Kulkarni Rucha, Grover Francis M, Shafer Anna, Schmitz Xenia, Gordon Keith E
Department of Biomedical Engineering, Northwestern University, McCormick School of Engineering, Evanston, IL 60208, USA.
Physical Therapy and Human Movement Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA.
Proc Biol Sci. 2024 Dec;291(2036):20242040. doi: 10.1098/rspb.2024.2040. Epub 2024 Dec 11.
People use the mechanical interplay between stability and manoeuvrability to successfully walk. During single-limb support, body states (position and velocity) that increase in lateral stability will inherently resist lateral manoeuvres, decrease medial stability and facilitate medial manoeuvres. Although not well understood, people can make behavioural decisions exploiting this relationship in anticipation of perturbations or direction changes. To characterize the behavioural component of the stability-manoeuvrability relationship, 24 participants performed many repetitions of a discrete stepping task involving mid-trial reactive manoeuvres (medial or lateral direction) in a Baseline (no external perturbations) and Perturbed (random mediolateral perturbations applied to their pelvis) environment. We hypothesized people would make systematic changes in lateral stability dependent on both environment (increasing lateral stability in the Perturbed environment) and anticipated manoeuvre direction (reducing lateral stability to facilitate lateral manoeuvres). Participants increased lateral stability in the Perturbed environment, coinciding with an increase in manoeuvre reaction time for laterally but not medially directed manoeuvres. Moreover, we observed lower lateral stability in both environments when people anticipated making a lateral manoeuvre when compared to medial manoeuvres. These results support the hypothesis that people behaviourally exploit the mechanical relationship between lateral stability and manoeuvrability depending on walk task goals and external environment.
人们利用稳定性和机动性之间的力学相互作用来成功行走。在单腿支撑期间，横向稳定性增加的身体状态（位置和速度）将固有地抵抗横向动作，降低内侧稳定性并促进内侧动作。尽管尚未完全理解，但人们可以利用这种关系做出行为决策，以应对干扰或方向变化。为了表征稳定性 - 机动性关系的行为成分，24名参与者在基线（无外部干扰）和受干扰（向其骨盆施加随机内外侧干扰）环境中多次重复进行离散的踏步任务，该任务涉及试验中的反应性动作（内侧或外侧方向）。我们假设人们会根据环境（在受干扰环境中增加横向稳定性）和预期的动作方向（降低横向稳定性以促进横向动作）对横向稳定性进行系统性改变。参与者在受干扰环境中增加了横向稳定性，但仅在对侧向而非内侧方向的动作时，动作反应时间有所增加。此外，与内侧动作相比，当人们预期进行侧向动作时，我们观察到在两种环境中横向稳定性都较低。这些结果支持了这样一种假设：人们根据行走任务目标和外部环境，在行为上利用横向稳定性和机动性之间的力学关系。
