Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin.
Department of Orthopaedic Surgery, Stanford University, Stanford, California.
J Neurotrauma. 2019 Sep 15;36(18):2688-2697. doi: 10.1089/neu.2018.5719. Epub 2019 Mar 28.
The aim of this study was to understand how high- and low-intensity locomotor training (LT) affects sympathetic-somatomotor (SS) coupling in people with incomplete spinal cord injury (SCI). Proper coupling between sympathetic and somatomotor systems allows controlled regulation of cardiovascular responses to exercise. In people with SCI, altered connectivity between descending pathways and spinal segments impairs sympathetic and somatomotor coordination, which may have deleterious effects during exercise and limit rehabilitation outcomes. We postulated that high-intensity LT, which repeatedly engages SS systems, would alter SS coupling. Thirteen individuals (50 ± 7.2 years) with motor incomplete spinal cord injuries (American Spinal Injury Association Impairment Scale C or D; injury level >T6) participated in a locomotor treadmill training program. Patients were randomized into either a high-intensity (high-LT; 70-85% of maximum predicted heart rate; = 6) group or a low-intensity (low-LT; 50-65% of maximum predicted heart rate; = 7) group and completed up to 20 LT training sessions over 4-6 weeks, 3-5 days/week. Before and after taining, we tested SS coupling by eliciting reflexive sympathetic activity through a cold stimulation, noxious stimulation, and a mental math task while we measured tendon reflexes, blood pressure, and heart rate. Participants who completed high- versus low-LT exhibited significant decreases in reflex torques during triggered sympathetic activity (cold: -83 vs. 13%, < 0.01; pain: -65 vs. 54%, < 0.05; mental math: -43 vs. 41%; < 0.05). Mean arterial pressure responses to sympathetic stimuli were slightly higher following high- versus low-LT (cold: 30 vs. -1.5%; pain: 6 vs. -12%; mental math: 5 vs. 7%), although differences were not statistically significant. These results suggest that high-LT may be advantageous to low-LT to improve SS coupling in people with incomplete SCI.
本研究旨在探讨高强度和低强度运动训练（LT）如何影响不完全性脊髓损伤（SCI）患者的交感-躯体运动（SS）耦合。交感和躯体运动系统之间的适当耦合允许对运动时的心血管反应进行受控调节。在 SCI 患者中，下行通路与脊髓节段之间的连接改变会损害交感和躯体运动的协调性，这可能在运动过程中产生有害影响，并限制康复效果。我们推测，高强度 LT 反复作用于 SS 系统，会改变 SS 耦合。13 名运动不完全性脊髓损伤患者（美国脊髓损伤协会损伤分级 C 或 D；损伤水平>T6）参加了跑步机运动训练计划。患者被随机分为高强度（高 LT；70-85%最大预测心率；n=6）组或低强度（低 LT；50-65%最大预测心率；n=7）组，并在 4-6 周内完成多达 20 次 LT 训练，每周 3-5 天。在训练前后，我们通过冷刺激、疼痛刺激和心算任务诱发反射性交感神经活动来测试 SS 耦合，同时测量腱反射、血压和心率。完成高 LT 训练的参与者在触发交感神经活动时的反射扭矩显著降低（冷刺激：-83%比 13%，<0.01；疼痛刺激：-65%比 54%，<0.05；心算任务：-43%比 41%，<0.05）。与低 LT 相比，高 LT 后对交感神经刺激的平均动脉压反应略高（冷刺激：30%比-1.5%；疼痛刺激：6%比-12%；心算任务：5%比 7%），尽管差异无统计学意义。这些结果表明，与低 LT 相比，高 LT 可能更有利于改善不完全性 SCI 患者的 SS 耦合。
