Effect of Bone on Vibration-Induced Muscle Strength Gain

Study Overview
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Brief Summary
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The aim of this study is to investigate whether there is a relation between bone mineral density of lower limbs exposed to vibration and the muscle strength gain in the knee extensors and flexors, and a relation serum sclerostin level and the muscle strength gain in the knee extensors and flexors in healthy young adult women. Forty healthy young adult women are planned to include in this study. The participants meeting the criteria were randomized into two groups: the training group (20 cases) and the Control group (20 cases). The whole-body vibration (WBV) training group will be trained on a WBV platform (Power Plate) 5 times a week for 4 weeks period. Participants will be asked to stand upright on WBV platform. Training volume and training intensity will be low at the beginning but progressed slowly according to the overload principle. The training volume will be increased systematically over the 4-week training period. The training intensity will be increased by increasing the amplitude (2-4 mm) and the frequency (40 Hz) of the vibration. The subjects will be asked to report negative side effects or adverse reactions in their training diary. In the Control group, sham stimulus will be performed by WBV platform 5 times a week for a 4 weeks period. Plasma sclerostin level and, the right and left knee flexor and extensor muscles strength will be measured before and after training period. Isokinetic torque will be measured with the Biodex (Biodex System 3 PRO Multijoint System Biodex Medical Inc. Shirley/NY USA)extremity-testing system. The right and left lower limbs bone mineral density (BMD) and muscle strength will be measured before training period. The BMD will be evaluated by bone densitometer (Norland XR-46 DXA, USA). Sclerostin levels will be measured by human sclerostin ELISA kit. The rest muscle electrical activity of right and left knee flexor and extensor muscles will be evaluated at pre-vibration, post- vibration and, during vibration. The rest muscle electrical activity will be measured by Powerlab (data acquisition system, ADInstruments, Australia) device.

Detailed Description
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Vibration has a strong osteogenic effect. Vibration-induced bone formation is neuronally regulated. Vibration can also effectively enhance muscle strength and power. Previous studies have shown that vibration increases muscle electromyographic (EMG) activity. Attempts to explain vibration-induced increases in EMG activity were based on the tonic vibration reflex. Tonic vibration reflex activates the muscle spindles, thereby enhancing the excitatory drive reflex of the alpha motoneurons. On the contrary, it was shown that the vibration treatment did not enhance the muscle spindle sensitivity and led to presynaptic inhibition of muscle spindle group Ia afferents. As an alternative to tonic vibration reflex, the recently described bone myoregulation reflex has been suggested to potentially explain the increased muscle strength and electrical activity induced by vibration. Based on the bone myoregulation reflex, bone is sensitive to mechanical stimuli and can send mechanical input signals to central nervous system and so can neuronally regulate the muscle activity. The cyclic mechanical loading to the bone stimulates the osteocytes. According to bone myoregulation reflex, the more the osteocytes are stimulated by the cyclic mechanical loading, the increase occurring in the muscle strength and activity may be more. The rate of osteocytes stimulated by vibration may be determined with serum sclerostin level. Sclerostin, the protein product of the SOST gene, is an osteocyte-specific cysteine knot-secreted glycoprotein that is a potent inhibitor of bone formation. Sost/sclerostin levels have been reported to be reduced by mechanical stimulation.

Official Title
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Effect of Bone Mineral Density on Vibration-Induced Muscle Strength Gain at The Lower Limbs

Conditions
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Bone Mass, Effects of Vibration

Intervention / Treatment
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* Device: whole-body vibration (WBV)
* Device: WBV (Sham stimulation)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy women, Women with ages varying between 20 and 40 years Right-handed women Exclusion Criteria: Bone, muscle/tendon, joint, vascular, dermatologic diseases in lower extremities and spine Medication that could affect the musculoskeletal system Postural abnormalities (scoliosis, kyphosis, etc) Systemic diseases Hypertension ( Diastolic > 85 mmHg, Systolic>135 mmHg) Heart Diseases (coronary heart disease, conduction or rhythmic problems, pacemaker etc.) Abdominal disease (Gallstone etc) Urinary disease (kidneystone etc) Gynecological disease (menstrual irregularities, etc) Infectious disease Endocrine diseases such as diabetes mellitus or other disease Neurologic disorders (central or peripheral) Pregnancy or lactation Obesity (BMI >30 kg/m2 or body weight > 80 kg ) Vertigo Cognitive dysfunction Professional/regular sports activity and heavy worker

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Very low magnitude vibration<br>Very low magnitude vibration | Device: WBV (Sham stimulation)<br>* Sham stimulus will be performed by WBV platform 5 times a week for a 4 weeks period.<br>|
| Experimental: Training<br>The whole-body vibration (WBV) training | Device: whole-body vibration (WBV)<br>* The whole-body vibration (WBV) training group will be trained on a WBV platform (Power Plate) 5 times a week for 4 weeks period. Training volume and training intensity will be low at the beginning but progressed slowly according to the overload principle. The training volume will be increased systematically over the 4-week training period. The training intensity will be increased by increasing the amplitude (2-4 mm) and the frequency (40 Hz) of the vibration.<br>* Other names: Cyclic mechanical loading;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vibration-induced muscle strength gain | Effects of bone mineral density on vibration-induced muscle strength gain | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Bone, Muscle strength, whole-body vibration