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The Physical Effects of Harmful Training Devices

By Niki Tudge and Susan Nilson*

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Training devices that cause pain or evoke fear can cause both physical and psychological damage © Can Stock Photo / susannec**

In addition to the potential psychological effects of using training devices that cause pain or evoke fear, there is also the issue of possible physical damage to consider. We present here a variety of perspectives offered by veterinarians, canine research scientists, a professional dog trainer, and an engineer:

Thyroid Gland

“The thyroid gland is a butterfly-shaped organ just in front of the larynx and trachea, and the mandibular salivary glands are found on the side of the face just below the ears. Thus, they can be easily injured by trauma and sudden pressure forces (like could occur from the slip ring and chain of metal collar, and a metal prong or hard braided leather collar).” – Dr. Jean Dodds (2013).

Laryngeal Nerve

“The all-important laryngeal nerve is *trivia alert* the longest nerve in the body, and it travels down the left-hand side of the neck near the windpipe. Anything that severely compresses this nerve can damage the way the larynx works. This is why choke collars are not recommended.” – Pippa Elliott (2017).

Laryngeal Paralysis

“A sudden jerk to the neck as part of inappropriate behavior training is another too common reason for laryngeal paralysis. It’s the fear-based, old school and ‘you must be dominant over your dog’ training, where neck pops with the leash, or prong or choke collars are used. When the trachea cartilage is popped repeatedly during this type of ‘training,’ the dog can wind up with tracheal damage. This type of handling puts a tremendous amount of pressure on the larynx because the collar sits right on top of it.” – Dr. Karen Becker (2017).

Emotional Damage

“I see many dogs who have been previously corrected with shock collars. Each and every one of these patients has become behaviorally worse than they were prior to the shock collars (more fearful, more aggressive). The emotional damage caused by shock collars is often beyond repair and requires a lifetime of treatment. The wounds I see are beyond skin-deep, they are soul deep.” – Dr. Lynn Honeckman (2018) (qtd. in Shock-Free Coalition).

Pressure Necrosis

Shock collars carry a risk of physical damage to the skin of the neck (Polsky, 1994): “To ensure that the metal pins are in close contact with the skin of the neck, an e-collar must be fitted tightly. Aside from being uncomfortable, the points where the metal pins make contact with the skin can become irritated, and this can result in the development of pressure necrosis or wounds.

Antibarking collars and electronic fence collars must be worn for long periods, so these risks are especially high in these contexts. Furthermore, there is a risk of device malfunction, which can lead to damage caused by electricity.” – Masson et al. (2018).


“Blogs written by well-respected trainers such as Grisha Stewart describe and provide photographic evidence of ‘burns’ on a dog’s neck, the result of a shock collar. Don Hanson, past president of the APDT and also a respected trainer, writes of personally witnessing burns on a dog’s neck. There are letters from veterinarians claiming to have treated burns created by shock collars.” – Jan Casey (2012).

Restriction of Blood Flow

“Assume a typical big dog: 80 pounds, 20-inch neck size. The dog can pull with more than his own weight because his weight is low and forward compared to the distance between his front and back feet, and he won’t lift his front feet by pulling until he’s pulling a lot more than he weighs. 80-pound dog: 120 pounds of pulling force is easily possible.

“Much more if he gets a running start before he gets to the end of his leash. Newton taught us that every action (force) has an equal and opposite reaction. So take the 1.5-inch web collar. The bottom of the collar supplies all the force to the dog’s neck.

“If he pulls with his own weight, the contact force is around 5⅓ pounds per square inch. (80 pounds/(10 inches of collar x 1.5 inches wide). Now consider a choke collar made of 25-inch nylon cord. A chain choke would be similar as the links make a nearly continuous contact band.

“Even if it does not slide tight, in the same configuration as the web collar the contact force will be 32 pounds per square inch – 6 times as much, before one even considers the drawstring effect. This is far more likely to cause injury to the larynx or restriction of blood flow in the neck.” – Jim Casey (2015) (qtd. in Garrod).

Blood Vessel Collapse

“A prong collar has a pair of prongs approximately every inch. The prongs are made of wire, approximately 0.09 inches in diameter. Still ignoring the drawstring effect – each prong contacts the neck with an area of only about 0.007 square inches. 20 prongs, 80 pounds, generate about 579 psi at each prong tip, assuming they are blunt and not pointy.

“If the prongs are located atop the larynx it is hard to imagine injury (at least bruising) NOT occurring. This pressure will easily collapse any blood vessel that suffers the fate of being beneath a prong. So: contact force is over 6 times greater for a simple choke, and over 100 times greater for prongs FOR THE SAME PULL.” – Jim Casey (2015) (qtd. in Garrod).


Becker, K. (2017). A Vet’s Dire Warning: This Favorite Product Can Cause a Life-Threatening Emergency Down the Road
Casey, J. (2012, March). Can Shock Collars Burn? BARKS from the Guild (1) 21-22
Dodds, W.J. (2013). Q&A with Dr. Dodds: Can Collars Really Damage the Thyroid? 
Elliott, P. (2017). How Choke Collars Can Cause Real Damage to Your Dog 
Garrod, D. (2015, January). The Argument against Prong Collars. BARKS from the Guild (10) 26-29
Pet Professional Education. (2017). The Shock Free Coalition – Ask The Experts Dr. Lynn Honeckman, Dr. Soraya Juarbe-Diaz, Ken Ramirez, Janis Bradley and more
Polsky, R.H. (1994). Electronic shock collars: Are they worth the risks? Journal of the American Animal Hospital Association 30 (5) 463-468


Pet Industry Regulation

* Excerpt from Pet Training and Behavior Consulting: A Model for Raising the Bar to Protect Professionals, Pets and Their People by Tudge, N.J, Nilson, S.J., Millikan, D.A., & Stapleton-Frappell, L.A. (2019). (n.p.): DogNostics Career Center Publishing. Get your free e-book here.

** There is no suggestion that the dog in the photo has been subjected to any training devices that can cause pain or evoke fear; image for illustration purposes only

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