Published October 5, 2026

A collar is not automatically harmful, and a harness is not automatically better. But when a dog repeatedly pulls, lunges, coughs against the leash, or already has neck, neurologic, or airway concerns, where that force is applied matters. Here is what I want pet parents to understand about collars, harnesses, and why walking equipment can become part of a canine rehabilitation conversation.

A Collar Is Not the Problem. Force Can Be.

I recently came across several posts warning about the damage collars can cause to a dog's neck. The anatomy caught my attention immediately, because underneath that relatively small area are muscles, cervical vertebrae, nerves, blood vessels, the trachea and other important structures. But I also think this conversation deserves more nuance than simply saying, “Collars are bad. Use a harness.”

A dog wearing a properly fitted collar and walking beside you on a loose leash is very different from a dog spending a 30-minute walk leaning hard into that collar, repeatedly hitting the end of the leash, or being pulled backward by the neck.

From a rehabilitation standpoint, force, repetition, direction and duration matter.

Research using both dogs and simulated canine neck models supports that distinction. Pressure beneath a collar changes depending upon the amount of force being applied, the collar itself and even the direction in which the dog is moving relative to the handler. In a laboratory model, stronger pulls and leash jerks produced substantially greater neck pressures, and no collar tested eliminated potentially concerning pressure when significant pulling occurred.

That doesn't mean I want pet parents frightened of putting an identification collar on their dog. It means I want us paying attention to what is happening between the dog, the equipment and the person holding the leash.

Think About What Happens When Your Dog Reaches the End of the Leash

Picture an enthusiastic dog walking ahead of you. He spots a squirrel and accelerates. His body continues forward until the leash suddenly becomes tight.

If the leash is attached to a neck collar, the restraint force is concentrated around the neck. If that happens occasionally and mildly, that is one situation. If the dog spends most walks pulling continuously or repeatedly lunging hard enough to cough or gag, that is quite another.

Studies measuring leash-related forces demonstrate that collar construction and leash tension influence the pressures applied to the canine neck. Research has also found that pressure through a collar can increase intraocular pressure in dogs; that finding may be particularly relevant for dogs with certain eye conditions.

And there are dogs for whom avoiding neck pressure is already part of medical management. The American College of Veterinary Surgeons, for example, recommends a body harness rather than a neck lead for dogs being managed after treatment for tracheal collapse.

So my concern isn't that a collar merely touches the neck. My concern increases when the collar becomes the place where substantial repetitive force is being absorbed.

Why This Matters to Me as a Rehabilitation Practitioner

This is where the subject becomes much more than a discussion about dog-walking equipment.

When I evaluate a dog, I don't see the neck as an isolated structure. I am looking at how the head, neck, shoulders, spine and limbs work together.

A dog experiencing cervical discomfort may hold the head lower or more rigidly. He may become reluctant to turn his head in one direction. The muscles around the neck and shoulder girdle may become guarded. His forelimb movement can change, and the body may begin developing compensatory strategies elsewhere.

With cervical intervertebral disc disease, for example, veterinary signs can include a stiff or painful neck, reluctance to move the head, a lowered head position, altered walking, muscle spasm around the neck and shoulders, and—in some dogs—forelimb weakness, knuckling or more significant neurological deficits.

Now imagine that dog walking several times a day while repeatedly pulling against a collar.

The collar may not have caused the dog's cervical problem. That distinction is important. But once I know the neck is painful or neurologically involved, I certainly don't want to unnecessarily add repeated external loading to an area we're trying to protect.

That is rehabilitation thinking: not simply asking what caused the problem, but identifying what may now be aggravating it or making comfortable movement harder.

The Shoulder Connection Matters Too

There's another reason I pay attention to walking equipment: changing where we place the leash force can change movement elsewhere.

Moving the leash from a collar to a harness distributes restraint away from the neck, but that doesn't mean every harness is biomechanically neutral. Small studies examining canine gait have found measurable changes in shoulder or forelimb motion with some harness designs. One study comparing two harness styles found reduced shoulder extension with both compared with no harness, while another study of tactical harnesses found changes at the shoulder, elbow and carpus. The clinical importance of some of these findings is still uncertain, and the existing studies are relatively small.

That is exactly why I don't believe in telling every pet parent to buy one particular harness. I want the harness to fit your dog.

I look at where straps cross the chest and shoulders, whether the harness shifts when the leash becomes tight, whether it rubs behind the front legs, whether the dog shortens his stride while wearing it, and whether he moves differently once it comes off.

For a dog already compensating through a painful shoulder or forelimb, those details become especially important.

“But I've Heard Harnesses Teach Dogs to Pull.”

I've heard this too, and there's a piece of truth hiding inside an oversimplification.

A back-attachment harness can allow a dog who already pulls to generate considerable force comfortably through the body. In one study of 52 shelter dogs, dogs produced greater leash tension and spent more time pulling toward a food reward while wearing a back-connection harness than while wearing a neck collar. Interestingly, that difference wasn't found when the dogs were pulling toward a toy, which tells us the relationship between equipment and behavior isn't quite as simple as “harness equals pulling.” PubMed

Another study found that a front-connection harness reduced measured pulling compared with a martingale collar, although the authors appropriately cautioned against assuming those results apply to every dog and every real-world walking situation. PubMed

So I wouldn't tell a pet parent that putting on a harness will magically stop pulling. I also wouldn't say that wearing one teaches a dog to pull. Equipment and training are two different pieces of the same walk.

A dog can learn to walk beautifully on a loose leash in a harness. A dog can also drag someone down the street in one. Likewise, simply putting a collar on a dog doesn't teach loose-leash walking.

If pulling is an ongoing behavioral problem, appropriate positive training matters. My role as a rehabilitation practitioner is somewhat different: I am asking where I want the physical load going while that dog is learning.

For a healthy young dog with no orthopedic, neurologic, cervical or airway concerns, the answer may be very different from the answer for my 13-year-old arthritic patient, my dog recovering from surgery, or my neurologic patient with cervical involvement.

When I Would Be Especially Interested in a Harness

There are circumstances in which moving leash pressure away from the neck deserves serious consideration.

A dog with known cervical pain or cervical IVDD is an obvious example. So is a dog with certain airway problems, particularly when a veterinarian has specifically recommended avoiding neck pressure. Dogs with neurological weakness may also benefit from equipment that gives the caregiver safer control or physical support without repeatedly loading the neck.

I may also raise the subject when I see a dog repeatedly coughing or gagging against his collar, hitting the end of the leash forcefully, or walking with continuous tension.

Post-surgical patients deserve individual consideration as well. Depending upon the procedure, restrictions and dog's movement pattern, I may want a harness that provides greater control or assistance—but I also need to make sure its placement doesn't interfere with an incision or encourage a movement we are currently trying to limit.

There isn't one piece of equipment I can recommend blindly for all of those dogs.

What I Want You to Watch During Your Next Walk

Instead of immediately changing equipment, watch your dog.

Notice whether the leash hangs loosely for most of the walk or remains tight. Listen for coughing, gagging or changes in breathing when tension comes onto the leash. Watch the position of your dog's head. Does he carry it comfortably and turn easily to both sides, or does he seem reluctant to look one direction?

Then look farther down the body.

Does one front leg take a shorter step? Does your dog begin scuffing a paw as the walk progresses? Is he pulling much harder than he used to? Does he come home and seem unusually sore, restless or reluctant to move his neck?

None of those observations diagnoses the problem. They are simply useful pieces of information.

A sudden change in gait, significant neck pain, weakness, knuckling, loss of coordination, difficulty breathing or other neurological changes deserves veterinary evaluation rather than an experiment with a new harness.

Where Rehabilitation Fits In

Once the veterinarian has identified or ruled out medical concerns, rehabilitation can help us look at the functional consequences.

During an in-home canine rehabilitation assessment, I may evaluate cervical movement, head carriage, shoulder mobility, soft-tissue tension, standing posture, weight distribution and gait. I also want to see what happens when the dog turns, backs up, transitions between positions and walks on the surfaces encountered every day.

When appropriate for the diagnosis, treatment may include gentle hands-on techniques for cervical and shoulder musculature, addressing compensatory soft-tissue restrictions, improving postural control, rebuilding strength and retraining more efficient movement patterns. And sometimes I want to see the leash and harness.

That may sound surprisingly simple compared with therapeutic exercise, but caregiver education and environmental modification are part of rehabilitation. If we spend an hour improving movement and then the dog repeatedly struggles against poorly fitted equipment several times every day, we've overlooked an important part of his real life.

Because I provide in-home canine rehabilitation, I have the advantage of seeing those everyday details. We can look at how the dog gets through the doorway, what happens on the driveway, whether the harness shifts when he turns, how the owner handles the leash, and whether a small equipment or handling change makes walking more comfortable.

Collar or Harness? I Don't Think That's the Best Question

The better questions are:

How does this particular dog move in it? Where does the force go? And what does this dog's body need right now?

A comfortable dog who walks politely on a loose leash may do perfectly well in an appropriately fitted collar. Another dog may have a medical reason that makes minimizing neck pressure particularly important. A harness may be an excellent choice for that dog—but it still needs to fit correctly, allow appropriate movement and be paired with good leash handling.

I don't want pet parents afraid of collars, and I don't want them believing a harness is automatically harmless. I want them looking at their dogs.

If something as ordinary as the equipment we use for two or three walks every day can be adjusted to support more comfortable movement, that is worth paying attention to. Rehabilitation is often about exactly those small, thoughtful choices: reducing unnecessary strain, supporting the body where it needs help, and making everyday movement just a little easier.