standardized and an empirical foundation for reporting guidelines for human WBV studies has only very recently been published. Controversies about safety and therapeutic dosage still exist. The present study aimed to investigate the metabolic and mechanical effects of low-intensity WBV according to the ISO 2631 norm on subjects with obesity. Forty-one obese subjects (BMI ≥ 35 kg/m2) were recruited to participate in a 3-week multidisciplinary inpatient rehabilitation program including fitness training and WBV training. During WBV the posture was monitored with an optoelectronic system with six infrared cameras (Vicon, Vicon Motion System, Oxford, UK). The primary endpoints were: variation in body composition, factors of metabolic syndrome, functional activity (sit-to-stand and 6-min walking test), muscle strength, and quality of life. The secondary endpoints were: modification of irisin, testosterone, growth hormone, IGF1 levels. We observed significant changes in salivary irisin levels, Group 2 (p < 0.01) as compared to the control group, while muscle strength, function, and other metabolic and hormonal factors did not change after a 3-week low-intensity WBV training with respect to the control group. Future studies are needed to further investigate the potential metabolic effect of low-intensity WBV in managing weight.

Effect of Whole-Body Vibration on Neuromuscular Activation of Leg Muscles During Dynamic Exercises in Individuals With Stroke

Liao, L-R, and Pang, MYC. Effect of whole-body vibration on neuromuscular activation of leg muscles during dynamic exercises in individuals with stroke. J Strength Cond Res 31(7): 1954-1962, 2017-This study examined the leg muscle activity during exposure to different whole-body vibration (WBV) intensities while performing various dynamic exercises in patients with chronic stroke. Thirty patients with chronic stroke performed a series of dynamic exercises under 3 conditions: (a) low-intensity WBV (peak acceleration: 0.96 units of gravity of Earth [g]), (b) high-intensity WBV (1.61 g), and (c) no WBV. Neuromuscular activation was recorded with surface electromyography (EMG) on bilateral biceps femoris (BF), vastus lateralis, tibialis anterior (TA), and gastrocnemius (GS) in both legs and was reported as EMGrms (root mean square) normalized to % maximal voluntary contraction. The EMG amplitude of all tested muscles was significantly increased by adding WBV during dynamic exercise (p ≤ 0.05). The EMG amplitude of BF, TA, and GS during exposure to high-intensity WBV was significantly greater than low-intensity WBV (p ≤ 0.05). The increase in EMG amplitude caused by WBV was exercise dependent in GS and TA (p ≤ 0.05). The EMG response to WBV in GS and BF in the affected leg was significantly greater than the corresponding muscles in the unaffected leg (p ≤ 0.05). The extent of WBV-induced muscle activity was dependent on the dynamic exercise, WBV intensity, and muscle trained among patients with chronic stroke.

Effect of low-intensity whole-body vibration on bone defect repair and associated vascularization in mice

Low-intensity whole-body vibration (LIWBV) may stimulate bone healing, but the involvement of vascular ingrowth, which is essential for bone regeneration, has not been well examined. We thus investigated the LIWBV effect on vascularization during early-stage bone healing. Mice aged 13weeks were subjected to cortical drilling on tibial bone. Two days after surgery (day 0), mice were exposed daily to sine-wave LIWBV at 30Hz and 0.1g peak-to-peak acceleration for 20min/day (Vib) or were sham-treated (sham). Following vascular casting with a zirconium-based contrast agent on days 6, 9, or 12 and sacrifice, vascular and bone images were obtained by K-edge subtraction micro-CT using synchrotron lights. Bone regeneration advanced more in the Vib group from days 9 to 12. The vascular volume fraction decreased from days 6 to 9 in both groups; however, from days 9 to 12, it was increased in shams, while it stabilized in the Vib group. The vascular volume fraction tended to be or was smaller in the Vib group on days 6 and 12. The vessel number density was higher on day 9 but lower on day 12 in the Vib group. These results suggest that the LIWBV-promoted bone repair is associated with the modulation of vascularization, but additional studies are needed to determine the causality of this association.

全身性微振動刺激による骨構造への影響と骨微小血管形成の関与

全身性微振動刺激による骨構造への影響と骨微小血管形成の関与

Whole-Body Vibration Intensities in Chronic Stroke: A Randomized Controlled Trial.

A single-blinded randomized controlled study was conducted to investigate the effects of different whole-body vibration (WBV) intensities on body functions/structures, activity, and participation in individuals with stroke. Eighty-four individuals with chronic stroke (mean age = 61.2 yr, SD = 9.2) with mild to moderate motor impairment (Chedoke-McMaster Stroke Assessment lower limb motor score: median = 9 out of 14, interquartile range = 7-11.8) were randomly assigned to a low-intensity WBV, high-intensity WBV, or control group. The former two groups performed various leg exercises while receiving low-intensity and high-intensity WBV, respectively. Controls performed the same exercises without WBV. All individuals received 30 training sessions over an average period of 75.5 d (SD = 5.2). Outcome measurements included knee muscle strength (isokinetic dynamometry), knee and ankle joint spasticity (Modified Ashworth Scale), balance (Mini Balance Evaluation Systems Test), mobility (Timed-Up-and-Go test), walking endurance (6-Minute Walk Test), balance self-efficacy (Activities-specific Balance Confidence scale), participation in daily activities (Frenchay Activity Index), perceived environmental barriers to societal participation (Craig Hospital Inventory of Environmental Factors), and quality of life (Short-Form 12 Health Survey). Assessments were performed at baseline and postintervention. Intention-to-treat analysis revealed a significant time effect for muscle strength, Timed-Up-and-Go distance, and oxygen consumption rate achieved during the 6-Minute Walk Test, the Mini Balance Evaluation Systems Test, the Activities-specific Balance Confidence scale, and the Short-Form 12 Health Survey physical composite score domain (P < 0.05). However, the time-group interaction was not significant for any of the outcome measures (P > 0.05). The addition of the 30-session WBV paradigm to the leg exercise protocol was no more effective in enhancing body functions/structures, activity, and participation than leg exercises alone in chronic stroke patients with mild to moderate motor impairments.

The effect of vertical whole-body vibration on lower limb muscle activation in elderly adults: Influence of vibration frequency, amplitude and exercise

ObjectiveThis study aimed to investigate how whole-body vibration (WBV) and exercise and their interactions influenced leg muscle activity in elderly adults. Study designAn experimental study with repeated measures design that involved a group of ambulatory, community-dwelling elderly adults (n=30; 23 women; mean age=61.4±5.3years). Main outcome measuresMuscle activity of the vastus lateralis (VL), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius (GS) was measured by surface electromyography (EMG), while participants were performing seven different exercises during 4 WBV conditions (condition 1: frequency=30Hz, amplitude=0.6mm, intensity=2.25 units of Earth’s gravity (g); condition 2: 30Hz, 0.9mm, 3.40g; condition 3: 40Hz, 0.6mm, 3.65g; condition 4: 40Hz, 0.9mm, 5.50g) and a no-WBV condition in a single experimental session. ResultsSignificantly greater muscle activity was recorded in VL (3%–148%), BF (16%–202%), and GS (19% –164%) when WBV was added to the exercises, compared with the same exercises without WBV (p≤0.015). The effect of vibration intensity on EMG amplitude was exercise-dependent in VL (p=0.002), and this effect was marginally significant in GS (p=0.052). The EMG activity induced by the four WBV intensities was largely similar, and was the most pronounced during static erect standing and static single-leg standing. ConclusionsThe EMG amplitude of majority of leg muscles tested was significantly greater during WBV exposure compared with the no-WBV condition. Low-intensity WBV can induce muscle activity as effectively as higher-intensity protocols, and may be the preferred choice for frail elderly adults.

Cardiovascular Stress Induced by Whole-Body Vibration Exercise in Individuals With Chronic Stroke

Although whole-body vibration (WBV) has sparked tremendous research interest in neurorehabilitation, the cardiovascular responses to WBV in people with stroke remain unknown. The aim of this study was to determine the acute effects of different WBV protocols on oxygen consumption (V̇o2), heart rate (HR), rate of perceived exertion (RPE), blood pressure (BP), and rate-pressure product (RPP) during the performance of 6 different exercises among people with chronic stroke (time since onset ≥6 months). A repeated-measures design was used. Each of the 48 participants experienced all 3 WBV protocols in separate sessions: (1) no WBV, (2) low-intensity WBV (peak acceleration=0.96 unit of gravity of Earth [g]), and (3) high-intensity WBV (1.61g). The order in which they encountered the WBV protocols was randomized, as was the order of exercises performed during each session. Oxygen consumption, HR, and RPE were measured throughout the study. Blood pressure and RPP were measured before and after each session. Low-intensity and high-intensity WBV induced significantly higher V̇o2 by an average of 0.69 and 0.79 mL/kg/min, respectively, compared with the control condition. These protocols also increased HR by an average of 4 bpm. The 2 WBV protocols induced higher RPE than the control condition during static standing exercise only. Although the diastolic and systolic BP and RPP were increased at the end of each exercise session, the addition of WBV had no significant effect on these variables. The results are generalizable only to ambulatory and community-dwelling people with chronic stroke. Addition of high- and low-intensity WBV significantly increased the V̇o2 and HR, but the increase was modest. Thus, WBV should not pose any substantial cardiovascular hazard in people with chronic stroke.

Leg Muscle Activity during Whole-Body Vibration in Individuals with Chronic Stroke

It has been previously shown that whole-body vibration (WBV) can augment muscle activity in young healthy adults. However, the EMG response of leg muscles during WBV in individuals with stroke is unknown. The objective of this study was to determine the influence of WBV on the activity of the vastus lateralis (VL) and gastrocnemius (GS) muscles during the performance of different exercises in chronic stroke patients. Forty-five chronic stroke patients were studied. Each subject was exposed to three WBV conditions of 1) no WBV, 2) low-intensity WBV protocol (peak acceleration: 0.96 unit of gravitational constant [g]), and 3) high-intensity WBV protocol (peak acceleration: 1.61g) while performing eight different static exercises involving upright standing, semisquat, deep squat, weight shifted forward, weight shifted backward, weight shifted to the side, forward lunge, and single-leg standing. Bilateral VL and GS muscle activity was recorded with surface EMG and expressed as a percentage of the EMG amplitude recorded during a maximal voluntary contraction of the respective muscles. Two-way repeated-measures ANOVA revealed that exposure to WBV (low- and high-intensity protocols) significantly increased VL and GS EMG amplitude (large effect size, partial η = 0.135-0.643, P < 0.001) on both the paretic and nonparetic sides in different exercise conditions compared with no WBV. No significant difference in EMG magnitude was found between the high- and the low-intensity WBV protocols (P > 0.05). With a few exceptions, WBV enhanced EMG activity in the paretic and nonparetic leg muscles to a similar extent in different exercise conditions. Leg muscle activity was increased significantly with the addition of WBV. Further clinical trials are needed to determine the effectiveness of different WBV protocols for strengthening leg muscles in chronic stroke patients.