One more post on core strength before continuing with upper body tuning. Learning to move this way will allow you to relax your neck more and relax your lower back. (Incidentally, it's also crucial to know how to do this if you're a tango dancer who wants to do amazing boleos).

Lie on the floor, knees bent, and find your abs. Then:

1. Leave one leg bent and straighten the other so it is resting completely on the floor.
2. Slightly suck your lower abs (just above your pelvis) down towards the floor, feeling your pelvis tip slightly down into the floor.
3. As your abs contract, your leg is lifted up in the air.
4. Slowly release your abs and let your leg return to the floor.
5. Remind yourself to relax the rest of your body.
6. Do this as many times as you can, but a few times less than your limit, so it doesn't feel like "work". You want to be interested in doing it again tomorrow.
7. Switch legs and repeat.

Refinements of this:

1. Stretch the straight leg as far away from you as you can


2. Make sure your neck is relaxed (easier to do if your butt is also relaxed).
   
3. Use a leg weight (don't do this at first. Concentrate on relaxed, smooth motion without a weight. You may never want to use a leg weight.)

If you feel like you are using your quadriceps a lot, refocus on contracting your abs, letting your pelvis tilt, and using that motion to "magically" lift your leg into the air.