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Akinobu Nishimura, Masaaki Sugita, Ko Kato, Aki Fukuda, Akihiro Sudo and Atsumasa Uchida

Purpose:

Recent studies have shown that low-intensity resistance training with vascular occlusion (kaatsu training) induces muscle hypertrophy. A local hypoxic environment facilitates muscle hypertrophy during kaatsu training. We postulated that muscle hypertrophy can be more efficiently induced by placing the entire body in a hypoxic environment to induce muscle hypoxia followed by resistance training.

Methods:

Fourteen male university students were randomly assigned to hypoxia (Hyp) and normoxia (Norm) groups (n = 7 per group). Each training session proceeded at an exercise intensity of 70% of 1 repetition maximum (RM), and comprised four sets of 10 repetitions of elbow extension and fexion. Students exercised twice weekly for 6 wk and then muscle hypertrophy was assessed by magnetic resonance imaging and muscle strength was evaluated based on 1RM.

Results:

Muscle hypertrophy was significantly greater for the Hyp-Ex (exercised fexor of the hypoxia group) than for the Hyp-N (nonexercised fexor of the hypoxia group) or Norm-Ex fexor (P < .05, Bonferroni correction). Muscle hypertrophy was significantly greater for the Hyp-Ex than the Hyp-N extensor. Muscle strength was significantly increased early (by week 3) in the Hyp-Ex, but not in the Norm-Ex group.

Conclusion:

This study suggests that resistance training under hypoxic conditions improves muscle strength and induces muscle hypertrophy faster than under normoxic conditions, thus representing a promising new training technique.

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Norihide Sugisaki, Taku Wakahara, Koichiro Murata, Naokazu Miyamoto, Yasuo Kawakami, Hiroaki Kanehisa and Tetsuo Fukunaga

Although the moment arm of the triceps brachii muscle has been shown to be associated with the muscle’s anatomical crosssectional area, whether training-induced muscle hypertrophy alters the moment arm of the muscle remains unexplored. Therefore, the current study aimed to examine this. Eleven men underwent a 12-week resistance training program for the triceps brachii muscle. The maximum muscle anatomical cross-sectional area (ACSAmax), the moment arm of the triceps brachii muscle, and the anterior-posterior dimension of the olecranon were measured using a magnetic resonance imaging system before and after intervention. The ACSAmax (33.6 ± 11.9%, P < .001) and moment arm (5.5 ± 4.0%, P = .001) significantly increased after training, whereas the anterior-posterior dimension of the olecranon did not change (P > .05). The change in moment arm was smaller than that expected from the relationship between the ACSAmax and the moment arm before the intervention. The present results indicate that training-induced triceps brachii muscle hypertrophy could increase the muscle moment arm, but its impact can be small or negligible.

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Matheus Barbalho, Victor Silveira Coswig, James Steele, James P. Fisher, Jurgen Giessing and Paulo Gentil

Purpose:

To compare the effects of different resistance training volumes on muscle performance and hypertrophy in trained men.

Methods:

37 volunteers performed resistance training for 24 weeks, divided into groups that performed five (G5), 10 (G10), 15 (G15) and 20 (G20) sets per muscle group per week. Ten repetition maximum (10RM) tests were performed for the bench press, lat pull down, 45º leg press, and stiff legged deadlift. Muscle thickness (MT) was measured using ultrasound at biceps brachii, triceps brachii, pectoralis major, quadriceps femoris and gluteus maximus. All measurements were performed at the beginning (pre) and after 12 (mid) and 24 weeks (post)

Results:

All groups showed significant increases in all 10RM tests and MT measures after 12 and 24 weeks when compared to pre (p <0.05). There were no significant differences in any 10RM test or changes between G5 and G10 after 12 and 24 weeks. G5 and G10 showed significantly greater increases for 10RM than G15 and G20 for most exercises at 12 and 24 weeks. There were no group by time interaction for any MT measure

Conclusions:

The results bring evidence of an inverted “U shaped” curve for the dose response curve for muscle strength. Whilst the same trend was noted for muscle hypertrophy, the results did not reach significance. Five to 10 sets per week might be sufficient for bringing about optimal gains in muscle size and strength in trained men over a 24-week period.

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Kevin D. Tipton

Adaptations to exercise training are determined by the response of metabolic and molecular mechanisms that determine changes in proteins. The type, intensity, and duration of exercise, as well as nutrition, determine these responses. The importance of protein, in the form of intact proteins, hydrolysates, or free amino acids, for exercise adaptations is widely recognized. Exercise along with protein intake results in accumulation of proteins that influence training adaptations. The total amount of protein necessary to optimize adaptations is less important than the type of protein, timing of protein intake, and the other nutrients ingested concurrently with the protein. Acute metabolic studies offer an important tool to study the responses of protein balance to various exercise and nutritional interventions. Recent studies suggest that ingestion of free amino acids plus carbohydrates before exercise results in a superior anabolic response to exercise than if ingested after exercise. However, the difference between pre- and post exercise ingestion of intact proteins is not apparent. Thus, the anabolic response to exercise plus protein ingestion seems to be determined by the interaction of timing of nutrient intake in relation to exercise and the nutrients ingested. More research is necessary to delineate the optimal combination of nutrients and timing for various types of training adaptations. Protein and amino acid intake have long been deemed important for athletes and exercising individuals. Olympic athletes, from the legendary Milo to many in the 1936 Berlin games, reportedly consumed large amounts of protein. Modern athletes may consume slightly less than these historical figures, yet protein is deemed extremely important by most. Protein is important as a source of amino acids for recovery from exercise and repair of damaged tissues, as well as for adaptations to exercise training, such as muscle hypertrophy and mitochondrial biogenesis.

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Ryan D. Andrews, David A. MacLean and Steven E. Riechman

Variability in protein consumption may influence muscle mass changes induced by resistance exercise training (RET). We sought to administer a post-exercise protein supplement and determine if daily protein intake variability affected variability in muscle mass gains. Men (N = 22) and women (N = 30) ranging in age from 60 to 69 y participated in a 12-wk RET program. At each RET session, participants consumed a post-exercise drink (0.4 g/kg lean mass protein). RET resulted in significant increases in lean mass (1.1 ±1.5 kg), similar between sexes (P > 0.05). Variability in mean daily protein intake was not associated with change in lean mass (r < 0.10, P > 0.05). The group with the highest protein intake (1.35 g · kg−1 · d−1, n = 8) had similar (P > 0.05) changes in lean mass as the group with the lowest daily protein intake (0.72 g · kg−1 · d−1, n = 9). These data suggest that variability in total daily protein intake does not affect variability in lean mass gains with RET in the context of post-exercise protein supplementation.

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Samuel R. Heaselgrave, Joe Blacker, Benoit Smeuninx, James McKendry and Leigh Breen

Skeletal muscle is pivotal in the maintenance of a healthy lifestyle, 1 favoring preservation and/or accretion of muscle mass, strength, and power. The most potent nonpharmacological stimulus inducing skeletal muscle hypertrophy and strength is resistance training (RT). Mechanical tension and

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Bruce M. Lima, Rafael S. Amancio, Diacre S. Gonçalves, Alexander J. Koch, Victor M. Curty and Marco Machado

Skeletal muscle mass is a critical biomarker for maintaining health and optimizing athletic performance. Increasing skeletal muscle mass is a major goal of many exercise regimens. There is a debate about the most effective training model to optimize muscle hypertrophy. Manipulation of several

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Vandre C. Figueiredo, Michelle M. Farnfield, Megan L.R. Ross, Petra Gran, Shona L. Halson, Jonathan M. Peake, David Cameron-Smith and James F. Markworth

Biology, 43 ( 9 ), 1267 – 1276 . PubMed ID: 21621634 doi: 10.1016/j.biocel.2011.05.007 Hulmi , J.J. , Lockwood , C.M. , & Stout , J.R. ( 2010 ). Effect of protein/essential amino acids and resistance training on skeletal muscle hypertrophy: A case for whey protein . Nutrition & Metabolism

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Yuya Watanabe, Michiya Tanimoto, Akane Ohgane, Kiyoshi Sanada, Motohiko Miyachi and Naokata Ishii

The authors investigated the effects of low-intensity resistance training on muscle size and strength in older men and women. Thirty-five participants (age 59–76 yr) were randomly assigned to 2 groups and performed low-intensity (50% of 1-repetition maximum) knee-extension and -flexion exercises with either slow movement and tonic force generation (LST; 3-s eccentric, 3-s concentric, and 1-s isometric actions with no rest between repetitions) or normal speed (LN; 1-s concentric and 1-s eccentric actions with 1-s rests between repetitions) twice a week for 12 wk (2-wk preparation and 10-wk intervention). The LST significantly increased thigh-muscle thickness, as well as isometric knee-extension and -flexion strength. The LN significantly improved strength, but its hypertrophic effect was limited. These results indicate that even for older individuals, the LST can be an effective method for gaining muscle mass and strength.

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Samantha J. Wilson, Bryan Christensen, Kara Gange, Christopher Todden, Harlene Hatterman-Valenti and Jay M. Albrecht

Context: Chronic plantarflexor (PF) stretching during ankle immobilization helps preserve calf girth, plantarflexion peak torque, and ankle dorsiflexion (DF) motion. Immobilization can lead to decreases in muscle peak torque, muscle size, and joint range of motion (ROM). Recurrent static stretching during a period of immobilization may reduce the extent of these losses. Objective: To investigate the effects of chronic static stretching on PF peak torque, calf girth, and DF ROM after 2 weeks of ankle immobilization. Design: Randomized controlled clinical trial. Setting: Athletic training facility. Participants: A total of 36 healthy college-aged (19.81 [2.48]) females. Interventions: Subjects were randomly assigned to one of 3 groups: control group, immobilized group (IM), and immobilized plus stretching (IM+S) group. Each group participated in a familiarization period, a pretest, and, 2 weeks later, a posttest. The IM group and IM+S group wore the Aircast Foam Pneumatic Walker for 2 weeks on the left leg. During this time, the IM+S group participated in a stretching program, which consisted of two 10-minute stretching procedures each day for the 14 days. Main Outcome Measures: One-way analysis of variance was used to determine differences in the change of ankle girth, PF peak torque, and DF ROM between groups with an α level of <.05. Results: A significant difference was noted between groups in girth (F 2,31 = 5.64, P = .01), DF ROM (F 2,31 = 26.13, P < .001), and PF peak torque (F 2,31 = 7.74, P = .002). Post hoc testing also showed a significance difference between change in calf girth of the control group compared with the IM group (P = .01) and a significant difference in change of peak torque in the IM+S group and the IM group (P = .001). Also, a significant difference was shown in DF ROM between the control group and IM+S group (P = .01), the control group and the IM group (P < .001), and the IM+S group and the IM group (P < .001). Conclusion: Chronic static stretching during 2 weeks of immobilization may decrease the loss of calf girth, ankle PF peak torque, and ankle DF ROM.