Re: bad technique vs. resistance
I have a saying that comes from homeopathic medical jargon that I apply to throwing arts. I call it the "Law of Similars".
In throwing arts, we need to float uike's whole body rather than just his/her upper torso. You will feel "resistance" when the uke's upper body is being stretched out while his/her lower body recenters itself inside their base.
If you only use your upper torso when practicing a technique, you only push or pull on the uper torso of uke. Thus the "law of similars".
The principle involved is about how long your leverage is. If you do your work from the bottoms of your feet, then you will float uke's whole body from the bottom of his/her feet. I believe that this rule is one of the most important principles we must follow.