Читать книгу Paddles Up!. Dragon Boat Racing in Canada онлайн

41 страница из 56

Running Duration Compared to Dragon Boating

All these energy pathways have time limits. A specific pathway is no longer used once a certain time elapses. Although there is some controversy about these limitations, the preceding chart relates the running duration with the approximated race components of dragon boating to show the use of the energy systems.

Muscle contraction produces ADP that is regenerated when coupled with CP. When muscles are actively contracted, they obtain ATP from the glucose that is stored in the bloodstream and from the breakdown of glycogen that is stored in the muscles. For exercise that lasts for longer periods, the complete oxidation of carbohydrates or free fatty acids in the mitochondria is required. The carbohydrate supply lasts approximately 90 minutes and the free fatty store lasts several days.

At the start of exercise, all three energy systems are actively contributing. The contribution, however, depends on the individual, the effort applied, and the rate at which energy is used. The following graph shows how the energy systems contribute to the manufacture of ATP over time when exercise is at 100 percent effort. The thresholds (T) indicate the point at which the energy system is exhausted. Training will improve the threshold times.