Dixon Philippe C, Stebbins Julie, Theologis Tim, Zavatsky Amy B
Department of Engineering Science, University of Oxford, Oxford, UK.
Nuffield Orthopaedic Centre, Oxford University Hospitals NHS Trust, Oxford, UK.
J Biomech. 2014 Nov 28;47(15):3726-33. doi: 10.1016/j.jbiomech.2014.09.011. Epub 2014 Oct 11.
Turning is a common locomotor task essential to daily activity; however, very little is known about the forces and moments responsible for the kinematic adaptations occurring relative to straight-line gait in typically developing children. Thus, the aims of this study were to analyse ground reaction forces (GRFs), ground reaction free vertical torque (TZ), and the lower-limb joint kinetics of 90° outside (step) and inside (spin) limb turns. Step, spin, and straight walking trials from fifty-four typically developing children were analysed. All children were fit with the Plug-in Gait and Oxford Foot Model marker sets while walking over force plates embedded in the walkway. Net internal joint moments and power were computed via a standard inverse dynamics approach. All dependent variables were statistically analysed over the entire curves using the mean difference 95% bootstrap confidence band approach. GRFs were directed medially for step turns and laterally for spin turns during the turning phase. Directions were reversed and magnitudes decreased during the approach phase. Step turns showed reduced ankle power generation, while spin turns showed large TZ. Both strategies required large knee and hip coronal and transverse plane moments during swing. These kinetic differences highlight adaptations required to maintain stability and reorient the body towards the new walking direction during turning. From a clinical perspective, turning gait may better reveal weaknesses and motor control deficits than straight walking in pathological populations, such as children with cerebral palsy, and could potentially be implemented in standard gait analysis sessions.
转身是日常活动中一项常见的运动任务；然而，对于在正常发育儿童中相对于直线步态发生的运动学适应所涉及的力和力矩，我们了解甚少。因此，本研究的目的是分析90°外侧（步转）和内侧（旋转变）肢体转身时的地面反作用力（GRF）、地面反作用自由垂直扭矩（TZ）以及下肢关节动力学。对54名正常发育儿童的步转、旋转变和直线行走试验进行了分析。所有儿童在走过嵌入人行道的测力板时，都佩戴了插件式步态和牛津足部模型标记集。通过标准的逆动力学方法计算净内部关节力矩和功率。使用平均差异95%自助置信带方法对整个曲线的所有因变量进行统计分析。在转身阶段，步转的GRF向内，旋转变的GRF向外。在接近阶段，方向相反且大小减小。步转显示踝关节产生的功率降低，而旋转变显示出较大的TZ。两种策略在摆动过程中都需要较大的膝关节和髋关节冠状面及横断面力矩。这些动力学差异突出了在转身过程中保持稳定性并使身体重新定向到新行走方向所需的适应性。从临床角度来看，在诸如脑瘫儿童等病理人群中，转身步态可能比直线行走更能揭示弱点和运动控制缺陷，并且有可能应用于标准步态分析环节。
