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.
For example, American Express card numbers start with 37; Carte Blanche and Diners Club with 38. 1  American Express-Digits three and four are type and currency, digits five through 11 are the account number, digits 12 through 14 are the card number within the account and digit 15 is a check digit.