Kingma Idsart, Faber Gert S, van Dieën Jaap H
Research institute MOVE, Department of Human Movement Sciences, VU University Amsterdam, Amsterdam, Netherlands.
Research institute MOVE, Department of Human Movement Sciences, VU University Amsterdam, Amsterdam, Netherlands.
J Biomech. 2016 Apr 11;49(6):881-889. doi: 10.1016/j.jbiomech.2015.09.035. Epub 2015 Oct 9.
When picking objects from the floor, low back pain patients often tend to support the upper body by leaning with one hand on a thigh. While this strategy may reduce back load, this has not yet been assessed, probably due to the difficulty of measuring the forces between hand and thigh. Ten healthy male subjects lifted a pencil and a crate from the floor, with four lifting techniques (free, squat, stoop and a Weight Lifters Technique (WLT)), each of which was performed with and without supporting with one hand on the thigh. A six Degrees of Freedom force transducer, with a comfortable surface to support the hand on, was mounted just above the subject׳s left knee. Hand forces, ground reaction forces, full body kinematics, and trunk EMG were measured. Using inverse dynamics and taking the forces between hand and thigh into account, we calculated 3D L5S1 joint moments, and subsequently estimated spine forces using an EMG-assisted trunk model. For lifting a pencil, hand support reduced average peak total moments by 17-25%, dependent on lifting technique. For crate lifting, hand support reduced total moments by 13-19% compared with one-handed lifting and by 14-26% compared to two-handed lifting. Hand support slightly increased asymmetric motions and caused a substantial increase in asymmetric moments in crate lifting. For compression forces, reductions (up to 28%) were seen in all techniques except in stoop lifts. It is concluded that leaning with a hand on the thigh can lead to substantial reductions of low back loading during lifting.
从地板上捡东西时，下背痛患者常常倾向于用一只手撑在大腿上，以此来支撑上半身。虽然这种方式可能会减轻背部负荷，但由于测量手和大腿之间的力存在困难，目前尚未得到评估。十名健康男性受试者采用四种提举技术（自由提举、深蹲提举、弯腰提举和举重运动员技术（WLT））从地板上捡起一支铅笔和一个板条箱，每种技术都分别在有和没有用一只手撑在大腿上的情况下进行。在受试者左膝上方安装了一个六自由度力传感器，其表面舒适，可供手支撑。测量了手部力量、地面反作用力、全身运动学和躯干肌电图。利用逆动力学并考虑到手和大腿之间的力，我们计算了L5S1关节的三维力矩，随后使用肌电图辅助的躯干模型估计脊柱受力。对于捡起一支铅笔，根据提举技术的不同，手部支撑可使平均峰值总力矩降低17%至25%。对于提起板条箱，与单手提起相比，手部支撑可使总力矩降低13%至19%，与双手提起相比可降低14%至26%。手部支撑略微增加了不对称运动，并在提起板条箱时导致不对称力矩大幅增加。对于压缩力，除了弯腰提举外，所有技术都出现了降低（高达28%）。研究得出结论，用手撑在大腿上可以在提举过程中大幅减轻下背部的负荷。
