main source of energy for an exercise of more than 2 – 3 minutes in duration and low intensity. Using oxygen, the body breaks down triacylglycerol (stored in the muscles and adipose tissues) to fatty acids. Then fatty acids break down to acetyl – CoA via beta – oxidation. Finally, acetyl – CoA enters into the Krebs cycle to generate ATP.

This system generates 460 ATPs from metabolizing one molecule of triacylglycerol.

 Sports with Dominating Aerobic System:

The aerobic system is the dominant energy system in the following sports:

1. Athletics:
   1. 1500 m.
   2. 5000 m.
   3. 10000 m.
   4. Marathon.
   5. 20 km walk.
   6. 50 km walk.
   7. 3000 m steeplechase.
2. Biathlon.
3. Bobsleigh.
4. Boxing.
5. Canoe/Kayak Sprint: men`s events (C-1 1000 m canoe single, C-2 1000 m canoe double, K-1 1000 m kayak single, K-2 1000 m kayak double, and K-4 1000 m kayak four).
6. Cycling:
   1. Road cycling.
   2. Track cycling.
   3. Cross – county cycling.
7. Modern pentathlon.
8. Rowing.
9. Skating:
   1. Speed skating (3000 m, 5000 m, 1000 m, team pursuit).
   2. Short track speed skating (5000 m relay).
   3. Figure skating (all events).
10. Skiing: cross – country skiing (10 km, 15 km, 4X10 km relay, team sprint, 7.5 km + 7.5 km skiathlon, 15 km + 15 km skiathlon, 30 km, 50 km).
11. Swimming:
    1. Backstroke swimming (200 m).
    2. Breaststroke swimming (200 m).
    3. Butterfly swimming (200 m).
    4. Freestyle swimming (200 m, 4X100 m relay, 400 m, 800 m, 1500 m).
    5. Medley swimming (200 m individual, 4X200 m relay, 400 m individual).
    6. Synchronized swimming (duet, team).
    7. Marathon 10 km.
12. Triathlon.