Here is some information on ATP production that even Richard can understand.
http://health.howstuffworks.com/sports-physiology5.htm
Exercise and Aerobic Respiration
+By two minutes of exercise, the body responds to supply working muscles
with oxygen. When oxygen is present, glucose can be completely broken
down into carbon dioxide and water in a process called
aerobic respiration. The glucose can come from three different places:+
- remaining glycogen supplies in the muscles
- breakdown of the liver's glycogen into glucose, which gets to working muscle through the bloodstream
- absorption of glucose from food in the intestine, which gets to working muscle through the bloodstream
+Aerobic respiration can also use
fatty acids
from fat reserves in muscle and the body to produce ATP. In extreme
cases (like starvation), proteins can also be broken down into
amino acids
and used to make ATP. Aerobic respiration would use carbohydrates
first, then fats and finally proteins, if necessary. Aerobic
respiration takes even more chemical reactions to produce ATP than
either of the above systems. Aerobic respiration produces ATP at the
slowest rate of the three systems, but it can continue to supply ATP
for several hours or longer, so long as the fuel supply lasts.+