Norio Saga

Effects of training volume on strength and hypertrophy in young men.

Abstract Sooneste, H, Tanimoto, M, Kakigi, R, Saga, N, and Katamoto, S. Effects of training volume on strength and hypertrophy in young men. J Strength Cond Res 27(1): 8–13, 2013—Knowledge of the effects of training volume on upper limb muscular strength and hypertrophy is rather limited. In this study, both arms of the same subject were trained in a crossover-like design with different training volumes (1 or 3 sets) to eliminate the effects of genetic variation and other individual differences. The purpose of this study was to investigate the effects of training volume on muscular strength and hypertrophy in sedentary, untrained young Japanese men. Eight subjects (age, 25.0 ± 2.1 years; body mass, 64.2 ± 7.9 kg; height, 171.7 ± 5.1 cm) were recruited. The subjects trained their elbow flexor muscles twice per week for 12 consecutive weeks using a seated dumbbell preacher curl. The arms were randomly assigned to training with 1 or 3 sets. The training weight was set at 80% of 1 repetition maximum for all sets. The 3-set protocol increased cross-sectional area significantly more than did 1 set (1 set, 8.0 ± 3.7%; 3 sets, 13.3 ± 3.6%, p < 0.05). Furthermore, gains in strength with the 3-set protocol tended to be greater than those with 1 set (1 set, 20.4 ± 21.6%; 3 sets, 31.7 ± 22.0%, p = 0.076). Based on the results, the authors recommend 3 sets for sedentary untrained individuals. However, this population should incorporate light training days of 1 set into their training program to prevent overtraining and ensure adherence. The findings are relevant for the sedentary, untrained young male population and must be interpreted within the context of this study.

Determinants of intramyocellular lipid accumulation after dietary fat loading in non‐obese men

Aims/Introduction:  Accumulation of intramyocellular lipid (IMCL) is associated with insulin resistance. However, the factors affecting the change in IMCL remain to be elucidated. The aim of the present study was to determine the factors that influence the change in IMCL level after high‐fat loading.

Microwave hyperthermia treatment increases heat shock proteins in human skeletal muscle

Objective: To test the hypothesis that microwave hyperthermia treatment (MHT) increases heat shock proteins (HSPs) in the human vastus lateralis muscle. Methods: Four untrained healthy male volunteers participated in this study. The lateral side of the thigh of one leg (heated leg) was heated with a microwave generator (2.5 GHz, 150 W) for 20 min. At 1 day after the MHT, a muscle sample was taken from the heated leg. A control sample was taken from the unheated leg on another day of the MHT. For both legs, HSP90, HSP72 and HSP27 levels were compared. Results: The HSP90, HSP72 and HSP27 levels in heated legs were significantly higher than those in control legs (p<0.05). Conclusions: Application of MHT can increase the levels of several HSPs in human skeletal muscle.

Changes in muscle temperature induced by 434 MHz microwave hyperthermia

Objective: To investigate the changes in temperature of human muscle during microwave hyperthermia. Methods: Skin surface and muscle temperatures were measured in 11 healthy adult men (mean (SD) age 24.3 (2.2) years; height 174.2 (6.1) cm; weight 70.0 (5.3) kg) during a 30 min exposure of the thigh to 434 MHz microwave hyperthermia. Skin temperature was maintained at the pilot temperature of 40°C, and the temperature of the water in the bolus was 38°C. The peak power output was set at 60 W and controlled automatically to maintain the pilot temperature. The temperature was measured in the vastus lateralis muscle at an average muscle depth of 2.0 (0.2) cm, using a 23 G Teflon-shielded thermocouple. Biopsy specimens were obtained for light microscopy from three subjects. A muscle-equivalent phantom was used to evaluate the vertical heating pattern. Results: Both skin and muscle temperatures increased from baseline, and muscle temperature was higher than skin temperature (skin temperature 39.2 (0.5)°C, temperature rise 5.0 (1.5)°C; muscle temperature 43.7 (0.8)°C, temperature rise 8.9 (1.4)°C). At the end of the hyperthermia treatment, muscle temperature decreased to 39.8 (0.9)°C, but was still 4.8 (1.5)°C higher than the baseline. No signs of muscle damage were observed on the basis of the blood creatine kinase activity and histological sections. Conclusions: The results show that the 434 MHz microwave hyperthermia treatment increased and maintained muscle temperature locally by 6.3–11.4°C without muscle damage. These findings suggest that the microwave hyperthermia system provides effective and safe treatment.

Association Between Expression of FABPpm in Skeletal Muscle and Insulin Sensitivity in Intramyocellular Lipid-Accumulated Nonobese Men

CONTEXT Intramyocellular lipid (IMCL) accumulation is observed in both insulin-resistant subjects and insulin-sensitive endurance athletes (athletes paradox). We hypothesized that the expression pattern of fatty acid transporters may influence oxidative capacity and determine the association between IMCL and insulin resistance. OBJECTIVE The objective of the study was to investigate the muscle expression of fatty acid transporters and their function related to insulin sensitivity in IMCL-accumulated subjects. DESIGN AND SETTING The study subjects were 36 nonobese healthy men. Their IMCL levels were measured by (1)H-magnetic resonance spectroscopy, and their insulin sensitivity was evaluated by steady-state glucose infusion rate (GIR) during a euglycemic-hyperinsulinemic clamp. Gene expression levels in the vastus lateralis were evaluated by quantitative RT-PCR. We compared the clinical phenotypes and the expression levels of genes involved in lipid metabolism in skeletal muscle between IMCL-accumulated high-GIR (H-GIR) subjects (n = 8) and low-GIR subjects (n = 9). The functions of candidate fatty acid transporters were determined by in vitro analyses. RESULTS Compared with the low-GIR group, body fat was lower and maximum oxygen uptake was higher in the H-GIR group. Several lipid oxidation genes in muscle were up-regulated in the H-GIR group, and this was associated with increased expression of higher plasma membrane-associated fatty acid-binding protein (FABPpm) and decreased expression of fatty acid transport protein (FATP)-1. Overexpression of FABPpm in C2C12 myotubes increased fatty acid oxidation coupled with the elevated expression of genes related to fatty acid oxidation. These changes were not observed in FATP1-overexpressed myotubes. CONCLUSIONS Differences in the gene expression of fatty acid transporters may, at least in part, affect insulin sensitivity in IMCL-accumulated nonobese men.