The answer was suprising. Most of the players will hop on a stationary bicycle and ride for a half hour. We asked Steve Millard. He said the players ride the bicycles to help remove lactic acid from their systems.
Lactic acid is what causes muscles to burn after strenuous exercise.
To really understand why riding a bicycle after playing a hockey game makes sense, let's look closer at lactic acid. Lactic acid forms as a by-product of energy production by the muscles. ATP is the energy source muscle fibers use to make muscles contract. Some of the reactions in converting glycogen to ATP take place without oxygen, and when this happens a compound called pyruvate is produced. Some of this pyruvate can be converted into energy, but the excess becomes lactic acid.