Department of Industrial and Systems Engineering, Auburn University, 3301-G Shelby Center Auburn, AL 36849, USA.
Hum Factors. 2010 Oct;52(5):560-73. doi: 10.1177/0018720810381996.
This study examined the impact of two common sizes of ballast on gait biomechanics. The terrain was designed to simulate a railroad work setting to investigate the variation in gait kinetics and muscle activation while walking.
Research and epidemiology suggest a potential link between walking surface characteristics and injury. However, few studies have investigated the impact of ballast surfaces, which is a surface of interest in the railroad and construction industries, on gait dynamics.
For this study, 20 healthy adult men walked along three distinct pathways (no ballast [NB], walking ballast [WB], and mainline ballast [MB]). WB and MB consisted of rock with an average size of 0.75 to I in. and 1.25 to 1.5 in., respectively. Full-body motion, ground reaction forces, and electromyographic (EMG) signals from lower extremity muscles were collected, and three dimensional joint moments were calculated. Parameters of interest were moment trajectories and ranges, EMG activity, and temporal gait measures.
Joint-specific differences indicate significant variations between surface conditions. Joint moment ranges were generally smaller for MB and WB compared with NB. EMG activity, in particular, co-contraction levels, was found to be significantly greater on ballast compared with NB. Temporal gait parameters were significantly different for MB than for either WB or NB.
Walking on ballast increases muscle activation to control the moments of the lower extremity joints.
The results suggest that ballast has an effect on muscles and joints; thus, the findings provide insight to improve and develop new work practices and methods for injury prevention.
本研究考察了两种常见尺寸的道砟对步态生物力学的影响。该地形旨在模拟铁路工作环境，以研究在行走时步态动力学和肌肉激活的变化。
研究和流行病学表明，行走表面特征与损伤之间存在潜在联系。然而，很少有研究调查道砟表面（铁路和建筑行业关注的表面）对步态动力学的影响。
在这项研究中，20 名健康成年男性沿着三条不同的路径行走（无道砟[NB]、行走道砟[WB]和主线道砟[MB]）。WB 和 MB 由平均尺寸为 0.75 至 1 英寸和 1.25 至 1.5 英寸的岩石组成。采集全身运动、地面反作用力和下肢肌肉的肌电图（EMG）信号，并计算三维关节力矩。感兴趣的参数是力矩轨迹和范围、EMG 活动和时间步态测量。
关节特异性差异表明表面条件之间存在显著差异。与 NB 相比，MB 和 WB 的关节力矩范围通常较小。特别是 EMG 活动，在道砟上的协同收缩水平明显高于 NB。与 WB 或 NB 相比，MB 的时间步态参数存在显著差异。
在道砟上行走会增加肌肉激活以控制下肢关节的力矩。
研究结果表明道砟对肌肉和关节有影响；因此，研究结果为改善和开发新的工作实践和预防损伤的方法提供了依据。
