著者

Hirofumi Zempo Mitsuaki Isobe Hisashi Naito

出版者

The Japanese Society of Physical Fitness and Sports Medicine

雑誌

The Journal of Physical Fitness and Sports Medicine (ISSN:21868131)

巻号頁・発行日

vol.6, no.1, pp.25-31, 2017-01-25 (Released:2017-01-21)

参考文献数

91

被引用文献数

12

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The mechanism which causes sarcopenia, a loss of muscle mass and strength with aging, remains unclear. Muscle mass is controlled by the net balance between protein synthesis and breakdown; however, net balance differences in the basal state do not contribute to sarcopenia. On the other hand, anabolic resistance, a reduction in muscle protein synthesis in response to protein intake, does seem to be involved in sarcopenia. Muscles which are subject to anabolic resistance do not show incremental blood flow volume during the fed-state. Because the vascular system transports amino acids and other nutrients that are essential for muscle protein synthesis, blood flow volume may be a regulator of anabolic resistance. There is some evidence of a link between blood flow and muscle protein metabolism. In addition, a combination of resistance training and amino acid supplementation promotes a positive net protein balance. Resistance training improves, and detraining reduces blood flow volume; therefore, blood flow volume may be involved as a background mechanism for sarcopenia. Moreover, previous studies have shown that sodium nitroprusside, a vasodilatory nitric oxide donor, enhances muscle protein synthesis. Conversely, angiotensin II, a major vasoconstrictive peptide, induces skeletal muscle protein breakdown. In this review, we discuss a possible role for blood flow in skeletal muscle protein metabolism in elderly adults. The regulation of blood flow may prove to be a beneficial treatment for sarcopenia.

著者

Takao Sugiura Naoko Ito Katsumasa Goto Hisashi Naito Toshitada Yoshioka Scott K. Powers

出版者

PHYSIOLOGICAL SOCIETY OF JAPAN

雑誌

The Journal of Physiological Sciences (ISSN:18806546)

巻号頁・発行日

vol.56, no.6, pp.393-399, 2006 (Released:2006-12-28)

参考文献数

43

被引用文献数

34 37

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We tested the hypothesis that estrogen administration would retard immobilization-induced muscle atrophy in adult male rats. The rats were injected for 24 days with either estrogen (40 μg/kg−1, β-estradiol 3-benzoate in olive oil vehicle), or vehicle alone. At day 14 of estrogen treatment, the hindlimb muscles of one leg were immobilized in plantar flexion position by the use of a plaster cast. Following 10 days of immobilzation, the atrophic and the contralateral soleus muscles were both removed and analyzed to determine the level of muscle atrophy along with the measurement of the protein levels of Cu-Zn-superoxide dismutase (Cu-Zn-SOD), heat shock protein 72 (HSP72), and selected proteases. Compared to placebo animals, estrogen treatment significantly reduced (–35%) muscle atrophy. Further, estrogen significantly abridged the expression of the calcium-activated protease, calpain, in the atrophied hindlimb muscle. In contrast, estrogen treatment did not alter the protein levels of HSP72 in the immobilized soleus muscle. These results support the postulate that estrogen attenuates the rate of disuse muscle atrophy, partly because of reductions in immobilization-induced calcium-activated protease levels.

著者

Hisashi Naito Toshinori Yoshihara Ryo Kakigi Noriko Ichinoseki-Sekine Takamasa Tsuzuki

出版者

The Japanese Society of Physical Fitness and Sports Medicine

雑誌

The Journal of Physical Fitness and Sports Medicine (ISSN:21868131)

巻号頁・発行日

vol.1, no.1, pp.125-131, 2012-05-25 (Released:2012-08-22)

参考文献数

61

被引用文献数

9 10

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Many researchers have been interested in the effects of heat stress on skeletal muscle. Recently, it has been demonstrated that heat stress on skeletal muscle results in an increase in muscle protein mass and subsequent muscle hypertrophy, and attenuation of muscle atrophy. Although the cellular mechanism remains unclear, it is thought that heat shock proteins (HSPs), which are highly conserved proteins induced by heat stress, play a major role in these phenomena. However, new insights suggest that heat stress-induced muscle hypertrophy and the prevention of muscle atrophy may be regulated not only by elevated HSP expression but also by multiple signaling pathways associated with protein synthesis and breakdown. Additionally, heat stress seems to cause various changes in other muscle functions. Although further studies are required to reveal the molecular biological mechanisms involved in the heat stress-induced changes in skeletal muscle, heat stress may be a useful tool for increasing muscle mass, attenuating disuse skeletal muscle atrophy, facilitating an early recovery from muscle damage, and improving glucose metabolism. This paper reviews studies of these effects of heat stress on skeletal muscle.

著者

Hayao Ozaki Takashi Abe Alan E. Mikesky Akihiro Sakamoto Shuichi Machida Hisashi Naito

出版者

一般社団法人日本体力医学会

雑誌

The Journal of Physical Fitness and Sports Medicine (ISSN:21868131)

巻号頁・発行日

vol.4, no.1, pp.43-51, 2015-03-25 (Released:2015-03-23)

参考文献数

69

被引用文献数

2 13

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This paper reviews the existing literature about muscle hypertrophy resulting from various types of training to document the significance of mechanical and metabolic stresses, and to challenge the conventional ideas of achieving hypertrophy that exclusively rely on high-load resistance training. Low-load resistance training can induce comparable hypertrophy to that of high-load resistance training when each bout or set is performed until lifting failure. This is attributable to the greater exercise volume and metabolic stress achieved with low-load exercise at lifting failure, which, however, results in a prolonged exercise bout. Endurance exercises (walking and cycling) at moderate intensity are also capable of eliciting muscle hypertrophy, but at much slower rates (months rather than weeks) in limited muscle or age groups. Blood flow restriction (BFR) in working muscles, however, accelerates the development of metabolic fatigue, alleviating the time consuming issue associated with low-load or endurance training. These alternative training methods, however, cannot completely replace conventional high-load resistance training, which provides superior strength gain as well as performance improvement even for trained individuals. The alternative approaches, therefore, may be considered for those who are less enthusiastic or under certain medical conditions, or who have limited or no access to proper equipment. However, people should be aware that low-load resistance training or endurance training entails substantial effort and/or discomfort at lifting failure or with BFR. Understanding the advantages and disadvantages of each method will help in assigning the most suitable training program for each client’s goals and needs.

著者

TAKASHI ABE YOSHIMITSU KOHMURA KOYA SUZUKI YUKI SOMEYA JEREMY P. LOENNEKE SHUICHI MACHIDA HISASHI NAITO

出版者

The Juntendo Medical Society

雑誌

順天堂醫事雑誌 (ISSN:21879737)

巻号頁・発行日

pp.JMJ23-0017-P, (Released:2023-07-24)

参考文献数

21

被引用文献数

4

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Handgrip strength as a biomarker is being studied as a factor in predicting disease onset. However, the effect of improving handgrip strength through physical exercises, such as sports during the developmental period, on disease prevention has yet to be fully elucidated. The Juntendo Fitness Plus (J-Fit Plus) Study is a unique database of anthropometric and physical fitness measurements with over 50 years of accumulated data. It has the potential to explore the effects of sports on the association between handgrip strength and morbidity/mortality. We first outline previous studies on the impact of physical exercise interventions on handgrip strength, separated into adulthood and developmental period. We then introduced a unique effort to investigate the effects of sports using the J-Fit Plus Study database and describe the challenges of finally elucidating the impact of exercise on the association between handgrip strength and health status.

著者

Akihiro Sakamoto Peter James Sinclair Hisashi Naito

出版者

一般社団法人日本体力医学会

雑誌

The Journal of Physical Fitness and Sports Medicine (ISSN:21868131)

巻号頁・発行日

vol.5, no.2, pp.153-166, 2016-05-25 (Released:2016-05-14)

参考文献数

73

被引用文献数

8

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Isoinertial resistance is imposed during natural human dynamics, where muscles contract at varying velocities and joint angles. In many sports, the ability to produce greater force at faster speed is essential for successful outcomes. Hence, power training under isoinertial resistance (e.g., body mass, weights or flywheel, etc.) provides event-specific adaptive stimuli. Conventional power training consists of a combination of strength-oriented (> 70% 1RM) and speed-oriented (< 30% 1RM, e.g., plyometrics) methods, with the aim of being able to overcome variable external loadings across a range of velocities. An alternative maximum power output training (Pmax training, 30-70% 1RM) has been found to elicit equivalent or greater effectiveness compared to the conventional methods. It is, however, difficult to precisely reproduce the prescribed intensities, given several concerns associated with 1RM testing and the variable accuracies of the repetition-intensity or velocity-intensity relationship. No matter what level of resistance is assigned to an exercise, it is far more important to exert as much effort (or fastest concentric speed) as possible per repetition, otherwise, the training effects are reduced. At light intensities, however, a large portion of the concentric phase is spent in deceleration for the subsequent phase transition, which may limit effort. Making projectile motions, therefore, are necessary. The utilization of stretch-shortening cycle effects, with increased power ability, may give a further training edge. Coaches and trainees should be aware that successful movements in power training are defined as greater acceleration, speed and displacement for every repetition, rather than simply neat form or smooth repetitiveness.

著者

Satomi ISHIGE Sawako WAKUI Yumi MIYAZAWA Hisashi NAITO

出版者

Japanese Society of Physical Therapy

雑誌

Physical Therapy Research (ISSN:21898448)

巻号頁・発行日

pp.E9982, (Released:2019-10-10)

参考文献数

43

被引用文献数

4 6

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Objective: In Japan, there were 1.17 million people with stroke in 2014; however, studies on community rehabilitation among stroke survivors are lacking. The Activities-specific Balance Confidence (ABC) scale is used in many languages to evaluate patients undergoing stroke rehabilitation. This study aimed to investigate the reliability and validity of the Japanese ABC scale (ABC-J) version among patients ≥6 months after stroke. Methods: This cross-sectional study was conducted with 88 post-stroke patients (mean age 66.5±9.5 years). The ABC-J was administered with the 10-meter walk test (10MWT), Timed Up and Go Test (TUG-T), Berg Balance Scale (BBS), Geriatric Depression Scale-Short version-Japanese (GDS-S-J), and the Falls Efficacy Scale-International (FES-I). After a 1-2-week interval, the ABC-J was completed again by 69 of the patients. Reliability was investigated for reproducibility (intra-class correlation coefficient [ICC], standard error of measurement [SEM], and minimal detectable change [MDC]) and internal consistency (Cronbach's α). Concurrent and convergent validities were assessed using Spearman's rank correlation coefficients. Results: The ABC-J showed excellent internal consistency (Cronbach's α = 0.95) and substantial test-retest reliability (ICC = 0.92, 95% confidence interval: 0.87-0.95), with SEM and MDC of 7.14 and 19.79, respectively. The total ABC-J score was significantly correlated with 10MWT (r = −0.51, p < 0.001), TUG-T (r = −0.55, p < 0.001), BBS (r = 0.61, p < 0.001), GDS-S-J (r = −0.27, p = 0.012), and FES-I (r = −0.77, p < 0.001). Conclusion: ABC-J is a valid and reliable measurement tool for investigating balance confidence among patients ≥6 months after stroke.

著者

MINORU KUNII SUSUMU S. SAWADA NAOFUMI YAMAMOTO YUKO GANDO HISASHI NAITO

出版者

The Juntendo Medical Society

雑誌

順天堂醫事雑誌 (ISSN:21879737)

巻号頁・発行日

pp.JMJ19-OA04, (Released:2019-12-13)

参考文献数

20

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Objective: The purpose of this study was to evaluate the relationship of freestyle swimming performance between adolescence and adult Japanese top-class swimmers.Methods: The 234 males and 134 females ranked in the top 100 records of 50, 100, 200 and 400 m freestyle short-course performances of over 22 years old during 2016 to 2018 (latest TIME), and their season best performances during 2006 to 2017 were analyzed. All data were collected from the public database “Swimrecord.com” by Japan Swimming Federation. Performance maturity status was determined by the ratio of each age record to the latest TIME and the relationship between the latest TIME and each age record was evaluated. Also, the subjects were divided into the upper or lower group with reference to the latest TIME and the developmental changes of performance were compared between the groups.Results: The performance maturity status was higher in females than males at each age. The correlation between the latest TIME and each age record became gradually stronger from males aged 17 years and females aged 14 years, but there was no clear correlation in the previous records. There was no difference in developmental changes in performance between the upper and lower groups in both males and females.Conclusions: The longitudinal analysis of the swimming performance in the growth period reveals that the Japanese top-class swimmers show high performance before 12 years old and that the time to approximate peak performance appeared earlier in females than in males and the relationship is different depending on swimming distance.

著者

TOMOHIRO NAKAMURA RYO KAKIGI NORIKO ICHINOSEKI-SEKINE TAKAMASA TSUZUKI HIROYUKI KOBAYASHI KAZUHIKO SAKUMA HISASHI NAITO

出版者

The Juntendo Medical Society

雑誌

順天堂醫事雑誌 (ISSN:21879737)

巻号頁・発行日

pp.JMJ19-OA08, (Released:2019-09-25)

参考文献数

21

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Objective: Alpha-actinin (ACTN) 3 R577X polymorphisms have three genotypes: RR, RX and XX. Only RR and RX genotypes express ACTN3 protein in type II fibers. The purpose of this study was to clarify whether there are differences in ACTN3 protein expression levels and myosin heavy chain (MyHC) composition between RR and RX genotypes in Japanese college-level male sprinters.Materials and Methods: Forty-three Japanese college-level male sprinters participated in this study. Subjects were genotyped for ACTN3 R577X using a real-time polymerase chain reaction assay. Furthermore, muscle biopsies from the vastus lateralis muscle were obtained from a subset of subjects who had R allele and gave their consent (4 RR and 9 RX). ACTN3 protein expression levels were assessed by western blotting. MyHC composition was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis.Results: There was no difference in 100-m sprint performance among RR, RX and XX genotypes in all 43 subjects. In 13 biopsy-sampled subjects, there was also no difference in 100-m sprint performance between RR and RX and ACTN3 protein expression levels tended to be higher in RR genotype than in RX genotype. Although there were no differences in the proportion of type I and II MyHC isoforms between both genotypes, RR genotype had a significantly higher proportion of type IIx MyHC isoform and a significantly lower proportion of type IIa MyHC isoform than RX genotype.Conclusions: ACTN3 protein expression levels and the proportion of type IIx MyHC isoform are higher in RR genotype compared with RX genotype in Japanese college-level male sprinters.

著者

Yuko Hashimoto Ko Matsudaira Susumu S. Sawada Yuko Gando Ryoko Kawakami Chihiro Kinugawa Takashi Okamoto Koji Tsukamoto Motohiko Miyachi Hisashi Naito

出版者

理学療法科学学会

雑誌

Journal of Physical Therapy Science (ISSN:09155287)

巻号頁・発行日

vol.29, no.6, pp.978-983, 2017 (Released:2017-06-07)

参考文献数

21

被引用文献数

24

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[Purpose] This study evaluated whether obesity is a risk factor for low back pain, by using body fat percentage (%FAT) and body mass index (BMI) as indices of obesity among Japanese males. [Subjects and Methods] This study included 1,152 males (average age: 28.0 ± 4.6 years). BMI was calculated from subject’s height and weight, and %FAT was estimated by the thickness of two parts of skin. Low back pain, drinking and smoking were surveyed using a self-administered questionnaire, and maximal oxygen uptake was measured by a submaximal exercise test using a cycle ergometer. [Results] A significant positive dose-response relationship was shown between %FAT and persistent low back pain prevalence. Similarly, a significant positive dose-response relationship was confirmed between BMI and persistent low back pain. [Conclusion] This study suggests that both high %FAT and BMI are risk factors for persistent low back pain.

著者

NORIYUKI FUKU ERI MIYAMOTO-MIKAMI NAOKI KIKUCHI HIROFUMI ZEMPO HISASHI NAITO

出版者

順天堂医学会

雑誌

順天堂醫事雑誌 (ISSN:21879737)

巻号頁・発行日

vol.62, no.Suppl.1, pp.22-28, 2016 (Released:2017-07-27)

参考文献数

41

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A number of familial and twin studies have assessed the relative contribution of genetic and environmental factors to physical performance or its-related traits, and a significant genetic component has been predicted to affect phenotypes. A twin study indicated that the heritability of athletic status is 66%. Thus, genetic factors appear to be important for determining elite sporting performance. To date, over 200 genes in both nuclear DNA and mitochondrial DNA (mtDNA) have been reported to be associated with physical performance and health-related fitness. However, most studies have been reported in European populations. In the Asian population, only 3 genetic loci have been linked to physical performance, including angiotensin I-converting enzyme and α-actinin-3 genetic polymorphisms and mtDNA polymorphisms (mitochondrial haplogroups). In this review, we discuss the genetics of elite sporting performance, particularly in Asian populations, and their effects on lifestyle-related diseases such as type 2 diabetes and age-related muscle wasting (i.e., sarcopenia).