A 400-Calorie Treadmill Workout That Targets Your Butt

If you want to burn 100 calories in 10 minutes, and tone your tush and legs at the same time, go for a run. For even greater lower-body-sculpting power, you’ll need to add hills to your workout. I know. I know. Hills suck! And if running up hills is way too challenging, walking briskly will…