This multitasking exercise from Jen Widerstrom, a trainer on The Biggest Loser, works both your inner and outer thighs and will help tone your biceps, too. Feel free to use an exercise band on the higher end of the resistance scale since your lower body will be doing most of the work—Widerstrom recommends a blue or black band. And remember to keep your core engaged during the entire move.
Here's how to do it: Stand on a resistance band with your feet hip-width apart and knees bent; hold the handles with your arms bent at 90 degrees, palms up and wrists straight. Go into a half squat; take a broad step to the side with your left foot; then step your right foot in. Take 3 more broad steps to the left. Repeat move on your right side. Do 3 sets, then 3 sets of 8 smaller quick steps per side.