The aim of this study was to investigate the plasticity of M1 innervating the tibialis anterior muscle (TA) induced by the long-term practice of football juggling using a transcranial magnetic stimulation (TMS) technique. Ten football juggling experts and ten novices participated in this study. Motor evoked potentials (MEP) and the H-reflex were recorded from the right TA during isometric dorsiflexion at 10% of maximum voluntary contraction. The MEP input-output curve of the experts was steeper than that of the novices, and reduced short-interval intracortical inhibition and long-interval intracortical inhibition were observed in the experts. In contrast, the ratio of Hmax to Mmax did not differ between the groups. Our results show that football juggling experts displayed enhanced excitability in the M1 innervating the TA, which was induced by the long-term practice of the ankle movements required to perform football juggling well.
Hirano, Kubota, Morishita, Uehara, and Funase are with the Graduate School of Integrated Arts and Sciences, and Fujimoto the Faculty of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan.