The school of thought has definitely become less common, but there are still many women who avoid strength training (e.g. lifting weights, resistance training, bodyweight exercise), either because they think it will make them look "too muscular" or even because they simply just don't know that it's actually an essential part of maintaining overall good health.
Strength training, or resistance training, is especially important for women not only because it helps to build and maintain strength, but also bone density.
As we age it’s possible to lose bone mass, and this is especially common for post-menopausal women due to decreased levels of estrogen, which is associated with an increased risk for osteoporosis.
“The activity of bone forming cells begins to decrease at age 35,” says Carol Michaels, a certified personal trainer with more than 20 years of experience and owner of Carol Michaels Fitness. “Weight bearing and resistance exercises are the best exercises for increasing bone density.”
Michaels said that for osteoporosis prevention and treatment, it’s especially important to focus on strength exercises that can contribute to better posture and balance.
And aside from the other important health benefits that result from a regular strength training routine—like a decreased risk for heart disease, a decrease in blood pressure, improved cholesterol levels, and as the American College of Sports Medicine puts it, improved “muscular fitness” for an enhanced quality of life— what many women don’t know about strength training is that it’s an extremely effective method for losing weight, and no, it won’t make you look “bulky” or “too muscular.”
"Women don't have the necessary testosterone levels to support that kind of muscle ‘bulk’.”says Chris Cooper, a Precision Nutrition coach and NSCA certified fitness professional.
Essentially, if you’re worried you’ll end up looking like a professional bodybuilder (which, by the way, there’s nothing wrong with), you’re concern isn’t legitimate.
Cooper said that women who gain and maintain a significant amount of muscle mass greatly increase the calories in their diets and the volume and intensity of their training programs to reach that goal.
Strength training will increase your muscle mass, but only to a certain extent, and because muscle is what’s referred to as “metabolically active tissue” that increase can help to enhance your fat loss efforts.
“Muscle is very metabolically active tissue and therefore the more of it you have, the more efficient your metabolism will be,” says Jilian McAffe, an ACSM certified personal trainer at Downsize Fitness in Chicago. “If you were to gain a pound of muscle, it can be estimated that this would increase your Basal Metabolic Rate— or rate at which your body burns the calories needed to survive each day—by 50 calories”.
In more simple terms, the more muscle you have the more efficient your metabolism will be.
This also explains why many exercisers who only perform cardiovascular workouts like running or cycling eventually find that their weight loss efforts come to a plateau, even after increasing the volume and duration of their workouts.
“While cardio is a great way to burn calories and is beneficial for the heart, oftentimes, it will burn away muscle because it is a catabolic activity,” says Maurice D. Williams, a NASM and NSCA certified trainer and the owner of Move Well Fitness. “Lifting weights helps to balance that out.”
Also, unnecessary amounts of cardio exercise can increase levels of cortisol, a hormone that promotes fat storage.
This is why a balanced combination of both cardio and strength training will yield the best results when it comes to burning fat.
By current guidelines, for adults this should include 150 minutes of moderate-intensity cardio exercise per week (achieved through spending 30 to 60 minutes working out moderately five days per week or spending 20 to 60 minutes working out vigorously three days per week), and strength training each major muscle group two or three days per week, leaving at least 48 hours for recovery between each training session.