title: Sitting on a sloping seat does not reduce the strain sustained by the postural chain.
abstract: The objective of this study was to explore the effect of a forward sloping seat on posture and muscular activity of the trunk and lower limbs. To this aim, twelve asymptomatic participants were tested in six conditions varying seat slope (0°, 15° forward) and height (high, medium, low). Angular position of head, trunk and pelvis was assessed with an inertial orientation system, and muscular activity of 11 superficial postural muscles located in the trunk and lower limbs was estimated using normalized EMG. Results showed that a forward sloping seat, compared to a flat seat, induced a greater activity of the soleus (p<0.01), vastus lateralis (p<0.05) and vastus medialis (p<0.05), as well a lower hip flexion (p<0.01). In contrast, no significant variation of head, trunk and pelvis angular position was observed according to seat slope. It was concluded that forward sloping seats increase the load sustained by the lower limbs, without a systematic improvement of body posture.
authors.affiliation: Laboratory of Posture and Movement Physiology, University Champollion, Albi, France; PRISSMH, University of Toulouse, University Paul Sabatier, Toulouse, France.
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.
authors.forename: Pier-Giorgio
authors.initials: PG
authors.lastname: Zanone
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004576:Electromyography; D006804:Ergonomics; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D055815:Young Adult