Sparto P J, Parnianpour M, Reinsel T E, Simon S
Biomedical Engineering Center, The Ohio State University, Columbus 43210, USA.
Spine (Phila Pa 1976). 1997 Nov 15;22(22):2647-54. doi: 10.1097/00007632-199711150-00013.
A repetitive lifting test in the sagittal plane was performed with a submaximal load at a maximal lifting rate to understand the effects of fatigue on kinematic and kinetic measures of performance.
To quantify the effect of fatigue during a highly repetitive lifting task, in terms of lifting force transmitted to the load, joint motion patterns, and internal joint load sharing.
Industrial surveillance and epidemiologic data suggest that repetitive lifting is a risk factor for low back pain. Previous studies examining the effect of fatigue have either been constrained to isolated trunk movement, or have not explored the internal load distribution and potential alteration in the loading patterns.
Sixteen healthy male subjects performed repetitive lifting in the sagittal plane with a load equal to 25% of their maximal lifting capacity, at a maximal lifting rate. Changes in lifting performance were determined from the power transferred to the box, joint kinematics, and joint kinetics. Data from three cycles at the start and end of the exercise were tested for the effect of fatigue using repeated-measures analysis of variance.
Fatigue was documented by a reduction in average lifting force and hip and spine torque generation, whereas internal joint load sharing was relatively unchanged. The fatigue was associated with decreased knee and hip motion, and increased lumbar flexion. Decreased postural stability also was evident.
The significant decrease in postural stability and force generation capability because of the repetitive lifting task indicated a higher risk of injury in the presence of unexpected perturbation. Multijoint coordinated lifting tasks provide a more realistic protocol to study neuromuscular fatigue.
在矢状面进行重复提举测试，采用次最大负荷并以最大提举速率进行，以了解疲劳对运动学和动力学性能指标的影响。
就传递至负荷的提举力、关节运动模式和关节内负荷分担而言，量化高度重复提举任务期间疲劳的影响。
工业监测和流行病学数据表明，重复提举是腰痛的一个风险因素。以往研究疲劳影响的试验要么局限于孤立的躯干运动，要么未探究内部负荷分布及负荷模式的潜在改变。
16名健康男性受试者在矢状面以等于其最大提举能力25%的负荷、以最大提举速率进行重复提举。根据传递至箱子的功率、关节运动学和关节动力学确定提举性能的变化。使用重复测量方差分析对运动开始和结束时三个周期的数据进行疲劳效应测试。
疲劳表现为平均提举力以及髋部和脊柱扭矩产生量降低，而关节内负荷分担相对未变。疲劳与膝关节和髋关节运动减少以及腰椎前屈增加有关。姿势稳定性降低也很明显。
由于重复提举任务导致姿势稳定性和力量产生能力显著下降，表明在存在意外扰动时受伤风险更高。多关节协调提举任务为研究神经肌肉疲劳提供了更现实的方案。
