EA4660-C3S Laboratory, Culture, Sport, Health and Society, University of Bourgogne Franche-Comté, Besançon, FRANCE.
CAPS, U1093 INSERM, Université de Bourgogne Franche-Comté, Facultés des Sciences du Sport, F-21078 Dijon, FRANCE.
Med Sci Sports Exerc. 2020 May;52(5):1031-1040. doi: 10.1249/MSS.0000000000002218.
It is not known yet whether the neurophysiological specificity of eccentric, concentric, and isometric contractions can also be observed when these are mentally simulated. Therefore, our aim was to assess corticospinal excitability during motor imagery (MI) of different contraction types and to test whether a passive movement during MI could have additional effects.
Twelve young participants imagined contractions of the wrist flexors, firstly with the arm motionless (static mode) and second, with a congruent passive movement (wrist extension during eccentric MI and wrist flexion during concentric MI). Motor-evoked potentials (MEP) and H-reflexes were elicited in flexor carpi radialis (FCR) at rest and during the three types of MI. As a secondary outcome, the MEP of one antagonist (extensor carpi radialis), elicited concomitantly with FCR MEP recording, were also analyzed.
In static mode, FCR MEP were facilitated during isometric (P = 0.046) and concentric (P = 0.039) MI, but not during eccentric MI (P = 0.902). With passive congruent movements, FCR MEP were enhanced during all imagined contraction types, including eccentric (P = 0.047). FCR H-reflexes increased only during eccentric MI accompanied with wrist extension (P = 0.003). Extensor carpi radialis MEP were modulated only when a passive congruent movement was provided (P = 0.040).
Like actual contractions, eccentric MI exhibits specific neural correlates, compared with isometric and concentric MI, which should be considered when using this modality for training. The present results showed that adding passive movements congruent to the eccentric MI task would enhance its impact over corticospinal structures.
目前尚不清楚在心理模拟这些运动时，离心、向心和等长收缩的神经生理学特异性是否也可以观察到。因此，我们的目的是评估不同收缩类型的运动想象（MI）期间皮质脊髓兴奋性，并测试 MI 期间的被动运动是否会产生额外的影响。
12 名年轻参与者首先在手臂静止（静态模式）的情况下想象腕屈肌的收缩，其次在与被动运动一致的情况下（离心 MI 时腕伸展，向心 MI 时腕屈曲）想象收缩。在桡侧腕屈肌（FCR）休息和三种 MI 期间引出运动诱发电位（MEP）和 H 反射。作为次要结果，还分析了同时记录 FCR MEP 时拮抗肌（桡侧腕伸肌）的 MEP。
在静态模式下，FCR MEP 在等长（P = 0.046）和向心（P = 0.039）MI 期间被促进，但在离心 MI 期间未被促进（P = 0.902）。在进行被动运动时，FCR MEP 在所有想象的收缩类型中均增强，包括离心（P = 0.047）。仅在伴有腕伸展的离心 MI 时，FCR H 反射增加（P = 0.003）。仅在提供被动运动时，桡侧腕伸肌 MEP 才会发生调制（P = 0.040）。
与等长和向心 MI 相比，离心 MI 表现出特定的神经相关性，这在使用这种方式进行训练时应加以考虑。本研究结果表明，在离心 MI 任务中添加与被动运动一致的运动将增强其对皮质脊髓结构的影响。
