Long-term Motor Practice Induces Practice-dependent Modulations of Peripheral and Central Nervous Systems in Elite Kendo Players

Abstract

We investigated the effects of long-term motor practice on peripheral and central nervous systems (CNS) by measuring motor nerve conduction velocity (MCV), as well as by measuring movement-related cortical potentials (MRCP) associated with self-paced right (dominant) and left (non-dominant) brisk handgrip movements with a 20% maximal voluntary contraction via electrodes placed on the scalp of elite kendo players and healthy young adults (control). In experiment 1, MCV was measured from the ulnar nerve in the forearm of all subjects. The MCV of both dominant and non-dominant limbs in athletes were significantly faster than those in controls. In experiment 2, three components (Bereitschaftspotential: BP, negative slope: NS’, and motor potential: MP) of MRCP were obtained from all subjects. The BP latency for the non-dominant handgrip task was significantly longer in the controls than in the kendo players. BP onset time appeared significantly earlier preceding the non-dominant handgrip task as compared with the dominant handgrip task only in the controls. Moreover, MP amplitudes in the kendo players were significantly larger than those in the controls. These findings suggest that long-term motor practice induces practice dependent changes in kendo players’ brain activities, especially in the non-dominant hand movement, compared to that in the dominant hand. In conclusion, long-term motor practice may exert adaptive changes not only on the peripheral nervous system but also on the CNS in humans.