Lying flat on your back with your legs straight and your arms above your head on the ground, you are bringing your legs straight up and your arms and shoulders off the ground simultaneously, reaching for your toes, briefly balancing on your tailbone. And, again at the same time, lower your whole body back down to the floor. You can add a dumbbell for more of a challenge, holding it on both ends with your hands.
Helpful tips and Tricks
If the large movement is too challenging, you can either do the Toe Reach exercise, or simply lower your legs only slightly instead of all the way.