3. BICYCLE CRUNCH
Lie on your back with your hands behind your head, and your legs raised and bent at 90 degrees. Alternate sides by bringing your right elbow towards your left knee then your left elbow towards your right knee, building up to 60 seconds. Try and hold the crunch for a two-count on each side to force a slower, concentrated movement.
Holland says: "With this movement, you’re targeting all three key areas at the same time. It combines a regular crunch, the side-to-side motion that targets the obliques, and the reverse crunch that hits the lower abs."