Why CrossFit Isn’t a good Test of Fitness

CrossFit claims to test the fittest on Earth, but if we take a closer look—especially from a physics and physiology standpoint—the playing field is far from level and all they’re testing really is who’s the best at CrossFit.

Problem Number 1 - No Weight Classes

In virtually every other sport—Olympic lifting, powerlifting, combat sports, even rowing—athletes are grouped by weight class. Why?

Because weight affects output, leverage, and metabolic demand. Yet CrossFit throws everyone—lightweights, heavyweights, tall and short—into the same leaderboard.

• Heavier athletes must move more mass every rep.

• Taller athletes must move that mass farther (longer limbs = more displacement).

• Smaller athletes? They do less work per rep and cover even less distance thus move faster.

It’s like running a 100m race where some people start at 80m and others at 110m—just because of body type.

And I know what you’re gonna say,”but the NBA isn’t fair to shorter people” yes but the NBA isn’t pretending to test the fittest on earth.

Power Output Isn’t Evenly Compared

CrossFit often celebrates “work capacity across broad time and modal domains.” But what’s that really mean? Work capacity is measured by power output—and here’s the kicker:

A smaller athlete can win an event by doing less total work, faster.

Meanwhile, a larger athlete may do significantly more total work, but finish slower—and lose. That’s not a measure of who’s more fit, just who can perform whatever arbitrary movement the fastest with the least energy cost per rep.

Let’s compare the mechanical power output and total work of performing burpees between Colten Mertens (~84 kg, 5’4”) and me (100 kg, 6’2”).

We’ll use the estimated vertical displacement of the hips during a burpee: 0.8 meters and 1m for me (includes lowering to the floor and jumping up), and apply basic physics:

Work = Mass × Gravity × Displacement

Power = Work / Time

Athlete	Bodyweight	Displacement	Work per Rep (Joules)	Power per Rep (Watts)
Colten Mertens	84 kg	0.8 m	659.2 J	659.2 W
Me	100 kg	1.0 m	981.0 J	981.0 W

I produce 321.8 more watts per burpee than Colten simply because I’m moving more mass over a greater distance.

Now imagine we both perform a 100 burpees for time

Athlete	Total Work (Joules)
Colten Mertens	65,923 J
Me	98,100 J

That’s a difference of 32,177 joules of total work—a massive energy gap, despite the movement being scored exactly the same in a typical CrossFit WOD.

Now Let’s Add Time to the Mix

• Colten’s time: 3:00 (180 sec)

• My time: 4:45 (285 sec)

Let’s calculate actual average power output:

Athlete	Time	Total Work	Power Output
Colten	3:00	65,923 J	366.2 W
You	4:45	98,100 J	344.2 W

As you can see Colten outputs more power because he finishes faster and power and time have an inverse relationship if the power in constant—but if you remember how much power per each rep was perform he’s performing between because he can do more reps because the movement is mechanically easier for him.

A taller and heavier athlete is generating less average power, not because you’re less fit—but because every rep is more physically taxing for a heavier, taller athlete.

Body Type Bias Is Baked Into Programming

• Short, compact athletes dominate gymnastic-heavy workouts (e.g., muscle-ups, handstand walks).

• Taller athletes tend to get told that they will get their win on other movement but truly it’s never in their favor and they get punished with longer cycle times anyway in stuff like box jumps and even Olympic lifts (longer bar path). It’s like yea the 60kg bar doesn’t feel as bad, but noo it has to travel so much distance?

• Workouts rarely account for range of motion—a person with 10 inches of barbell travel isn’t doing the same work as someone with 20 inches.

This leads to an unspoken truth:

CrossFit often rewards a “Goldilocks” body type—short enough to cycle fast, but just strong enough to lift heavy. Everyone else is out of luck.

Everyone Is Doing a Different Workout

Here’s the philosophical dagger:

If two athletes are moving different distances, different weights, and at different metabolic costs—are they even doing the same workout?

In many cases, the answer is: not really.

A 60kg athlete doing 100 burpees is not the same as a 100kg athlete doing the same. The lighter athlete is doing far less work and burning fewer calories. But in CrossFit, it’s scored the same.

Imagine powerlifting where the heaviest guy has to lift 1000 lbs, and the lightest guy lifts 400—and both get the same score. Sounds ridiculous, right? That’s what’s happening in every bodyweight WOD.

So What’s the Fix to this dilemma?

Introduce weight classes.

CrossFit may test a kind of fitness, but not necessarily the fittest—unless you fit the mold.

And that’s not hating. I actually love CrossFit, that’s just physics.

Problem number 2 - the skills have to go

Skills Have Stopped Being Skills

Here’s something nobody wants to say out loud in the CrossFit world:

Skills aren’t being treated like skills anymore.

In theory, high-skill movements should test coordination, balance, timing, and motor control. But in CrossFit? Once an athlete can cycle the movement, it just becomes another piece of cardio.

When a Skill Turns Into Just Another Rep

Let’s look at an example we all understand: walking.

If someone gets injured and loses the ability to walk, they have to relearn it as a skill—step by step, with intention and feedback. It’s technical. It’s draining. They can’t just do it for 5 minutes straight.

Now think about handstand walks in CrossFit:

• Performed under fatigue

• Over long distances

• In workouts with other high-output movements

• Often just used to elevate heart rate or “burn the shoulders”

At that point—it’s not a skill expression anymore. It’s a cardio tool with a fancier name. It might as well be jump rope or shuttle sprints.

Skills Should Be Tested as Skills

If we truly want to test skill, then treat it like Olympic lifting is treated at the Games:

• Build a separate platform

• Create a focused event

• Remove fatigue as a confounding factor

• Score athletes on execution, precision, and control

Think of gymnastics:

• Clean mat

• Controlled environment

• Judged on technical quality, not just completion

Imagine if CrossFit tested higher handstand skills, ring routines or tumbling routines not for time, but for cleanliness and technique. That’s a real skill test.

Until Then… It’s Just Cardio in Disguise

If you’re performing “skill” movements for volume, while gassed, and with zero technical standards—it’s not a skill test anymore.

It’s just another way to keep your heart rate up.

Anyway that’s all I have to say, within those terms CrossFit isn’t creating and testing the fittest on earth.