i believed one of the problem with using structure alignment to resist a push is the power of the push pins your body in place, which is not good if you want to be mobile afterward, as the push continues. as Hunter mentioned, structure alignment will fail with sufficient force, but that's the next stage. resisting a simple direction push is only part of the requirement, but we need to understand the bigger picture of this which includes mobility, manage increasing load, and multiple directional forces. so what we do for a simple directional push must fit into the larger picture later. we can't just do one thing for this and use different set of respond for others. see Vlad comment (second hand) in this post
http://www.aikiweb.com/forums/showpo...31&postcount=2