COMPARISON OF BIODYNAMIC RESPONSES IN STANDING AND SEATED HUMAN BODIES

✍ Scribed by Y. MATSUMOTO; M.J. GRIFFIN

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 175 KB
• Volume: 238
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.2000.3133

✦ Synopsis

The dynamic responses of the human body in a standing position and in a sitting position have been compared. The apparent mass and transmissibilities to the head, six locations along the spine, and the pelvis were measured with eight male subjects exposed to vertical whole-body vibration. In both postures, the principal resonance in the apparent mass occurred in the range 5}6 Hz, with slightly higher frequencies and lower apparent mass in the standing posture. There was greater transmission of vertical vibration to the pelvis and the lower spine and greater relative motion within the lower spine in the standing posture than in the sitting posture at the principal resonance and at higher frequencies. Transmissibilities from the supporting surface (#oor or seat) to the thoracic region had similar magnitudes for both standing and sitting subjects. The lumbar spine has less lordosis and may be more compressed and less #exible in the sitting posture than in the standing posture. This may have reduced the relative motions between lumbar vertebrae and both the supporting vibrating surface and the other vertebrae in the sitting posture. The characteristics of the vibration transmitted to the pelvis may have di!ered in the two postures due to di!erent transmission paths. Increased forward rotation of the pelvis in the standing posture may have caused the di!erences in responses of the pelvis and the lower spine that were observed between the two postures.

2000 Academic Press