Apparent mass of the standing human body when using a whole-body vibration training machine: Effect of knee angle and input frequency
| Autor: | Sadeque Hamdan, Naser Nawayseh |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Adult
Male Materials science Adolescent Acoustics Acceleration 0206 medical engineering Bent molecular geometry Biomedical Engineering Biophysics 02 engineering and technology Bending Vibration Young Adult 03 medical and health sciences 0302 clinical medicine Humans Surface Tension Whole body vibration Knee Orthopedics and Sports Medicine Rehabilitation Work (physics) Training (meteorology) Resonance 020601 biomedical engineering Biomechanical Phenomena Standing Position 030217 neurology & neurosurgery |
| Zdroj: | Journal of Biomechanics. 82:291-298 |
| ISSN: | 0021-9290 |
| Popis: | Several studies have investigated the transmission of vibration from the vibrating plate of a whole-body vibration training machine (WBVTM) to different locations on the human body. No known work has investigated the interface force between the vibrating plate of the machine and the human body. This paper investigates the effect of bending the knees and the vibration frequency on the interface force (presented as apparent mass (AM)) between the vibrating plate and the body. Twelve male subjects stood with four different knee angles (180, 165, 150 and 135°) and were exposed to sinusoidal vertical vibration at eight frequencies in the range of 17–42 Hz. The vertical acceleration and the interface force between the body and the vibrating plate were measured and used to calculate the AM. The acceleration and force depended on the frequency and were found to vary with both the adopted posture and subject. The AM generally decreased with increasing the frequency but showed a peak at 24 Hz which was clearer when the knees were bent. Bending the knees showed an effect similar to increasing the damping of a system with base excitation; increasing the damping reduced the AM in the resonance region but increased the AM at higher frequencies. Users of WBVTMs have to be careful when choosing the training posture: although, as shown in previous studies, bending the knees reduces the transmission of vibration to the spine, it increases the interface forces which might indicate increased stresses on the lower legs and joints. |
| Databáze: | OpenAIRE |
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