| For more than fifty years, athletes in sports requiring | | | | muscle. Muscles require far more oxygen to burn fat |
| endurance have used a training technique called | | | | than to burn sugar for energy. So when a muscle runs |
| carbohydrate loading. A recent study from South | | | | out of its stored sugar, called glycogen, it becomes |
| Africa shows that this technique slows sprint | | | | less efficient, hurts, is difficult to co-ordinate and slows |
| performance of cyclists ( Journal of Applied Physiology | | | | you down. Many previous studies show that it doesn't |
| , January 2006). | | | | make any difference what an trained endurance |
| Competitive bicycle racers ate a high fat or | | | | athlete eats on the week before competition because |
| high-carbohydrate diet for six days followed by a | | | | the muscles of trained athletes store the most |
| high-carbohydrate diet for one day and completed | | | | glycogen when they reduce training for several days, |
| time trials on their bikes. Then they ate the opposite | | | | regardless of what they eat. Any difference in the |
| diet for six days followed by a high carbohydrate diet | | | | muscle and fat concentration inside muscles becomes |
| for one day and repeated their time trial. Diets did not | | | | unimportant during endurance competition. |
| affect their times or power output for 100 kilometers | | | | This study shows that a high-fat diet before sprint |
| (62 miles), but the high fat diet slowed their sprint | | | | competition hurts performance. A high fat diet causes |
| performance over one kilometer (0.6 miles.) | | | | muscles to burn a higher percentage of fat. Using fat |
| Muscles get their energy from sugar and fat stored in | | | | for energy requires more oxygen than carbohydrates |
| muscles and coming into muscles from the | | | | do, and how fast you can sprint 0.6 miles on a bicycle |
| bloodstream. The limiting factor in how fast an | | | | is limited by how rapidly you can deliver oxygen to |
| endurance athlete can exercise is the time it takes to | | | | muscles. |
| transport oxygen from the blood in the lungs to the | | | | |