Fukuoka Prefectural University

Suita, Japan

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

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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 | Horsch S.E.,University of Nevada, Las Vegas | Agnelli C.,University of Nevada, Las Vegas | McClellan J.,University of Nevada, Las Vegas | Mercer J.A.,University of Nevada, Las Vegas
International Journal of Sports Medicine | Year: 2014

We investigated muscle activity during deep water running (DWR) and treadmill running on dry land (TMR) at similar physiological responses. 9 subjects (30.7±10.4 years) participated in this study. The baseline conditions consisted of TMR at 3 ratings of perceived exertion (RPE) level (RPE 11, 13, and 15) with heart rate (HR) recorded during each condition. The target HR for each level of DWR condition was determined by the HR recorded during the TMR. Muscle activity from the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius (GA) were measured. As originally planned, HR was not different between modes (P>0.05) and was different between exercise intensities (P<0.001). Only TA muscle activity was influenced by the interaction of mode and intensity (P<0.05). Muscle activity from the GA during DWR was significantly lower than that of TMR (a 34-48% decrease; P<0.05), although muscle activity from the remaining tested muscles were not influenced by modes of exercise (P>0.05). These observations suggest that matching HR can be recommended to produce similar magnitude of lower extremity muscle activity during DWR to that of TMR, with the exception of the GA. © Georg Thieme Verlag KG Stuttgart - New York.

Liebenberg J.,University of Nevada, Las Vegas | Scharf J.,University of Nevada, Las Vegas | Forrest D.,University of Nevada, Las Vegas | Dufek J.S.,University of Nevada, Las Vegas | And 2 more authors.
Journal of Sports Sciences | Year: 2011

The aim of this study was to investigate how lower extremity muscles are influenced by body weight support during running at different speeds. Nine participants (age 24 ± 2 years, height 1.75 ± 0.12 m, mass 73.5 ± 15.7 kg) ran at 100%, 115%, and 125% of preferred speed at 100%, 90%, 80%, 70%, and 60% of body weight on a treadmill that provided body weight support. Preferred speed was self-selected by each participant and represented a speed that he or she could sustain if going for a 30 min run. Electromyography (EMG) data were recorded (1000 Hz, 1 min) from the bicep femoris, rectus femoris, tibialis anterior, and gastrocnemius for each condition together with knee angle (electrogoniometer). Average and root mean square EMG were calculated across 30 s. Muscle patterns were determined by smoothing (low-pass filter, 4 Hz) and extracting patterns for 49 cycles defined by consecutive maximum knee flexion angles. Repeated-measures analyses of variance were used to compare average and root mean square across body weight and speeds. Correlations were computed between the 100% speed/100% body weight condition and all other conditions per muscle. There was no interaction between body weight and speed (P> 0.05). Average and root mean square decreased as body weight decreased for all muscles (P< 0.05) and increased across speeds for all muscles (P< 0.05). Correlations for all muscles between conditions were high (range: 0.921-0.999). Although a percent reduction in body weight did not lead to the same reduction in muscle activity, it was clear that reducing body weight leads to a reduction in muscle activity with no changes in muscle activity patterns. © 2011 Taylor & Francis.

Masumoto K.,Fukuoka Prefectural University | Applequist B.C.,University of Nevada, Las Vegas | Mercer J.A.,University of Nevada, Las Vegas
Gait and Posture | Year: 2013

The purpose of this study was to compare muscle activity during deep water running (DWR) and treadmill running on dry land (TMR) as well as to investigate effect of stride frequency (SF) on muscle activity while using different styles of DWR (high-knee and cross-country styles, DWR-HK and DWR-CC, respectively). Eight subjects participated in this study. The baseline condition consisted of TMR at the preferred stride frequency (PSF). The remaining conditions consisted of DWR-HK and DWR-CC at PSF, PSF-15%, and PSF+15%. Muscle activity was recorded from the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius. Rectus femoris and biceps femoris muscle activity during DWR-CC-PSF were significantly greater than that of TMR-PSF (. P<. 0.05). However, rectus femoris muscle activity during DWR-HK-PSF was significantly lower than that of TMR-PSF (. P<. 0.05). Gastrocnemius muscle activity during both DWR-HK-PSF and DWR-CC-PSF were significantly lower than that of TMR-PSF (. P<. 0.05). Furthermore, muscle activity from all tested muscles during DWR-HK and DWR-CC increased with increasing SF (. P<. 0.05). These observations indicated that muscle activity is influenced not only by running in the water but also by the style of DWR (DWR-HK, DWR-CC) used. © 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.

Masumoto K.,Fukuoka Prefectural University | Hamada A.,Kyushu University | Tomonaga H.-O.,Tomonaga Clinic of Internal Medicine | Kodama K.,Kyushu University | Hotta N.,Kyushu University
Journal of Sport Rehabilitation | Year: 2012

Context: Walking in water has been included in rehabilitation programs. However, there is a dearth of information regarding the influence of a water current on physiological responses, rating of perceived exertion (RPE), and stride characteristics of subjects while they walk in water. Objective: To compare physiological responses, RPE, and stride characteristics of subjects walking in water (with and without a current) with those of subjects walking on dry land. Design: Repeated measures. Setting: University laboratory. Participants: 7 male adults (mean age = 21.6 y). Intervention: Subjects walked on a treadmill on dry land and on an underwater treadmill immersed to the level of the xiphoid process. The walking speeds in water were set to be half of that on dry land. Main Outcome Measures: Oxygen consumption (VO2), respiratory-exchange ratio (RER), heart rate (HR), minute ventilation (VE), RPE (for breathing and legs, RPE-Br and RPE-Legs, respectively), systolic (SBP) and diastolic (DBP) blood pressures, and stride frequency (SF) were measured. In addition, stride length (SL) was calculated. Results: There was no significant difference in the VO2, RER, HR, VE, RPE-Br, and RPE-Legs while walking in water with a current compared with walking on dry land (P >.05). Furthermore, VO2, RER, HR, VE, RPE-Br, RPE-Legs, SF, and SBP while walking in water were significantly higher with a water current than without (P <.05). Conclusions: These observations suggest that half the speed should be required to work at the similar metabolic costs and RPE while walking in water with a current, compared with walking on dry land. Furthermore, it was suggested that the physiological responses and RPE would be higher while walking in water with a current than without. © 2012 Human Kinetics, Inc.

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.

Nishii K.,National Defense Medical College | Kobayashi Y.,National Defense Medical College | Shibata Y.,Fukuoka Prefectural University
Zygote | Year: 2016

Gap junctional intercellular communication is assumed to play an important role during pre- and peri-implantation development. In this study, we eliminated connexin43 (Cx43) and connexin45 (Cx45), major gap junctional proteins in the pre- and peri-implantation embryo. We generated Cx43 -/- Cx45 -/- embryos by Cx43 +/- Cx45 +/- intercrossing, because mice deficient in Cx43 (Cx43 -/-) exhibit perinatal lethality and those deficient in Cx45 (Cx45 -/-) exhibit early embryonic lethality. Wild-type, Cx43 -/-, Cx45 -/-, and Cx43 -/- Cx45 -/- blastocysts all showed similar outgrowths in in vitro culture. Moreover, Cx43 -/- Cx45 -/- embryos were obtained at the expected Mendelian ratio up to embryonic day 9.5, when the Cx45 -/- mutation proved lethal. The Cx43 -/- Cx45 -/- embryos seemed to have no additional developmental abnormalities in comparison with the single knockout strains. Thus, pre- and peri-implantation development does not require Cx43 and Cx45. Other gap junctional proteins are expressed around these stages and these may compensate for the lack of Cx43 and Cx45. © CopyrightCambridge University Press 2015.

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