著者
渡邊 大輝
出版者
一般社団法人日本体力医学会
雑誌
体力科学 (ISSN:0039906X)
巻号頁・発行日
vol.67, no.3, pp.207-218, 2018-06-01 (Released:2018-05-16)
参考文献数
72

Ryanodine receptors (RyRs) are tetrameric Ca2+ release channels of sarcoplasmic reticulum (SR). This review attempts to detail the key mechanism of RyR channel gating and to discuss the hypothesis that skeletal muscle fatigue, defined as reduced force production, would result from functional changes in both individual RyR channel opening and coupling among RyR channels. Previous studies have shown that RyR channels in skeletal muscle open simultaneously, called coupled gating, because of physical interaction among channels. In this review, mechanisms underlying muscle fatigue are discussed with consideration of the coupling effect. Fatigue mechanisms are thought to be different between acute exercise and long-term exercise training. The impairments in individual channel opening and coupling between RyR channels can occur after acute exercise, leading to decreased SR Ca2+ release and force depression. On the contrary, during long-term exercise training, individual channel opening would be enhanced but coupling between channels would be impaired. If this were to continue for long periods, SR Ca2+ content would reduce, leading to less Ca2+ release and lower force production.
著者
猪口 清一郎 岩本 壮太郎 石川 博 東 慶紀
出版者
一般社団法人日本体力医学会
雑誌
体力科学 (ISSN:0039906X)
巻号頁・発行日
vol.29, no.1, pp.45-51, 1980-03-01 (Released:2010-09-30)
参考文献数
26
被引用文献数
1

The muscle fibers of M. rectus abdominis from 3 sportsmen (Weight-lifting, Boxing and Body-building) were examined histologically and compared with the mean of 22 human control subjects. Following results were obtained.1. Compared with the M, rectus abdominis of control subjects, the sportsmen's rectus abdominis muscle area was about 4 times the cross-sectional area of muscle belly and the number of muscle fibers per sq, mm, were 1/3 that of the control specimens. The total number and mean size of sportsmen muscle fibers corresponded to the respective maxima of the controls, and the muscle fiber density in sportsmen corresponded to the minimum control value.2. Comparing the myofibrous organization of 3 specimens, the muscle of the boxer was largest in cross-sectional area, in frequency of muscle fibers with large diameter, and in volume of interstitial connective tissue. It was the smallest of the 3 specimens in the number of muscle fibers per sq. mm. We found that the muscle of the weight-lifter was intermediate in these four categories.
著者
真田 樹義 宮地 元彦 山元 健太 村上 晴香 谷本 道哉 大森 由実 河野 寛 丸藤 祐子 塙 智史 家光 素行 田畑 泉 樋口 満 奥村 重年
出版者
一般社団法人日本体力医学会
雑誌
体力科學 (ISSN:0039906X)
巻号頁・発行日
vol.59, no.3, pp.291-302, 2010-06-01
参考文献数
23
被引用文献数
2 8

The purpose of this study was to develop prediction models of sarcopenia in 1,894 Japanese men and women aged 18-85 years. Reference values for sarcopenia (skeletal muscle index, SMI; appendicular muscle mass/height<sup>2</sup>, kg/m<sup>2</sup>) in each sex were defined as values two standard deviations (2SD) below the gender-specific means of this study reference data for young adults aged 18-40 years. Reference values for predisposition to sarcopenia (PSa) in each gender were also defined as values one standard deviations (1SD) below. The subjects aged 41 years or older were randomly separated into 2 groups, a model development group and a validation group. Appendicular muscle mass was measured by DXA. The reference values of sarcopenia were 6.87 kg/m<sup>2</sup> and 5.46 kg/m<sup>2</sup>, and those of PSa were 7.77 kg/m<sup>2</sup> and 6.12 kg/m<sup>2</sup>. The subjects with sarcopenia and PSa aged 41 years or older were 1.7% and 28.8% in men and 2.7% and 20.7% in women. The whole body bone mineral density of PSa was significantly lower than in normal subjects. The handgrip strength of PSa was significantly lower than in normal subjects. Stepwise regression analysis indicated that the body mass index (BMI), waist circumference and age were independently associated with SMI in men; and BMI, handgrip strength and waist circumference were independently associated with SMI in women. The SMI prediction equations were applied to the validation group, and strong correlations were also observed between the DXA-measured and predicted SMI in men and women. This study proposed the reference values of sarcopenia in Japanese men and women. The prediction models of SMI using anthropometric measurement are valid for alternative DXA-measured SMI in Japanese adults.
著者
下方 浩史 安藤 富士子
出版者
一般社団法人日本体力医学会
雑誌
体力科学 (ISSN:0039906X)
巻号頁・発行日
vol.66, no.2, pp.133-142, 2017-04-01 (Released:2017-03-19)
参考文献数
24
被引用文献数
3

The state in which physical and mental functions are deteriorated with aging is called frailty, and decrease in muscle mass and muscle strength with aging accompanying deterioration of physical function is called sarcopenia. Frailty and sarcopenia are found in older adults, which is a major obstacle to achieve healthy longevity. Estimation of prevalence and number of patients, as well as elucidation of risk factors in frailty and sarcopenia are important for the prevention of frailty and sarcopenia. The prevalence of frailty determined by criteria based on the method of Fried et al. was 5.2% for men and 20.9% for women in a cohort of randomly selected community-living population, and the estimated number of people with frailty was about 0.77 million men and 2,22 million women among the population aged 65 years and over in Japan. The prevalence of sarcopenia by the Asian Working Group for Sarcopenia (AWGS) criteria was 9.6% for men and 7.7% for women. The number of people aged 65 years and over with sarcopenia in Japan was estimated to be 1.64 million for men and 1.39 million for women. The onset of frailty was related to physique, physical function, cognitive function, depression, and various chronic diseases. Depression and lack of exercise were significant risk factors of sarcopenia. Physical activity, nutrition and control of chronic diseases are required for the prevention of frailty and sarcopenia, and the prevention will be an important issue for health and longevity in Japan.
著者
松竹 貴大 夏原 隆之 小井土 正亮 鈴木 健介 田部井 祐介 中山 雅雄 浅井 武
出版者
一般社団法人日本体力医学会
雑誌
体力科学 (ISSN:0039906X)
巻号頁・発行日
vol.67, no.1, pp.107-123, 2018-02-01 (Released:2018-01-19)
参考文献数
62
被引用文献数
2

In this study, observing football players under simulated playing conditions to measure event-related potentials (ERPs, i.e. P300), electromyography reaction time (EMG-RT), and reaction time (RT), we investigated neural correlates of information processing during selective reaction challenges. A high performance group included 13 collegiate football players who had previously won the All Japan University Championships. A low performance group included 13 collegiate football players who never competed at the national level or played in prefectural or regional competitions. We conducted a 4 vs. 2 ball possession task (i.e. a Go/NoGo task) under simulated playing conditions that required situational assessment. Our results showed that the high-performance group had a significantly higher correct response rate than did the low-performance group in 4 vs. 2 ball possession tasks. Moreover, the EMG-RT and RT of the high-performance group were significantly shorter than that of the low-performance group. Furthermore, the P100 and P300 latencies of the high-performance group was significantly shorter than those of the low-performance group. These findings indicated that high-performance football players could perform the task-relevant stages of information processing (such as visual information processing, stimulus evaluation, and motor response output) in a short time. There was no correlation between EMG-RT and P100 (Go, NoGo stimulation), indicating that initial visual information processing did not contribute to the execution of the final motor response. There was no correlation between EMG-RT and Go P300 latency, whereas a significant correlation with NoGo P300 latency was shown. This suggested that the stimulus evaluation system by NoGo stimuli (response inhibition) is strongly involved in the final motor output reaction.
著者
金久 博昭
出版者
一般社団法人日本体力医学会
雑誌
体力科学 (ISSN:0039906X)
巻号頁・発行日
vol.65, no.1, pp.43-43, 2016
被引用文献数
2
著者
Yasuro Furuichi Nobuharu L. Fujii
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.6, no.5, pp.311-316, 2017-09-25 (Released:2017-09-29)
参考文献数
51
被引用文献数
4

Skeletal muscle stem cells, known as satellite cells, participate in postnatal skeletal muscle growth, regeneration, and hypertrophy. They are quiescent in the resting state, but are activated after muscle injury, and subsequently replicate and fuse into existing myofibers. The behavior of satellite cells during muscle regeneration is regulated by extrinsic factors, such as the extracellular matrix, mechanical stimuli, and soluble factors. Myokines, muscle-derived secretory factors, are important regulators of satellite cell activation, proliferation, and differentiation. It is well known that muscle injury induces the release of various growth factors from myofibers, and these growth factors affect satellite cells. It has recently been shown that myokines secreted from myofibers without cell damage also regulate satellite cell functions. Here, we summarize myokines with known roles in the regulation of satellite cells and the mechanism underlying this regulatory process.
著者
白山 正人
出版者
一般社団法人日本体力医学会
雑誌
体力科学 (ISSN:0039906X)
巻号頁・発行日
vol.45, no.3, pp.395-398, 1996-06-01 (Released:2010-09-30)
参考文献数
13
被引用文献数
1 1
著者
Shoko Nishizono Zi Wang Yukari Watanabe Yoshihisa Ohata Takuya Chiba
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.6, no.4, pp.201-207, 2017-07-25 (Released:2017-07-12)
参考文献数
44
被引用文献数
2

More than 80 years ago, McCay and colleagues first reported that limiting the amount of food provided to experimental animals (i.e. calorie restriction or CR) prolongs their lifespan and suppresses the onset and progression of various age-related diseases. Today, CR remains the most reliable method of delaying aging in experimental animals, and research into its underlying molecular mechanisms is ongoing. CR has been reported to have anti-aging and life-extension effects on primates, with progress being made toward applications for humans. Studies on mechanisms underlying the onset and prevention of lifestyle-related diseases such as diabetes have elucidated the cellular signaling pathways that regulate energy metabolism, and commonalities have been discovered between the targets of existing diabetes drugs and the signaling pathways affected by CR. This finding has led to research into the discovery of drugs that have the anti-aging effects of CR in the absence of food intake limitations, namely CR mimetics (CRM). Several drugs have been reported to extend the lifespan of experimental organisms, which may thus have the potential to also extend human lifespan. In this article, we outline and compare those drugs that have been reported to date and discuss the possibility of taurine as a CRM, which is a topic of our ongoing research.