title: Discomfort of seated persons exposed to low frequency lateral and roll oscillation: Effect of backrest height.
abstract: Backrests influence the comfort of seated people. With 21 subjects sitting with three backrest heights (no backrest, short backrest, high backrest) discomfort caused by lateral, roll, and fully roll-compensated lateral oscillation was investigated at frequencies between 0.25 and 1.0 Hz. With lateral oscillation, the short backrest reduced discomfort at frequencies less than 0.63 Hz and the high backrest reduced discomfort at frequencies less than 1.0 Hz. With roll oscillation, the high backrest reduced discomfort at frequencies less than 0.63 Hz, but increased discomfort at 1.0 Hz. With fully roll-compensated lateral oscillation, the short backrest reduced discomfort at 0.4 Hz and the high backrest reduced discomfort at 0.5 and 0.63 Hz. As predicted by current standards, a backrest can increase discomfort caused by high frequencies of vibration. However, a backrest can reduce discomfort caused by low frequencies, with the benefit depending on the frequency and direction of oscillation and backrest height.
authors: Human Factors Research Unit, Institute of Sound and Vibration Research, University of Southampton, United Kingdom.
authors: George F
authors: GF
authors: Beard
authors: Human Factors Research Unit, Institute of Sound and Vibration Research, University of Southampton, United Kingdom. Electronic address: m.j.griffin@soton.ac.uk.
authors: Michael J
authors: MJ
authors: Griffin
mesh_terms: D000054:Acceleration / Q000009:adverse effects*; D000328:Adult; D001336:Automobiles; D001416:Back Pain / Q000209:etiology* / Q000517:prevention & control; D004867:Equipment Design / Q000009:adverse effects; D006804:Ergonomics / Q000295:instrumentation* / Q000379:methods; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D011187:Posture; D014732:Vibration / Q000009:adverse effects; D055815:Young Adult
keywords: Backrest; Discomfort; Vibration