The vegetable that can increase your endurance and improve your speed are BEETS!
In June of 2011 a research study done by the England's Exeter University showed that cyclists that drank 1/2 Liter of beet juice for 6 days were 11 seconds faster over a 2/5 mile course and 45 seconds faster over a 10 mile course.
The reason for this is that beet juice is full of nitrates. Once you ingest nitrates, the body converts the nitrates into nitric oxide which causes blood vessels to relax and widen ( vasodilation). This increases the body's ability to pump more oxygen rich blood to the muscles.
Ryan Hall who is running in the Olympic Marathon this Sunday on August 9, 2012 is a believer in the power of beet juice.
Beets have 310 grams of nitrates in 16 ounces of juice. GO RYAN HALL!