caa a22 4500 467942382 CHVBK 20180406153017.0 cr unu---uuuuu 170328e20060501xx s 000 0 eng 10.1007/s00421-005-0103-7 doi (NATIONALLICENCE)springer-10.1007/s00421-005-0103-7 Phase-dependent chronotropic response of the heart during running in humans [Elektronische Daten] [Kunihiko Nomura, Yoshiaki Takei, Masaki Yoshida, Yasuyoshi Yanagida] Heartbeat modulation by muscle contraction during rhythmic exercise involving a small muscle mass is phase-dependent, reflecting the timing of the muscle contraction within the cardiac cycle, but it remains unclear whether such modulation occurs during whole body exercise. To determine whether phase-dependent chronotropic changes in the heart would occur during running, we investigated the relationship between R-R interval (RRI) and the timing of vastus lateralis muscle contractions within the cardiac cycle. Seven healthy subjects were examined during high intensity running where the target heart rate was 160beats·min−1. The running pitch was made to wax and wane periodically in the neighborhood of the target heart rate to scan the effect of footfall timing within the cardiac cycle on heart period. We found that when muscle contraction occurred early in the cardiac cycle, RRI was reduced from the mean RRI (P<0.05). Conversely, when muscle contraction occurred in the latter half of the cardiac cycle, RRI tended to increase (P>0.05). Thus, the curve reflecting this phase-dependent relationship between heart period and timing of muscle contraction showed a positive slope within the first one-quarter to three-quarters of the cardiac cycle. Our results suggest the existence of a mechanism that provides beat-by-beat regulation of RRI even when it is very short (∼ 375ms), i.e., a cardio-locomotor synchronization develops during running, when the frequencies of the two rhythms approach one another. Springer-Verlag, 2006 Entrainment nationallicence Synchronization nationallicence Coupling nationallicence Phase-response curve nationallicence Rhythmic exercise nationallicence Nomura Kunihiko Department of Biomedical Engineering, Osaka Electro-Communication University, 1130-70 Kiyotaki Shijonawate-shi, 575-0063, Osaka, Japan aut Takei Yoshiaki Faculty of Human Development, Kobe University, 3-11 Tsurukabuto Nada-ku Kobe-shi, 657-8501, Hyougo, Japan aut Yoshida Masaki Department of Biomedical Engineering, Osaka Electro-Communication University, 1130-70 Kiyotaki Shijonawate-shi, 575-0063, Osaka, Japan aut Yanagida Yasuyoshi Faculty of Human Development, Kobe University, 3-11 Tsurukabuto Nada-ku Kobe-shi, 657-8501, Hyougo, Japan aut European Journal of Applied Physiology Springer-Verlag 97/2(2006-05-01), 240-247 1439-6319 97:2<240 2006 97 421 https://doi.org/10.1007/s00421-005-0103-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00421-005-0103-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Nomura Kunihiko Department of Biomedical Engineering, Osaka Electro-Communication University, 1130-70 Kiyotaki Shijonawate-shi, 575-0063, Osaka, Japan aut NATIONALLICENCE 700 1- Takei Yoshiaki Faculty of Human Development, Kobe University, 3-11 Tsurukabuto Nada-ku Kobe-shi, 657-8501, Hyougo, Japan aut NATIONALLICENCE 700 1- Yoshida Masaki Department of Biomedical Engineering, Osaka Electro-Communication University, 1130-70 Kiyotaki Shijonawate-shi, 575-0063, Osaka, Japan aut NATIONALLICENCE 700 1- Yanagida Yasuyoshi Faculty of Human Development, Kobe University, 3-11 Tsurukabuto Nada-ku Kobe-shi, 657-8501, Hyougo, Japan aut NATIONALLICENCE 773 0- European Journal of Applied Physiology Springer-Verlag 97/2(2006-05-01), 240-247 1439-6319 97:2<240 2006 97 421 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 467942315 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer