walking with just a collar

I have been using the newtrix for about a year now, and I have to say it is great, but I would like to use just a collar to walk Bree.
when she runs with my hubby he uses just a collar and when he rollerblads with her he also uses just a collar when we play with her we use just a collar, but when we try and walk Bree with just a collar she pulls and pulls and pulls,

Is there any way we can use just a collar instead of the newtrix?? I tried just a collar today (boy my arm is sooo sore.)
and is switching back and forth confusing her??

I don't think that its switching collars that's confusing her so much as switching activities. Playing, running and roller blading are all fast pace things. Walking, well, its slower. Basically, when she goes out with just a collar on, she's expecting to be doing something that's faster.

Its sort of like seeing eye dogs, when they have their harnesses on, they are working, they don't play or interact with other people/animals because they are on the job, but put them in the same situation will just a leash and collar and they are game to play... Make sense?