Background and Purpose. Previous studies suggest that individuals poststroke can achieve substantial gains in walking function following high-intensity locomotor training (LT). Recent findings also indicate practice of variable stepping tasks targeting locomotor deficits can mitigate selected impairments underlying reduced walking speeds. The goal of this study was to investigate alterations in locomotor biomechanics following 3 different LT paradigms. Methods. This secondary analysis of a randomized trial recruited individuals 18 to 85 years old and >6 months poststroke. We compared changes in spatiotemporal, joint kinematics, and kinetics following up to 30 sessions of high-intensity (>70% heart rate reserve [HRR]) LT of variable tasks targeting paretic limb and balance impairments (high-variable, HV), high-intensity LT focused only on forward walking (high-forward, HF), or low-intensity LT (<40% HRR) of variable tasks (low-variable, LV). Sagittal spatiotemporal and joint kinematics, and concentric joint powers were compared between groups. Regressions and principal component analyses were conducted to evaluate relative contributions or importance of biomechanical changes to between and within groups. Results. Biomechanical data were available on 50 participants who could walk ≥0.1 m/s on a motorized treadmill. Significant differences in spatiotemporal parameters, kinematic consistency, and kinetics were observed between HV and HF versus LV. Resultant principal component analyses were characterized by paretic powers and kinematic consistency following HV, while HF and LV were characterized by nonparetic powers. Conclusion. High-intensity LT results in greater changes in kinematics and kinetics as compared with lower-intensity interventions. The results may suggest greater paretic-limb contributions with high-intensity variable stepping training that targets specific biomechanical deficits. Clinical Trial Registration. https://clinicaltrials.gov/ Unique Identifier: NCT02507466

中文翻译：

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中风后可变环境下高强度步进训练后的运动运动学和动力学

背景和目的。先前的研究表明，中风后个体在接受高强度运动训练 (LT) 后可以显着提高步行功能。最近的研究结果还表明，针对运动缺陷的可变步进任务的实践可以减轻步行速度降低的选定障碍。本研究的目的是调查遵循 3 种不同 LT 范式的运动生物力学变化。方法。这项随机试验的二次分析招募了 18 至 85 岁且卒中后 6 个月以上的个体。我们比较了针对瘫痪肢体和平衡障碍（高变量，HV）的可变任务长达 30 次高强度（> 70% 心率储备 [HRR]）LT 后时空、关节运动学和动力学的变化，高强度 LT 仅侧重于向前行走（high-forward，HF），或低强度 LT（<40% HRR）的可变任务（low-variable，LV）。比较组间矢状面时空和关节运动学以及同心关节力量。进行回归和主成分分析以评估生物力学变化对组间和组内的相对贡献或重要性。结果。50 名参与者的生物力学数据可以在电动跑步机上以≥0.1 m/s 的速度行走。在 HV 和 HF 与 LV 之间观察到时空参数、运动学一致性和动力学的显着差异。所得主成分分析的特征在于 HV 后的麻痹能力和运动一致性，而 HF 和 LV 的特征在于非麻痹能力。结论。与低强度干预相比，高强度 LT 会导致运动学和动力学发生更大的变化。结果可能表明，针对特定生物力学缺陷的高强度可变步进训练对瘫痪肢体的贡献更大。临床试验注册。https://clinicaltrials.gov/ 唯一标识符：NCT02507466