Mountain Climbers Finish off your warmup with a boost of cardio — Freeman says you can challenge yourself by amping up the pace for the last 10 seconds. Start in a simple plank on your hands and toes. Make sure your body is one long line from your head to your heels. Alternate bringing one knee in at a time as fast as you can for 30 seconds without compromising on form. Click here for more health and wellness stories, tips, and news. Image Source: Amanda Freeman