If you’re ever in need of getting your heart rate up quickly, like when you need to add a quick cardio burst to your workout routine, try this super-simple exercise. All you need to do is jog in place but raise your knees as high as you can (waist-high is about right). This will get you working harder than a normal jog and it will be great for your legs and butt. Remember to keep your abs tight as you’re doing it!
