title: Differential modulation of motor cortex plasticity in skill- and endurance-trained athletes.
abstract: OBJECTIVE
  Extensive evidence exists that regular physical exercise offers neuroplastic benefits to the brain. In this study, exercise-specific effects on motor cortex plasticity were compared between 15 skilled and 15 endurance trained athletes and 8 controls.
  
  
  METHODS
  Plasticity was tested with a paired associative stimulation (PAS) protocol. PAS is a non-invasive stimulation method developed to induce bidirectional changes in the excitability of the cortical projections to the target muscles. Motor cortex excitability was assessed by motor-evoked potentials (MEPs) in the task-relevant soleus muscle, elicited with transcranial magnetic stimulation, before and following PAS. To test for changes at the spinal level, soleus short latency stretch reflexes (SLSR) were elicited before and after PAS.
  
  
  RESULTS
  PAS induced a significant (76 ± 83 %) increase in MEP amplitude in the skill group, without significant changes in the endurance (-7 ± 35 %) or control groups (21 ± 30 %). Baseline MEP/post MEP ratio was significantly different between the skill and endurance groups. SLSR remained unchanged after the PAS intervention.
  
  
  CONCLUSIONS
  The possible reason for differential motor cortex plasticity in skill and endurance groups is likely related to the different training-induced adaptations. The findings of the current study suggest that long-term skill training by skill group induced preferable adaptations in the task-related areas of the motor cortex because increased plasticity is known to enhance motor learning.
authors.affiliation: Department of Health Science and Technology, Center for Sensory-Motor Interaction (SMI), Aalborg University, Fredrik Bajersvej 7 D 3, 9220, Aalborg, Denmark, susanne.kumpulainen@jyu.fi.
authors.forename: Susanne
authors.initials: S
authors.lastname: Kumpulainen
authors.forename: Janne
authors.initials: J
authors.lastname: Avela
authors.forename: Markus
authors.initials: M
authors.lastname: Gruber
authors.forename: Julian
authors.initials: J
authors.lastname: Bergmann
authors.forename: Michael
authors.initials: M
authors.lastname: Voigt
authors.forename: Vesa
authors.initials: V
authors.lastname: Linnamo
authors.forename: Natalie
authors.initials: N
authors.lastname: Mrachacz-Kersting
mesh_terms: D000328:Adult; D056352:Athletes; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult