QT: Questionable Causation Doesn’t Disprove Correlation

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We all know that correlation doesn’t prove causation, right?

Recently, I started thinking about this saying but in reverse.

Does a lack of direct causation disprove any and all correlation?

I don’t think so.

Break Down Correlation v Causation

Just to ensure we are on the same page, let’s refresh a couple of correlations that don’t prove causation scenarios.

One of my favorites, though also one of the most frustrating to me, is the lactic acid and muscle soreness situation.

In case you’ve been misinformed, lactic acid does not cause muscle soreness.

The two are absolutely correlated.

When you do a hard workout, your body produces lactic acid as a byproduct of anaerobic glycolysis.

After a hard workout, you’re likely to experience muscle soreness from the microtears of your muscle tissue due to the intensity of the workout.

So both are related to the hard workouts, but one (lactic acid) does not cause the other (muscle soreness).

Another great example is the whole ice cream sales and shark bite relationship.

In the summertime in an oceanside town, there may be an increase in both ice cream sales and the number of shark bites.

But it’s not that selling more ice cream cones whipped the sharks into a frenzy where they just bite every person that dares get into the ocean.

It’s hot, so people are more likely to buy ice cream.

And also, when it’s hot, people are more likely to get in the ocean. More people in the ocean means there’s a better chance a shark takes an unfortunate nibble.

In both cases, there is a correlation between the two but, fairly clearly, no direct link of causation.

Strength Training Correlations Without Causation

Recently, I’ve been seeing a rather well-known running coach/exercise physiologist “busting” a few common running myths.

He’s been railing on strength training, saying that it’s a myth to think that strength training is beneficial for runners as either a performance enhancer or injury preventer.

And while my first instinct was to clutch my pearls, I’ve tried to see things a bit more objectively.

I didn’t do a deep dive into the scientific literature, but the more I think about it the more I’m convinced this is one of those scenarios where the running science is less straightforward than we would like it to be.

So let’s say, for the sake of moving the conversation forward, that there is no causal relationship between strength training and running faster.

Ok, but what do we know with a fair degree of certainty, and research to back it up, about the benefits of strength training for runners?

Strength training can help to increase your power output. And if you generate more power with each stride, you’ll cover more ground per stride which increases speed.

Building muscle strength and endurance are also likely to prevent your form from falling apart later in a race. The longer you’re able to maintain your form, the more consistent your pace will be.

So while you might not be technically faster in terms of top speed, your race times are likely to improve.

What about injury prevention?

Again, there may not be any direct cause/effect situations, but that doesn’t mean there isn’t a correlation there.

Stronger muscles are going to be more resilient to the stresses and strains of running.

Can you still be injured from running? Sure.

But by doing strength training regularly you’re giving your body a better chance of not breaking down as the miles pile up.

And what about the overall benefits of strength training for living a long and healthy life?

If you want to keep running until you’re into your 70s or 80s (and beyond), building and maintaining muscle strength is vital.

So even if strength training doesn’t help you perform better in your next race (which I’d argue but have no solid science to fall back on), it’ll help you run a 5k with your grandkids 30+ years from now!

Do It

Same Applies to Stretching and Mobility

There are no studies that conclusively show that stretching prevents injury.

Ditto performance-enhancing effects of stretching.

That’s fine.

Don’t pretend like you don’t feel a little better after you do a bit of stretching.

But beyond just feeling good, a bit of elasticity in your muscles is helpful.

Every time your foot hits the ground, there’s an eccentric lengthening that goes on in your calf.

I’ll spare you the physiology deep dive, but if your calf is able to lengthen appropriately during this phase of your running movement, it becomes something of a spring to help you conserve energy and propel you forward.

This may not be able to be measured in a proper study, and there is admittedly more to this scenario than simply the elasticity of your calf.

But is there a positive correlation without direct causation?

Yeah, I think so.

Final Thought

At the end of the day, the fact remains that human bodies are complicated.

Scientific research, not just as it relates to running but in all aspects of our health, is a good thing.

Just do your best to not be blinded by the science.

And remember that while correlation doesn’t prove causation, it doesn’t mean that we should just disregard all correlations, either.


Just because there isn't a direct causation, doesn't mean there isn't a correlation. #runchat Click To Tweet

How do Decide Whether a Correlation is Strong Enough to Believe In?

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