Body building is probably the healthiest activity that any individual can perform. The scientific literature documents that resistance exercise not only serves to induce positive physiological changes but also can help to enhance and maintain our functional ability in later life. While this is all to the good, it remains true that the first reason most people have for working out is to improve their appearance, and in this respect, bodybuilding is without peer in the fitness world. Running, for example, being an activity that is restricted predominantly to the lower body, cannot significantly improve your upper-body strength, nor can it enhance your flexibility. Stretching or yoga can enhance your flexibility, within certain genetically determined limits, but neither can improve your cardiovascular efficiency to any meaningful degree