I would question anyone that teaches correction based training methods but objects to the prong (or pinch) collar.
Here is a quote from the follwing website:
http://www.geocities.com/Heartland/Plains/4620/prong.html#AStudy
"A Study on Prong Collars was done in Germany:
100 dogs were in the study. 50 used choke and 50 used prong.
The dogs were studied for their entire lives. As dogs died, autopsies were performed.
Of the 50 which had chokes, 48 had injuries to the neck, trachea, or back. 2 of those were determined to be genetic. The other 46 were caused by trauma.
Of the 50 which had prongs, 2 had injuries in the neck area, 1 was determined to be genetic. 1 was caused by trauma. "
Choke collars place far more stress on the dogs neck and trachea than a prong collar. The prong collar spreads the force more evenly around the circumference of the neck, while the choker chain concentrates most of the stress on a small portion of the front of the neck and trachea.
Also, typically a lot less force is required to deliver a correction with the prong collar v.s the choke chain. This means that you get the correctional point across with less force. This equates to less force and lower possibility of damage to the dog.
Lastly, if you are using physical punishment, then the punishment is most meaningful and effective if the punishment is severe. It is doubtful that a choker chain can deliver a meaningful correction to an 85lb dog. What happens is the trainer corrects as best as he/she can, but the dog just sort of shrugs it off and the behavior is not impacted much at all. On the other hand, if the punishment is of the correct level, the dog will get the point and the behavior will be impacted. With using insufficiently intense corrections, what happens is the dog gets desensitized to the corrections and becomes "harder". After that happens, your corrections mean nothing. Correcting an 85 lb dog with a choker chain is pointless, in my opinion. If you are going to use corrections, make them count -- a prong collar will allow you to do that.
Tom C