Neuromuscular and Rehabilitation Robotics Laboratory (NeuRRo Lab), Department of Physical Medicine and Rehabilitation, Michigan Medicine, University of Michigan, Ann Arbor, Michigan.
Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.
Sports Health. 2019 Jul/Aug;11(4):306-315. doi: 10.1177/1941738119835163. Epub 2019 Apr 5.
Persistent quadriceps weakness and activation failure are common in individuals with anterior cruciate ligament (ACL) reconstruction. A growing body of evidence indicates that this chronic quadriceps dysfunction could be partly mediated due to reduced corticospinal excitability. However, current rehabilitation approaches do not directly target corticospinal deficits, which may be critical for restoring optimal clinical outcomes after the surgery. This case study tested the feasibility of operant conditioning of torque responses evoked by transcranial magnetic stimulation (TMS) to improve quadriceps function after ACL reconstruction.
Operant conditioning of motor evoked torque responses would improve quadriceps strength, voluntary activation, and corticospinal excitability.
Case study and research report.
Level 5.
A 24-year-old male with an ACL reconstruction (6 months postsurgery) trained for 20 sessions (2-3 times per week for 8 weeks) to increase his TMS-induced motor evoked torque response (MEP torque) of the quadriceps muscles using operant conditioning principles. Knee extensor strength, voluntary quadriceps muscle activation, and quadriceps corticospinal excitability were evaluated at 3 time points: preintervention (pre), 4 weeks (mid), and immediately after the intervention (post).
The participant was able to successfully condition (ie, increase) the quadriceps MEP torque after 1 training session, and the conditioned MEP torque gradually increased over the course of 20 training sessions to reach about 500% of the initial value at the end of training. The participant's control MEP torque values and corticospinal excitability, which were measured outside of the conditioning paradigm, also increased with training. These changes were paralleled by improvements in knee extensor strength and voluntary quadriceps muscle activation.
This study shows that operant conditioning of MEP torque is a feasible approach to improving quadriceps corticospinal excitability and quadriceps function after ACL reconstruction and encourages further testing in a larger cohort of ACL-reconstructed individuals.
Operant conditioning may serve as a potential therapeutic adjuvant for ACL rehabilitation.
前交叉韧带（ACL）重建后，股四头肌无力和激活失败很常见。越来越多的证据表明，这种慢性股四头肌功能障碍可能部分是由于皮质脊髓兴奋性降低所致。然而，目前的康复方法并没有直接针对皮质脊髓缺陷，这对于术后恢复最佳临床效果可能至关重要。本病例研究测试了经颅磁刺激（TMS）诱发的扭矩反应操作性条件作用改善 ACL 重建后股四头肌功能的可行性。
操作性条件作用运动诱发电位扭矩反应将改善股四头肌力量、自愿激活和皮质脊髓兴奋性。
病例研究和研究报告。
5 级。
一名 24 岁男性，ACL 重建术后 6 个月，使用操作性条件作用原理，接受 20 次训练（8 周内每周 2-3 次），以增加 TMS 诱发的股四头肌运动诱发电位扭矩反应（MEP 扭矩）。在 3 个时间点评估膝关节伸肌力量、自愿股四头肌肌肉激活和股四头肌皮质脊髓兴奋性：干预前（pre）、4 周（mid）和干预后立即（post）。
参与者在 1 次训练后成功地进行了（即增加了）股四头肌 MEP 扭矩的条件作用，并且在 20 次训练过程中，条件 MEP 扭矩逐渐增加，在训练结束时达到初始值的约 500%。参与者的控制 MEP 扭矩值和皮质脊髓兴奋性，这些值是在条件作用范式之外测量的，也随着训练而增加。这些变化与膝关节伸肌力量和自愿股四头肌肌肉激活的改善相平行。
本研究表明，MEP 扭矩的操作性条件作用是改善 ACL 重建后股四头肌皮质脊髓兴奋性和功能的一种可行方法，并鼓励在更大的 ACL 重建人群中进一步测试。
操作性条件作用可能作为 ACL 康复的一种潜在治疗辅助手段。
