Thanks for the reply. I probably shouldn't have even mentioned my experience. I was just interested in hearing specifically what it is about wrist grabbing that makes it ineffective, and thought it might relate. Considering my lack of ability I should have probably assumed it didn't and stuck with the question itself.
So it's just ineffective? No specific reasons why?
If only were it that we stood on our hands and presented our feet to be grabbed instead, perhaps training with grabs would be more effective. It would get the arms to learn to transfer force from the ground to the spine and teach the legs, pelvis, and lower spine to be more mobile and extensive.