title: Post-activation potentiation: The neural effects of post-activation depression.
abstract: BACKGROUND
  Our knowledge of the neurophysiology of post-activation potentiation (PAP) is limited. The purpose of this study was to examine the effect of PAP on twitch torque and H-reflex amplitude after a 10-s maximal voluntary contraction (MVC).
  
  
  METHODS
  PAP measurements were assessed with the plantarflexors in a relaxed state and during a tonic contraction at 10% MVC.
  
  
  RESULTS
  The H-reflex/maximum M-wave ratio (H/M) decreased significantly (P<0.05) and returned to baseline levels after 1 min. The decrement in H/M was depressed when the plantarflexors were active at 10% MVC, and the depression was more obvious in the lateral gastrocnemius than in the soleus muscle.
  
  
  CONCLUSIONS
  The inhibition induced immediately after contraction could be attributed to post-activation depression. We conclude that PAP after a 10-s MVC cannot be attributed to increased motor neuron excitability through the reflex pathway as assessed by the H-reflex technique.
authors.affiliation: Laboratory of Coaching and Sport Performance, Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Serres, Greece.
authors.forename: Anthi
authors.initials: A
authors.lastname: Xenofondos
authors.affiliation: Laboratory of Neuromechanics, Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Ag. Ioannis, 62110, Serres, Greece.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Patikas
authors.affiliation: Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Koceja
authors.affiliation: Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana, USA.
authors.forename: Tahayori
authors.initials: T
authors.lastname: Behdad
authors.affiliation: Laboratory of Coaching and Sport Performance, Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Serres, Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Bassa
authors.affiliation: Laboratory of Neuromechanics, Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Ag. Ioannis, 62110, Serres, Greece.
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Kellis
authors.affiliation: Laboratory of Coaching and Sport Performance, Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Serres, Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Kotzamanidis
mesh_terms: D000293:Adolescent; D000328:Adult; D004576:Electromyography / Q000379:methods; D005260:Female; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D017774:Long-Term Potentiation / Q000502:physiology; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D055815:Young Adult
keywords: H-reflex; plantarflexors; post-activation depression; post-activation potentiation; reflex potentiation