The association of R577X polymorphism with sports specificity in Japanese elite athletes.

The α-actinin-3 proteins regulate muscle function and are located in the Z-line of the fast skeletal muscle. A common null polymorphism of R577X in α-actinin-3 gene () results in its complete absence in fast-twitch muscles. The R577X polymorphism is associated with sprint/power performance in athletes.

Morning Heart Rate Variability as an Indication of Fatigue Status in Badminton Players during a Training Camp.

This study aimed to clarify whether changes in the fatigue status of elite athletes during a precompetition period could be evaluated using morning heart rate variability (HRV) indices. Eight Japanese National Badminton Team players (age, 23.0 ± 2.

Lack of association between genotype score and sprint/power performance in the Japanese population.

Objectives: This study aimed to examine the association between a total genotype score (TGS) based on previously published genetic polymorphism candidates and differences in sprint/power performance.

Design: Case-control association study.

Methods: We analysed 21 polymorphisms, which have previously been associated with sprint/power performance and related phenotypes, in 211 Japanese sprint/power track and field athletes (77 regional, 72 national, and 62 international athletes) and 649 Japanese controls using the TaqMan SNP genotyping assay.

Effects of systemic hypoxia on human muscular adaptations to resistance exercise training.

This study investigated the effect of resistance exercise training performed under systemic hypoxia or normoxia on biochemical and molecular muscular adaptations in healthy male subjects. Our findings demonstrate that resistance training under systemic hypoxia led not only to muscle hypertrophy, but most interestingly, to a greater increase in muscular endurance. This increase in muscular endurance was potentially caused by the increased angiogenesis as determined by capillary‐to‐fiber ratio.

Effects of systemic hypoxia on human muscular adaptations to resistance exercise training.

Hypoxia is an important modulator of endurance exercise-induced oxidative adaptations in skeletal muscle. However, whether hypoxia affects resistance exercise-induced muscle adaptations remains unknown. Here, we determined the effect of resistance exercise training under systemic hypoxia on muscular adaptations known to occur following both resistance and endurance exercise training, including muscle cross-sectional area (CSA), one-repetition maximum (1RM), muscular endurance, and makers of mitochondrial biogenesis and angiogenesis, such as peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), citrate synthase (CS) activity, nitric oxide synthase (NOS), vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1 (HIF-1), and capillary-to-fiber ratio.

Comprehensive analysis of common and rare mitochondrial DNA variants in elite Japanese athletes: a case-control study.

The purpose of the present study was to identify mitochondrial DNA (mtDNA) polymorphisms and rare variants that associate with elite Japanese athletic status. Subjects comprised 185 elite Japanese athletes who had represented Japan at international competitions (that is, 100 endurance/middle-power athletes: EMA; 85 sprint/power athletes: SPA) and 672 Japanese controls (CON). The entire mtDNA sequences (16 569 bp) were analyzed by direct sequencing.

Increased hemoglobin mass and VO2max with 10 h nightly simulated altitude at 3000 m.

Purpose: To quantify the changes of hemoglobin mass (Hbmass) and maximum oxygen consumption (VO2max) after 22 days training at 1300-1800 m combined with nightly exposure to 3000-m simulated altitude. We hypothesized that with simulated 3000-m altitude, an adequate beneficial dose could be as little as 10 h/24 h.

Methods: Fourteen male collegiate runners were equally divided into 2 groups: altitude (ALT) and control (CON).

Mitochondrial haplogroups associated with elite Japanese athlete status.

Purpose: It has been hypothesised that certain mitochondrial haplogroups, which are defined by the presence of a characteristic cluster of tightly linked mitochondrial DNA polymorphisms, would be associated with elite Japanese athlete status. To examine this hypothesis, the frequencies of mitochondrial haplogroups found in elite Japanese athletes were compared with those in the general Japanese population.

Methods: Subjects comprised 139 Olympic athletes (79 endurance/middle-power athletes (EMA), 60 sprint/power athletes (SPA)) and 672 controls (CON).

Inhibitory effects of an orexin-2 receptor antagonist on orexin A- and stress-induced ACTH responses in conscious rats.

Orexins, recognized for their diverse functions in sleep/wakefulness/arousal and appetite regulation, may play provocative roles in stress response. Although the PVN of the hypothalamus expresses an abundance of orexin-2 receptor (OX-2R), the involvement of OX-2R in regulating ACTH response to stress remains unclear. To address this, we examined effects of a selective antagonist to OX-2R (N-{(1S)-1-[6,7-dimethoxy-3,4-dihydro-2(1H)-isoquinolinyl]carbonyl}-2,2-dimethylpropyl)-N-{4-pyridinylmethyl}amine upon plasma ACTH concentrations after administration of orexin A and swimming stress.

Increased c-fos gene expression in alpha motoneurons in rat loaded hindlimb muscles with inclined locomotion.

The potential usefulness of c-fos gene expression as an indicator of the activity level of spinal alpha motoneurons was examined in loaded locomotive rats. The motor pools of the plantaris (PL) and soleus muscles (SOL), mainly composed respectively of fast- and slow-twitch muscle fibers, were investigated in rats under locomotion at 25 m/min on a 20% incline. We first labeled motoneurons with a retrograde tracer, Nuclear Yellow (NY), and then quantified the c-fos mRNA expression level in the NY-labeled alpha motoneurons by means of in situ hybridization.