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Fukuoka Prefectural University is a public university in Tagawa, Fukuoka, Japan, established in 1992. Wikipedia.

Mercer J.A.,University of Nevada, Las Vegas | Applequist B.C.,University of Nevada, Las Vegas | Masumoto K.,Fukuoka Prefectural University
Journal of Sport Rehabilitation | Year: 2014

Background: Body-weight (BW) support during running can be accomplished using deep-water running (DWR; 100% BW support) and a lower-body positive-pressure (LBPP) treadmill. Purpose: To compare lower-extremity muscle activity during DWR and running on an LBPP treadmill at matched stride frequency. Methods: Eight subjects (40 ± 6.5 y, 173 ± 7.2 cm, 66.9 ± 11.7 kg) completed 4 running conditions all at a preferred stride frequency that was determined while running with no support. Two conditions were running on the LBPP treadmill at 60% and 80% of BW, and the other 2 conditions were different DWR styles: high knee (DWR-HK) and cross-country (DWR-CC). Average (AVG) and root-mean-square (RMS) electromyography (rectus femoris, biceps femoris, gastrocnemius, and tibialis anterior) were each compared among conditions (repeated-measures analysis of variance). Results: Results for AVG and RMS variables were identical for statistical tests for each muscle. Rectus femoris electromyography during DWR-HK was lower than that of DWR-CC (P <.05) but not different than either 60% BW or 80% BW (P >.05). Biceps femoris electromyography was less during DWR-HK than DWR-CC (P <.05) but greater during DWR-HK than either BW 60% or BW 80% (P <.05). Neither gastrocnemius nor tibialis anterior electromyography differed between conditions (P >.05). Conclusion: Neither the mechanism of BW support nor style of DWR influenced gastrocnemius or tibialis anterior muscle activity during running at the same stride frequency. However, rectus femoris and biceps femoris muscle activity were influenced by not only the mechanism of BW support but also the style of DWR. © 2014 Human Kinetics, Inc.

Mercer J.A.,University of Nevada, Las Vegas | Applequist B.C.,University of Nevada, Las Vegas | Masumoto K.,Fukuoka Prefectural University
Research in Sports Medicine | Year: 2013

Little information exists on how body weight (BW) support influences running biomechanics. The study aim was to determine how reducing BW by 50%-80% influences muscle activity while running at different speeds. Subjects (n = 7) ran at 100%, 115%, 125% of preferred speed at 100%, 50%, 40%, 30%, 20% of BW per speed. Average (AVG) electromyography of the rectified signal was compared (within subject design; 3-speeds × 5-BW, repeated measures ANOVAs; biceps femoris [BF], rectus femoris [RF], tibialis anterior [TA], gastrocnemius [GA]). RF, BF, and GA AVG were not influenced by BW-speed interaction (p >.05) and increased across speeds (p <.05). RF and GA AVG signal was reduced as BW was reduced (p <.05), but BF only tended to be different (p =.08). TA was influenced by BW-speed interaction (p <.05) with EMG decreasing across BW (p <.05) while increasing across speeds except at 100% BW. Overall, muscle activity increased with speed and decreased by BW reductions. © 2013 Taylor & Francis Group, LLC.

Masumoto K.,Fukuoka Prefectural University | Nishizaki Y.,Kyushu University | Hamada A.,Kyushu University
Gait and Posture | Year: 2013

We investigated the effect of stride frequency (SF) on metabolic costs and rating of perceived exertion (RPE) during walking in water and on dry land. Eleven male subjects walked on a treadmill on dry land and on an underwater treadmill at their preferred SF (PSF) and walked at an SF which was lower and higher than the PSF (i.e., PSF±5, 10, and 15stridesmin-1). Walking speed was kept constant at each subject's preferred walking speed in water and on dry land. Oxygen uptake, heart rate, RPE, PSF and preferred walking speeds were measured. Metabolic costs and RPE were significantly higher when walking at low and high SF conditions than when walking at the PSF condition both in water and on dry land (P<0.05). Additionally, the high SF condition produced significantly higher metabolic costs and RPE than the equivalent low SF condition during walking in water (P<0.01). Furthermore, metabolic costs, RPE, PSF, and the preferred walking speed were significantly lower in water than on dry land when walking at the PSF (P<0.05). These observations indicate that a change in SF influences metabolic costs and RPE during walking in water. © 2012 Elsevier B.V.

Qiu Y.,Kyushu University | Qiu Y.,Shenyang University | Tanaka T.,Kyushu University | Tanaka T.,Fukuoka University | And 3 more authors.
Endocrinology | Year: 2012

The mechanisms involved in the antiatherosclerotic effects of androgens are unclear. Although lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in endothelial cells plays critical roles in atherosclerosis, the effects of androgens on endothelial LOX-1 expression has not been examined. Therefore, to investigate the effects of dihydrotestosterone (DHT) on LOX-1 expression in rabbit aortic endothelial cells and cultured human aortic endothelial cells (HAEC), pellets containing DHT or placebo were sc implanted into 26 male New Zealand white rabbits at the time of castration or sham operation. The rabbits were then fed a high-cholesterol diet (HCD) for 2 wk. Microscopic examination of the aortic arch revealed that DHT significantly reduced HCD-induced LOX-1 expression in endothelial cells compared with placebo. In cultured HAEC, DHT at concentrations above 10-9 to 10 -7 mol/liter inhibited TNFα-induced LOX-1 mRNA and protein expression. Deletion and mutation analysis of human LOX-1 promoter-luciferase constructs transfected into HAEC with an androgen receptor (AR) expression plasmid revealed that the 12-O-tetradecanoylphorbol-13-acetate (TPA) response element (TRE; nucleotides -60/-53) contributed to the inhibitory effects of DHT on TNFα-induced LOX-1 expression. Chromatin immunoprecipitation (ChIP) and re-ChIP assays revealed that TNFα- and TPA-dependent enrichment of p65 and phosphorylated c-Jun in the TRE chromatin region was inhibited by DHT-AR. Consistent with these results, DHT also suppressed TPA-induced expression of LOX-1. In conclusion, DHT exerts antiatherosclerotic effects by suppressing endothelial LOX-1 expression. This effect is partly mediated by the suppression of nuclear factor-κB- and activator protein 1-dependent activation of the LOX-1 promoter. Copyright © 2012 by The Endocrine Society.

Ishizaki R.,Fukuoka Prefectural University | Inoue M.,Kagoshima University
Physica A: Statistical Mechanics and its Applications | Year: 2013

Time-dependent pattern entropy is a method that reduces variations to binary symbolic dynamics and considers the pattern of symbols in a sliding temporal window. We use this method to analyze the instability of daily variations in foreign exchange rates, in particular, the dollar-yen rate. The time-dependent pattern entropy of the dollar-yen rate was found to be high in the following periods: before and after the turning points of the yen from strong to weak or from weak to strong, and the period after the Lehman shock. © 2013 Elsevier B.V. All rights reserved.

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