Sawers Andrew, Bhatt Tanvi
Department of Kinesiology, University of Illinois at Chicago , Chicago, Illinois.
Department of Physical Therapy, University of Illinois at Chicago , Chicago, Illinois.
J Neurophysiol. 2018 Oct 1;120(4):1534-1546. doi: 10.1152/jn.00286.2018. Epub 2018 Jul 11.
Is there a neuromuscular basis for falls? If so, it may provide new insight into falls and their assessment and treatment. We hypothesized that falls and recoveries from a laboratory-induced slip would be characterized by differences in multimuscle coordination patterns. Using muscle synergy analysis, we identified different multimuscle coordination patterns between older adults who fell and those who recovered from a laboratory-induced "feet-forward" slip. Participants who fell recruited fewer muscle synergies than participants who recovered. This suggests that a fall may result from recruitment of an inadequate number of muscle synergies to produce the necessary mechanical functions required to maintain balance. Participants who fell also recruited different muscle synergies, including one with high levels of coactivity consistent with a startle-like response. These differences in multimuscle coordination between slip outcomes were not accompanied by differences in slip difficulty or gait kinematics before or during the slip response. The differences in neuromuscular control may therefore reflect differences in sensorimotor control rather than kinematic constraints imposed by the slip, or the musculoskeletal system. Further research is required to test the robustness of these results and their interpretation with respect to additional mechanical variables (e.g., joint torques, ground reaction forces), responses to other fall types (e.g., trips), and within rather than between individuals. NEW & NOTEWORTHY Do falls and recoveries possess distinct neuromuscular features? We identified differences in neuromuscular control between older adults who fell and those who recovered from a "feet-forward" slip. Differences in neuromuscular control were not accompanied by differences in gait or slip kinematics before or during the slip response, suggesting differences in sensorimotor control rather than kinematics dictated the observed differences in neuromuscular control. An analysis of additional mechanical variables is required to confirm this interpretation.
跌倒是否存在神经肌肉基础？如果是这样，它可能为跌倒及其评估和治疗提供新的见解。我们假设，实验室诱发滑倒后的跌倒和恢复将以多肌肉协调模式的差异为特征。通过肌肉协同分析，我们确定了跌倒的老年人与从实验室诱发的“向前滑倒”中恢复的老年人之间不同的多肌肉协调模式。跌倒的参与者比恢复的参与者募集的肌肉协同作用更少。这表明，跌倒可能是由于募集的肌肉协同作用数量不足，无法产生维持平衡所需的必要机械功能。跌倒的参与者还募集了不同的肌肉协同作用，包括一种具有与惊吓样反应一致的高共激活水平的协同作用。滑倒结果之间多肌肉协调的这些差异，在滑倒反应之前或期间，并未伴随着滑倒难度或步态运动学的差异。因此，神经肌肉控制的差异可能反映了感觉运动控制的差异，而不是滑倒或肌肉骨骼系统所施加的运动学限制。需要进一步的研究来测试这些结果的稳健性，以及它们对于其他机械变量（例如关节扭矩、地面反作用力）、对其他跌倒类型（例如绊倒）的反应以及个体内部而非个体之间的解释。新内容与值得关注的点：跌倒和恢复是否具有独特的神经肌肉特征？我们确定了跌倒的老年人与从“向前滑倒”中恢复的老年人之间神经肌肉控制的差异。神经肌肉控制的差异在滑倒反应之前或期间，并未伴随着步态或滑倒运动学的差异，这表明感觉运动控制的差异而非运动学决定了观察到的神经肌肉控制差异。需要对其他机械变量进行分析以证实这一解释。
