Altered Movement Structure in the Elderly

描述(申请人提供)：老年人的运动迟缓和变异性增加与运动微结构的变化有关。在瞄准、到达和指向运动中，这些变化表现为目标附近主次移动的缩短和次次移动的出现。以前的研究认为二次潜水运动是靶点精度要求的结果。然而，除了以所需的精度命中目标外，离散瞄准运动还包括至少两个先前研究忽视的其他子任务：终止手在目标上的运动，以及在到达的传输阶段协调关节运动。这项建议的目的是调查这三个因素如何分担老年人初级次级运动缩短的责任。我们将调查三个因素中的每一个对与缩短的初级亚运动相关的瞄准运动的年龄相关缺陷的影响：肌肉活动模式改变，对视觉的更高依赖，以及无法通过练习改善运动微结构。前两个因素(目标精度和目标处运动终止)的影响将通过目标大小、运动类型(要求在目标处终止运动的离散目标和不具有此要求的连续目标)和目标类型(有助于被动终止运动的实心目标和需要主动终止运动的灵活目标)的操纵来区分。第三个因素(联合协调)将通过具有联合协调模式复杂性的操作与前两个因素进行对比。建议的实验将有助于我们加深对与年龄相关的成绩下降的因素的了解。他们还将有助于了解运动组织的基本原理，因为这三个因素对青少年瞄准动作的影响也没有被研究过。

DESCRIPTION (provided by applicant): Movement slowness and increased variability in the elderly is related to changes in movement microstructure. During aiming, reaching, and pointing movements, these changes are represented by shortened primary sub movement and emergence of secondary sub movements near the target. Previous research has considered secondary sub movements a result of accuracy requirement at the target. However, in addition to hitting the target with the required accuracy, discrete aiming movements include at least two other subtasks that have been overlooked by previous research: termination of hand motion at the target, and coordination of joint movements during the transport phase of reaching. The purpose of this proposal is to investigate how these three factors share the responsibility for shortened primary sub movements in elderly adults. We will investigate the influence of each of the three factors on age-related deficits in aiming movements associated with the shortened primary sub movements: altered muscle activity pattern, elevated reliance on vision, and inability to improve movement microstructure with practice. The influence of the first two factors (the target accuracy and the termination of motion at the target) will be distinguished through manipulations with target size, movement type (discrete that require termination of motion at the target and continuous that do not have this requirement) and target type (a solid target that helps to terminate motion passively and a flexible target that requires active termination of motion). The third factor (joint coordination) will be contrasted to the first two through manipulations with complexity of joint coordination pattern. The proposed experiments will be beneficial for developing our knowledge of the factors responsible for age related declination of performance. They will also contribute in the knowledge of fundamental principles of movement organization, since influence of the three factors on aiming movements of young adults has not been studied as well.