Abbasi Saeedeh, Minoonejad Hooman, Abbasi Hamed, Mousavi Seyed Hamed
Department of Sports Injury and Biomechanics, Faculty of Sport Sciences and Health, University of Tehran, Tehran, Iran.
Department of Sport Injuries and Corrective Exercises, Sport Sciences Research Institute, Tehran, Iran.
BMC Musculoskelet Disord. 2025 Mar 26;26(1):299. doi: 10.1186/s12891-025-08525-y.
Low back pain developers (PDs) are individuals at a high risk of developing low back pain (LBP), especially during prolonged standing. Understanding their characteristics is essential for devising effective preventive strategies. Prolonged standing has been associated with increased co-contraction of trunk muscles and elevated activity of the trunk extensor muscles. This study aims to examine the effects of using a normalized footrest height and altering arm positions on muscle activity in PDs.
Twenty-four female PDs, identified by a > 10 mm increase on the visual analog scale (VAS) during prolonged standing, were recruited. They were randomly divided into two groups: Group A used a footrest intermittently, while Group B used a footrest combined with changes in arm positions (shoulder flexion and hands crossed on the clavicles). Muscle activity was monitored using electromyography (EMG) over a one-hour standing protocol.
Both interventions significantly reduced lumbar erector spinae (LES) muscle activity, as well as co-contraction of the trunk flexor and extensor muscles (p < 0.05). The group that adjusted their arm positions (Group B) experienced a greater reduction in muscle activity (p = 0.05). Additionally, transversus abdominis (TrA) muscle activity slightly increased in both groups, with a more notable increase in Group B (p > 0.05). Although lumbar spine muscle activity decreased, thoracic spine extensor (TES) activity increased in Group B. This increase is attributed to the engagement of the thoracic spine during upper limb movement, compensating for the reduced lumbar muscle activity, which may help alleviate back pain.
Using footrests cyclically and adjusting arm positions can help prevent back pain during prolonged standing by promoting muscle relaxation, reducing fatigue, and improving posture. These findings offer practical strategies for enhancing workplace ergonomics, particularly for occupations involving prolonged standing.
This study is registered in the Clinical Trial Registry ( http://www.irct.ir/ ) with Trial ID 71,648 and IRCT ID IRCT20230628058610N1, dated January 20, 2024.
下背痛易患人群（PDs）是患下背痛（LBP）风险较高的个体，尤其是在长时间站立期间。了解他们的特征对于制定有效的预防策略至关重要。长时间站立与躯干肌肉的协同收缩增加以及躯干伸肌的活动增强有关。本研究旨在探讨使用标准化脚凳高度和改变手臂位置对PDs肌肉活动的影响。
招募了24名女性PDs，这些女性在长时间站立期间视觉模拟量表（VAS）上的增加幅度大于10毫米。她们被随机分为两组：A组间歇性使用脚凳，而B组使用脚凳并结合手臂位置的变化（肩部屈曲和双手交叉于锁骨处）。在一小时的站立试验中，使用肌电图（EMG）监测肌肉活动。
两种干预措施均显著降低了竖脊肌（LES）的肌肉活动，以及躯干屈肌和伸肌的协同收缩（p < 0.05）。调整手臂位置的组（B组）肌肉活动的降低幅度更大（p = 0.05）。此外，两组腹横肌（TrA）的肌肉活动均略有增加，B组增加更为明显（p > 0.05）。虽然腰椎肌肉活动减少，但B组胸椎伸肌（TES）活动增加。这种增加归因于上肢运动期间胸椎的参与，以补偿腰椎肌肉活动的减少，这可能有助于减轻背痛。
周期性使用脚凳和调整手臂位置有助于通过促进肌肉放松、减轻疲劳和改善姿势来预防长时间站立期间的背痛。这些发现为改善工作场所人体工程学提供了实用策略，特别是对于涉及长时间站立的职业。
本研究已在临床试验注册中心（http://www.irct.ir/）注册，试验编号为71,648，IRCT编号为IRCT20230628058610N1，日期为2,024年1月20日。
