Sensing Different Types of Force

Today, I was pushing hands with my teacher, after which I pushed hands with other students in the class. I came to realise that I can sense two types of force: the taiji force that my teacher uses (steady but flexible) and the rigid force that the other students were using. Relax doesn't mean to be soft, that much we know. My teacher's force is strong, flexible, but nothing rigid like the force that other students use. So what is the difference between the two? I think it is the source of the force. One is rooted and moves using the kua, the other is local and depends on pure muscular strength.

So now that I can sense the difference between the two, it is about how to neutralise both types of force, and learn how to use both types of force against my opponents.