The effects of a sloped ground surface on trunk kinematics and L5/S1 moment during lifting
The effects of a sloped ground surface on trunk kinematics and L5/S1 moment during lifting
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DOI：
10.1080/00140130310001653066
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发表时间：
2004-05-15
期刊：
影响因子：
2.4
通讯作者：
Mirka, G
中科院分区：
文献类型：
--
作者：
Shin, G;Mirka, G
许多工作环境要求工人在不完全平坦的地面上执行手动材料搬运任务（例如在农业、建筑和海事工作场所）。这些倾斜的地面可能会对举重者采用的举重策略/技术产生影响，进而可能改变脊柱的生物力学负荷。描述躯干运动学和动力学的变化是评估这些变化影响的第一步，也是当前研究的重点。记录受试者站立在两个倾斜表面（面向向上倾斜：10 度和 20 度）、两个倾斜表面（面向向下倾斜：- 10 度和 - 20 度）和平坦表面（0 度）时使用三种举升技术（抬腿、背部举升和自由式举升）举起一个 10 公斤的盒子时的全身运动。然后将这些数据用于二维五段动态生物力学模型（自上而下），以评估这些斜率对 L5/S1 关节净力矩的影响。这项研究的结果显示了一个有趣的相互作用效应，其中净 L5/S1 力矩在背部举升条件下对倾斜角度的变化相对不敏感，但在腿部举升和自由式举升条件下表现出显着的影响。结果表明，在自由式举升条件下，倾斜表面的峰值 L5/S1 力矩明显高于平坦表面（高 6.8%）或倾斜表面（高 10.0%）。随后的成分分析表明，躯干弯曲角度和躯干角加速度都驱动了这种反应。总的来说，这项研究的结果表明，地面坡度角度确实会影响提升运动学和动力学，因此在评估这些工作条件下腰部受伤的风险时需要考虑到。
There are many work environments that require workers to perform manual materials handling tasks on ground surfaces that are not perfectly flat (e.g. in agriculture, construction, and maritime workplaces). These sloped ground surfaces may have an impact on the lifting strategy/technique employed by the lifter, which may, in turn, alter the biomechanical loading of the spine. Describing the changes in kinematics and kinetics of the torso is the first step in assessing the impact of these changes and is the focus of the current research. Subjects' whole-body motions were recorded as they lifted a 10 kg box while standing on two inclined surfaces (facing an upward slope: 10degrees and 20degrees), two declined surfaces (facing a downward slope: - 10degrees and - 20degrees), and a flat surface (0degrees) using three lifting techniques (leg lift, back lift and freestyle lift). These data were then used in a two-dimensional, five-segment dynamic biomechanical model (top-down) to evaluate the effect of these slopes on the net moment about the L5/S1 joint. The results of this study showed an interesting interaction effect wherein the net L5/S1 moment was relatively insensitive to changes in slope angle under the back lift condition, but showed a significant effect during the leg lift and freestyle lifting conditions. The results show that under the freestyle lifting condition the peak L5/S1 moment was significantly higher for the inclined surfaces as compared to the flat surfaces (6.8% greater) or declined surfaces (10.0% greater). Subsequent component analysis revealed that both trunk flexion angle and angular trunk acceleration were driving this response. Collectively, the results of this study indicate that ground slope angle does influence the lifting kinematics and kinetics and therefore needs to be considered when evaluating risk of low back injury in these working conditions.