Reducing whole-body vibration and musculoskeletal injury with a new car seat design.

A new car seat design, which allows the back part of the seat (BPS) to lower down while a protruded cushion supports the lumbar spine, was quantitatively tested to determine its effectiveness and potentials in reducing whole-body vibration (WBV) and musculoskeletal disorders in automobile drivers. Nine subjects were tested to drive with the seat in: 1) the conventional seating arrangement (Normal posture); and 2) the new seating design (without BPS (WO-BPS) posture). By reducing contact between the seat and the ischial tuberosities (ITs), the new seating design reduced both contact pressure and amplitude of vibrations transmitted through the body. Root-mean-squared values for acceleration along the z-axis at the lumbar spine and ITs significantly decreased 31.6% (p < 0.01) and 19.8% (p < 0.05), respectively, by using the WO-BPS posture. At the same time, vibration dose values significantly decreased along the z-axis of the lumbar spine and ITs by 43.0% (p < 0.05) and 34.5% (p < 0.01). This reduction in WBV allows more sustained driving than permitted by conventional seating devices, by several hours, before sustaining unacceptable WBV levels. Such seating devices, implemented in large trucks and other high-vibration vehicles, may reduce the risk of WBV-related musculoskeletal disorders among drivers.

Reducing whole-body vibration of vehicle drivers with a new sitting concept.

A new car seat design, which allows the back part of the seat (BPS) to lower down while a protruded cushion supports the lumbar spine, was quantitatively tested to determine its effectiveness in reducing whole-body vibration (WBV) in automobile drivers. Results on 12 drivers show that, by reducing contact between the seat and the ischial tuberosities (TTs), the new seating design reduced both contact pressure and amplitude of harmful vibrations transmitted through the body. Significant reduction of WBV, in terms of RMS and VDV, was found as large as 30% by this seating design (P < 0.05), especially at lumbar spine region. This reduction in WBV allows more sustained driving than permitted by conventional seating devices, by around 2 hours daily, before reaching harmful WBV levels. The new seating design also promotes improved posture by restoring normal spinal curvature. Such seating devices, implemented in cars, buses, large trucks, and other high-vibration vehicles, may effectively reduce the risk of musculoskeletal disorders among long term drivers.