The term Lucy comes from the song by the Beatles Lucy in the Sky with Diamonds which is commonly thought to be about LSD. Lucy is often used as a code word for LSD when referring to the drug in a public setting or over the phone where one does not want to openly discuss illegal activities. Lucy is used like a person's name in such discussions. Like saying Lucy took me on a trip last night to indicate you tripped on LSD the previous night. I tripped balls with Lucy last weekend!
The capacity of your body to store muscle and liver glycogen, however, is limited to approximately 1,800 to 2,000 calories worth of energy, or enough fuel for 90 to 120 minutes of continuous, vigorous activity.
They are specially equipped for explosive function for very short periods. The energy supply for those who run from about 60 seconds to three minutes is also stored energy, but in this case it is primarily glycogen stored in muscles (and blood glucose) that provides energy. Glycogen must be oxidized to pyruvate, lactate and CO2 to provide the ATP required for muscle activity.