Mariscal Dulce M, Sombric Carly J, Torres-Oviedo Gelsy
Sensorimotor Learning Laboratory, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA, 15260.
Center for the Neural Basis of Cognition, University of Pittsburgh, PA, USA, 15260.
bioRxiv. 2023 Aug 24:2023.08.10.552802. doi: 10.1101/2023.08.10.552802.
Previous work has shown that compared with young adults, older adults generalize their walking patterns more across environments that impose different motor demands (i.e., split-belt treadmill vs. overground). However, in this previous study, all participants walked at a speed that was more comfortable for older adults than young participants, which leads to the question of whether young adults would generalize more their walking patterns than older adults when exposed to faster speeds that are more comfortable for them. To address this question, we examined the interaction between healthy aging and walking speed on the generalization of a pattern learned on a split-belt treadmill (i.e., legs moving at different speeds) to overground. We hypothesized that walking speed during split-belt walking regulates the generalization of walking patterns in an age-specific manner. To this end, groups of young (<30 y/o) and older (65+ y/o) adults adapted their gait on a split-belt treadmill at either slower or faster walking speeds. We assessed the generalization of movements between the groups by quantifying their aftereffects during overground walking, where larger overground aftereffects represent more generalization, and zero aftereffects represent no generalization. We found an interaction between age and walking speed in the generalization of walking patterns. More specifically, older adults generalized more when adapted at slower speeds, whereas younger adults did so when adapted at faster speeds. These results suggest that comfortable walking speeds lead to more generalization of newly acquired motor patterns beyond the training contexts.
先前的研究表明，与年轻人相比，老年人在不同运动需求的环境中（即分带式跑步机与地面行走）更能概括他们的行走模式。然而，在先前的这项研究中，所有参与者行走的速度对老年人来说比对年轻参与者更舒适，这就引发了一个问题：当年轻人接触到对他们来说更舒适的更快速度时，他们是否会比老年人更能概括自己的行走模式。为了解决这个问题，我们研究了健康衰老与行走速度之间的相互作用，即研究在分带式跑步机上学习的一种模式（即双腿以不同速度移动）在地面行走时的概括情况。我们假设，分带式行走时的速度以特定年龄的方式调节行走模式的概括。为此，年轻组（<30岁）和老年组（65岁以上）的成年人在分带式跑步机上以较慢或较快的行走速度调整他们的步态。我们通过量化他们在地面行走时的后效应来评估两组之间运动的概括情况，其中较大的地面后效应表示更多的概括，零后效应表示没有概括。我们发现，在行走模式的概括方面，年龄和行走速度之间存在相互作用。更具体地说，老年人在以较慢速度适应时概括得更多，而年轻人在以较快速度适应时概括得更多。这些结果表明，舒适的行走速度会导致新获得的运动模式在训练环境之外得到更多的概括。
