Department of Psychology, Durham University, South Road, Durham, DH1 3LE, UK.
Department of Psychology, Uppsala University, Box 1225, 75121, Uppsala, Sweden.
Exp Brain Res. 2019 Nov;237(11):2875-2883. doi: 10.1007/s00221-019-05629-5. Epub 2019 Aug 30.
Adults use vision during stepping and walking to fine-tune foot placement. However, the developmental profile of visually guided stepping is unclear. We asked (1) whether children use online vision to fine-tune precise steps and (2) whether precision stepping develops as part of broader visuomotor development, alongside other fundamental motor skills like reaching. With 6-(N = 11), 7-(N = 11), 8-(N = 11)-year-olds and adults (N = 15), we manipulated visual input during steps and reaches. Using motion capture, we measured step and reach error, and postural stability. We expected (1) both steps and reaches would be visually guided (2) with similar developmental profiles (3) foot placement biases that promote stability, and (4) correlations between postural stability and step error. Children used vision to fine-tune both steps and reaches. At all ages, foot placement was biased (albeit not in the predicted directions). Contrary to our predictions, step error was not correlated with postural stability. By 8 years, children's step and reach error were adult-like. Despite similar visual control mechanisms, stepping and reaching had different developmental profiles: step error reduced with age whilst reach error was lower and stable with age. We argue that the development of both visually guided and non-visually guided action is limb-specific.
成年人在行走和迈步时会利用视觉来微调脚步位置。然而，视觉引导的迈步发展情况尚不清楚。我们提出了以下两个问题：（1）儿童是否会利用在线视觉来微调精确的步伐；（2）精确的迈步发展是否是与其他基本运动技能（如伸手）一起作为更广泛的运动视觉发展的一部分。我们对 6 岁（N=11）、7 岁（N=11）、8 岁（N=11）儿童和成年人（N=15）进行了实验，在迈步和伸手时对视觉输入进行了操作。我们使用运动捕捉技术测量了步伐和伸手的误差以及姿势稳定性。我们预计（1）步伐和伸手都会受到视觉引导；（2）具有相似的发展轨迹；（3）存在促进稳定性的脚步位置偏差；（4）姿势稳定性和步伐误差之间存在相关性。儿童会利用视觉来微调步伐和伸手。在所有年龄段，脚步位置都存在偏差（尽管方向与预期不符）。与我们的预测相反，步伐误差与姿势稳定性之间没有相关性。到 8 岁时，儿童的步伐和伸手误差与成年人相似。尽管存在类似的视觉控制机制，但迈步和伸手的发展轨迹却不同：随着年龄的增长，步伐误差会降低，而伸手误差则会随着年龄的增长而降低且保持稳定。我们认为，无论是视觉引导还是非视觉引导的动作，其发展都是特定于肢体的。
