Background

Recent studies provide compelling evidence that recruiting a common pool of motor modules across behaviors (i.e., motor module generalization) may facilitate motor performance. In particular, motor module generalization across standing reactive balance and walking is associated with both walking speed and endurance in neurologically impaired populations (e.g., stroke survivors and individual’s with Parkinson’s disease). To test whether this phenomenon is a general neuromuscular strategy associated with well-coordinated walking and not limited to motor impairment, this relationship must be confirmed in neurologically intact adults.

Research Question

Is motor module generalization across standing reactive balance and walking related to walking performance in neurologically intact young adults?

Methods

Two populations of young adults were recruited to capture a wide range of walking performance: professionally-trained ballet dancers (i.e., experts, n = 12) and novices (n = 8). Motor modules (a.k.a. muscle synergies) were extracted from muscles spanning the trunk, hip, knee and ankle during walking and multidirectional perturbations to standing. Motor module generalization was calculated as the number of modules common to these behaviors. Walking performance was assessed using self-selected walking speed and beam-walking proficiency (i.e., distance walked on a narrow beam). Motor module generalization between experts and novices was compared using rank-sum tests and the association between generalization and walking performance was assessed using correlation analyses.

Results

Experts generalized more motor modules across standing reactive balance and walking than novices (p = 0.009). Across all subjects, motor module generalization was moderately associated with increased beam walking proficiency (r = 0.456, p = 0.022) but not walking speed (r = 0.092, p = 0.349).

Significance

Similar relationships between walking performance and motor module generalization exist in neurologically intact and impaired populations, suggesting that motor module generalization across standing reactive balance and walking may be a general neuromuscular mechanism contributing to the successful control of walking.

中文翻译：

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站立反应平衡和行走中运动模块募集的概括与年轻人的横梁行走表现有关

背景

最近的研究提供了令人信服的证据，表明跨行为（即运动模块泛化）招募共同的运动模块池可能会促进运动表现。特别是，站立反应平衡和步行的运动模块泛化与神经受损人群（例如，中风幸存者和帕金森病患者）的步行速度和耐力有关。为了测试这种现象是否是与协调良好的步行相关的一般神经肌肉策略，而不仅限于运动障碍，必须在神经功能完好的成年人中证实这种关系。

研究问题

站立反应平衡和步行的运动模块泛化与神经功能完好的年轻人的步行表现有关吗？

方法

招募了两个年轻人群体来捕捉广泛的步行表演：受过专业训练的芭蕾舞演员（即专家，n = 12）和新手（n = 8）。运动模块（又名肌肉协同作用）是从行走和多向扰动到站立过程中跨越躯干、臀部、膝盖和脚踝的肌肉中提取的。电机模块泛化被计算为这些行为共有的模块数量。使用自行选择的步行速度和横梁行走能力（即在窄横梁上行走的距离）评估步行性能。使用秩和检验比较专家和新手之间的运动模块泛化，并使用相关分析评估泛化与步行性能之间的关联。

结果

与新手相比，专家在站立反应平衡和步行方面概括了更多的运动模块（p = 0.009）。在所有受试者中，运动模块泛化与横梁行走能力的增加（r = 0.456，p = 0.022）但与步行速度（r = 0.092，p = 0.349）无关。

意义

步行性能和运动模块泛化之间的类似关系存在于神经功能完整和受损的人群中，这表明跨站立反应平衡和步行的运动模块泛化可能是有助于成功控制步行的一般神经肌肉机制。