Masashige Suzuki

The effects of light resistance exercise using dumbbells and rubber band with mild energy restriction on body composition and physical fitness were studied in 11 mildly obese Korean women aged 38-59 years. The subjects performed dumbbell exercises with pairs of 0.5-1 kg dumbbells and rubber band exercise 3 days per week for approximately 40 min. Subjects were restricted to approximately 80% of energy intake RDA for Korean women for 12 weeks. Subjects were measured for body composition, physical fitness, and blood and serum biochemical data before commencing the experiment and again at 12 weeks while still dieting. During the 12-week experimental period, body weight and body fat decreased significantly without reducing fat free mass. Grip and back strength increased significantly during the experimental period. These results suggest that combination of dumbbell and rubber band exercises decreases body weight and body fat without reducing FFM while increasing physical fitness.

To identify the effects of a tower-climbing exercise on bone marrow heme biosynthesis and hematological status in rats given glucocorticoid-injections as a model of aging, 29 male Sprague-Dawley rats, 10 weeks of age, were assigned to three groups: a saline control (C, n = 9), a glucocorticoid-sedentary (GS, n = 10) group, and a glucocorticoid-exercise (GE, n = 10) group. The GS and GE groups were given 2 mg/kg prednisolone daily, and the C group was given 2 ml of saline daily, subcutaneously. Each group was meal-fed commercial rat chow isoenergetically and given free access to water for 8 weeks. The GE group were allowed to climb a 200-cm tower to drink water from a bottle set at the top of it. Weight gain during the 8-week experimental period was greater in the C group than in the GS and GE groups. The gastrocnemius and tibialis anterior muscles were heavier in the C group than in other groups. The hematological parameters were not influenced by glucocorticoid administration with or without climbing exercise. Bone marrow delta-aminolevulinic acid dehydratase activity was significantly higher in the GE group than in the C group. These results suggest that 8 weeks of climbing exercise increases heme biosynthesis without alteration of hematological status in rats given glucocorticoid-injections. Resistance exercise may be a preventive therapy for iron-deficiency anemia associated with aging.

To determine the effects of resistance versus aerobic exercise on the mass, strength and turnover of bone, thirty Sprague Dawley rats (4 weeks of age) were assigned to one of three experimental groups: sedentary, running or jumping. In the jumping group, the trunk was kept upright during electrically stimulated jumping exercise for 1 h every other day. The running rats ran at speeds of 24 m/min for 1 h every other day. After 4 weeks, the jumping rats exhibited increases in the mass and strength of the lumbar vertebrae and of the mid-diaphysis of the femur (mid-femur), and increases in the cross-sectional morphology of these bones: the trabecular bone volume per bone surface, the trabecular thickness, the trabecular bone formation rate per bone surface (BFR/BS). In addition, they exhibited reduced trabecular separation and the area of osteoclast surface per bone surface. The running and sedentary rats showed no such changes. With regard to the mid-femur, in both the jumping and running rats the periosteal BFR/BS was increased. However, only the jumping rats showed a reduction in the BFR/BS at the endocortical surface. These results suggest that resistance exercise accelerates cortical drift and increases the bone mass and strength by stimulating bone formation more efficiently than does aerobic exercise.

The effects of high‐fat diet feeding over generations on body fat accumulation were studied in rats. Male and female Sprague‐Dawley rats fed a high‐fat (HF) diet or a low‐fat (LF) diet were mated in the same diet group at age 13 weeks, and the male pups (1st generation) obtained were used in this experiment. The 1st generation rats were nurtured by their own mothers (Experiment 1) or F344 foster mother rats (chow‐fed) during pregnancy (Experiment 3) and the suckling period (Experiments 2 and 3). After weaning, rats with HF and LF dietary histories were fed a purified diet for 12–17 weeks. Body weights and abdominal adipose tissue weights were greater in rats with HF dietary histories than in those with LF dietary histories, even controlling for environmental backgrounds related to the mother rats during pregnancy and suckling periods. The levels of lipoprotein lipase and leptin mRNA in the perirenal adipose tissue were higher in rats with HF dietary histories. These results suggest that the effects on body fat accumulation of HF diet feeding over generations are not only associated with environmental factors but also with genetic factors. The obesogenous effects of HF diet feeding over generations may be associated with lipoprotein lipase and leptin gene expression on rat adipose tissues.

To study the effect of meal timing after exercise on body composition, 20 male rats were assigned to either a group fed a meal right after exercise (R) or a group fed a meal 4 h after exercise (L). Resistance exercise (squatting) was conducted from 6:00 to 7:00, 3 d/wk for 10 wk. Meals were consumed from 7:00 to 8:00 and from 19:00 to 20:00 for R, and from 11:00 to 12:00 and from 19:00 to 20:00 for L. The room was lighted from 7:00 to 19:00. After 10 wk, the body weight was comparable between the groups. The hindlimb muscle weight was higher in R than in L by 6% (p < 0.05), whereas the sum of the weight of perirenal, epididymal, and mesenteric adipose tissues was lower in R than in L by 24% (p < 0.01). The soleus lipoprotein lipase (LPL) activity was higher in R than in L by 70% (p < 0.01), and the activity negatively correlated with the adipose tissue weight (r = -0.49, p < 0.05). These results suggest the possibility that ingesting a meal right after resistance exercise may contribute to an increase in the muscle mass and to a decrease in the adipose tissue compared to ingesting a meal several hours later.