พลังงานที่ใช้ในการออกกำลังกายและเล่นกีฬา

Abstract

Three major systems producing energy (ATP) for exercise, phosphagen, glycolactic-acid, and aerobic systems are clarified. The phosphagen system provides energy for burst muscle contraction of a very short time (endurance 8–10 seconds), while the glycogen-lactic acid system provides energy for lesser muscle power but of a longer time (endurance 80–100 seconds). The aerobic system concerns with prolonged muscle works. It can provide energy for exercise as long as oxygen and fuels (glucose, free fatty acid and amino acid) can be supplied. Some hormones and chemicals stimulating the energy productions and accumulation of substances for energy production, as well as increasing endurance and performance are also mentioned. Examples of what types of sports use which energy systems are given for consideration of planning. Carbohydrate is considered to be the best food rather than fat and protein for restoration of glycogen contents in the muscle and the liver, and so carbohydrate loading is emphasized. In the early stages of heavy exercise, glycogen is primarily used, but after glycogen content is nearly depleted, the energy used depends mainly on the oxidation of fat and little amount of protein. During heavy exercise, stored glycogen, fat and protein are used and have to be replenished after exercise. Thus, the suitable ratio of carbohydrate, fat and protein consumption as well as suitable body fat composition for athletes are suggested. Finally, energy planning before, during and after the matches are suggested for consideration by the author.