Effects of Training on Athletes. Sports physiology is the study of the long-and short-term effects of training and conditions on athletes. This specialized field of study goes hand in hand with human anatomy. Anatomy is about structure, where physiology is about function.
Visa and Mastercard always have 16 digits whereas American Express has 15 digits. The short answer is that American Express cards have a different PAN format than Visa, MasterCard and Discover because they offer a different kind of financial service.
Look for the 3-digit number immediately following the regular number on the back of your card: American Express Card. Look for the 4-digit number slightly above the embossed (raised) account number on the face of the card. In some instances it is located on the left side of the card, but is always above the account number.