Debunking Myths: Why Endurance Athletes Can (and Should) Do CrossFit

Pursuing optimal athletic performance often leads coaches and athletes down a path of rigid training protocols and strict specialization.

There’s merit in targeted training.

Testing your limits requires that you focus your training to support your goals. This is true whether you're an Olympic sprinter, an age-group triathlete, or a marathoner chasing a new personal best.

There’s also merit in targeting training that you enjoy.

We sometimes lose sight of the most fundamental aspect of fitness: consistency through enjoyment.

I came across a blog post from Matt Fitzgerald, the guy behind the “80/20” training methodology. Fitzgerald argues against CrossFit for endurance athletes.

What is 80/20 Endurance Training

For a quick background, "80/20 endurance training" is a strategic method of balancing workout intensities. By dedicating the majority of training time to low-intensity exercise and reserving only a small fraction for high-intensity efforts, athletes optimize their body's ability to adapt and improve.

80/20 training suggests that spending most workouts at an easy, conversational pace actually enables more effective performance during the few intense training sessions. The method helps endurance athletes prevent burnout, reduces injury risks, and allows for more sustainable progress by giving the body ample opportunity to recover and build strength between challenging workouts.

I can attest that Fitzgerald’s training methodology works. It’s easy to follow and uncomplicated. I’ve successfully used it when training for marathons - the principles are sound.

Why 80/20 endurance training isn’t for everyone

80/20 training has a critical flaw: it’s boring.

Variety is the spice of life.

People tend to burn out after grinding through zone-2 workouts day after day, week after week, month after month.

Even die-hard endurance athletes appreciate variety in their training plans.

Debunking CrossFit myths for endurance athletes

Matt Fitzgerald encourages his 80/20 athletes to avoid CrossFit. His arguments for skipping the WOD are generic - they’re blanket generalizations that fail to account for the uniqueness of individual athletes.

Myth: CrossFit Workouts are too intense for endurance athletes

Endurance fitness and performance improve most when high-intensity work accounts for about 20 percent of total training time.

Some of Fitzgerald’s complaints are valid - CrossFit is designed to take you out of zone 2. So, it doesn’t fit neatly into the “80% low-intensity bucket” of the 80/20 training methodology.

This overlooks the fact that CrossFit fits perfectly into the “20% high-intensity bucket” - a few things will stimulate your body’s anaerobic system like a high-intensity CrossFit workout.

Myth: CrossFit causes too much fatigue for endurance athletes

Fitzgerald argues that CrossFit generates significant muscle fatigue and damage, which can negatively affect performance in subsequent endurance training sessions.

CrossFit workouts are highly taxing, generating significant levels of fatigue and muscle damage and thereby often compromising performance in subsequent endurance workouts.

He’s not wrong.

CrossFit can be intense, and it can take a while for new athletes to adapt to the increased intensity.

But, if you’re an endurance athlete exploring CrossFit, you’re likely excited by the variety and intensity.

Endurance athletes are allowed to do CrossFit. And, contrary to Fitzgerald’s limited worldview, it will improve your athletic abilities.

Scale your workouts and slowly incorporate them into your training plan. You’ll build strength, functional fitness, and cardio capacity.

Don’t be scared, be smart.

Myth: CrossFit will make endurance athletes bulky

Look at the physiques of top competitive CrossFitters. Do you want to haul around all that beef in your next race?

Fitzgerald implies that the muscular build developed through CrossFit might be disadvantageous for endurance athletes who typically prefer a leaner body type.

As a coach, I know this is a borderline misinformation campaign. No one accidentally adds 40 pounds of muscle doing CrossFit. Building muscle takes time, focus, and diet. You won’t become too bulky to run a marathon by chance.

Fitzgerald should know better. As a coach and athlete, he should know that strength gains are hard-won.

He should also know that the audience for people reading his website is not “top competitive CrossFitters” - the top <0.1% of global CrossFit athletes.

There are plenty of everyday endurance athletes who enjoy incorporating CrossFit-style functional fitness workouts into their training programs.

Myth: CrossFit workouts don’t apply to endurance sports

Fitzgerald specifically calls out exercises like handstand push-ups as being irrelevant for cyclists and runners.

Handstand push-ups, for example, are a waste of time for cyclists and runners.

Again, he’s not entirely wrong.

You don’t need to be able to do handstands to run fast marathons. You don’t need to be able to walk on your hands to sprint up a hill on the bike.

But he is missing the point of cross-functional fitness.

CrossFit is about building strength, power, and endurance. It’s about building a strong, durable body that can handle the demands of your sport.

And, if you’re an endurance athlete, you can use CrossFit to improve your sport-specific performance.

Learning handstand push-ups may not directly help you run faster. But, it will improve your core strength, balance, and stability -- all critical modalities for endurance athletes.

Myth: CrossFit isn’t good cross-training for runners

Fitzgerald thinks that some CrossFit elements, like rowing, may not provide the most beneficial cross-training for specific endurance sports. For instance, the author suggests runners would benefit more from activities closer to running -

Runners in particular who want to supplement their running with nonimpact endurance training are better off choosing an activity that is much more similar to running itself, such as outdoor elliptical biking.

I don’t know about you... I’d rather hop on the rower than hit the streets on an elliptical bike looking like this dweeb.

Should endurance athletes do CrossFit?

As an endurance athlete exploring CrossFit, you might encounter advice warning you about potential training inefficiencies. These warnings typically focus on technical details like heart rate, muscle fatigue, and sport-specific movements. But here's a critical perspective often overlooked: the most effective workout is the one you'll actually do.

For the vast majority of adults juggling work, family, and personal commitments, finding time for exercise is already challenging.

If CrossFit sparks your motivation, brings you joy, and gets you moving regularly, that's infinitely more valuable than adhering to a theoretically perfect training regimen.

The difference between a marginally optimized workout and an enjoyable one you look forward to is the difference between sporadic effort and sustainable lifestyle change.

Professional athletes may need hyper-specialized training. But for most of us? Consistency is king.

If CrossFit makes you excited to exercise, if it creates community, if it makes you feel strong and capable - those intangible benefits far outweigh minor training inefficiencies.

The ultimate goal of fitness isn't just performance. It's health, happiness, and the development of a lifelong relationship with physical activity. So choose a movement that energizes you, that you're passionate about, and that fits into your life.

Your body and mind will thank you.