Popsugar Fitness Athletes Surfer Carissa Moore's Favorite Home HIIT Exercises Try Olympic-Bound Surfer Carissa Moore's Favorite HIIT Cardio Moves to Do at Home March 23, 2021 by Samantha Brodsky View On One Page Photo 2 of 5 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 2 High Knees Run in place while lifting your knees high to the level of your waist (or belly button). Engage your abs as your knees comes up, and pump your arms to warm up your upper body. If you want a more advanced move, try combining high knees with skaters to do lateral bound to lateral high-knee run. Previous Next Start Slideshow Summer Olympics 2021OlympicsHome WorkoutsAthletesSportsCardioHIITSurfing