This Pilates-inspired move uses the same pressing action as the static press to deepen the engagement of your abdominal. The weight of your extended leg makes it more challenging.  Lie on your back and bend both knees into your chest, feet flexed. Interlace your fingers on top of your right thigh and extend your left leg out parallel to the floor.

 Lift your head and shoulders off the floor, curling up over the top of your rib cage and looking at your legs. Press your palms against your right thigh while tipping your pelvis to bring your right knee in towards your chest (your hands should add resistance to your leg). Switch legs and press your palms against the left thigh as your right leg extends parallel to the floor. That's one rep. Do up to 3 sets of 10 repetitions in a row. Read more here: