Trunk response and stability in standing under sagittal-symmetric pull-push forces at different orientations, elevations and magnitudes
Type de document
Études primaires
Année de publication
2018
Langue
Anglais
Titre de la revue
Journal of Biomechanics
Première page
166
Dernière page
174
Résumé
To reduce lifting and associated low back injuries, manual material handling operations often involve pulling-pushing of carts at different weights, orientations, and heights. The loads on spine and risk of injury however need to be investigated. The aim of this study was to evaluate muscle forces, spinal loads and trunk stability in pull–push tasks in sagittal-symmetric, static upright standing posture. Three hand-held load magnitudes (80, 120 and 160 N) at four elevations (0, 20, 40 and 60 cm to the L5-S1) and 24 force directions covering all pull/push orientations were considered. For this purpose, a musculoskeletal finite element model with kinematics measured earlier were used. Results demonstrated that peak spinal forces occur under inclined pull (lift) at upper elevations but inclined push at the lowermost one. Minimal spinal loads, on the other hand, occurred at and around vertical pull directions. Overall, spinal forces closely followed variations in the net external moment of pull–push forces at the L5-S1. Local lumbar muscles were most active in pulls while global extensor muscles in lifts. The trunk stability margin decreased with load elevation except at and around horizontal push; it peaked under pulls and reached minimum at vertical lifts. It also increased with antagonist activity in muscles and intra-abdominal pressure. Results provide insight into the marked effects of variation in the load orientation and elevation on muscle forces, spinal loads and trunk stability and hence offer help in rehabilitation, performance enhancement training and design of safer workplaces.
Mots-clés
Soulèvement des charges, Manual lifting, Colonne vertébrale, Spinal column, Mécanique humaine, Body mechanics, Lésion du tronc, Trunk injury, Affection dorsale, Back disorder, Maux de dos, Backache, Manutention manuelle, Manual handling, Force de traction, Pulling strength, Force de traction, Pulling strength
Numéro de projet IRSST
2014-0009
Citation recommandée
El Ouaaid, Z., Shirazi-Adl, A. et Plamondon, A. (2018). Trunk response and stability in standing under sagittal-symmetric pull–push forces at different orientations, elevations and magnitudes. Journal of Biomechanics, 70, 166-174. https://doi.org/10.1016/j.jbiomech.2017.10.008