Central command generated prior to arbitrary motor execution induces muscle vasodilatation at the beginning of dynamic exercise.
The purpose of this study was to examine the role of central command, generated prior to arbitrary motor execution, in cardiovascular and muscle blood flow regulation during exercise. Thirty two subjects performed 30 s of two-legged cycling or 1 min of one-legged cycling (66 ± 4% and 35% of the maximal exercise intensity, respectively), which was started arbitrarily or abruptly by a verbal cue (arbitrary vs. cued start). We measured the cardiovascular variables during both exercises and the relative changes in oxygenated-hemoglobin concentration (Oxy-Hb) of noncontracting vastus lateralis muscles as index of tissue blood flow and femoral blood flow to nonexercising leg during one-legged cycling. Two-legged cycling with arbitrary start caused a decrease in total peripheral resistance (TPR), which was smaller during the exercise with cued start. The greater reduction of TPR with arbitrary start was also recognized at the beginning of one-legged cycling. Oxy-Hb of noncontracting muscle increased by 3.6 ± 1% (P < 0.05) during one-legged cycling with arbitrary start, whereas such increase in Oxy-Hb was absent with cued start. The increases in femoral blood flow and vascular conductance of nonexercising leg were evident (P < 0.05) at 10 s from the onset of one-legged cycling with arbitrary start, whereas those were smaller or absent with cued start. It is likely that when voluntary exercise is started arbitrarily, central command is generated prior to motor execution and then contributes to muscle vasodilatation at the beginning of exercise. Such centrally induced muscle vasodilatation may be weakened and/or masked in the case of exercise with cued start.
Department of Integrative Physiology and.
Kei
K
Ishii
Department of Integrative Physiology and matsuk@hiroshima-u.ac.jp.
Kanji
K
Matsukawa
Department of Integrative Physiology and.
Nan
N
Liang
Department of Integrative Physiology and.
Kana
K
Endo
Department of Integrative Physiology and.
Mitsuhiro
M
Idesako
Department of Integrative Physiology and.
Ryota
R
Asahara
Department of Integrative Physiology and.
Akito
A
Kadowaki
Department of Integrative Physiology and.
Rie
R
Wakasugi
Department of Biomechanics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Makoto
M
Takahashi
D000328:Adult; D001642:Bicycling / Q000502:physiology; D002490:Central Nervous System / Q000378:metabolism / Q000502:physiology*; D003326:Coronary Circulation / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D009046:Motor Neurons / Q000378:metabolism / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology*; D010108:Oxyhemoglobins / Q000378:metabolism; D052097:Quadriceps Muscle / Q000378:metabolism / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology; D014664:Vasodilation / Q000502:physiology*
D010108:Oxyhemoglobins
arbitrary vs. cued start; central command; muscle blood flow; near-infrared spectroscopy; ultrasound Doppler flowmetry