Dept. of Kinesiology & Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada.
Dept. of Kinesiology & Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada.
Gait Posture. 2019 Jul;72:16-21. doi: 10.1016/j.gaitpost.2019.05.016. Epub 2019 May 22.
Collision avoidance between two walkers involves a mutual adaptation to speed and orientation in order to successfully avoid a collision. Minimum Predicted Distance (MPD) is the distance at which two walkers would collide if their speed and path trajectory were maintained at first sight of one another. MPD has been used to describe the risk of collision and its evolution over time between two adult walkers when on a collision course. Middle-aged children have been shown to have poor perception-action coupling during static and dynamic collision avoidance tasks. Research has yet to examine whether perception-action coupling deficits persist in a dynamic collision avoidance task involving a child and another walker.
Can the metric MPD(t) be used to examine collision avoidance strategies between children and adults?
Eighteen children (age: 10 ± 1.5 years) and eighteen adults (34 ± 9.6 years) walked along a 12.6 m pathway while avoiding another participant (child or adult). Groups of three children and three adults were recruited per session. Trials were randomized equally such that each adult interacted with another adult 20 times, each child interacted with another child 20 times, and each adult interacted with a child 21 times, for a total of 141 trials. 3D kinematic data of each participant's head was recorded using the Vicon system.
The results demonstrated: (1) MPD(t) can be used to predict future collisions in children, (2) MPD(t) is an absolute measure that is consistently lower when a child is involved compared to two adult walkers, (3) the individual passing second, even when it is a child, contributes more to MPD(t) than the walker passing first.
It appears children have developed adult-like strategies during a collision avoidance task involving two walkers. Body anthropometrics should be considered when determining collision avoidance strategies between children and adults.
两名行人之间的避碰需要相互适应速度和方向，以便成功避免碰撞。最小预测距离（MPD）是指如果两个行人在第一次看到彼此时保持速度和路径轨迹，他们将碰撞的距离。MPD 已被用于描述两个成年行人在碰撞过程中碰撞的风险及其随时间的演变。研究表明，中年儿童在静态和动态避碰任务中感知-动作耦合能力较差。目前还没有研究检验在涉及儿童和另一名行人的动态避碰任务中，感知-动作耦合缺陷是否仍然存在。
MPD(t) 能否用于检验儿童和成人之间的避碰策略？
18 名儿童（年龄：10 ± 1.5 岁）和 18 名成人（34 ± 9.6 岁）在 12.6 米的路径上行走，同时避开另一名参与者（儿童或成人）。每次试验中招募 3 名儿童和 3 名成人。试验随机平均分配，每个成人与另一个成人交互 20 次，每个儿童与另一个儿童交互 20 次，每个成人与一个儿童交互 21 次，共 141 次试验。每个参与者头部的 3D 运动学数据使用 Vicon 系统记录。
结果表明：（1）MPD(t) 可用于预测儿童未来的碰撞；（2）MPD(t) 是一个绝对的度量，当涉及到儿童时，它始终比两个成人行人的 MPD(t) 低；（3）第二个通过的人，即使是儿童，对 MPD(t) 的贡献也大于第一个通过的行人。
在涉及两名行人的避碰任务中，儿童似乎已经发展出成人般的策略。在确定儿童和成人之间的避碰策略时，应考虑身体人类学因素。
