I know, Dr. Stephen makes everything look easy, but this variation of the “Crunch” is a core builder. Alternate with sets of push ups, squats and pull ups for a total body workout (sets of ten each for 4-5 rounds, no stopping).
This is a super simple but great movement to do on a regular basis – like Overhead Squats, Kettlebell Swings help “undo” the bad effects of all the sitting we do (like me creating this post – dang!)
Notice in the video how Dr. Stephen is using the hip thrust motion to “swing” the kettle bell – although the arms are active and involved, it’s not their motion that brings the weight to vertical; the arms simply continue the momentum of the motion of what the hips generate.
That (above) being said, use your arm strength to maintain a controlled stop at the top.
One thing to be careful of: Don’t hyper-extend your lower back at the top – engage your core (your abs and upper torso) to stop the motion of your pelvis at vertical – meaning DON’T arch your back.