Department of Physical Therapy, Georgia State University, Atlanta, GA, 30302, USA.
Department of Exercise Science, Lebanon Valley College, Annville, PA, 17003, USA.
Gait Posture. 2021 Feb;84:169-174. doi: 10.1016/j.gaitpost.2020.11.028. Epub 2020 Dec 8.
Backward walking and fast walking have distinctive gait patterns in adults; however, there is minimal literature describing these gait modifications in typically developing children. Additionally, most of previous research focused on overground backward walking, but not on a treadmill.
How do typically developing children adapt their gait patterns, including spatiotemporal parameters, joint kinematics, and muscle activation, to changes in direction and speed during treadmill walking?
We recruited 19 children (10 M/9 F) aged 6-12 years. Treadmill conditions included forward and backward walking at three speeds: slow (75 % of normal speed), normal speed, and fast (125 % of normal speed). Subjects completed a 2-minute trial under each condition. Spatiotemporal, kinematic, kinetic and electromyography data were collected and analyzed. Correlations between forward and time-reversed backward walking were calculated for joint angles and vertical ground reaction force.
During backward walking, children (a) decreased step lengths and increased step widths and foot clearance, (b) decreased peak hip and knee flexion and increased peak ankle dorsiflexion, and (c) increased muscle activity at the vastus lateralis, rectus femoris, and tibialis anterior. At faster speeds, children increased step lengths and inconsistently increased overall muscle activity. Both the hip and knee showed high correlation between forward and time-reversed backward walking, while correlation at the ankle was low.
Overall, children adapt their gait to changes in direction and speed of treadmill walking in similar ways to adults. However, notable differences emerged in that children limited their ankle range of motion. Our results suggest that, while many aspects of gait are mature enough by this age to adapt to backward walking on a treadmill, neuromuscular control at the ankle may still be lacking in children while walking backward on a treadmill.
成年人倒走和快走具有独特的步态模式；然而，关于正常发育儿童的这些步态改变，文献记载甚少。此外，之前的大多数研究都集中在地面倒走，但不在跑步机上。
正常发育的儿童如何在跑步机上改变行走方向和速度时，调整其步态模式，包括时空参数、关节运动学和肌肉激活？
我们招募了 19 名 6-12 岁的儿童（10 名男性/9 名女性）。跑步机条件包括三种速度的正向和倒向行走：慢（正常速度的 75%）、正常速度和快（正常速度的 125%）。每个条件下，受试者完成 2 分钟的试验。收集和分析时空、运动学、动力学和肌电图数据。计算关节角度和垂直地面反作用力的正向和时间反转的反向行走之间的相关性。
在倒走时，儿童（a）减少步长，增加步宽和足离地间隙，（b）降低髋关节和膝关节的峰值屈曲度，增加踝关节的峰值背屈度，（c）增加股外侧肌、股直肌和胫骨前肌的肌肉活动。在更快的速度下，儿童增加了步长，并不一致地增加了整体肌肉活动。髋关节和膝关节在正向和时间反转的反向行走之间具有高度相关性，而踝关节的相关性较低。
总的来说，儿童以与成年人相似的方式适应跑步机行走方向和速度的变化。然而，有一些显著的差异，即儿童限制了他们的踝关节活动范围。我们的研究结果表明，虽然许多方面的步态在这个年龄段已经足够成熟，可以适应在跑步机上倒走，但在儿童在跑步机上倒走时，他们的踝关节的神经肌肉控制可能仍不够完善。
