Continuing on with our reverse crunch discussion, I view this move as the pantheon of both attaining sacral counter nutation as well as strengthening the lower abs. I find myself knocking out sets throughout the day to reestablish my toe touch, but what I also notice is that my endurance in maintaining this position is still relatively lacking.
The next step for me has been incorporating longer holds while maintaining a lower rib tuck (the specific cue would be to bring the "belly button to belt buckle") What I came up with is incorporating holds with my legs increasing extended. The lower I move toward the ground, the more difficult this will be. This was Bruce Lee's signature move back in the day and he called it the dragon flag. A caveat here is that this exercise shouldn't be a 9 out of 10 difficulty. Our lower ab muscles are postural muscles which respond to lower levels of tension.
Here are four progressive holds I have been using to build endurance. I recommend holding for 30-60 seconds with deep inhales thru the nose and exhale thru the mouth:
1. Dragon flag hold- Short range/short lever
2. Dragon flag hold- Long range/short lever
3. Dragon flag hold- Short range/long lever
4. Dragon flag hold- Long range/Long lever
One thing you will notice is that, unlike Bruce Lee, my legs are not directly in line with my body. This is because a) I am no Bruce Lee and b) getting straighter over time is a good way to make progress.