Dooley Stephen, Kim Sunwook, Nussbaum Maury A, Madigan Michael L
Grado Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, VA 24061, United States.
Grado Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, VA 24061, United States.
J Biomech. 2023 Apr;151:111533. doi: 10.1016/j.jbiomech.2023.111533. Epub 2023 Mar 6.
Occupational exoskeletons have become more prevalent as an ergonomic control to reduce the physical demands of workers. While beneficial effects have been reported, there is relatively little evidence regarding potential adverse effects of exoskeletons on fall risk. The purpose of this study was to investigate the effects of a leg-support exoskeleton on reactive balance after simulated slips and trips. Six participants (three females) used a passive, leg-support exoskeleton that provided chair-like support in three experimental conditions (no exoskeleton, low-seat setting, high-seat setting). In each of these conditions, participants were exposed to 28 treadmill perturbations from an upright standing posture simulating a backward slip (0.4-1.6 m/s) or a forward trip (0.75-2.25 m/s). The exoskeleton increased the probability of a failed recovery, and adversely affected reactive balance kinematics, after simulated slips and trips. After simulated slips, the exoskeleton decreased initial step length 0.039 m, decreased mean step speed 0.12 m/s, anteriorly displaced touchdown position of the initial recovery step by 0.045 m, and decreased PSIS height at initial step touchdown by 1.7 % sof its standing height. After simulated trips, the exoskeleton increased trunk angle at step 2.4 degrees, and decreased initial step length 0.033 m. These effects appeared to result from the exoskeleton inhibiting regular stepping motion due to its posterior placement on the lower limbs, added mass, and mechanical constraints on participant movement. Our results suggest care may be needed among leg-support exoskeleton users when at risk of slips or trips and motivate potential exoskeleton design modifications to reduce fall risk.
作为一种减轻工人身体负荷的人体工程学控制手段，职业外骨骼已变得越来越普遍。尽管已有关于其有益效果的报道，但关于外骨骼对跌倒风险潜在不利影响的证据相对较少。本研究的目的是调查腿部支撑外骨骼对模拟滑倒和绊倒后反应性平衡的影响。六名参与者（三名女性）在三种实验条件下（不穿外骨骼、低座椅设置、高座椅设置）使用了一种提供类似椅子支撑的被动式腿部支撑外骨骼。在每种条件下，参与者从直立站立姿势在跑步机上接受28次扰动，模拟向后滑倒（0.4 - 1.6米/秒）或向前绊倒（0.75 - 2.25米/秒）。在模拟滑倒和绊倒后，外骨骼增加了恢复失败的概率，并对反应性平衡运动学产生了不利影响。模拟滑倒后，外骨骼使初始步长减少0.039米，平均步速降低0.12米/秒，初始恢复步的触地位置向前移位0.045米，初始步触地时的坐骨结节高度比站立时降低了1.7%。模拟绊倒后，外骨骼使第二步时的躯干角度增加2.4度，并使初始步长减少0.033米。这些影响似乎是由于外骨骼放置在下肢后部、增加了重量以及对参与者运动的机械限制，从而抑制了正常的迈步动作。我们的结果表明，腿部支撑外骨骼使用者在有滑倒或绊倒风险时可能需要格外小心，并促使对外骨骼设计进行潜在改进以降低跌倒风险。
