There's a longer-term benefit to all that lifting, too: Muscle accounts for about a third of the average woman's weight, so it has a profound effect on her metabolism, says Kenneth Walsh, director of Boston University School of Medicine's Whitaker Cardiovascular Institute. Specifically, that effect is to burn extra calories, because muscle, unlike fat, is metabolically active. In English: Muscle chews up calories even when you're not in the gym. Replace 10 pounds of fat with 10 pounds of lean muscle and you'll burn an additional 25 to 50 calories a day without even trying.
Former ballet dancer and Ballet Beautiful founder Mary Helen Bowers has serious fitness cred thanks to training Natalie Portman for her role in Black Swan. With this free workout video, she takes her expertise outside the dance studio. The 15-minute mat workout will help tone your lower body with graceful ballet-inspired movements like bridge variations.
We're going to mix it up this week! Instead of Straight Sets, you're going to complete your workout in a circuit style. This week, you'll complete 1 set of each exercise for 15 reps, then you'll immediately move on to the next movement with no rest in between. For example, on the Day 1 workout, you'll perform your first set of leg presses for 15 reps, then you'll immediately go to the goblet squat and perform 15 reps and then continue on to the next exercise with no rest in between movements. At the end of these four movements, you'll rest for one minute, then complete the circuit two more times.