Here at K9 Trail Time we are constantly researching and learning more about dog anatomy and physiology to help us understand the impact working a dog in harness will have on the natural movement of the dog. Part of this study has involved reading the latest research into dog movement undertaken by Dr Martin Fischer in the Jena study and his most recent work which has yet to be published. The findings have been summarised nicely here:
You might be thinking ‘what has this got to do with me and my dog?’ but we believe that to understand the dogs’ natural motion helps us to understand why a harness may or may not work for your dog based on it’s skeletal structure and how it was designed to move.
The first thing to say is that dogs are designed to move most efficiently in a ‘trotting’ gait and so if your dog is a trotter when they are pulling, they are using their energy efficiently and moving minimally. If your dog is ‘bounding’ when pulling in harness, either in a canter or a gallop (more likely at higher speeds when attached to a bike or scooter but if you run fast enough then canicross too) then your dog is exerting more effort than the efficient trot pace and it is even more important you have the correct fitting harness to ensure they have the freedom of movement necessary so as not to restrict them in any way.
The single biggest problem we see is harnesses which are too big on the dog and so are inadvertently restricting shoulder movement because the neck of the harness is encroaching on the shoulder when the dog moves. It is so important the neck on your sport harness is nice and snug to avoid this restriction but also to avoid your harness slipping up into the armpit of your dog when they might pull to one side and this again then restricts shoulder movement.
Below are 4 pictures of one of the K9 Trail Time dogs, Yogi, in 4 different sizes of the Non-stop Freemotion harness and in all honestly to the untrained eye it might be hard to tell which fits and which doesn’t. From top to bottom Yogi is wearing the size 4 Yellow flash (too small) size 5 Red flash (perfect fit) size 6 Blue flash (too big) and size 7 White flash (far too big).
Now looking at these picture you might think the size 6 is the one which fits Yogi best and we’d agree that based purely on the photos, it does perhaps look like it is sitting in the best place but if you look closely the top of the shoulder is slightly restricted and when slotting your hand in the neck (you can’t tell that from the photo) there is a huge amount of room for the harness to slide around on his neck. The size 4 is obviously too small being too close behind his front legs and the angle is wrong on his ribs. The size 7 is obviously too big, coming too far back on his body and when he pulls into it, the straps on his ribs will come behind the last ribs and pull up into his soft stomach region – not good!
At this point it is also worth saying you cannot always tell correct harness fit from a photo. Yogi is an easier candidate to judge from a photo because he lacks thick fur but even then you can only tell the neck on the size 6 Freemotion was too loose by feeling the gap when it is pulled tight. We see a lot of people asking for advice on social media and lots of people who comment haven’t got the first idea what they are even looking for, let alone have the experience to make a critical evaluation of harness fit based on a couple of photos!
Our advice would be if you’re unsure about your dogs’ harness fit get along to see someone who is experienced with correct harness fit in person and let them have a feel of the harness on your dog and observe how they move in it, this is by far the best way to get proper advice on harness fit. By asking people on social media you risk getting bad advice and ending up with something which could potentially cause your dog damage in the long term.
Another thing to look out for is that your harness is not too long. This doesn’t happen so often with the shorter harnesses although you do have to ensure the harness is not coming back behind the last ribs and pulling up into the stomach area. Again I have used pictures of Yogi below to demonstrate this (because he lacks the thick fur of my others!).
In the first photo the Zero DC Short is too big and is sitting right on the end of his rib cage. When Yogi pulls forward properly in this harness it will come further back still from where it is sitting in the photo and pull up behind his ribs into his stomach. In the second photo the Zero DC Short is much more snugly fitting on his neck and sits better against his ribs, you can still see he has room behind his front legs for movement but because of his (relatively) deep chest compared to his length the harness is sitting further forward on him than it would ideally.
The below photo of Judo shows the Zero DC Short harness as an ideal fit on him and as you can see it sits much further back from the front legs than on Yogi, this is because Judo hasn’t got the deep chest that Yogi has but this harness is still fitting him correctly and not restricting his shoulder by being too big or by coming too far along the ribs and likely to pull into the stomach.
It is most important with the longer harnesses that they are not too long as this can really have an impact on the way your dog moves. With a harness such as an X-Back or even the Zero DC Long you need to be very careful that when the harness is pulled into that it doesn’t extend back beyond the base of the tail. This may mean that when the harness is not being pulled into it looks as if it may be too short. I think this is demonstrated perfectly in the photo below.
Donnie is wearing the Zero DC Cross harness and it’s the correct size for him, however when it’s not being pulled it seems to sit quite far up his back. You can’t really see (the problem with a hairy dog) but it’s sitting perfectly on his neck and has enough clearance behind his front legs so that it will not be restricting front shoulder movement in any way.
You can see from the photo of the harness being pulled that it’s now sitting further back on his body and along the ribs in the correct way. The black webbing straps (not the cord) come to the base of his tail when the harness is pulled and will come back even a fraction more if he were to pull strongly into it, so it is in the correct place for a well fitted x-back harness.
Below is a photo of Donnie in an x-back harness which he used to wear (when he was heavier) and you can see what a harness looks like if it is too long. The length of the side straps mean it’s coming right back onto his hips when it is pulled and this will be even worse when he pulls forward into the harness. The neck on this harness is actually still ok and not causing any restriction to his shoulder but that extra length means the harness will be putting pressure on his hips if he bounds forwards and really pulls into this harness which is not great for his natural movement and could cause him to get sore spots in this area with repeated use.
So hopefully this blog and these photos give you a bit more of an insight into how your dogs’ harness should fit on your dog. We offer a free harness consultation service for our customers and you can either come and see us in person at one of our trade stands or pop up shops listed here:
or we do offer an online service for those who can’t make an event. If you are interested then e-mail us at firstname.lastname@example.org after answering the questions here:
If you can get to an event then that is always the best way to get a harness fitted for your dog, however we have successfully fitted thousands of happy, active, dogs with harnesses based on information taken online. So why not get in touch and see what might work best for your dog for the sport you take part in.
This Post Has 2 Comments
This was SO helpful. I’ve been scouring the internet looking for detailed information like this. I have a 70ish lb lab/GSP mix with a deep chest and weirdly long torso who always ends up in between sizes.
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