title: The effect of school bag design and load on spinal posture during stair use by children.
abstract: Thirteen male children ascending and descending stairs with loads that equalled 0%, 10%, 15% and 20% of their body weight were the subject of our research: the boys were wearing an asymmetrical single-strap athletic bag or a symmetrical double-strap backpack during our experiments with them. The maximum spinal tilt to the loading side and to the support side, and the range of spinal motions, were obtained by using a motion analysis system. Our results showed that symmetry of spinal posture was observed both when they ascended staircase with all loads and descended in a backpack. When carrying an athletic bag with 15% and 20% of their body weight while ascending the staircase, the lateral spinal tilt to the supporting side was significantly increased. We concluded that a symmetrical backpack with a load not exceeding 20% or an asymmetrical single-strap athletic bag with a load not exceeding 10% should be recommended for school children in order to promote safer staircase use. STATEMENT OF RELEVANCE: Children carrying heavy school bags may develop spinal problems. This study suggested that when they are using stairs, a symmetrical backpack with a load within 20% body weight is acceptable for them. When they are carrying an asymmetrical single-strap athletic bag, the bag's weight should not exceed 10% of the body weight in order to avoid excessive spinal tilt.
authors: Department of Sports Medicine, Chengdu Sports University, Chengdu, China.
authors: Youlian
authors: Y
authors: Hong
authors: Daniel Tik-Pui
authors: DT
authors: Fong
authors: Jing Xian
authors: JX
authors: Li
mesh_terms: D000293:Adolescent; D002648:Child; D004867:Equipment Design; D004864:Equipment and Supplies / Q000009:adverse effects; D006801:Humans; D017770:Lifting / Q000009:adverse effects*; D008297:Male; D011187:Posture / Q000502:physiology; D012449:Safety; D013131:Spine / Q000503:physiopathology*; D016474:Weight-Bearing / Q000502:physiology*