Francis Karen L, Macrae Priscilla G, Spirduso Waneen W, Eakin Tim
Exercise and Sport Science Harney Science Center University of San Francisco, CA 94117, USA.
Curr Aging Sci. 2012 Feb;5(1):2-12.
The effects of age on control of fingertip forces, across five days of practice, were determined for an isometric precision pinch grip task. The task involved controlling a computer cursor so that it traveled upward and horizontally on a 45 degree template line by applying X-axis isometric force with contraction of the thumb, and Y-axis force with the index finger. Upon reaching a reverse circle target, the cursor was returned to the start by controlling the steady release of isometric force. Participants' control across the 6 segments of the template line (3 applying and 3 releasing force) was examined. Healthy participants comprised three age groups: Y20 (mean = 21 ± 4 years), O70 (mean = 70 ± 3 years) and O80 (mean = 79 ± 3 years). The results indicated that 1) overall the Y20 group was faster in completing the task than the O80 group, 2) age differences in task duration time (speed) increased over 4 days, 3) the Y20 and O70 groups, but not the O80 group, improved performance (increased accuracy and decreased within-participant variability for time and accuracy) with practice, 4) circle target proximity (segments 3 and 6) was a potent factor; all groups were slower, less accurate, and less consistent irrespective of force direction in the segments approaching a circle target goal (reverse/end). A task maneuver preceding a directional reversal of force modulation, from increasing to decreasing, was the most difficult element for the O80 group followed by the O70 and Y20 groups. These old adults improved tracing accuracy and consistency, but not performance speed with practice on this precision pinch force control task.
针对一项等长精确捏握任务，研究了年龄对指尖力量控制的影响，该研究为期五天。任务是通过拇指收缩施加X轴等长力以及食指施加Y轴力来控制计算机光标，使其在45度的模板线上向上和水平移动。到达反向圆形目标后，通过控制等长力的稳定释放将光标返回起点。研究人员检查了参与者在模板线6个部分（3个施力部分和3个释力部分）的控制情况。健康参与者分为三个年龄组：Y20组（平均年龄 = 21 ± 4岁）、O70组（平均年龄 = 70 ± 3岁）和O80组（平均年龄 = 79 ± 3岁）。结果表明：1）总体而言，Y20组完成任务的速度比O80组快；2）任务持续时间（速度）的年龄差异在4天内有所增加；3）Y20组和O70组在练习后表现有所改善（提高了准确性，降低了时间和准确性方面的参与者内部变异性），但O80组没有；4）圆形目标接近度（第3和第6部分）是一个重要因素；在接近圆形目标（反向/终点）的部分，无论力的方向如何，所有组的速度都较慢、准确性较低且一致性较差。对于O80组来说，在力调制方向从增加变为减少之前的任务操作是最困难的部分，其次是O70组和Y20组。通过练习这项精确捏力控制任务，这些老年人提高了追踪准确性和一致性，但没有提高执行速度。
