Although bodybuilders lift weights in order to achieve their physical goals, bodybuilding is not an activity in which the absolute amount of weight you can lift is important. The aim of bodybuilding is to use a sufficient amount of weight for each exercise to cause the adaptive changes in the body that result in the creation of an ideal blend of mass, muscularity, symmetry and proportion.
Weightlifters train with weights also but they are only interested in learning to lift as much weight as possible and then only for the few particular lifts that are involved in competition.
It was long thought that bodybuilders weren't really all that strong, that the mass they developed in the gym was somehow not "real" muscle. This is simply not true. Strength is a necessary by-product of the development of mass and the success of bodybuilders in recent strongman competitions proves it.
But the use of weights in progressive-resistance training is a common denominator among bodybuilders, weightlifters, athletes training for certain sports, individuals with injuries trying to rehabilitate their bodies, and all those millions who are now training for health and fitness.
Weight training, in its most general sense, just means doing some movement or activity using added weight to increase the difficulty. This would include putting weights on your ankles before you run, or swinging a lead-filled bat before your turn at the plate, but usually we restrict the meaning to contracting your muscles in certain prescribed exercises against the resistance of dumbbells, barbells or resistance exercise machines.
Bodybuilders actually have more in common with the man training for fitness than with competition weightlifters. After all, both are more interested in physical self-improvement than in breaking lifting records. But there is a large difference in degree. It is as if bodybuilders were Formula I racing cars, and the average man or woman a reliable sports-sedan. Both want a certain degree of performance but on two distinct levels. The technology that comes out of Grand Prix racing eventually filters down to the family car and, in the same way, the discoveries made by serious bodybuilders in the gym can be adapted and made use of by those who are using weights to stay trim and healthy.
You may personally have no desire to train for hours a day to become a Mr. America, but exercise physiologists have shown us how much alike in their physical needs are the athlete and the non-athlete. If you apply the techniques that work for champions, only at a level of intensity that suits your own purposes, you will be able to share in the same process that creates, shapes, and firms the human body, melts away unwanted fat, and builds a strong dependable cardiovascular system.
Of course better results come from those with the right genetic potential, but that doesn't mean there is no benefit from weight training for the average man. Quite the contrary; for all but a few there is a definite increase in strength and muscular size along with an improvement in shape and contour of the musculature. The body gets firmer as muscle fibers become more dense and fat is burned off. Some people will change a lot, and others somewhat less but even seemingly small changes can make a dramatic change in your physique. An inch or two added to the chest coupled with a loss of a couple of inches in your waist will completely transform how you look. You can never step outside of your natural somatotype but you can accomplish a great deal within those limits. But remember, even if you don't really want to get any bigger, all you are doing is increasing your strength to its natural optimum and letting the muscles assume whatever mass and shape is natural to them. It's all up to you.