Like an empty vessel?
Yes indeed. Now whenever you hear someone saying it as an advanced martial artist you will have an idea of where they are coming from. I have heard Segal say it before as one example of someone you may know. I'm sure it has been said many times by many past people too.
Here's the thing......in the way I teach anyway, and those I know doing similar. I have no qualms styarting from spiritual. Thus I tell them outright we are not here on the mat to learn about physical strength or connective tissue or but merely principles.
Thus they learn to see what is there beyond physical. They learn there is a center, there is a centre line, there is space, there is circle there is geometric pathways of energy, there are all these talked about things and they are real.
The reality comes through emptying the body much like emptying the mind. Once its empty you can then allow it to be filled but now you are one controlling such things. In fact I wouldn't say controlling as much as allowing.