著者
Yuki Tamura Hideo Hatta
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.3, pp.151-158, 2017-05-25 (Released:2017-05-17)
参考文献数
50

Heat stress treatment is a classic physical therapy, which is employed in the orthopedic field. In the field of physical fitness/sports science, morphological changes of skeletal muscle by heat stress have been well studied. In recent years, energy metabolic adaptations by heat stress have also been actively studied. In this review, we provide an overview of recent findings on heat stress-induced mitochondrial adaptations in skeletal muscles, and further discuss our unpublished data and recent findings in related research fields. First, we summarized heat stress-induced positive regulation of mitochondrial content and its underlying molecular mechanisms from perspectives of mitochondrial biogenesis and degradation. Consequently, we reviewed beneficial effects of heat stress on mitochondrial health in disused and aged muscles, focusing on mitochondrial stress response at the organelle level (mitochondrial selective autophagy; mitophagy) and molecular level (mitochondrial unfolded protein response). Finally, we overviewed future directions to better understand heat stress-induced mitochondrial adaptations in skeletal muscle.
著者
Shigenobu Shibata Yu Tahara
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.3, no.1, pp.65-72, 2014-03-25 (Released:2014-03-20)
参考文献数
99

In mammals, the circadian clock organizes physiological processes, including sleep/wake patterns, hormonal secretion, and metabolism, and regulates athletic performance. The circadian system is responsive to environmental changes such as light/dark cycles, food intake, and exercise. In this review, we will focus on the central and peripheral circadian molecular clock system, discussing how circadian rhythm affects athletic performance and muscle metabolism, and how exercise entrains the circadian rhythm. Importance of exercise training in rescuing circadian deficit–induced metabolic disorder is also discussed. The interaction of the circadian clock and exercise, called “chrono-exercise,” is poised to become an important research field of chronobiology.
著者
Hirofumi Zempo Mitsuaki Isobe 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.6, no.1, pp.25-31, 2017-01-25 (Released:2017-01-21)
参考文献数
91

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
Ryoichi Ema Ryota Akagi Taku Wakahara Yasuo Kawakami
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.1, pp.37-46, 2016-03-25 (Released:2016-03-18)
参考文献数
97

The present review summarizes current evidence and unresolved issues regarding training-induced changes in the architecture of human skeletal muscles. As architectural parameters, we focused on the fascicle length and pennation angle, which are related to force-generating capability of pennate muscles. Cross-sectional studies in sport athletes suggested changes in both the parameters following chronic sport-specific activities. Longitudinal training intervention experiments indicated direct evidence of the plasticity of the two parameters induced by resistance training, but no consensus has been reached regarding the factors influencing those changes. Considering the importance of fascicle arrangement on muscle function, future studies are required to explain the underpinning mechanisms of the adaptation.
著者
Taichi Yamaguchi Kojiro Ishii
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.3, no.1, pp.121-129, 2014-03-25 (Released:2014-03-20)
参考文献数
62
被引用文献数
2 or 0

Previous studies have indicated that dynamic stretching acutely improves explosive performance, and dynamic stretching is now incorporated into warm-up protocols prior to sports activities that require explosive performance. The optimal protocol for dynamic stretching, however, has not been clarified. The purpose of this review is to clarify the optimal protocols for velocity and volume (i.e., repetition or distance x set) in dynamic stretching to improve explosive performance by systematic investigation. For velocity, the rate of change in explosive performance when dynamic stretching was performed “as fast as possible” (7.6 ± 3.8%) was significantly (P < 0.01) greater compared to when dynamic stretching was performed “without setting the velocity” (1.1 ± 5.3%). This finding suggested that dynamic stretching should be performed “as fast as possible”. As for volume, the repetition of dynamic stretching was significantly (P < 0.01) negatively correlated with the rate of change in explosive performance only when dynamic stretching was performed without setting the velocity. The distance of dynamic stretching was also significantly (P < 0.05) negatively correlated with the rate of change in explosive performance. These findings suggest that explosive performance might become impaired as the volume of dynamic stretching increases. By combining simple regression analysis of the repetition or the distance of dynamic stretching and the rate of change in explosive performance with a systematic investigation, it was found that the optimal “repetition” or “distance” x “set” of dynamic stretching was “10-15 repetitions” or “10 yards-20 meters” x “1-2 sets”, respectively.
著者
Tetsuya Izawa Jun-etsu Ogasawara Takuya Sakurai Sachiko Nomura Takako Kizaki Hideki Ohno
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.1, no.3, pp.381-387, 2012-09-25 (Released:2012-10-23)
参考文献数
64

White adipose tissue (WAT) is located beneath the skin as subcutaneous adipose tissue (SAT), around internal organs as visceral adipose tissue (VAT), pericardial and epicardial adipose tissue, and inside muscles in human beings. Recent studies indicate that developmental and patterning genes are differentially expressed in SAT and VAT, and some of these genes exhibit changes in expression that closely correlate with the extent of obesity and pattern of fat distribution. Furthermore, the development of adipocytes from mesenchymal stem/progenitor cells is thought to be mediated by developmental signaling molecules including nodal, Wnt/wingless (Wg), bone morphogenetic proteins (BMPs), fibroblast growth factors (FGF), and others. Of these, BMPs and the FGF family have been suggested to play a role in maintaining energy homeostasis. However, it remains unclear whether these developmental and patterning genes are associated with morphological changes in WAT in response to exercise training (TR). On the other hand, when TR reduces the number of adipocytes in WAT, it increases preadipocyte factor 1 mRNA expression but down-regulates peroxisome proliferator-activated receptor-γ mRNA expression in stromal-vascular fraction cells, including adipose tissue-derived stromal cells, via the up-regulation of hypoxia-inducible factor-1α, which may also up-regulate the mRNA expression of vascular endothelial growth factor-A and its receptor. The purpose of this review is to summarize the research to date on the morphology of WAT and adipose tissue cellularity in exercise adaptation.
著者
Yudai Takarada
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.123-130, 2016-03-25 (Released:2016-05-14)
参考文献数
29

Low-to-moderate intensity resistance exercise with vascular occlusion induces increased muscle mass and strength, comparable to that after conventional heavy resistance training. Also, participants feel as if they require greater force (effort) to lift a weight when undergoing resistance exercise following vascular occlusion. Vascular occlusion of the proximal upper arm increased perceived magnitude of exerted hand-grip force without causing any accompanying changes either in electromyographic or efferent/afferent activity of the median nerve. There was also no effect on motor evoked potentials in the hand following resting-state transcranial magnetic stimulation (TMS) over the primary motor cortex (M1). Moreover, low-frequency, repetitive transcranial magnetic stimulation (lf-rTMS) over the left primary somatosensory cortex did not significantly affect estimations of right-hand grip force exertion. Thus, the primary factor responsible for the overestimation of force exertion with increased voluntary effort (“sense of effort”) during occlusion was the central signal related to motor command size. Brain imaging studies show that vascular occlusion increases M1 activity during force exertion, which may be related to functions of motor-related cortical areas, e.g., supplementary motor area, as sources of excitatory input to M1. M1 suppression by lf-rTMS during force exertion causes participants’ sense of effort and force perception to increase. This mechanism may also operate during muscular contraction with vascular occlusion. It is easy to imagine perceiving maximal effort when we consciously try to produce maximal force; however, does M1 activity become maximal at that point in time? In this study, the liberation of potential muscular strength, focusing on the motor system state before awareness of motor intention, is looked at.
著者
Yoshihisa Umemura
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.1, pp.7-12, 2016-03-25 (Released:2016-03-18)
参考文献数
37
被引用文献数
1 or 0

Mechanical loads on the skeleton imposed by exercise increase bone mass and strength. The sensor in the osteocyte that detects mechanical stress, the mechano-sensor, responds to bone strain caused by mechanical loading. Greater magnitude and rate of strain increases osteogenic response, making high-impact exercise, which imposes large and dynamic strain on the skeleton, an effective mode of exercise. However, the sensitivity of the mechano-sensor (mechano-sensitivity) drops after a large number of repetitions performed within an exercise session, which has diminishing returns. It takes several hours or several days to reestablish mechano-sensitivity after the last loading session. It is important to consider the time to recovery of mechano-sensitivity when determining optimal exercise frequency.
著者
Yumiko Takahashi Yutaka Matsunaga Yuki Tamura Eiki Urushibata Shin Terada Hideo Hatta
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.3, no.5, pp.531-537, 2014-11-25 (Released:2014-12-05)
参考文献数
26
被引用文献数
1 or 0

Previous studies suggested that taurine (2-aminoethanesulfonic acid) administration enhances glucose uptake, one of the rate-limiting factors for glycogen synthesis. In this study, we investigated the effects of post-exercise taurine administration on glycogen repletion in skeletal muscle in ICR mice. In experiment 1, we orally administered either taurine (0.5 mg/g body weight) solution or physiological saline immediately after treadmill running at 25 m/min for 90 min. The serum free fatty acid (FFA) concentration at 60 min after the exercise was significantly higher in the taurine-treated group compared with the control group (p < 0.05). At 120 min after the exercise, the tibialis anterior muscle glycogen concentration in the taurine-treated group was significantly higher than that in the control group (p < 0.05). In experiment 2, we orally administered either glucose (1 mg/g body weight) solution or glucose solution containing taurine immediately after and at 60 min after the exercise. The area under the curve (AUC) for blood glucose concentration from 0 to 60 min after the exercise was significantly smaller in the taurine-treated group compared with the control group (p < 0.01). Our results show that post-exercise taurine administration enhances glycogen repletion in skeletal muscle. Higher skeletal muscle glycogen concentration by taurine administration may be partly due to the acceleration of glucose uptake. In addition, as the elevation of blood FFA level leads to an increase in fat oxidation, it is possible that a higher serum FFA concentration by taurine treatment is related to the sparing of carbohydrate for glycogen repletion.
著者
Kaito Iwayama Kumpei Tokuyama
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.1, no.2, pp.307-316, 2012-07-25 (Released:2012-09-11)
参考文献数
56

Indirect calorimetry with a room-size respiratory chamber provides an ideal setting to monitor energy metabolism for a prolonged period. During the last 10 years, experiments with this method have raised interesting observations such as: 1) exercise intensity has no effect on 24 h fat oxidation, 2) exercise has little, if any, effect on 24 h fat oxidation, and 3) exercise before breakfast increases 24 h fat oxidation. To some of the scientific community and general public, the first two statements may be unacceptable. But it can be factually explained that the impact of exercise on energy metabolism is not confined to the period of physical activity itself, and that fat oxidation remains elevated during the post-exercise period. The third observation seems to be insignificant, but contradicts the second one. It is premature to conclude that exercise has no effect on 24 h fat oxidation.
著者
Keishi Soga Keita Kamijo Hiroaki Masaki
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.1, pp.57-67, 2016-03-25 (Released:2016-03-18)
参考文献数
78

An increasing number of studies have examined the effects of acute aerobic exercise on executive function (i.e., higher-order cognitive abilities involved in goal-directed behaviors) in healthy children. More recently, studies have begun to extend these empirical findings to children with neurodevelopmental disorders such as attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Here, we review what is known about the effects of acute exercise on executive function in children with and without neurodevelopmental disorders. Overall, moderate acute aerobic exercise can transiently improve executive function in children with and without neurodevelopmental disorders. Further, these effects of acute exercise may differ depending on type of exercise, participant characteristics (e.g., fitness levels, executive function capacity, type of neurodevelopmental disorder), and timing of cognitive task administration (i.e., after versus during exercise). Despite the increasing number of findings, it is still premature to suggest effective exercise types and/or intensity levels to produce improvements in executive function in children. Further studies are needed to address this issue. Finally, future research directions are discussed in more detail.
著者
Keiji Hayashi
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.2, pp.143-149, 2015-05-25 (Released:2015-05-28)
参考文献数
59

More than a hundred years ago, it was first reported that increases in body temperature stimulate minute ventilation. Since then, the characteristics, mechanisms and physiological meaning of this ventilatory response to increasing body temperature, so-called hyperthermia-induced hyperventilation, have gradually been uncovered. For example, it is now known that hyperthermia-induced hyperventilation has a core temperature threshold, like heat-dissipating responses (sweating and cutaneous vasodilation); but several factors affecting heat-dissipating responses do not influence the ventilatory response to increasing body temperature. On the other hand, evidence from several studies suggests there may be some relation between hyperthermia-induced hyperventilation and heat-dissipating responses. In addition, more recent evidence indicates that hyperthermia-induced hyperventilation may be related to central fatigue, which is considered to be one of the reasons exercise performance is diminished in heat. In fact, it has been suggested that hyperthermia-induced hyperventilation causes cerebral blood perfusion to be reduced, which decreases cerebral oxygenation and heat removal. This review presents an overview of the characteristics of the ventilatory response to increasing body temperature and its effect on central fatigue.
著者
Yuhei Makanae Riki Ogasawara Satoshi Fujita
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.2, pp.217-221, 2015-05-25 (Released:2015-05-28)
参考文献数
48

Concurrent training, which is a combination of resistance exercise (RE) and endurance exercise (EE) performed in succession, is used to improve both muscle strength and cardiovascular function. Although numerous studies have investigated the effects of concurrent training on muscle adaptation, no consensus has been reached. Skeletal muscle adaptation is induced by the cumulative effects of the repeated cellular and molecular responses to an acute bout of exercise. Divergent exercise modes induce different molecular signaling responses depending on the muscle contraction type. It is well known that RE induces the mammalian target of the rapamycin complex 1 (mTORC1) signaling pathway while EE activates AMP-activated protein kinase (AMPK) signaling, and the signaling pathways stimulated by each exercise could interfere with each other. Thus, the inconsistencies in the effects of concurrent training on muscle adaptation may be explained by the different signaling interactions occurring in response to RE and EE. This review article describes the signaling pathways induced by RE, EE, and concurrent training.
著者
Masayuki Konishi Masaki Takahashi Naoya Endo Shigeharu Numao Shun Takagi Masashi Miyashita Taishi Midorikawa Katsuhiko Suzuki Shizuo Sakamoto
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.2, no.1, pp.121-126, 2013-03-25 (Released:2013-04-08)
参考文献数
31
被引用文献数
1 or 0

The aim of this study was to investigate the effects of one night of sleep deprivation on maximal fat oxidation during a graded exercise test. Ten healthy young males underwent two 2-day control and sleep deprivation trials. Participants were allowed normal sleep from 2300 to 0700 for the control trial, whereas they were required to stay awake for 34 h during the sleep deprivation trial. At 1700 on day 2, participants performed a graded exercise test to exhaustion on a treadmill; this allowed us to determine maximal oxygen uptake and maximal fat oxidation. Before and immediately after the graded exercise test, blood samples were collected in order to measure glucose, insulin, free fatty acid, and triglyceride concentrations. Plasma glucose concentrations were significantly higher in the sleep deprivation trial than in the control trial before the graded exercise test. Serum insulin and free fatty acid concentrations were not significantly different between the two trials. Serum triglyceride concentrations were significantly lower in the sleep deprivation trial than in the control trial. The maximal fat oxidation rate, oxygen uptake, and heart rate at maximal fat oxidation intensity, during the graded exercise test, were not significantly different between the two trials. These findings suggest that maximal fat oxidation during graded exercise is unaffected by one night of sleep deprivation.
著者
Masaki Takahashi Katsuhiko Suzuki Hideki Matoba Shizuo Sakamoto Shigeru Obara
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.1, no.1, pp.183-189, 2012-05-25 (Released:2012-08-22)
参考文献数
36
被引用文献数
2 or 0

The purpose of this study was to investigate the effects of three different intensities of exercise on oxidative stress and antioxidant capacity. Eight healthy male subjects performed three different intensities of exercise for 20 minutes: (1) 70% anaerobic threshold (AT) (light intensity, LI), (2) 100% AT (moderate intensity, MI), and (3) 130% AT (high intensity, HI) on a cycle ergometer. A control (C) trial was conducted under resting conditions. Blood samples were taken pre-exercise, immediately and 30 min after exercise. In the HI trial only, the concentrations of plasma derivatives of reactive oxygen metabolites (d-ROMs) were significantly higher immediately (P<0.01) and 30 min after exercise (P<0.05) than at pre-exercise. Furthermore, plasma trolox equivalent antioxidant capacity was significantly higher immediately after exercise in the HI trial (P<0.01). And, plasma glutathione peroxidase (GPX) activity was significantly higher immediately after exercise than at pre-exercise in the MI (P<0.05) and HI trials (P<0.01). These data suggest that 20 min of pedaling exercise above the AT level may increase ROS production, while endogenous enzyme activity (especially GPX activity) or non-enzymatic antioxidants may modulate exercise-induced ROS generation. Thus, exercise under the AT level induces very little oxidative stress damage in young people.
著者
Kana Konishi Tetsuya Kimura Atsushi Yuhaku Toshiyuki Kurihara Masahiro Fujimoto Takafumi Hamaoka Kiyoshi Sanada
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.2, pp.111-117, 2017-03-25 (Released:2017-03-19)
参考文献数
40

Exercise-induced changes in executive function affect the control of action in a dynamic environment. This study aimed to examine the effect of sustained high-intensity exercise on executive function. Nine healthy male and female participants (age, 21-28 years) completed an exercise session with 65-min treadmill running at 75% VO2max. Executive function was assessed before and after exercise with the Stroop Color and Word Test that included congruent and incongruent conditions. The reaction time and response accuracy of the test were measured, and the task difficulty was controlled by adjusting the stimulus duration so that each participant could maintain at least 80% response accuracy to exclude the effect of a speed–accuracy trade-off. The levels of plasma norepinephrine and adrenocorticotropic hormone were examined. A significant interaction with the reaction time was found (condition × time, P = 0.024), in which the reaction time significantly increased after exercise only in the incongruent condition (P = 0.019). The response accuracy was not significantly different between before and after exercise in both conditions, which indicated that the response accuracy was controlled as intended. The levels of plasma norepinephrine and adrenocorticotropic hormone were significantly increased after exercise (P < 0.05). These results demonstrated that the reaction time in the incongruent condition increased after sustained high-intensity exercise with a cognitive function test with the response accuracy controlled, indicating a decline in executive function. Increased levels of plasma norepinephrine and adrenocorticotropic hormone may contribute, at least in part, to such decline in executive function.
著者
Yujiro Yamanaka Jim Waterhouse
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.4, pp.287-299, 2016-09-25 (Released:2016-10-03)
参考文献数
66

The human circadian system derives from two distinct circadian oscillators that separately regulate circadian rhythms of body temperature and plasma melatonin, and of the sleep-wake cycle. The oscillator for body temperature and melatonin is the central circadian pacemaker, located in the hypothalamic suprachiasmatic nucleus (SCN), and the oscillator for sleep-wake cycle is another oscillator, located in the brain but outside the SCN. Although bright light is a primary zeitgeber for circadian rhythms, non-photic time cues such as a strict sleep schedule and timed physical exercise act as a non-photic zeitgeber for the sleep-wake cycle under dim light conditions, independent on the SCN circadian pacemaker. Recently, timed physical exercise under bright light has been shown to accelerate re-entrainment of circadian rhythms to an advanced sleep schedule. Physical exercise may enhance the phase-shift of circadian rhythm caused by bright light by changing light perception. In the field of sports medicine and exercise science, adjustment of the circadian rhythm is important to enable elite athletes to take a good sleep and enhance exercise performance, especially after inter-continental travel and jet lag.
著者
Keiko Unno
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.117-122, 2016-05-25 (Released:2016-05-14)
参考文献数
53

Since aging is the most important risk factor for dementia, measures to slow the onset of brain aging are an important strategy for preventing dementia. Accumulation of oxidative damage is considered to be a major cause of aging. Catechins in green tea (GTCs) have powerful antioxidative activity. Ingestion of GTCs suppressed oxidative damage, brain atrophy and cognitive decline in aged mice. Age-related cognitive decline was significantly suppressed in mice when middle-aged mice started to drink green tea catechins. Middle-aged people are thus expected to be able to suppress brain aging by ingestion of GTCs. In addition, numerous people are stressed under various conditions. Brain aging was accelerated and lifespan shortened in experimental animals that were chronically and psychosocially stressed. Theanine, an amino acid in green tea, suppressed stress-induced aging. However, the anti-stress effect of theanine is blocked by catechins and caffeine that are main components in green tea. Daily drinking of several cups of green tea is considered to suppress brain aging. In addition, theanine-rich green tea or green tea with a lowered level of caffeine is expected to suppress stress and stress-induced aging.
著者
Yuka Watanabe Yuko Miyagoe-Suzuki
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.73-82, 2015-03-25 (Released:2015-03-23)
参考文献数
114

Muscle mass and strength decline with age. When severe, the loss is called sarcopenia. Sarcopenia is drawing attention worldwide, especially in highly aged societies, as a disease that should be treated. At present, we have limited tools to combat sarcopenia (e.g. resistance training and nutritional intervention), but accumulating knowledge of the molecular and cellular mechanisms of sarcopenia is accelerating the development of pharmacological therapies for sarcopenia. Because sarcopenia is a complicated pathological condition caused and modified by many aging-related factors, such as inactivity, loss of motor neurons, poor nutrition, decline of anabolic hormones, chronic inflammation, oxidative stress, impaired stem cell function, and comorbidity, the proposed target molecules or pathways for pharmacological intervention are diverse. Here we review recent progress in drug development with emphasis on small-molecule compound-based therapies and review the literature to identify new therapeutic targets to prevent, delay, or reverse sarcopenia.
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 or 0

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.