- 著者
- Naomi YOSHII Koji SATO Riki OGASAWARA Toshiyuki KURIHARA Takafumi HAMAOKA Satoshi FUJITA
- 出版者
- Center for Academic Publications Japan
- 雑誌
- Journal of Nutritional Science and Vitaminology (ISSN:03014800)
- 巻号頁・発行日
- vol.63, no.6, pp.379-388, 2017 (Released:2018-01-12)
- 参考文献数
- 47
- 被引用文献数
- 6
Dietary protein intake is critical for maintaining an optimal muscle mass, especially among older individuals. Although protein supplementation during resistance training (RT) has been shown to further augment training-induced muscle mass in older individuals, the impact of daily variations in protein intake on training-induced muscle mass has not been explored thus far. Therefore, this study aimed to investigate the relationship between the dietary protein and amino acid intake and RT-induced muscle hypertrophy among older individuals. Ten healthy older men (n=10; mean age=69±2 y; body weight (BW)=61.5±2.2 kg; height=1.65±0.02 m) participated in progressive RT performed 3 times/wk for 12 wk. Body composition (using DXA) and nutritional assessments (using a 3-d dietary record) were performed before and after the training period. Leg lean mass (LLM) increased significantly (15.0±0.8 vs. 15.4±0.8 kg, p<0.05) after RT, with no change in dietary nutrient intake. The average dietary protein intake was 1.62±0.11 g/kg BW/d, while essential amino acids was 600±51 mg/kg BW/d. Although the correlation between the increase in LLM and dietary protein intake was not significant, a significant correlation was found between the increase in LLM and dietary essential amino acid (EAA) intake. Furthermore, there were significant correlations between the increase in LLM and protein as well as EAA (especially leucine) intake at breakfast among subjects with suboptimal protein intake (p<0.05). Our study findings indicate that dietary protein as well as EAA intake may be significant contributing factors in muscle hypertrophic response during RT among healthy older men.
- 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
- 被引用文献数
- 1
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
- Naokata Ishii Riki Ogasawara Koji Kobayashi Koichi Nakazato
- 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.83-94, 2012-05-25 (Released:2012-08-22)
- 参考文献数
- 118
- 被引用文献数
- 2 11 6
To learn the mechanisms underlying resistance exercise-induced muscle hypertrophy, recent studies on muscle protein metabolism and myogenic progenitor cells were reviewed. Numerous studies have suggested that activation of the translation process plays a major role in a resistance exercise-induced increase in muscle protein synthesis, and also in muscle hypertrophy after a prolonged period of training. Among regulators of the translational activity, the mTORC1 signaling pathway has been shown to be important, although the relation between its upstream regulation and exercise regimen remains unclear. In addition, the muscle satellite cells play a part, even if not indispensable, in exercise-induced muscle hypertrophy, by supplying muscle fibers with new myonuclei. Middle to high exercise intensity has been regarded as essential for gaining muscle mass, because it causes the recruitment of large motor units with fast, type II muscle fibers, which are readily hypertrophied through activation of mTORC1 signaling. However, several studies have shown that low-intensity resistance exercises with either large exercise volume or prolonged contraction time effectively activate protein synthesis and induce muscle hypertrophy. These findings suggest that various strategies are possible in exercise regimens, and exercise intensity is not necessarily a primary factor for gaining muscular size.