...that "even if you train hard every day, you still might not be able to make your muscles perform as well as another person's. Athletes are not just made; they are born, too. Strength, power and endurance may be due in part to the distribution of fiber types within an individual's muscles." For more on this subject and to learn the different types of muscled fibers, visit http://health.howstuffworks.com/sports-physiology15.htm.