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.

The validity of the visceral fat evaluation based on B-mode ultrasonography was tested on 30 healthy young women (mean age 19.6 years). The mass of visceral fat (VFM) was estimated by subtracting the subcutaneous fat mass (SFM) from the total body fat mass. The SFM was calculated as the sum of segmental subcutaneous fat mass determined from the surface area and mean thickness of adipose tissue in six body segments (face and neck, upper arm, forearm, thigh, lower leg, and trunk). Reproducibility of the determination of VFM by the repeated measures of SFM and total fat mass was sufficiently high with the difference of 5.0%. Serial cross-sectional areas of visceral adipose tissue (VATarea) were measured by magnetic resonance imaging (MRI) at three different positions of the trunk (at umbilicus and at 3.5 cm upper and lower positions). The VFM correlated significantly to each VATarea (r = 0.75 to r = 0.78, P < 0.01). The present findings suggest that the VFM can be determined with the use of B-mode ultrasonography for the clinical assessment and field surveys.

This review discusses some of the beneficial effects of a dietary amino acid supplement on muscle function, fatigue, and recovery in exercising athletes. The supplement, a mixture of amino acids that included the branched-chain amino acids, arginine and glutamine, was studied chronically at several daily dose levels for extended periods of time (10, 30, and 90 d). Outcome variables included physical measures of muscle strength, fatigue and damage, and blood indices of muscle damage and oxygen-carrying capacity. One beneficial effect of the amino acid supplement was a quicker recovery from the muscle fatigue that followed eccentric exercise training. A dose-response study of the amino acid mixture at 2.2, 4.4, and 6.6 g/d for 1 mo showed that at the highest dose, indices of blood oxygen-carrying capacity were increased and those of muscle damage were decreased at the end of the trial. When the amino acid mixture was given for 90 d to elite rugby players during training at a dose of 7.2 g/d, a blood-component analysis indicated improvements in the oxygen-carrying capacity of the blood. Together, the studies suggest that the amino acid supplement contributed to an improvement in training efficiency through positive effects on muscle integrity and hematopoiesis.

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Vacuolar degeneration at the dermoepidermal junction is a common histological feature in ECDS and perivascular and/or periappendageal lymphocytic infiltrate and vacuolar degeneration of follicular epithelium are characteristic especially in early ECDS, further supporting a canonical idea that the elimination of mutated epidermal cells by immune surveillance contributes to tissue damage and resultant fibrosis in localized scleroderma.