Entity

Time filter

Source Type

Kobe, Japan

Kobe Design University is a private university in Kobe, Hyōgo, Japan.It was established in 1989 by Tanioka Gakuen Educational Foundation , which runs several schools such as Osaka University of Commerce. Wikipedia.


Amano T.,Kobe University | Koga S.,Kobe Design University | Inoue Y.,Osaka International University | Nishiyasu T.,University of Tsukuba | Kondo N.,Kobe University
European Journal of Applied Physiology | Year: 2013

The purpose of this study was to compare sweating function in sprinters who have trained for several years with untrained subjects and trained endurance runners. Two separate experiments were conducted. Nine sprinters, eight untrained men, and nine distance runners (VO2max 50.9 ± 1.4, 38.2 ± 1.8, and 59.1 ± 1.2 mL/kg/min, respectively; P < 0.05) were passively heated for 50 min (Experiment 1), and ten sprinters, 11 untrained men and nine distance runners (similar VO2max levels compared with Experiment 1 in each group) had their sweat gland capacity assessed based on acetylcholine-induced sweating rate (SR) (Experiment 2). The slope of the mean non-glabrous SR plotted against change in mean body temperature during passive heating did not differ significantly between sprinters and untrained men (1.21 ± 0.10 and 0.97 ± 0.12 mg cm-2/min/ C, respectively); in contrast, compared with untrained men, distance runners exhibited a significantly greater slope (1.42 ± 0.11 mg cm-2/min/ C, P < 0.05). The mean body temperature threshold for SR was not significantly different among the groups. Acetylcholine-induced SR did not differ significantly between sprinters and untrained men, whereas distance runners showed a significantly higher induced SR compared with untrained men. The sweating function was not improved in sprinters who have trained 2-3 h/day, 5 days/week, for at least 3 years compared with untrained men, although the VO2max was markedly greater in sprinters. Thus, there is a case that daily training was not sufficient to improve sweating function in sprinters relative to those in distance runners. © 2013 Springer-Verlag Berlin Heidelberg. Source


Koga S.,Kobe Design University | Poole D.C.,Kansas State University | Kondo N.,Kobe University | Oue A.,Toyo University | And 2 more authors.
European Journal of Applied Physiology | Year: 2014

Purpose: We quantified the contribution of skin blood flow (SkBF) to tissue oxygenation/deoxygenation of the flexor digitorum profundus muscle during cutaneous vasodilation.Methods: Time-resolved near-infrared spectroscopy (TRS-NIRS) was utilized to measure the potential influence of optical factors [mean optical pathlength (PL) and coefficients of absorption (μa) and reduced scattering ((Formula presented.))] on the NIRS-derived signals of eight male subjects.Results: The approximately threefold elevation of SkBF during 1 h whole-body heating (increased internal temperature ~0.9 °C) increased both μa and (Formula presented.) without changing PL. Assuming that the (Formula presented.) coefficient remained constant, i.e., as with continuous-wave (CW) NIRS, resulted in a significant increase in the apparent oxygenation [oxy(Hb + Mb), from 113 ± 13 μM (mean ± SD) for control to 126 ± 13 for the increased SkBF condition, P < 0.01]: this was in marked contrast to the unchanged TRS-derived values. The deoxygenation [deoxy(Hb + Mb)] also increased from control to elevated SkBF (CW-NIRS, from 39 ± 8 to 45 ± 7; TRS, from 38 ± 6 to 44 ± 7 μM; P < 0.01 for both), but less than that seen for oxy(Hb + Mb) and not different between TRS- and CW-NIRS. Further, and in contrast to oxy(Hb + Mb), temporal profiles of deoxy(Hb + Mb) measured by the two NIRS methods were not different.Conclusions: These findings support use of either NIRS method to estimate local muscle fractional O2 extraction, but not oxygenation, when SkBF is increased at rest. © 2014, Springer-Verlag Berlin Heidelberg. Source


Koga S.,Kobe Design University | Rossiter H.B.,University of Leeds | Heinonen I.,University of Turku | Heinonen I.,Erasmus Medical Center | And 2 more authors.
Medicine and Science in Sports and Exercise | Year: 2014

Resolving the bases for different physiological functioning or exercise performance within a population is dependent on our understanding of control mechanisms. For example, when most young healthy individuals run or cycle at moderate intensities, oxygen uptake (V̇O2) kinetics are rapid and the amplitude of the V̇O2 response is not constrained by O 2 delivery. For this to occur, muscle O2 delivery (i.e., blood flow × arterial O2 concentration) must be coordinated superbly with muscle O2 requirements (V̇O2), the efficacy of which may differ among muscles and distinct fiber types. When the O2 transport system succumbs to the predations of aging or disease (emphysema, heart failure, and type 2 diabetes), muscle O2 delivery and O2 delivery-V̇O2 matching and, therefore, muscle contractile function become impaired. This forces greater influence of the upstream O2 transport pathway on muscle aerobic energy production, and the O2 delivery-V̇O2 relationship(s) assumes increased importance. This review is the first of its kind to bring a broad range of available techniques, mostly state of the art, including computer modeling, radiolabeled microspheres, positron emission tomography, magnetic resonance imaging, near-infrared spectroscopy, and phosphorescence quenching to resolve the O2 delivery-V̇O2 relationships and inherent heterogeneities at the whole body, interorgan, muscular, intramuscular, and microvascular/myocyte levels. Emphasis is placed on the following: 1) intact humans and animals as these provide the platform essential for framing and interpreting subsequent investigations, 2) contemporary findings using novel technological approaches to elucidate O2 delivery-V̇O 2 heterogeneities in humans, and 3) future directions for investigating how normal physiological responses can be explained by O 2 delivery-V̇O2 heterogeneities and the impact of aging/disease on these processes. © 2014 by the American college of Sports Medicine. Source


Ouchi K.,Kobe Design University | Horita T.,Osaka Prefecture University | Yamada T.,KIT Senior Academy
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011

The chaotic phase synchronization transition is studied in connection with the zero Lyapunov exponent. We propose a hypothesis that it is associated with a switching of the maximal finite-time zero Lyapunov exponent, which is introduced in the framework of a large deviation analysis. A noisy sine circle map is investigated to introduce this hypothesis and it is tested in an unidirectionally coupled Rössler system by using the covariant Lyapunov vector associated with the zero Lyapunov exponent. © 2011 American Physical Society. Source


Koga S.,Kobe Design University | Kano Y.,University of Electro - Communications | Barstow T.J.,Kansas State University | Ferreira L.F.,University of Florida | And 3 more authors.
Journal of Applied Physiology | Year: 2012

The overarching presumption with near-infrared spectroscopy measurement of muscle deoxygenation is that the signal reflects predominantly the intramuscular microcirculatory compartment rather than intramyocyte myoglobin (Mb). To test this hypothesis, we compared the kinetics profile of muscle deoxygenation using visible light spectroscopy (suitable for the superficial fiber layers) with that for microvascular O 2 partial pressure (i.e., Pmv O2, phosphorescence quenching) within the same muscle region (0.5̃1 mm depth) during transitions from rest to electrically stimulated contractions in the gastrocnemius of male Wistar rats (n = 14). Both responses could be modeled by a time delay (TD), followed by a close-to-exponential change to the new steady level. However, the TD for the muscle deoxygenation profile was significantly longer compared with that for the phosphorescencequenching Pmv O2 [8.6 ± 1.4 and 2.7 ± 0.6 s (means ± SE) for the deoxygenation and Pmv O2, respectively; P < 0.05]. The time constants (τ) of the responses were not different (8.8 ± 4.7 and 11.2 ± 1.8 s for the deoxygenation and Pmv O2, respectively). These disparate (TD) responses suggest that the deoxygenation characteristics of Mb extend the TD, thereby increasing the duration (number of contractions) before the onset of muscle deoxygenation. However, this effect was insufficient to increase the mean response time. Somewhat differently, the muscle deoxygenation response measured using nearinfrared spectroscopy in the deeper regions (̃5 mm depth) (̃50% type I Mb-rich, highly oxidative fibers) was slower (τ = 42.3 ± 6.6 s; P < 0.05) than the corresponding value for superficial muscle measured using visible light spectroscopy or Pmv O2 and can be explained on the basis of known fiber-type differences in Pmv O2 kinetics. These data suggest that, within the superficial and also deeper muscle regions, the τ of the deoxygenation signal may represent a useful index of local O 2 extraction kinetics during exercise transients. Copyright © 2012 the American Physiological Society. Source

Discover hidden collaborations