Rozand Vianney, Lebon Florent, Papaxanthis Charalambos, Lepers Romuald
INSERM U1093, Faculty of Sport Sciences, University of Burgundy, Dijon, FRANCE.
Med Sci Sports Exerc. 2014 Oct;46(10):1981-9. doi: 10.1249/MSS.0000000000000327.
Mental training, as physical training, enhances muscle strength. Whereas the repetition of maximal voluntary contractions (MVC) induces neuromuscular fatigue, the effect of maximal imagined contractions (MIC) on neuromuscular fatigue remains unknown. Here, we investigated neuromuscular alterations after a mental training session including MIC, a physical training session including MVC, and a combined training session including both MIC and MVC of the elbow flexor muscles.
Ten participants performed 80 MIC (duty cycle, 5-s MIC and 10-s rest), 80 MVC (identical duty cycle), or 80 MVC and 80 MIC (5-s MVC, 2-s rest, 5-s MIC, and 3-s rest) in three separate sessions. MVC torque was assessed five times over the course of the training and 10 min after the end of the training in the three protocols. Central activation ratio (CARc), reflecting central fatigue, and corticospinal excitability, at rest and during MIC, were estimated using transcranial magnetic stimulation.
Both the physical training and the combined training induced an approximately 40% drop of MVC torque, accompanied with an approximately 10% decrease of CARc without significant difference between the two sessions. On the contrary, the repetition of MIC did not reduce maximal force production capacity and did not alter CARc. Corticospinal excitability was always facilitated during MIC compared with that during rest, ensuring that the participants imagined the desired movement.
These results suggested that one session of mental training alone or combined with physical training do not induce (additional) neuromuscular fatigue despite the repetitive activation of the corticospinal track. Motor imagery may be added to physical practice to increase the total workload without exacerbating neuromuscular fatigue.
与体育训练一样，心理训练可增强肌肉力量。虽然最大自主收缩（MVC）的重复会诱发神经肌肉疲劳，但最大想象收缩（MIC）对神经肌肉疲劳的影响尚不清楚。在此，我们研究了包括MIC的心理训练、包括MVC的体育训练以及包括肘部屈肌的MIC和MVC的联合训练后神经肌肉的变化。
10名参与者在三个单独的时段分别进行80次MIC（占空比为5秒MIC和10秒休息）、80次MVC（相同占空比）或80次MVC和80次MIC（5秒MVC、2秒休息、5秒MIC和3秒休息）。在三种方案的训练过程中以及训练结束后10分钟对MVC扭矩进行了五次评估。使用经颅磁刺激估计静息时和MIC期间反映中枢疲劳的中枢激活率（CARc）和皮质脊髓兴奋性。
体育训练和联合训练均导致MVC扭矩下降约40%，同时CARc下降约10%，两个时段之间无显著差异。相反，MIC的重复并未降低最大力量产生能力，也未改变CARc。与静息时相比，MIC期间皮质脊髓兴奋性始终增强，确保参与者想象出期望的动作。
这些结果表明，单独的一次心理训练或与体育训练相结合不会诱发（额外的）神经肌肉疲劳，尽管皮质脊髓通路会反复激活。运动想象可添加到体育练习中，以增加总工作量而不加重神经肌肉疲劳。
