18/03/2022
CORRELATION =/= CAUSATION
I wanted to write a response to the graphic that's floating around asserting the various things that INCREASE and DECREASE the risk of CCL rupture. This graphic is an oversimplification of a survey of 1262 AGILITY DOGS with 260 that ruptured their CCL, and 1262 that did not. Owners self-reported the parameters of their pups activity.
It's important to know, this survey-based study determines correlation not causation. This survey-based study is looking at trends and giving researchers a place to start.
Three major factors that were shown to be correlated with an INCREASED risk of CCL rupture are...
1. Female dogs spayed under a year of age seem to be twice as likely to rupture their CCL as those who waited until after a year of age to be spayed.
We know growth plates may not be closed in dogs under a year of age. And hormones are heavily involved in bone growth, and stopping growth of the long bones. So it's not surprising dogs with longer long bones, and the resulting straighter angulation are more at risk for CCL rupture because of the resulting longer lever arm.
2. Dogs participating in agility AND fly ball also seem to have a greater risk of CCL rupture. The researchers didn't postulate why they thought this could be the case.
3. And there seemed to be a data spike around three breeds participating in agility (Australian Shepherds Rottweilers and Labradors). The researchers postulated this may be the result of not having a tail... (Although that interpretation doesn't really fit the data because of course Labradors have a tail). More likely the size/speed of these dogs and the inherent forces that come with increased size/speed and the relationship to agility are the underlying factors that relate increased risk.
The only non-sport related physical activities that showed an increased risk of CCL rupture were short walks / runs over hilly or flat terrain that happened weekly.... But this was shown mostly in young/immature dogs. Researchers postulated that these dogs still lacked coordination and strength, or at times over exercising without appropriate rest days... And as a result the increased risk.
This is a great example of how correlation does not equal causation. It's unlikely the short walks CAUSED the issue... And more likely the population of dogs (young dogs, over aroused, not fully aware of their bodies, etc) is just generally more susceptible to injury. This of course we know, which is why implementing a structured fitness protocol is promoted so heavily by this group... So we can increase core strength, and coordination in young dogs.
What showed a DECREASED risk...
1. Surprisingly, dogs that competed more frequently in agility events and competed at a higher level on more technically rigorous types of courses were shown statistically to rupture the CCL less frequently than those who competed less often.
This is another great example of correlation not causation. Competing at high level events did not cause the dog to be at less risk... But more likely the handlers who compete professionally or semi-professionally at a very high level likely put in more time with risk mitigation modalities like conditioning, body work, frequent rehab professional exam, etc.
Also, to qualify for these high level events, these handlers themselves have to be very skilled. And it was shown in a previous survey study that having a handler with less than 5 years of experience increased dogs risk of CCL rupture.
So please don't assume practicing agility at a high level, on technical courses and national events is going to *cause* your dog to not rupture their CCL. This is absolutely not the case... But instead, implement the same warm-up/cooldown, maintenance and secondary care routines high level handlers do and you'll likely find the decrease risk applied to your own dog.
2. The survey study also showed dog/handler teams who participated in any conditioning programming we're less likely to rupture their CCL. But even when statistically, data aligns with the things we agree with, it's important to hold our confirmation bias up to scrutiny as well.
While human studies have shown increased coordination, muscle balance and strength result in a decrease risk of injury, this data point can also be skewed because dog/handler teams who are willing to put in this type of effort are also likely implementing other types of risk mitigation. So conditioning itself is a component that should be implemented along with other typed of risk mitigation.
Lastly... This one small paragraph really struck me as shocking... And it's another example of how the questionnaire itself can result in skewed data collection. Here's the paragraph.
"While regular activity, like swimming, playing fetch or frisbee, walking or running didn’t increase the risk of injury, it didn’t lower the odds either."
It seems like regular activities like swimming, playing fetch, frisbee walking and running may have been lumped together in the questionnaire... Either formally as a result of poor question wording on the part of the researcher... or equally likely, mentally in the handler/survey taker's mind.
As a result, the data wasn't separated out, resulting in the inability of the researchers to draw conclusions from that information. This is another reason why survey based studies should be seen as data gathering and drawing correlation, but not used to assert causation.
So please don't assume these above to mentiond activities are truly neutral in their impact on the CCL... It's more likely there was simply an error in the data collection and as a result, not enough information speaking to these activities individually.
My main goal in writing this is to highlight the flaws of assuming correlation is the same as causation. It's important to appropriately assess data for what it is... And in this case, it's an awesome starting point for further research!! But drawing absolute conclusions / jumping to causation is premature, and doesn't factor in the highly complicated nature of CCL rupture.
