To investigate the involvement of the primary motor cortex (M1) in the coordination performance of karate athletes through transcranial magnetic stimulation (TMS).
Thirteen right-handed male karate athletes (25.0±5.0 years) and 13 matched non-athlete controls (26.7±6.2 years) were enrolled. A single-pulse TMS was applied using a figure-eight coil stimulator. Resting motor threshold (rMT) was determined. Surface electromyography was recorded from the first dorsal interosseous muscle. Motor evoked potential (MEP) latencies and amplitudes at rMT, 110%, and 120% of rMT were considered. Functional assessment of the coordination performance was assessed by in-phase (IP) and anti-phase (AP) homolateral hand and foot coordination tasks performed at 80, 120, and 180 bpm.
Compared to controls, athletes showed lower rMT (p<0.01), shorter MEP latency (p<0.01) and higher MEP amplitude (p<0.01), with a significant correlation (r = 0.50, p<0.01) between rMT and MEP latency. Coordination decreased with increasing velocity, and better IP performances emerged compared to AP ones (p<0.001). In general, a high correlation between rMT and coordination tasks was found for both IP and AP conditions.
With respect to controls, karate athletes present a higher corticospinal excitability indicating the presence of an activity-dependent alteration in the balance and interactions between inhibitory and facilitatory circuits determining the final output from the M1. Furthermore, the high correlation between corticospinal excitability and coordination performance could support sport-specific neurophysiological arrangements.
PLoS One. 2016 May 24;11(5):e0155998. doi: 10.1371/journal.pone.0155998. eCollection 2016. Functional Assessment of Corticospinal System Excitability in Karate Athletes. Moscatelli F1,2, Messina G1,3, Valenzano A1, Monda V3, Viggiano A4, Messina A3, Petito A1, Triggiani AI1, Ciliberti MA1, Monda M3, Capranica L2, Cibelli G1.
Author information: 1Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy. 2Department Of Motor, Human and Health Science, University of Rome, “Foro Italico”, Rome, Italy. 3Department of Experimental Medicine, Second University of Naples, Naples, Italy. 4Department of Medicine and Surgery, University of Salerno, Salerno, Italy.