If you can't contract a muscle then you will have a tough time building that area. I have seen many people perform abdominal exercises and when they are in the contracted position (shortening of the muscle fibers) the area is still soft. They are not engaging their abdominals. They are using momentum and other muscle groups to perform the exercise. It is important to know how to engage a muscle before actually lifting the weight. What I do is I will contract the muscle in the lengthened position. This isometric contraction will start to fire the neural conjuctions on the muscle and will allow for more muscle recruitment. The muscle spindles will begin to get stimulated and this will help provide a stronger contraction in the muscle as I lift the weight. It is important to know how to turn on the muscle on before you do work with it. A simple trick to do to see if you are able to activate muscle is to try and contract the area you are working as hard as you can. For example, many people have lower back fat (lateral-posterior oblique area) and they cannot contract the area. They will never burn fat from that area. I see many women who develop lower abdominal fat (below the belly button) and they feel that they are doomed to have to carry that fat for ever. But the problem is that they have lost neural innervation to the area due to inactivity. What they need to do is to practice learning how to contract that area to innervate more nerves.
We are told that a person cannot spot reduce. However, I believe that the muscle pulls fat out of areas that are closest to the contraction. Fat that is closest to the contraction gets burned up first. When you look at muscle you will see that fat is marbled in the muscle. That marbled fat is the first to be metabolized. When you heat up the muscle the intramuscular fat will burn up. Subcutaneous fat is the stuff under the skin and on top of the muscle. This is the type of fat that is metabolized when the there is no more intramuscular fat available. This is where the spot reduction theory comes in. You can't spot reduce subcutaneously, but you can active localized intramuscular fat.
If you can't contract the area that you are trying to work then the area will remain cold and you most likely will have developed a higher concentration of intramuscular fat in that area. This is why bodybuilders have such little body fat because they are constantly contracting their muscle. Body building poses force the muscle neural connection and this allows the muscle to develop proper contractibility. So, when the body builder trains they have the ability to control the muscle and to contract the area as hard as possible this in effect burns intramuscular fat. Weight training when performed correctly will produce the greatest effect on muscle contractibility. So, remember what ever exercise you do you must be able to feel the muscle contract if you can't feel it then you could be wasting your efforts and not see any change in fat metabolism or muscle definition.
Tags; fat metabolism, weight training, exercise, weight loss, obesity, fat, muscle, body building, fitness, cardiovascular, thermogenic effect