By using the fundamental premise of resistance, strength training allows the muscles to work against the extra pounds to build strength, anaerobic resistance, and develop the size of skeletal muscles. It is one of the oldest disciplines that mankind has been aware of. There is a legend that the famous wrestler of Ancient Greece, Milo of Croton, used to train for strength by carrying a calf on his back. Well, today we do not really use a calf to build strength, but the basic concept of strength training remains the same.