According to the American Council on Exercise, you can lose up to a half pound of muscle every year after age 25. This makes you weaker, slows your metabolism and over time changes your body composition to less muscle and more fat. Strength training slows down this process and can increase your metabolism to combat weight gain. The more lean muscle mass you have in your body versus fat, the more calories you will burn, even at rest. The amount of muscle mass obtained from a strength training program depends on the kind of workouts done, body type and gender.
Women generally build less muscle than men because they have less testosterone in their bodies.
However, women who desire less muscular definition should stick to lighter weights. If you desire increased strength, work out with heavier weights with fewer repetitions. To increase endurance, use lighter weights with more repetitions. These sites will open in a new browser window.