High Speed, High Impact

Haven at High Speed

Dogs are born to run. Fast. Much of their physiology is geared for speed due to their wolf ancestry, as wolves rely on the ability to pursue and take down prey on the run. Even though a dog’s running prowess is rooted in predatory needs, this very ability can also cause severe injury or even death for the dog.

Such was the case for Moon, a greyhound who died after colliding with a golden retriever at a dog park. Apparently the force of the collision hurtled Moon into the air and resulted in a fatal spinal injury — either from the collision itself or upon impact with the ground. While this may sound like a freak accident, the potential for speed-related injury is very real among dogs.

Speed can kill. It’s not the dog’s fault — it’s physics that deserves the blame.

The key to surviving any impact — whether a dog-on-dog collision, a fall off a ladder, or even a car accident — is the dissipation of energy. Objects in motion possess kinetic energy (KE) and this energy has to be dissipated somewhere if that object suddenly comes to rest or changes direction abruptly due to an impact. Under normal circumstances there’s enough time to gradually slow down where the kinetic energy is usually dissipated as heat, such as heat from a dog’s muscle contractions as they decelerate from a run to a walk, or heat from the friction of a car’s brakes. However in an impact scenario the kinetic energy has to dissipate very quickly, often via physical crushing or fracturing such as broken bones or crumpled fenders.

Where speed comes into play is in the formation of kinetic energy, the formula for which is:

Kinetic energy equation

…where m = mass and v = velocity. The relation to notice is that if you double an object’s mass then its KE is also doubled; however, if you double an object’s velocity then its KE is quadrupled.

Most larger dogs weigh 50-100 pounds, which is generally half of what an adult human weighs. We’re twice as massive as dogs yet you don’t see football players dying from making a tackle (although there are certainly lots of severe injuries in that sport). There are three main reasons for this: 1) football players wear padding, 2) the larger mass of human bones, muscles and tissues can absorb more impact energy before injury, and 3) humans are slow; we can’t run fast enough to build up a lethal amount of kinetic energy.

To illustrate this concept let’s compare a greyhound to an NFL player. For this exercise I chose Detroit Lions linebacker Ernie Sims. Why him? He’s big, strong, fast, and hard-hitting — a fine example of kinetic energy unleashed upon impact. I also chose Ernie Sims because he’s an animal lover, a responsible pet owner, and plans to become a veterinarian after his football days are over. A refreshing representative for the NFL compared to a more infamous dog abuser.

During the NFL combine (a sort of tryout mini-camp) Sims weighed 231 pounds and ran the 40 yard dash in 4.55 seconds, good for almost 18 mph. In order to use standard units of measure for energy — the Joule — I converted to metric. Sims weighs 105 kg and runs 29 km/h (8 meters per second), yielding a total KE of 6783 Joules.

A greyhound, in comparison, typically weighs 30 kg (about 66 lb) and can run over 65 km/h (about 40 mph, or 18 meters per second) and thus can generate an impressive 9785 Joules of kinetic energy, 44% more energy than Ernie Sims. A quarterback would rather take a sack from a blitzing linebacker than the impact of a blitzing greyhound!

The true lesson here isn’t the physics so much as it is the caution to be heeded when exercising your dog off leash. Be careful when dogs are chasing each other and if they get too carried away and start to crash into each other, intervene and calm them down. Remember that mentally and emotionally dogs are similar to young children and have the judgment to match. Luckily for parents, toddlers can’t run fast enough to hurt themselves too badly when they display similar poor judgment and slam into a wall, even if they do cry for a while.

While large dogs are generally both faster and heavier than small dogs and thus more susceptible to high speed injury, small dogs are also at risk. Even little terriers can easily top 20 mph, a speed that many humans can’t reach. A couple years ago playing softball my teammate and I collided while running full speed chasing a fly ball. It hurt. A lot. We were “speeding” along at only 10-15 mph yet our collision was truly scary and not something I want to repeat.

I should also mention the potential for dog-human collisions. I’ve noticed that dogs love to use human legs to “set a pick” when getting chased by another dog, where the chased dog runs very close to a person’s legs hoping to force the pursuing dog to deviate around the human. The chasing dog can be so focused on its target, however, that it sometimes fails to notice the pair of legs in its path and slams right into your knees. Be alert for this, although the safest thing to do is simply stand still and bend your knees. Moving around makes you less predictable — the dog is expecting you to stay put — while bending the knees makes them more able to absorb impact without injury. Or you could sit on a bench or stand against a wall or fence and you’ll be just fine.

It’s hard to convince a dog to slow down but that’s OK — dogs should be allowed to run full speed once in a while. My suggestion is to allow a dog’s blazing speed to occur in more controlled settings such as an open field, as opposed to a crowded dog park or heavily wooded terrain, where dogs would be at increased risk for colliding with other dogs, people, or even trees. Dogs are as quick and agile as they are fast and continue to amaze us with their ability to dodge and weave at full tilt, but even they can make a mistake and when they do, the high speed can result in a serious high impact.

Photo: Amanda Schrauben

18 Responses to “High Speed, High Impact”

  1. G in INdiana says:

    Speed impact injuries can happen in closed areas as well. Our GSD hit our basement wall because she was so focused on her ball. Instead of turning right to go around and chase it, she opted for left and slammed into the wall. She had a mild concussion and was rather groggy for a day or so. We kept a very close eye on her and no longer played ball with her inside the house, which she did miss a lot.

  2. RoonieRoo says:

    Great post and has given me a lot to think about. Our 6 month old does his “idiot runs” at top speed around the yard and he’s often very uncoordinated during the “idiot runs”, as we lovingly call them. But I never really thought about their potential for him hitting a fence or me and really injuring himself. I’m going to review the layout of our backyard and his idiot run path for safety.

    Thanks for the food for thought.

  3. Carolyn & Maggie says:

    Great informative article. Years ago I was hit by an adult Malanois chasing his brother. He hit me so hard in the back of the knees (we were walking and I never saw him coming), that I flew up in the air and fell flat on my back. Knocked the wind right out of me and it took awhile to regain my breath again. Lucky I wasn’t hurt. I thought it was a freak accident, but after reading the article I see that was not the case!

  4. kaefamily says:

    I know all about dog and human collisions … I had a swollen upper lip and a bruise knee to prove how fast a 10 year old male Dalmation could run and the damage he could produce!

    Just recently, I almost crashed my face on the pavement while walking our slightly uncoordinated and easily excited 2 year old Border Collies … he wanted to chase every bird, dog and critters he saw!

    Thanks for the info. Now I am much more careful to protect our dogs and ourselves :-)

  5. Lynne says:

    About six months ago my mother-in-law told me of a collision between two greyhounds playing at the park. One was injured so badly he had to be put down. I had never heard of such a thing but now see that it happens more often than we realize.

  6. Diella says:

    This is very interesting. I always see dogs colliding with eachother at dog park and sometimes with humans(non resulting in injury) and think it’s funny but now that I think about it…it’s quite dangerous. My dog has never actually collided with any other dog..he is either able to dodge them or will choose to jump over them since he is a big dog but he does have issues with running while excited and trying to get around people by squeezing through small spaces which has pushed me off to the side and nearly lost balance a few times. I still like dog parks but it makes me wonder how we can avoid these situation because when our dogs get to running like that…I don’t know how we would be able to stop them.

  7. janet says:

    It scares me so much when my whippet runs around in the yard at top speed but I have to let him run a little because that’s what he was born to do. Even in the house I am careful to not throw the ball very far or fast as I can see how a dog could run into the wall and injure himself. I guess no matter how scary, you have to take some chances in life or live in a padded cell.

  8. mittens says:

    greyhounds in particular through their natural genetics and breeding are built for speed bursts - really fast sprints. (besides this theyre also known ironically to be ‘couch potatoes’). you aren’t allowed to adopt the ex-racers in particular if you do not AGREE TO KEEP IT ON A LEASH AT ALL TIMES except in enclosed areas. off leash in a dog park is a space fraught with danger for greyhounds- sight hounds, they could take off in a nano second if something strikes them as prey on the run. they can go over 45 mph and with other dogs who think the running is interactive play and humans standing around like door stops things can go horribly wrong as it did in this case. they’re known to have really bad road sense-they have have no street smarts- they get hit by cars a lot. they tend to view all open gates and doors as starting gates to burst out of at top speed . people who do not know how to handle a trigger happy( it’s how they’re trained- it’s not their fault) speed machine on a leash shouldn’t even walk them.

    the idea that they’re just meant to ‘ run’ because they’re ‘ wolves’ is while appealing untrue for modern domestic dogs.( in fact some ex racers refuse to run while retired and adopted out) they’re not wolves anymore- they’re centuries removed from it and like all dog breeds have been bred by humans to retain those wolf aspects we’d like to use for our purposes. a free running greyhound is a greyhound in jeopardy. the dog shouldn’t have been off the leash at the dog park for the obvious reason that doesn’t require higher mathematics to understand- off leash for a greyhound with many unpredictable objects in it’s path is unsafe for the animal and those around him. it’s very sad when an accident like this happens but as in most things there are things to be done to avoid such an out come. it’s called a leash and understanding that you have a domestic dog not a free ranging wolf, not a wild animal and you are responsible for its safety in a world that bears no resemblance to the ‘ natural’ environment of a wolf which does not include humans as anything else but a threat and fellow bigger predator.

  9. Jennifer Moore says:

    Excellent article. These are things I just don’t stop to think about–I don’t currently have dogs–but now that I think on it, I have been knocked down in the past by speeding dogs. Not fun.

    This was very informative and fascinating.

    Jennifer Moore

  10. Belgian_owner says:

    My dog collided head on with a lab while both were going for the same ball in a park, and SNAP! His upper canine broke in half.

    He’s a much more careful dog these days…

  11. Mike C says:

    Interesting speculation and a nice mini-review of basic physics. HOWEVER, short on facts. How often, in fact, do “fatal collisons” occur. Is it more common in Greyhounds specifically due to their unique physiology?

    ONE cited example, and some serious speculation, does NOT make this anything more then the authors imaginative extrapolation.

    I would have liked to see something a little more concrete then the authors’ pronouncement that “the potential for speed-related injury is very real among dogs”. This type of article (speculative and short on facts) seems rather frequent in the media these days.

    Just one mans opinion…

  12. Nancy G. says:

    All Sighthounds have speed in their genes- I have owned Borzoi and Italian Greyhounds. When running, they are oblivious to everything else, and so many who escape a yard or a leash soon get killed by cars, they think they can outrun everything. And then there’s the prey instinct they also have, to chase down anything smaller that moves- a cat, a small dog, even a bird. One of my Borzoi girls was so fast she actually did catch birds. But they are like race horses, running is bred into them for thousands of years, it’s what they love to do. So you have to be careful with them. That’s not to say that any dog, focused on something, couldn’t barrel into a person, wall, or another dog and do serious harm. But while a shepherd might have the instinct to “herd”, and a retriever to “fetch”, a Sighthound has the instinct to “RUN!!!”

  13. Nora and Rufus says:

    Oddly enough, My Rufus, who is a good 78lbs solid dog himself, had a side collision at the dog park with a Greyhound-Black lab cross who was fast, tall, and oh so powerful, and running around like crazy……..At first Rufus acted like he had a broken leg and whined and limped towards me, dangling that leg as if it was shattered…….fortunately…it was just a good jolt and he was fine in minutes…..but it REALLY scared me. I thought my Rufus was really hurt!

  14. rikki says:

    I had a Maltese that sustained an injury as a result of her fondness for zipping around our then very large yard at break-neck speed. She tore/ruptured a ligament (anterior cruciate ligament)…expensive surgery and a long recuperation period ensued.

    (She was a couple years old when this happened and in good health otherwise. She lived until just short of her 20th B’day so I don’t think the injury was caused by anything other than the fast running and turning incident.)

    I continue to have Maltese and mixes but I don’t allow any of them to run like my other dog did…We actually have old films taken at gatherings and you can see her racing in and out of the frame in the background as she does her silly run. She was definitely having fun at the time, but she was not having fun when that ligament ruptured!

    Many years later there was an incident at our local off-leash park where a greyhound ran into this same dog and knocked her end over end so that was it for dog parks for our dogs. (No little dog area at that facility.)

    Another relative broke her leg when her much-adored black lab went sliding into her, she lost her balance and the dog and she went to the ground in a heap.

    I found the article interesting also.


  15. mary ann mcneal says:

    I was searching for dog survival sites. Sabrina, my 6 yr old Italian Greyhound
    was with me at Casa Verde lodge in Honduras. We were on a deck on the 3rd level.
    The spacing on the rail was large enough for her to easily pass through.
    She wanted to go down and run to the river where she had swam the day before
    …class 3 kayaking…..
    Out of the corner of my eye I saw her take a flying leap and emit a small howl.
    I imagined her a mass of broken bones and my heart broke. When I looked over the rail she had landed about 20 feet forward. Standing on all 4 legs in a slight brace
    Stunned. By the time I got down she was still very dazed. Suddenly she turned her head and walked slowly toward me. No injury of any kind.
    She is now called Sabrina the Flying Wonder Dog.

  16. edwin says:

    Dogs are not the only ones hurt at dog parks. I got blind-sided in the knee by 60 lb. dog.

  17. Pat says:

    I had an incident just tonight. I was leaving my cousin’s house (I am 62)and her Bernese mountain dog decided to fool around and I wasn’t paying attention. She was running full speed and collided with the side of my right knee, which hurts like a bugger. Hopefully, it is nothing serious. Having trouble doing steps and it is really hurting. Wish me well.

  18. Kris says:

    Please get your knee checked out - I was hit in the side of the knee by a golden retriever running at full speed. Because I was standing with that leg locked, I suffered medial ligament damage that still gives me hell every now and then (this occurred in 2000) it hurts most when I put full weight on that leg going up stairs. I hope you seek medical attention - it’s not something that just heals with time!

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