title: Effect of seat and table top slope on the biomechanical stress sustained by the musculo-skeletal system.
abstract: The purpose of this study was to assess the effect of table and seat slope on the biomechanical stress sustained by the musculo-skeletal system. Angular position of the head and trunk, and surface electromyography of eleven postural muscles were recorded while seated under different conditions of seat slope (0°, 15° forward) and table slope (0°, 20° backward). The specific stress sustained by C7-T1 joint was estimated with isometric torque calculation. The results showed that the backward sloping table was associated with a reduction of neck flexion and neck extensors EMG, contrasting with a concurrent overactivity of the deltoideus. The forward sloping chair induced an anterior pelvic tilt, but also a higher activity of the knee (vasti) and ankle (soleus) extensors. It was concluded that sloping chairs and tables favor a more erect posture of the spine, but entails an undesirable overactivity of upper and lower limbs muscles to prevent the body from sliding.
authors.affiliation: Laboratory of Posture and Movement Physiology, University Champollion, Albi, France; PRISSMH, University of Toulouse, University Paul Sabatier, Toulouse, France. Electronic address: alain.hamaoui@univ-jfc.fr.
authors.forename: Alain
authors.initials: A
authors.lastname: Hamaoui
authors.affiliation: Laboratory of Posture and Movement Physiology, University Champollion, Albi, France; PRISSMH, University of Toulouse, University Paul Sabatier, Toulouse, France.
authors.forename: Myriam
authors.initials: M
authors.lastname: Hassaïne
authors.affiliation: PRISSMH, University of Toulouse, University Paul Sabatier, Toulouse, France; CNRS, LAAS, 7 Avenue du Colonel Roche, 31400 Toulouse, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Watier
authors.affiliation: PRISSMH, University of Toulouse, University Paul Sabatier, Toulouse, France.
authors.forename: Pier-Giorgio
authors.initials: PG
authors.lastname: Zanone
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004576:Electromyography / Q000379:methods; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D009333:Neck / Q000502:physiology; D011187:Posture / Q000502:physiology*; D013131:Spine / Q000502:physiology; D013314:Stress, Mechanical
keywords: Ergonomic furniture; Seated posture; Sloping chair; Sloping table; Spine