title: The effects of seat height and foot placement on lumbar spine load during sit-to-stand tasks.
abstract: The purpose of this study was to determine the influence of seat height and foot position in the sagittal plane on L5-S1 joint load. Fourteen healthy male adults stood up from a chair with three different seat heights and positions of the feet in the sagittal plane. L5-S1 net joint torque, mechanical work, range of motion and electromyographic activity of the erector spinae muscle were measured. L5-S1 net joint work increased by about 50% from high to low seat position. The mean and peak L5-S1 net joint torques increased about 30% from foot-back to foot-neutral position. These results were reinforced by a greater integrated electromyography signal from the erector spinae from high to low seat position and from foot-back to foot-neutral position. A high chair and placement of the feet behind the knees may be advisable to lessen lumbar load during sit-to-stand movements.
authors.affiliation: a Centre de Recherche et d'Innovation sur le Sport , Université Claude Bernard , Lyon , France.
authors.forename: Y
authors.initials: Y
authors.lastname: Blache
authors.forename: B
authors.initials: B
authors.lastname: Pairot de Fontenay
authors.forename: K
authors.initials: K
authors.lastname: Monteil
mesh_terms: D000328:Adult; D004576:Electromyography; D005528:Foot; D006801:Humans; D007374:Interior Design and Furnishings; D008159:Lumbar Vertebrae / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D011187:Posture / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology*
keywords: L5-S1 joint; biomechanics; electromyography; joint work