Flurrer kicks
 

Flutter kick

Lie back and lift your heels a couple of inches from the floor by contracting your core. Alternately lift raise one leg and lower it, mimicking the kick you do in a pool.

Top tip: Start crossing your legs from side-to-side out in front of you, not just up and down. This’ll work your abs in multiple directions and hit your obliques for a solid centre that extends further than the six cobblestones in front of you.