Differences in corticospinal system activity and reaction response between karate athletes and non-athletes

The aim of this study was to verify the hypothesis that transcranial magnetic stimulation (TMS) parameters over the hand region of the motor cortex, such as resting motor threshold (rMT) and motor evoked potential (MEP) latency, predict the behavioural performance of karate athletes in the response time (RT) test. Twenty-five male karate athletes (24.9 +/- 4.9 years) and 25 matched non-athletes (26.2 +/- 4.5 years) were recruited. Using TMS, we investigated cortico-spinal system excitability. Compared with controls, the athletes showed faster RT (p < 0.001), lower rMT (p < 0.01), shorter MEP latency (p < 0.01), and higher MEP amplitude (p < 0.01); moreover, there was a significant positive linear correlation between RT and rMT (p < 0.001), between RT and MEP latency (p < 0.0001), and a negative correlation between RT and MEP amplitude (p < 0.001). The practice of competitive sports affects both the central and peripheral nervous system. Subjects that showed higher cortical excitability showed also higher velocity, at which the neural signal is propagated from the motor cortex to the muscle and consequently better RT. The lower rMT and the shorter MEP latency observed in athletes support the effects of training in determining specific brain organizations to meet specific sport challenges.