Marchini Amanda, Pereira Rafael, Pedroso Wellington, Christou Evangelos, Neto Osmar Pinto
a Arena235 , Consultoria Esportiva , São José dos Campos , Brazil.
b Department of Biological Sciences , State University of Southwest Bahia (UESB) , Jequié , Bahia , Brazil.
Somatosens Mot Res. 2017 Jun;34(2):96-101. doi: 10.1080/08990220.2017.1313220. Epub 2017 Apr 19.
Older adults are more variable than young adults on tasks that demand the simultaneous control of more than one effector, and the difference between age groups may be related to their different capacity of coordinating the force output of the involved effectors. The goal of this study was to determine whether age-associated differences in motor output variability during tasks involving the simultaneous dorsiflexion of two feet can be partially explained by differences in coordination and possibly attenuated by physical training. Ten young and 22 old adults (10 trained and 12 untrained old adults) volunteered to participate in the study. Trained older adults had experience in a high-intensity mixed modality training (MMT) regime for a minimum of 1 year. Volunteers performed successive trials of a constant force task and a goal-directed task, with and without visual feedback. Within- and between-trial variability were calculated and coordination was quantified using the uncontrolled manifold (UCM) approach (i.e., co-variation of the force outputs of both feet were used to quantify a motor synergy index). Older adults exhibited greater variability and lower synergy (p < .05), independently of physical training status, than young adults. Removal of visual feedback caused greater variability and lower synergy for all groups (p < .05). Our results suggest that older adults exhibit greater motor output variability in tasks involving the simultaneous dorsiflexion of both feet possibly due to a lack of coordination between the feet.
在需要同时控制多个效应器的任务中，老年人比年轻人的变异性更大，年龄组之间的差异可能与他们协调相关效应器力输出的不同能力有关。本研究的目的是确定在涉及双脚同时背屈的任务中，与年龄相关的运动输出变异性差异是否可以部分由协调差异来解释，以及是否可以通过体育锻炼来减轻。10名年轻人和22名老年人（10名受过训练的老年人和12名未受过训练的老年人）自愿参与该研究。受过训练的老年人有至少1年高强度混合模式训练（MMT）的经验。志愿者在有和没有视觉反馈的情况下，进行恒定力任务和目标导向任务的连续试验。计算试验内和试验间的变异性，并使用非控制流形（UCM）方法（即，使用双脚力输出的协变来量化运动协同指数）对协调性进行量化。与年轻人相比，无论体育锻炼状况如何，老年人都表现出更大的变异性和更低的协同性（p < 0.05）。去除视觉反馈会导致所有组的变异性更大和协同性更低（p < 0.05）。我们的结果表明，老年人在涉及双脚同时背屈的任务中表现出更大的运动输出变异性，这可能是由于双脚之间缺乏协调性。
