This is the second in a 3-part series. If you missed the first one, check it out here.

For my second post, I’d like to debunk the common line of thinking that doing some sort of long-slow distance (LSD) running will translate into faster WOD times. Before we get to that though, let’s remember why we CrossFit in the first place:

1. CrossFit is: constantly varied, functional movement, done at a (relative to you) high intensity

2. Functional movements: are unmatched in their ability to improve fitness because of their capacity to move large loads, long distances, quickly (plain english translation: you can finally carry ALL THE GROCERIES from your call in one shot)

3. CrossFit’s goal is: to increase your work capacity across broad time and modal domains (plain english translation: you get more capable to handle life)

We train functional movements because of their ability to move large loads, long distances, quickly. Storing luggage in the overhead compartment? 

Helping a friend move boxes up a flight of stairs?

Picking up your kids from the ground?

These are examples of real-world, functional movements. The things we do every day in the box replicate those movements.

When we increase your ability to perform these tasks across a wide variety of time domains, we have effectively increased your level of fitness.

Now, back to the traditional thought pattern of training LSD runs to achieve faster WOD times. In short, it does not work that way. LSD does exactly what it says: it trains your body to run slowly, albeit very efficiently.

You will get better.

At going slow.

Nothing more.

But it won’t help a lick at moving large loads, long distances, quickly. It won’t help increase your ability to do real-world work.

“Wait, wait wait, this [major fitness magazine] says that to burn FAT and lose weight quickly, I need to run on the treadmill for at least an hour a day!”

Busted! You got me. Guilty as charged. Yes, toiling away on a treadmill for hours at a time will burn fat. There, I said it.

There is only one problem: treadmill work, and traditional “roadwork” (as identified by the endurance community), is terribly inefficient at burning fat…when compared to doing high-intensity work like we do in CrossFit. I’m not just making this stuff up – it’s scientifically proven.

Caveat, and thanks to Jay Bradley for pointing this out: Physiologically speaking, LSD work is more efficient at fat burning. It’s very nature, if you recall from the first cardio post, is that it is aerobic, i.e. needs oxygen. This is for fat burning. So, chalk one up for LSD – it does burn fat quite well. It just does so slowly, and hinders anything else we want to achieve – squat more, do more box jumps, run a faster 400. You sacrifice being well-rounded.

However, when viewed through a lens focused on time commitment, LSD loses out. Remember, we don’t want to be chained to the dreadmill for an hour or more a day. Want some numbers to see?

We’ll use an example of a 150lb man:

– The LSD model: In one mile of running, you burn about 100 calories at a 10min/mi pace. At this rate, you’d burn about 600 calories in an hour.

– For high-intensity work, the hourly caloric burn rate is about 1000-1200 cal/hour.

If you want to play around with the numbers on your own, check out this resource here.

But the “caloric burn rate” is only half the story.

High intensity interval work, which we do on a daily basis, is much more effective at eliciting the type of systemic response that we are all looking for…the reason we all put ourselves through the torture of the daily WODs: RESULTS!

– Faster WOD times

– Decreased body fat %

– Increased lean body %

– Increased strength, power, and speed

LSD does not offer any of those things. 

Remember, results come through intensity…POWER output. Why is Fran such a good model of this? Because the power output is through the roof. Curious about how much horsepower you generate during a specific WOD? Then check this out: Power Output Calculator. It’s pretty neat, and very humbling, to see. It’s also a great way to measure your progress for benchmark WODs you’ve done multiple times.

So, yes, CrossFit workouts leave you gassed. But increasing your time spent on the dreadmill, a glider or recumbent stationary bike won’t reduce that much.  Long Slow Distance will improve your ability to go long and slow but with a significant time investment and at a detriment to other goals you may have.