Training my abs is always tough, so I figured why not push it even further? I swapped out the usual sit-ups and Russian twists for a four-move dumbbell workout to really spice things up.

Place your hands by your temples, with your elbows pointing out to the side. Lift your left knee, and at the same time, bend ...

This core workout involves just four moves, but with dumbbells and minimal rest, it delivers a serious burn and maximum results.