@ownedbyspencer:
So a choke collar might be an acceptable way to train in Ava's case? I believe that there is a way to do it using only the noise as a negative reinforcement (in much the way that the clicker is a positive reinforcement). I might not be so opposed to that, if someone knew exactly how to do it, but some of the trainers I've talked to believe in a physical correction, with the animal's behavior determining how "physical" the correction would be. As stubborn as Ava is, I would be afraid they would hurt her. She's such a little thing to be so mulish.
I wouldn't use a choke collar. It's too easy to cause physical damage. And I don't know without seeing her that she is being alpha/stubborn. Certainly when she gets upset enough to have diarrhea, that is a sign of fear, not dominance.
The best trainers use only enough force to get the desired result, and it's likely wrong to label it force. More like pressure. Negative reinforcement, used correctly, is simply creating an uncomfortable situation that the animal would prefer to escape. "Fix it up and let them find it". After a bit, a little pressure or discomfort provokes a search by the animal for whatever turns off the pressure. With horses, you tend to use either pressure from reins or legs or a whip (used with a light tap that irritates, rather than causes pain). When the desired action happens, the pressure ceases. Dogs are not motivated the same way as horses, and are more inclined to resist pressure, even to the point of injury, as happens with collars and leashes on occasion. ( a relatively sharp jerk is likely better than allowing them to lean on the leash, however)
I think what differentiates a great trainer is their powers of observation. They see the intent before the action, and are able to circumvent it with a distraction or mild correction before the animal actually makes that mistake. Timing and consistency are what get you there. And patience!! 
