title: Effect of aging on region-specific functional role and muscle geometry along human rectus femoris muscle.
abstract: BACKGROUND
  We compared the region-specific neuromuscular activation and muscle morphology along the rectus femoris (RF) muscle between young and elderly.
  
  
  METHODS
  Ratios of surface electromyography amplitude between hip flexion and knee extension (HF/KE) were compared among regions along the muscle for 9 young and 9 elderly men. Muscle thickness was also compared among the regions.
  
  
  RESULTS
  HF/KE in the proximal region was significantly greater than in the middle and distal regions for both the young and elderly (P < 0.05). However, a significant difference in HF/KE between the middle and distal regions was found in the young (P < 0.05), but not in the elderly (P > 0.05). A difference in the region-specific muscle thickness was observed between the young and elderly.
  
  
  CONCLUSIONS
  These findings suggest that functional role and muscle morphology are regionally affected by aging along the RF muscle. Muscle Nerve 56: 982-986, 2017.
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: School of Health and Sports Sciences, Chukyo University, Nagoya, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Moritani
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D004576:Electromyography; D006615:Hip / Q000000981:diagnostic imaging / Q000294:innervation*; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D052097:Quadriceps Muscle / Q000000981:diagnostic imaging / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology*; D014463:Ultrasonography; D055815:Young Adult
keywords: bi-articular muscles; elderly; multichannel surface electromyography; muscle thickness; neuromuscular compartment; ultrasonography