Effect of more amount intake of protein in competitive season on body composition and various body functions. In case of varsity throwers / 体力科学

ABSTRACT

The present study examined the effects of having bigger amount of protein than usual in competitive season on lean body weight (LBW), cross-sectional area of thigh and abdomen, muscle strengths, blood constituents and urinary urea nitrogen. Seventeen male varsity throwers (javelin, discus, hammer and shot put) ranging from 19 to 22 years of age, were divided into two groups ; Group A (N=9) with a more protein diet (2.1 g·kg<SUP>-1</SUP>·d<SUP>-1</SUP>), and Group B (N=8) with a usual amount diet (1.5 g·kg<SUP>-1</SUP>·d<SUP>-1</SUP>) . The experimental period was 62 days. During this period, they practiced six days a week. Three days were for throwing practice. Other three days were for weight training. All subjects lived in the same dormitory, and their life styles were similar to each other. The averaged daily diet of Group A evaluated by means of a weighing method had 3824 kcal with 175 g of protein (2.0 g·kg<SUP>-1</SUP>·d<SUP>-1</SUP>), 115 g of fat and 552 g of carbohydrate. The averaged daily diet of Group B had 3441 kcal with 130 g of protein (1.5 g·kg<SUP>-1</SUP>·d<SUP>-1</SUP>), 76 g of fat and 559 g of carbohydrate. All the intakes of vitamins (A, B<SUB>1</SUB>, B<SUB>2</SUB>, C) and minerals (calcium and iron) of the diet of each group were higher than the Japanese recommended dietary allowance. After the period, body weight, %fat, fat and LBW of both groups did not change significantly. Muscle strengths and cross-sectional areas in abdomen and thigh of both groups did not change significantly. Urinary urea nitrogen of both groups did not change significantly. Blood constituents (RBC, Hb, Ht, TP, Alb, BUN) of each group were still in normal ranges in spite of significant changes. No significant changes in body composition and muscle strengths were found in each group. These results, therefore, indicated that the more protein diet (2.0 g·kg<SUP>-1</SUP>·d<SUP>-1</SUP>) was not effective for increasing LBW and muscle strength of varsity throwers in competitive season.