Steele Katherine M, Shuman Benjamin R, Schwartz Michael H
Mechanical Engineering, University of Washington, Seattle, WA, United States.
Mechanical Engineering, University of Washington, Seattle, WA, United States.
J Biomech. 2017 Jul 26;60:170-174. doi: 10.1016/j.jbiomech.2017.06.036. Epub 2017 Jul 5.
Children with cerebral palsy (CP) expend more energy to walk compared to typically-developing peers. One of the most prevalent gait patterns among children with CP, crouch gait, is often singled out as especially exhausting. The dynamics of crouch gait increase external flexion moments and the demand on extensor muscles. This elevated demand is thought to dramatically increase energy expenditure. However, the impact of crouch severity on energy expenditure has not been investigated among children with CP. We evaluated oxygen consumption and gait kinematics for 573 children with bilateral CP. The average net nondimensional oxygen consumption during gait of the children with CP (0.18±0.06) was 2.9 times that of speed-matched typically-developing peers. Crouch severity was only modestly related to oxygen consumption, with measures of knee flexion angle during gait explaining only 5-20% of the variability in oxygen consumption. While knee moment and muscle activity were moderately to strongly correlated with crouch severity (r=0.13-0.73), these variables were only weakly correlated with oxygen consumption (r=0.02-0.04). Thus, although the dynamics of crouch gait increased muscle demand, these effects did not directly result in elevated energy expenditure. In clinical gait analysis, assumptions about an individual's energy expenditure should not be based upon kinematics or kinetics alone. Identifying patient-specific factors that contribute to increased energy expenditure may provide new pathways to improve gait for children with CP.
与发育正常的同龄人相比，脑瘫（CP）儿童行走时消耗的能量更多。蹲伏步态是脑瘫儿童中最常见的步态模式之一，通常被认为特别耗费体力。蹲伏步态的动力学增加了外部屈曲力矩以及对伸肌的需求。这种增加的需求被认为会显著增加能量消耗。然而，尚未在脑瘫儿童中研究蹲伏严重程度对能量消耗的影响。我们评估了573名双侧脑瘫儿童的氧气消耗量和步态运动学。脑瘫儿童步态期间的平均净无量纲氧气消耗量（0.18±0.06）是速度匹配的发育正常同龄人消耗量的2.9倍。蹲伏严重程度与氧气消耗量仅存在适度关联，步态期间的膝关节屈曲角度测量仅解释了氧气消耗量变异性的5-20%。虽然膝关节力矩和肌肉活动与蹲伏严重程度呈中度至高度相关（r=0.13-0.73），但这些变量与氧气消耗量仅呈弱相关（r=0.02-0.04）。因此，尽管蹲伏步态的动力学增加了肌肉需求，但这些影响并未直接导致能量消耗增加。在临床步态分析中，关于个体能量消耗的假设不应仅基于运动学或动力学。识别导致能量消耗增加的患者特异性因素可能为改善脑瘫儿童的步态提供新途径。
