Department of Kinesiology, San Francisco State University, San Francisco, CA 94132, USA.
Universidade Federal do ABC, Santo Andre, SP, 09210580, Brazil.
Hum Mov Sci. 2021 Jun;77:102788. doi: 10.1016/j.humov.2021.102788. Epub 2021 Mar 30.
While a number of studies have focused on movement (a)symmetries between the arms in adults, less is known about movement asymmetries in typically developing children. The goal of this study was to examine interlimb differences in children when adapting to novel visuomotor and dynamic conditions while performing a center-out reaching task. We tested 13 right-handed children aged 9-11 years old. Prior to movement, one of eight targets arranged radially around the start position was randomly displayed. Movements were made either with the right (dominant) arm or the left (nondominant) arm. The children participated in two experiments separated by at least one week. In one experiment, subjects were exposed to a rotated visual display (30° about the start circle); and in the other, a 1 kg mass (attached eccentrically to the forearm axis). Each experiment consisted of three blocks: pre-exposure, exposure and post-exposure. Three measures of task performance were calculated from hand trajectory data: hand-path deviation from the straight target line, direction error at peak velocity and final position error. Results showed that during visuomotor adaptation, no interlimb differences were observed for any of the three measures. During dynamic adaptation, however, a significant difference between the arms was observed at the first cycle during dynamic adaptation. With regard to the aftereffects observed during the post-exposure block, direction error data indicate considerably large aftereffects for both arms during visuomotor adaptation; and there was a significant difference between the arms, resulting in substantially larger aftereffects for the right arm. Similarly, dynamic adaptation results also showed a significant difference between the arms; and post hoc analyses indicated that aftereffects were present only for the right arm. Collectively, these findings indicate that the dominant arm advantage for developing an internal model associated with a novel visuomotor or dynamic transform, as previously shown in young adults, may already be apparent at 9 to 11-year old children.
虽然许多研究都集中在成年人手臂运动的（运动）对称性上，但对于正常发育儿童的运动不对称性知之甚少。本研究的目的是在执行中心向外伸手任务时，检查儿童在适应新的视觉运动和动态条件时的肢体间差异。我们测试了 13 名 9-11 岁的右利手儿童。在运动之前，随机显示围绕起始位置排列的八个目标中的一个。运动可以用右手（优势手）或左手（非优势手）进行。孩子们在至少一周的时间内参加了两个实验。在一个实验中，受试者暴露于旋转的视觉显示（起始圆周围 30°）；在另一个实验中，将 1 公斤的质量（偏心地附加到前臂轴上）。每个实验都由三个块组成：预暴露、暴露和暴露后。从手轨迹数据中计算了三个任务性能指标：手路径相对于直线目标线的偏差、峰值速度时的方向误差和最终位置误差。结果表明，在视觉运动适应过程中，三个指标均未观察到手部之间的差异。然而，在动态适应过程中，在动态适应的第一个周期中，手臂之间观察到显著差异。关于暴露后块中观察到的后效，方向误差数据表明，在视觉运动适应过程中，两个手臂的后效都非常大；手臂之间存在显著差异，导致右臂的后效显著增大。同样，动态适应结果也显示手臂之间存在显著差异；事后分析表明，只有右臂存在后效。总之，这些发现表明，与年轻成年人之前显示的情况一样，与新的视觉运动或动态变换相关的内部模型的发展中，优势手臂的优势可能已经在 9 至 11 岁的儿童中显现出来。
