Most of you probably already know how to do high knees (they’re pretty self-explanatory). But there are two things you should focus on to make them the most effective. First, make sure you are keeping your core tight and swinging your arms as if you were running. This will also help with your posture. Second, try to bring your ankle up and over your knee; when you’re tired or performing the exercise to quickly it’s easy to fail to bring your knees as high as they can go. Really check yourself to make sure you’re not just running in place but rather performing actual high knees.