How Much Muscle Can a Woman Gain With Strength Training?

While women rarely bulk up as dramatically as men because they have lower testosterone levels, some women build muscle more easily than others. The exact amount of muscle a woman gains depends on her age, fitness level, body type, diet and program. Understanding the important role strength training plays in your overall health and how your body responds to it can help you determine the best way to include weights into your weekly fitness routine.

Strength training affects women in different ways depending on body type. Some women have body types that are genetically predisposed to gaining muscle more readily than others. Mesomorphs, who are more muscular, build muscle mass faster and more dramatically than ectomorphs, who are naturally slim in shape --even when they follow the same training programs. Your ratio of testosterone to estrogen and the type of muscle fibers you have are genetically determined and affect the rate and way in which you put on muscle.

Another body type, the endomorph, tends to be curvy and possess higher levels of body fat. For women with this body type to look lean and gain muscle, they must lose weight in the form of body fat. Slim ectomorphs may never build tremendously large-looking muscles, but they can build considerable strength. If you are a mesomorph and find you get "huge" with strength training, emphasize lighter weights with more repetitions to build muscular endurance, recommends the American Council on Exercise.

Most people average about a half-pound of muscle growth per week, notes CNN nutrition expert Dr. Melina Jampolis. Conduct regular strength training and adhere to specific dietary strategies to achieve this rate. According to the American Council on Exercise, most women will gain about 20 to 40 percent in muscular strength after several months of resistance training.

Pay attention to your diet as well as to your exercise routine. Eating a whole-food diet that emphasizes lean proteins, whole grains, fresh produce and unsaturated fats -- while eschewing processed foods containing refined flours, added sugars, excess sodium and trans and saturated fats -- will maximize your muscle-building results at the gym. Eat a slightly higher percentage of protein daily to help muscles grow and repair after training. The International Society of Sports Nutrition recommends between 1.4 and 2 g of protein per kg of body weight daily. Aim for the higher end of the range if you are extremely active.

Women's training protocols should not differ from men's. To gain muscle, a woman must lift weights heavy enough to cause fatigue in eight to 12 repetitions. Lifting lighter weights for more repetitions only improves muscular endurance -- or the ability of the muscle to do an exercise longer. Muscular endurance does not improve tone, size or strength, notes Lou Schuler, author of "The New Rules of Lifting for Women." Perform full-body routines at least two times per week, leaving at least 48 hours between sessions. Choose free weights whenever possible to stimulate both primary and stabilizing muscles.

Change your routine by adding new exercises or increasing weight every four to six weeks to stimulate your muscles in new ways so they continue to grow and be challenged. When you are able to easily perform 12 repetitions with a weight with proper form, increase your weight by about 5 percent.