Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, IL, USA.
Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
Top Stroke Rehabil. 2023 Mar;30(2):137-145. doi: 10.1080/10749357.2021.2008596. Epub 2022 Jan 4.
Stroke often leads to chronic motor impairments in the paretic lower limb that can constrain lower extremity movement and negatively impact the ability to navigate stairs or curbs. This cross-sectional study investigated the differences in hip and knee biomechanical strategies during a step-up task between five adults with hemiparetic stroke and five age-matched adults without stroke.
Participants were instructed to step up onto a 10.2 cm platform, where joint biomechanics were quantified for the hip in the frontal plane and the hip and knee in the sagittal plane. Peak joint kinematics were identified during the leading limb swing phase, and peak joint moments and power were identified during the leading limb pull-up phase of stance. Mixed effects regression models estimated fixed effects of limb (three levels: control dominant, stroke non-paretic, and stroke paretic) on biomechanical outcomes, while a random effect of participant controlled for within-participant correlations.
Repeated assessments within participants (approximately 60 trials per lower limb) increased the effective sample size to between 12.0 and 19.6. Altered biomechanical strategies of the paretic lower limb included reduced flexion angles and increased pelvic obliquity angles during swing, decreased power generation in the hip frontal plane during stance, and decreased moment and power generation in the knee sagittal plane during stance. A strategy of substantial interest was the elevated hip sagittal plane moment and power generation in both stroke limbs.
Our findings suggest that chronic motor impairments following stroke can lead to inefficient biomechanical strategies when stepping up.
中风常导致瘫痪下肢的慢性运动障碍，从而限制下肢运动，并对上下楼梯或跨越路缘的能力产生负面影响。本横断面研究调查了 5 名偏瘫中风患者和 5 名年龄匹配的无中风患者在台阶上升任务中髋关节和膝关节生物力学策略的差异。
要求参与者迈上 10.2 厘米高的平台，在额状面测量髋关节，在矢状面测量髋关节和膝关节的关节生物力学。在主导侧摆动阶段确定关节运动学的峰值，在主导侧支撑阶段的拉起阶段确定关节力矩和功率的峰值。混合效应回归模型估计了肢体（三个水平：对照优势侧、中风非瘫痪侧和中风瘫痪侧）对生物力学结果的固定效应，而参与者的随机效应则控制了参与者内的相关性。
参与者的重复评估（每条下肢约 60 次试验）将有效样本量增加到 12.0 到 19.6 之间。瘫痪下肢的生物力学策略改变包括摆动时的屈曲角度减小和骨盆倾斜角度增加、支撑阶段髋关节额状面的功率生成减少以及支撑阶段膝关节矢状面的力矩和功率生成减少。一个特别有趣的策略是两个中风侧髋关节矢状面力矩和功率生成增加。
我们的研究结果表明，中风后慢性运动障碍可导致台阶上升时的生物力学策略效率低下。
