Motor flexibility, the ability to employ multiple motor strategies to meet task demands, may facilitate ambulation in complex environments that constrain movements; loss of motor flexibility may impair mobility. The purpose of this study was to determine the effects of obesity (a specific model of mobility impairment) and advanced age on motor flexibility during a task that constrained foot placement while walking. Twenty-one community-dwelling obese (OB) and 25 normal weight (NW) older adults (46 total older adults-OA) and 10 younger adults (YA) walked normally on a treadmill (baseline) then walked while stepping on lighted cues projected onto the treadmill at locations corresponding to average foot placement during normal walking (cued). The uncontrolled manifold (UCM) analysis was used to partition total variance in a set of seven lower-limb segment angles into components that did ("bad" variance) and did not ("good" variance) affect step-to-step variance in the trajectory of the swing foot. Motor flexibility was operationalized as an increase (baseline to cued) in total variance with an increase in good variance that exceeded the change in bad variance. There was no significant group × walking task interaction for total and good variance for OB vs NW, but there was a strong and significant interaction effect for OA vs YA (p < 0.01; Cohen's d > 1.0). Whereas YA reduced both good and bad variance, OA increased good variance beyond the change in bad variance. In OA, these changes were associated with several functional measures of mobility. Cued walking may place greater demands on OA requiring greater reliance on motor flexibility, although otherwise healthy older obese adults may be able to compensate for functional and cognitive declines associated with obesity by increasing motor flexibility under such tasks. The extent to which motor flexibility is employed during novel or constrained tasks may be a biomarker of healthy aging and a target for (re)habilitation.

中文翻译：

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年龄较大但较年轻的成年人在执行新颖的提示行走任务时依靠多关节协调来稳定摆动的肢体。

运动灵活性，即采用多种运动策略来满足任务需求的能力，可能会在限制运动的复杂环境中促进移动。失去马达柔韧性可能会损害机动性。这项研究的目的是确定肥胖（一种行动不便的特定模型）和高龄人士在限制步行时脚部放置的任务中对运动灵活性的影响。21个居住在社区的肥胖（OB）和25个正常体重（NW）的成年人（总共46个老年人-OA）和10个年轻的成年人（YA）在跑步机上（基线）正常行走，然后踩着投影的灯光提示行走在跑步机上的位置与正常步行（提示）期间平均脚部位置相对应。使用不受控制的歧管（UCM）分析将一组七个下肢节段角中的总方差划分为影响（“差”方差）和不（“良好”方差）影响步阶变化的分量。摆动脚的轨迹。电机的灵活性随着总方差的增加（从基线到提示）而实现，良好方差的增加超过了不良方差的变化。OB vs NW没有显着的组×步行任务交互作用，总的和良好的方差，但是OA vs YA有很强的交互作用（p <0.01； Cohen d> 1.0）。YA减少了好方差和坏方差，而OA增加了好方差，超出了坏方差的变化。在OA中，这些变化与移动性的几种功能度量相关。提示式步行可能对OA提出更高的要求，要求更大地依赖运动灵活性，尽管否则健康的老年肥胖成年人可能能够通过在此类任务下增加运动灵活性来弥补与肥胖相关的功能和认知下降。在新的或受限的任务中使用马达灵活性的程度可能是健康衰老的生物标志，也是（再）康复的目标。