Recent Japanese young people do not care of their every day meals, however, they are interested in nutritional supplements at the same time. So do young athletes. Any kinds of nutritional supplements so called “for strengthening muscle, decreasing fat mass, increasing endurance power” et ct. are popular among young athletes.
　If they obtain good nutritional information and dine properly, their fatigue will be able to decrease and muscle and bone mass increase after physical training.
　We recruited 29 young American football players aged 27±3.4 and investigated for 16 weeks from beginning of the season. They were divided into 2 groups; twenty subjects were given with proper nutritional information and also given with 500 ml/day of milk plus more 500 ml/day after physical training (dietary group), and the other 9 subjects were given none of the information or milk (control group). Their muscle, bone mass and bone mineral density were measured by dual energy X-ray absorptiometry (DXA). Fatigue was observed by POMS (profile of mood state) and “subjective fatigue” score by Japan Society for Occupational Health.
　While body fat in the trunk and legs increased in the control group, muscle mass in the trunk was increased in the dietary group after 16 weeks of their training. Bone mass of the trunk and bone density in the lumber and femoral Ward's triangle was also increased in dietary group, while bone density in the femoral neck was increased in the control group. POMS fatigue and “subjective fatigue” symptoms scores of the dietary group were significantly decreased in 16 weeks after physical training, while these scores were not decreased in the control group.
Proper nutritional information and taking nutritional balanced food such as milk should increase lean body mass and decrease fatigue symptoms after physical training for 14 weeks.

DESCENTE SPORTS SCIENCE Vol.24/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE