Mistake: You Only Do Cardio
If your workout consists of hours of cardio and no weight training, you're setting yourself up for a less-than-firm body. Muscle burns calories even when you're resting, so less muscle means fewer calories burned throughout the day, not to mention a lack of muscle tone. And as you age, your muscles become a use-it or lose-it situation: "We start losing muscle at the rate of approximately a half pound a year after the age of 25—or five pounds a decade—without regular strength training," says Jessica Matthews, MS, an exercise physiologist with the American Council on Exercise.
The fix: Include strength training in your workout program at least 2 to 3 days per week to maintain and build lean body mass and decrease body fat percentage. (No need to make friends with the meatheads—these 25 toning moves for women are designed just for you.)
More: 3 Basic Strength Training Exercises
Mistake: You Neglect Your Posture
Few things make you look older than a hunched posture. Worse, the shape of a person's spinal column may predict her risk of requiring assistance in old age, according to a recent Japanese study published in the Journals of Gerontology. "Everything in life pulls us forward, from sitting and leaning in, to all the new technologies that require us to bend forward to text and type," says Tom Holland, MS, CSCS, exercise physiologist and author of Beat the Gym.
The fix: Reverse this trend by including pulling and reverse movements in your workout such as seated rows, suggests Holland. Yoga poses such as the Cobra, Mountain Pose and Tree Pose also help improve posture if incorporated into your workout once or twice weekly.
More: 3 Tips to Improve Your Posture
Mistake: You Don't Know Your Pelvic Floor Is Part of Your Core
In your quest for a flatter belly, you probably focus on your obliques (the muscles responsible for rotation) and your rectus abdominis (the muscles responsible for the "six pack" effect). But you should also be focusing on your pelvic floor, says Guy Andrews, MA, CSCS, executive director of Exercise ETC, Inc., a provider of fitness education programs in Florida. Neglect your pelvic floor muscles, and you can end up with that soft, round belly many women develop after middle age, as well as urinary incontinence, says Andrews.
The fix: Performing Kegels to activate the pelvic floor is an important part of strengthening your entire core (check out these simple step-by-step Kegel instructions!). Aim for three sets of 10 repetitions, three times a day.