Wu Jianhua, Beerse Matthew, Ajisafe Toyin, Liang Huaqing
J. Wu, PhD, Department of Kinesiology and Health, Georgia State University, 125 Decatur St, Atlanta, GA 30302 (USA).
M. Beerse, MS, Department of Kinesiology and Health, Georgia State University.
Phys Ther. 2015 May;95(5):740-9. doi: 10.2522/ptj.20140210. Epub 2014 Dec 18.
A force-driven harmonic oscillator (FDHO) model reveals the elastic property of general muscular activity during walking.
This study aimed to investigate whether children with Down syndrome (DS) have a lower K/G ratio, a primary variable derived from the FDHO model, compared with children with typical development during overground and treadmill walking and whether children with DS can adapt the K/G ratio to walking speeds, external ankle load, and a treadmill setting.
A cross-sectional study design was used that included 26 children with and without DS, aged 7 to 10 years, for overground walking and 20 of them for treadmill walking in a laboratory setting.
During overground walking, participants walked at 2 speeds: normal and fastest speed. During treadmill walking, participants walked at 75% and 100% of their preferred overground speed. Two load conditions were manipulated for both overground and treadmill walking: no load and an ankle load that was equal to 2% of body mass on each side.
Children with DS showed a K/G ratio similar to that of their healthy peers and increased this ratio with walking speed regardless of ankle load during overground walking. Children with DS produced a lower K/G ratio at the fast speed of treadmill walking without ankle load, but ankle load helped them produce a K/G ratio similar to that of their healthy peers.
The FDHO model cannot specify what muscles are used or how muscles are coordinated for a given motor task.
Children with DS show elastic property of general muscular activity similar to their healthy peers during overground walking. External ankle load helps children with DS increase general muscular activity and match their healthy peers while walking fast on a treadmill.
力驱动谐波振荡器（FDHO）模型揭示了步行过程中一般肌肉活动的弹性特性。
本研究旨在调查与发育正常的儿童相比，唐氏综合征（DS）患儿在地面行走和跑步机行走时，是否具有较低的K/G比值（FDHO模型的一个主要变量），以及DS患儿是否能够根据步行速度、外踝负荷和跑步机设置来调整K/G比值。
采用横断面研究设计，纳入26名7至10岁有或无DS的儿童进行地面行走研究，其中20名儿童在实验室环境中进行跑步机行走研究。
在地面行走过程中，参与者以两种速度行走：正常速度和最快速度。在跑步机行走过程中，参与者以其偏好的地面速度的75%和100%行走。对地面行走和跑步机行走均设置两种负荷条件：无负荷和两侧各等于体重2%的踝部负荷。
DS患儿在地面行走时的K/G比值与健康同龄人相似，且无论踝部负荷如何，该比值均随步行速度增加。在无踝部负荷的跑步机快速行走时，DS患儿的K/G比值较低，但踝部负荷有助于他们产生与健康同龄人相似的K/G比值。
FDHO模型无法确定在给定的运动任务中使用了哪些肌肉或肌肉是如何协调的。
DS患儿在地面行走时表现出与健康同龄人相似的一般肌肉活动弹性特性。外踝负荷有助于DS患儿在跑步机上快速行走时增加一般肌肉活动并与健康同龄人相匹配。
