Post-stroke motor recovery processes remain unknown. Timescales and patterns of upper-limb (UL) recovery suggest a major impact of biological factors, with modest contributions from rehabilitation. We assessed a novel impairment-based training motivated by motor control theory where reaching occurs within the spasticity-free elbow range. Patients with subacute stroke (≤ 6 month; n = 46) and elbow flexor spasticity were randomly allocated to a 10-day UL training protocol, either personalized by restricting reaching to the spasticity-free elbow range defined by the tonic stretch reflex threshold (TSRT) or non-personalized (non-restricted) and with/without anodal transcranial direct current stimulation. Outcomes assessed before, after, and 1 month post-intervention were elbow flexor TSRT angle and reach-to-grasp arm kinematics (primary) and stretch reflex velocity sensitivity, clinical impairment, and activity (secondary). Results were analyzed for 3 groups as well as those of the effects of impairment-based training. Clinical measures improved in both groups. Spasticity-free range training resulted in faster and smoother reaches, smaller (i.e., better) arm-plane path length, and closer-to-normal shoulder/elbow movement patterns. Non-personalized training improved clinical scores without improving arm kinematics, suggesting that clinical measures do not account for movement quality. Impairment-based training within a spasticity-free elbow range is promising since it may improve clinical scores together with arm movement quality.

Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique Identifier: NCT02725853; Initial registration date: 01/04/2016.

中风后运动恢复过程仍然未知。上肢（UL）恢复的时间尺度和模式表明生物因素的主要影响，康复的贡献不大。我们评估了一种由运动控制理论推动的新颖的基于损伤的训练，其中到达发生在无痉挛的肘部范围内。患有亚急性中风（≤ 6 个月；n = 46）且肘部屈肌痉挛的患者被随机分配接受为期 10 天的 UL 训练方案，或者通过限制达到由强直牵张反射阈值 (TSRT) 定义的无痉挛肘部范围来进行个性化训练）或非个性化（非限制）和有/无阳极经颅直流电刺激。干预前、干预后和干预后 1 个月评估的结果是肘屈肌 TSRT 角度和抓握手臂运动学（主要）以及牵张反射速度敏感性、临床损伤和活动（次要）。对 3 组的结果以及基于损伤的训练的效果进行了分析。两组的临床指标均有所改善。无痉挛范围训练导致更快、更平滑的伸展、更短（即更好）的手臂平面路径长度以及更接近正常的肩部/肘部运动模式。非个性化训练提高了临床分数，但没有改善手臂运动学，这表明临床测量并不能考虑运动质量。在无痉挛的肘部范围内进行基于损伤的训练是有希望的，因为它可以提高临床评分和手臂运动质量。

临床试验注册： URL：http://www.clinicaltrials.gov。唯一标识符：NCT02725853；初始注册日期：2016 年 1 月 4 日。