Health and behavioural risks of ill-fitting dog harnesses

There is plenty of evidence to show that using a collar and lead to restrain a ‘lead pulling’ dog can cause them physical harm. For this reason, harnesses have become a popular option to guide, restrain and control a dog when out and about.

But a word of warning - there is no perfect solution to physically restrain a pulling dog! Physical force + restraint will create physical pressure on a dog’s body. And research shows that any type of dog harness will alter a dog’s gait to some degree (even if they aren’t pulling) (1). This means the design and fit of a harness is of critical importance. A poorly designed and/or ill-fitting harness can not only cause discomfort, but it can also expose your dog to significant health and behavioural risks.

In this blog article, we aim to explore what an ‘anatomically correct fit’ means with respect to dog harnesses. We’ll also explore specific health and behavioural risks associated with ill-fitting dog harnesses; and we’ll provide some practical guidance on how to choose the best harness for your dog.

When it comes to dog harnesses, what does an ‘anatomically correct fit’ mean?

With reference to a dog harness, an 'anatomically correct fit' means that the harness is designed to fit the natural shape and structure of a dog's body. There are 4 key features of a harness that demonstrates an ‘anatomically correct fit’:

Range of movement: The harness should align with the dog's skeletal and joint structure. This means that that harness should allow full range of joint movement and enable the dog to move with its natural gait.
Pressure distribution: The harness distributes pressure evenly across the dog's body rather than concentrating it on one spot. And if the dog pulls while wearing the harness, any pressure created is focused on those areas of most bone structure and muscularity, rather than soft and sensitive areas such as the trachea, armpits and stomach.
Natural posture: The harness allows a dog to maintain a natural posture when standing, sitting, or moving. This means that when the dog is pulling or being led, their posture isn't altered in a way that could cause strain over time.
Adjustability: Given the variety of dog breeds, shapes and sizes, and the likelihood that your dog will change shape as he/she ages, an ‘anatomically correct’ harness should have multiple points of size adjustment.

What are the different types of dog harness?

While there are many different dog harness designs and brands available, but only two core shapes that cover most varieties (see descriptions and image below) (1):

1. Horizontal chest strap (also known as a “Norwegian” or “Restrictive” harness)

2. Y-shaped chest strap (also known as an “H-shaped” or “Non-Restrictive” harness).

While head-halters are sometimes described as being harnesses, we do not consider these to be harnesses as they fit around the dog’s head rather than around their body.

Health and behavioural risks of ill-fitting dog harnesses

As a harness is used to guide, control and restrain a dog (usually when it is in motion), it will inflict some level of physical pressure on your dog’s body (the extent of which will of course depend on your dog’s behaviour). By inflicting pressure, even if it is light, a harness can have a significant impact on your dog’s health. There are 6 ways that an ill-fitting harness can negatively impact or effect your dog’s health and behaviour – each of these is discussed in more detail below (2)(3).

Musculoskeletal strain – imagine your dog trying to enjoy a walk but hindered by a harness that restricts their movement. An improperly fitted harness can cause significant musculoskeletal issues by altering their natural gait or applying uneven pressure. Over time, this can lead to shoulder impingement, altered walking patterns, and even contribute to conditions like arthritis or muscle strains.
Respiratory distress – when harnesses are too tight around the chest or neck, they can impede breathing and put a dangerous level of pressure on the trachea. This not only causes a dog discomfort and distress but can also lead to tracheal irritation or collapse. This risk is greatest for brachycephalic (or flat-nosed) dog breeds such as bulldogs or pugs.
Skin lesions and fur loss – when harnesses rub against the skin due to poor fit or design, they can cause chafing, fur/hair loss, and skin irritation. In severe cases, constant friction might lead to pressure sores or even infections.
Neurological damage – less visible but equally concerning are the neurological risks posed by a harness that's too tight or poorly designed. Pressure on the spine or nerve pathways can lead to nerve compression or damage, manifesting in pain, numbness, or changes in the way your dog moves.
Restricted circulation – a harness that is too tight may restrict circulation, potentially affecting blood flow to your dog's limbs or causing discomfort in other areas.
Stress-related behaviours – physical discomfort often leads to behavioural changes. Dogs can become anxious, aggressive, or reluctant to engage in physical activity if their harness causes pain. Chronic discomfort can lead to engrained stress-related behaviours.

Warning signs that your dog’s harness is not a good fit

When assessing different harnesses, there are some immediate and short-term warning signs that indicate that the harness in question is not a good fit for your dog – these include:

Immediate visual signs that the harness is the wrong size or does not fit your dog’s body shape i.e. notable skin rolls around the straps, pinched skin etc.
Signs of excessive friction on your dog’s body – such as fur loss or visible skin irritation, redness or chafing.
Signs of muscle strain or pain such as changes in gait, limping, stiffness or indications of joint/back pain (whining, abnormal posture, panting, trembling, lethargy, difficulty walking etc.) (5)
Signs of irritation or discomfort such as frequent stops to scratch or bite at the harness straps.

How to choose an ‘anatomically correct’ harness for your dog

To choose a harness, start by first measuring your dog carefully. At a minimum, you’ll need to measure your dog’s girth – this is the widest part of their chest (or rib cage) located directly behind their front legs (tip: make sure you include some slack in the measuring tape to allow for breathing and movement). When you know you dog’s size, look for a harness that includes the following critical features (3)(4):

Numerous points of size adjustment
Primary lead attachment-point on the back (a front attachment point can also be useful, but shouldn’t be the only option)
Shoulder/neck straps that do not cross over or impede the dog’s shoulder joint
Should/neck straps sit closer to the top of the sternum (chest bone) rather than around the throat
Girth straps that do not rub under the dog’s armpits
Girth straps do not sit behind the rib cage (this puts pressure on the stomach)
Chest straps or plate (that go between the front legs) do not rub the inside of the legs or restrict leg movement i.e. should not be too wide
Enough structure that the harness cannot be pulled off or slide around
Symmetrical design so that the harness doesn’t constantly rotate to one side.

Generally, the style of harness that meets the above criteria is the Y-shaped chest strap harness. But it’s important to note different dog breeds can have dramatically different body shapes and some shapes might be better suited to the horizontal chest strap harness. In his blog article titled “To Harness or Not to Harness? That is the Question”, Chris Zink (DVM, PhD DACVSMR) highlights that all harnesses alter a dog’s gait. And that if you choose a Y-shaped chest strap harness, make sure it’s tightly fitted around the dog’s neck so that it doesn’t slide back and put pressure on the shoulders. And if you choose a horizontal chest strap harness, make sure it is loosely fitted, so that it can slide away from the dog’s shoulder as needed (1).

At Led & Collared®, we offer both harness styles. Our version of the Y-shaped chest strap harness is the Anatomical Dog Harness and our version of the horizontal chest-strap harness is the Quick Release Harness.

Conclusion

In conclusion, while harnesses are generally preferred over collars for managing dogs that pull on the lead, they are not without their risks. Ill-fitting harnesses expose your dog to a range of health and behavioural risks, including musculoskeletal strain, respiratory issues, skin lesions, neurological damage, restricted circulation, and stress-related behaviours.

As such, it is of critical importance that you choose a harness that fits/suits your dog’s unique body shape to ensure the harness supports your dog's natural movements, distributes pressure evenly, maintains a natural posture, and is size adjustable.

The 'Y-Shaped' harness is often recommended for its design benefits that cater to these anatomical considerations, but the suitability can vary with different breeds and individual dog anatomies. The key to minimising pressure-related harm lies in careful harness selection and careful/on-going observation of your dog's behaviour and physical responses to the harness.

And a final (but important) concluding comment – remember that there is simply no substitute for training your dog to walk with a loose lead. If your dog does not pull on their lead, the risk of pressure-related health or behavioural problems is close to non-existent.

– January 2025

Author: Lorna Brennan, Managing Director, Led & Collared®

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