Start on all fours with your hands directly underneath your shoulders, your knees directly underneath your hips, and your toes tucked. Find a neutral spine and long neck.
With control, engage your core and lift your knees one or two inches off the ground. Try to keep your back flat.
Hold for 10 to 30 seconds, then rest for a maximum of 30 seconds. Repeat the entire ab circuit one to three more times.
Tamara Pridgett was the associate editor for PS Fitness. Likes: box jumps, chai lattes, and sprinting. She's a NASM-certified personal trainer and a Precision Nutrition level 1 coach. She's also a Division 1 All-American sprinter.