Re: Aikido vs....
If black is on his back, he has white in his guard (could be open or closed, I'd prefer closed).
From having someone in my guard, if I can hit them in the face, then they can hit me...I'd prefer to extend my hips and push them away so that I don't get pounded by having them in range. Conversely, I might pull them in tight and work for an arm bar or something...it just depends.
This last post illustrates very clearly why the MMA/BJJ crowd are VERY good at what they do...there is an entire language, methodology, positional framework, etc. that they train repeatedly to accomplish their goals. If you are outside of that...it gets difficult enough to discuss, let alone defend. If you haven't spent time with someone in your guard, you may not realize just how much damage can happen and how quickly if you don't push them away with your hips, and how weak your own strikes will be from that position.
Ron (and I don't even really do this stuff...)