Strength training is considered the best way to improve tone and definition. For most exercisers, a cardio-only program is not enough to achieve sculpted, defined muscles. The physiological changes from resistance training include increased muscle-fiber size, but this takes time.

Everyone who trains with weights responds at a different rate and with different degrees of success. Some people see results sooner than others. With patience and good form, you should see a noticeable change in your physique in six to 12 weeks. (As always, see a physician before beginning any exercise program or significantly changing your existing program.)

WEEK 1: Expect your body to be sore. Beginning a new strength-training program is going to cause stress on your body. Usually this soreness can be cured with rest, ice and an over-the-counter pain reliever. If pain persists for more than 72 hours, you should see your physician.

WEEKS 2-3: You should notice an improvement in coordination. At first your muscles will not respond in a coordinated, directed fashion, but around week two or three these same muscles "learn" to accomplish the work more efficiently.

WEEKS 3-8: Most people see increased innervation by this point, meaning more muscle fibers begin to join the others in performing the work. You might notice an increase in the amount of weight you are able to push at this time because there are more square inches of fiber doing what they are being asked to do. There is still not much growth yet.

WEEKS 8-12: By now your muscles might actually begin to hypertrophy, or grow. It is at this time that you will likely see another increase in the amount of weight you can push and pull. Most exercisers start liking the look of their new muscles after about 10 to 12 weeks. Now you have begun to add lean body mass to your figure -- the whole reason you began the program 12 long weeks ago. Success!

To maximize your results, eat a healthy diet and drink lots of fluids.