A group of professional bodybuilders, including Arnold Schwarzenegger, perform various workouts to prepare for the Mr. Olympia competitions.

Eddy performs a set of squats with encouragement from Arnold Schwarzenegger. He falls to the ground after he finishes the set because he is exhausted from the exercise.

Lou Ferrigno works out his shoulders in preparation for the Mr. Olympia competitions. His facial expressions and inability to complete a set show that he's experiencing muscle fatigue.

This clip explains how air intake while exercising pumps oxygen into the muscles which combines with ATP to create muscle contractions.

Take a look inside a swimmer's strength and conditioning routine to protect their muscles and become one of the best swimmers.