Moon Seong H, Frames Christopher W, Soangra Rahul, Lockhart Thurmon E
School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ,85281, USA.
Crean College of Health and Behavioral Sciences, Chapman University, Orange, CA, 92866, USA.
Int J Progn Health Manag. 2021;12(4). doi: 10.36001/ijphm.2021.v12i4.2778. Epub 2021 Aug 24.
Various factors are responsible for injuries that occur in the U.S. Army soldiers. In particular, rucksack load carriage equipment influences the stability of the lower extremities and possibly affects gait balance. The objective of this investigation was to assess the gait and local dynamic stability of the lower extremity of five subjects as they performed a simulated rucksack march on a treadmill. The Motek Gait Real-time Interactive Laboratory (GRAIL) was utilized to replicate the environment of the rucksack march. The first walking trial was without a rucksack and the second set was executed with the All-Purpose Lightweight Individual Carrying Equipment (ALICE), an older version of the rucksack, and the third set was executed with the newer rucksack version, Modular Lightweight Load Carrying Equipment (MOLLE). In this experiment, the Inertial Measurement Unit (IMU) system, Dynaport was used to measure the ambulatory data of the subject. This experiment required subjects to walk continuously for 200 seconds with a 20kg rucksack, which simulates the real rucksack march training. To determine the dynamic stability of different load carriage and normal walking condition, Local Dynamic Stability (LDS) was calculated to quantify its stability. The results presented that comparing Maximum Lyapunov Exponent (LyE) of normal walking was significantly lower compared to ALICE (P=0.000007) and MOLLE (P=0.00003), however, between ALICE and MOLLE rucksack walking showed no significant difference (P=0.441). The five subjects showed significantly improved dynamic stability when walking without a rucksack in comparison with wearing the equipment. In conclusion, we discovered wearing a rucksack result in a significant (P < 0.0001) reduction in dynamic stability.
多种因素导致美国陆军士兵受伤。特别是，背包负重装备会影响下肢稳定性，并可能影响步态平衡。本研究的目的是评估五名受试者在跑步机上进行模拟背包行军时下肢的步态和局部动态稳定性。利用Motek步态实时交互实验室（GRAIL）来模拟背包行军的环境。第一次步行试验不背背包，第二次试验使用老式背包“通用轻型单兵携行装备”（ALICE）进行，第三次试验则使用更新的背包版本“模块化轻型负载携行装备”（MOLLE）。在本实验中，使用惯性测量单元（IMU）系统Dynaport来测量受试者的动态数据。本实验要求受试者背负20kg背包连续行走200秒，以模拟实际的背包行军训练。为了确定不同负重行走和正常行走状态下的动态稳定性，计算局部动态稳定性（LDS）以量化其稳定性。结果显示，与正常行走相比，背负ALICE背包（P=0.000007）和MOLLE背包（P=0.00003）时的最大Lyapunov指数（LyE）显著降低，然而，在背负ALICE背包和MOLLE背包行走之间没有显著差异（P=0.441）。与背负装备行走相比，五名受试者在不背背包行走时动态稳定性显著提高。总之，我们发现背负背包会导致动态稳定性显著降低（P<0.0001）。
