title: Heterogeneous neuromuscular activation within human rectus femoris muscle during pedaling.
abstract: BACKGROUND
  We investigated the effect of workload and the use of pedal straps on the spatial distribution of neuromuscular activation within the rectus femoris (RF) muscle during pedaling movements.
  
  
  METHODS
  Eleven healthy men performed submaximal pedaling exercises on an electrically braked ergometer at different workloads and with or without pedal straps. During these tasks, surface electromyograms (SEMGs) were recorded from the RF using 36 electrode pairs, and central locus activation (CLA) was calculated along the longitudinal line of the muscle.
  
  
  RESULTS
  CLA moved markedly, indicating changes in spatial distribution of SEMG within the muscle, during a crank cycle under all conditions (P < 0.05). There were significant differences in CLA among different workloads and between those with and without pedal straps (P < 0.05).
  
  
  CONCLUSIONS
  These results suggest that neuromuscular activation within the RF is regulated regionally by changes in workload and the use of pedal straps during pedaling.
authors.affiliation: Laboratory of Neuromuscular Biomechanics, School of International Liberal Studies, Chukyo University, Yagotohonmachi, Showa-ku, Nagoya, 466-8666, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Laboratory of Neurophysiology, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan.
authors.forename: Motoki
authors.initials: M
authors.lastname: Kouzaki
authors.affiliation: Laboratory of Applied Physiology, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Moritani
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001696:Biomechanical Phenomena; D004576:Electromyography / Q000379:methods; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D052097:Quadriceps Muscle / Q000294:innervation / Q000502:physiology*; D011999:Recruitment, Neurophysiological / Q000502:physiology; D055815:Young Adult
keywords: bi-articular muscles; cycling; high-density surface electromyography; multichannel surface electromyography; neuromuscular compartment; quadriceps femoris muscle