Hamstring stretching significantly changes the sitting biomechanics
| Autor: | Sangeun Jin, Ilseok Lee, Sunghyun Sim |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
musculoskeletal diseases
030506 rehabilitation medicine.medical_specialty business.industry 05 social sciences Public Health Environmental and Occupational Health Biomechanics Human Factors and Ergonomics Lumbar vertebrae musculoskeletal system Sitting Trunk 03 medical and health sciences Lumbar medicine.anatomical_structure Physical medicine and rehabilitation Medicine 0501 psychology and cognitive sciences Tibia 0305 other medical science business 050107 human factors Pelvis Hamstring |
| Zdroj: | International Journal of Industrial Ergonomics. 84:103163 |
| ISSN: | 0169-8141 |
| DOI: | 10.1016/j.ergon.2021.103163 |
| Popis: | The tightened hamstring connecting the tibia to the pelvis provides more posterior pelvic tilting and consequent backward curvature of the sacral and lumbar vertebrae. Therefore, the study goal was to quantitatively investigate the effect of hamstring and low back stretching on the trunk biomechanics in a system-level perspective. Twelve healthy subjects performed two stretching interventions (hamstring only (HS); hamstring + low back (HLS)) for 40 s on two separate days. They sat on a stool before and after the intervention while capturing trunk kinematics and EMG. In addition, the lumbar flexion angle at which the L4 paraspinals deactivate (i.e., flexion-relaxation phenomenon; FRP) was monitored while trunk flexion-extension trials, performed before and after the protocol. The FRP onset angle was captured to verify the biomechanical changes in the lower extremity and trunk systems. In the results, the stretching intervention significantly increased the reaching distance by 6.3 cm in the sit-and-reach test performed immediately before and after the intervention. The flexible hamstring improved the lumbar flexion angle and head postures in both the HS and HLS. However, the HLS induced laxity in lumbar passive tissues, as confirmed by changes in the FRP, and significantly increased co-activation in the low back. The stress-relaxation of the hamstring and surrounding passive tissues could help to maintain better lumbar flexion angle (i.e., lumbar lordosis) while sitting. Periodic HS for 40 s without any significant lumbar flexion may be recommendable for office workers who sit for long periods. |
| Databáze: | OpenAIRE |
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