title: Modulations of interlimb and intralimb cutaneous reflexes during simultaneous arm and leg cycling in humans.
abstract: OBJECTIVE
  We investigated to what extent intralimb and interlimb cutaneous reflexes are altered while simultaneously performing arm and leg cycling (AL cycling) under different kinematic and postural conditions.
  
  
  METHODS
  Eleven subjects performed AL cycling under conditions in which the arm and leg crank ipsilateral to the stimulation side were moved synchronously (in-phase cycling) or asynchronously (anti-phase cycling) while sitting or standing. Cutaneous reflexes following superficial radial or superficial peroneal nerve stimulation (2.0-2.5 times radiating threshold, 5 pulses at 333 Hz) were recorded at 4 different pedal positions from 12 muscles in the upper and lower limbs. Cutaneous reflexes with a peak latency of 80-120 ms were then analyzed.
  
  
  RESULTS
  The magnitude of interlimb and intralimb cutaneous reflexes in the arm and leg muscles was significantly modulated depending on the crank position for the relevant limb (phase-dependent modulation). A significant correlation between the magnitude of the cutaneous reflex and background EMG was observed in the majority of muscles during static contraction, but not during AL cycling (task-dependent modulation). No significant difference was found in comparisons of the magnitude of intralimb and interlimb cutaneous reflexes obtained during in- and anti-phase AL cycling. Qualitatively, the same results were obtained during AL cycling while sitting or standing. In addition, the modulation of cutaneous reflexes in arm muscles was identical among in-phase, anti-phase and isolated arm cycling. Results were the same for leg muscles.
  
  
  CONCLUSIONS
  Cutaneous reflexes in arm muscles are little influenced by rhythmic movement of the legs and vice versa during AL cycling. It is likely that neural components that control interlimb reflexes are loosely coupled during AL cycling while sitting or standing.
  
  
  CONCLUSIONS
  Our results provide a better understanding of the coordination between the upper and lower limbs during rhythmic movement.
authors.affiliation: Division of Health and Sport Education, United of Graduate School of Education, Tokyo Gakugei University, 1-33 Yayoi-cho, Inage-Ku, Chiba City 263-8522, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Sakamoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Endoh
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Nakajima
authors.forename: Toshiki
authors.initials: T
authors.lastname: Tazoe
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Shiozawa
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Komiyama
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology*; D001642:Bicycling / Q000502:physiology; D001696:Biomechanical Phenomena; D004551:Elbow Joint / Q000502:physiology; D004558:Electric Stimulation; D004576:Electromyography; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D007866:Leg / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D010543:Peroneal Nerve / Q000502:physiology; D011187:Posture / Q000502:physiology; D011826:Radial Nerve / Q000502:physiology; D012018:Reflex / Q000502:physiology*; D012867:Skin / Q000294:innervation*