Muscle activity and acceleration during whole body vibration: Effect of frequency and amplitude

Pollock, Ross D.; Woledge, Roger C.; Mills, Kerry; Martin, Finbarr C.; Newham, Di J.

doi:10.1016/j.clinbiomech.2010.05.004

Cited by 149 publications

(132 citation statements)

References 27 publications

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“…The relatively small increases of the resultant force fit with the small accelerations measured at hip level [11] and the measured muscle-activity increase in the lower leg [10]. The magnitude of the measured force during WBV is usually less than that during walking, which is a crucial activity with high spinal loads.…”

Section: Discussionmentioning

confidence: 58%

“…Dynamic accelerations during WBV also increase the loads in the skeleton. However, as was shown by Pollock et al [10], the various body parts experience particular accelerations. Therefore, predicting the spinal load increase due to dynamic accelerations and muscle activities is not an easy task.…”

Section: Introductionmentioning

confidence: 72%

“…The muscle-activity increase during WBV varies strongly, depending on the muscle. Pollock et al [10] measured values ranging from 5 to 50 % of the maximal voluntary contraction for muscles in the leg and hip region. The increased muscle activity is most likely reflected in the increase of the mean force, whereas the difference between the mean and peak forces is mainly due to accelerations of the upper body mass.…”

Section: Discussionmentioning

confidence: 99%

“…The focuses during therapy are on preventing or reducing osteoporosis [5,6], on muscle training [7] to prevent falls and the resulting bone fractures [8], and on the prevention of back pain [9]. WBV activates muscles and may lead to rapid accelerations of body segments [6,10]. Therefore, it is often expected that large forces are acting on the spine and on the joints of the lower extremities during WBV.…”

Section: Introductionmentioning

confidence: 99%

“…Pollock et al [10] studied the effect of frequency and amplitude on the muscle activity and accelerations throughout the body during WBV. They found an increase in muscle activities of 5-50 % of the maximal voluntary contractions, with the greatest increase in the lower legs.…”

Section: Introductionmentioning

confidence: 99%

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In vivo measurements of the effect of whole body vibration on spinal loads

et al. 2013

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Purpose It is assumed that whole body vibration (WBV) improves muscle strength, bone density, blood flow and mobility and is therefore used in wide ranges such as to improve fitness and prevent osteoporosis and back pain. It is expected that WBV produces large forces on the spine, which poses a potential risk factor for the health of the spine. Therefore, the aim of the study was to measure the effect of various vibration frequencies, amplitudes, device types and body positions on the loads acting on a lumbar vertebral body replacement (VBR). Methods Three patients suffering from a fractured lumbar vertebral body were treated using a telemeterized VBR. The implant loads were measured during WBV while the patients stood on devices with vertically and seesawinduced vibration. Frequencies between 5 and 50 Hz and amplitudes of 1, 2 and 4 mm were tested. The patients stood with their knees straight, slightly bent, or bent at 60°. In addition, they stood on their forefeet. Results The peak resultant forces on the implant increased due to vibration by an average of 24 % relative to the forces induced without vibration. The average increase of the peak implant force was 27 % for vertically induced vibration and 15 % for seesaw vibration. The forces were higher when the legs were straight than when the knees were bent. Both the vibration frequency and the amplitude had only a minor effect on the measured forces. Conclusions The force increase due to WBV is caused by an activation of the trunk muscles and by the acceleration forces. The forces produced during WBV are usually lower than those produced during walking. Therefore, the absolute magnitude of the forces produced during WBV should not be harmful, even for people with osteoporosis.

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Section: Discussionmentioning

confidence: 58%

Section: Introductionmentioning

confidence: 72%

Section: Discussionmentioning

confidence: 99%