The 4 Key Endurance Markers Every CrossFitter Should Know
When we test endurance, there are four main physiological markers worth paying attention to. See muscular endurance for CrossFit for training applications. Each one tells you something different about your engine.
Aerobic threshold
This is your easy, sustainable pace. Most people think of it as zone 2. You can hold this effort for a very long time. It's the foundation that supports everything else.
Anaerobic threshold
This is the harder, grindy pace that sits right at the edge of what you can sustain. For most athletes this falls somewhere between 40 and 60 minutes. In CrossFit this intensity shows up constantly. A lot of metcon work happens right around here or slightly below it.
This marker is especially relevant because it directly influences how well you can hold pace when workouts get long and uncomfortable.
VO2 max
This represents the highest power you can produce while still using mostly aerobic energy. We use testing to get an approximation of the wattage where you hit this point. It's a measure of your upper aerobic capacity.
Peak power
This is your very short, maximal output. Think 5 to 10 second efforts. It shows your ability to produce force quickly and is more anaerobic in nature.
Together these four points give you a simple map of your endurance profile. You can see where you're relatively strong and where you have clear room to improve.
Key Takeaways
Aerobic threshold is your forever pace and the base everything else builds on.
Anaerobic threshold (the 40-60 minute grind) is highly relevant for CrossFit because many workouts live in or near this zone.
VO2 max and peak power show your upper limits for aerobic and short anaerobic power.
Want help testing your actual endurance markers and building training around them?
Frequently Asked Questions
Do I need to test all four markers?
Not necessarily every time. Many athletes get the most value from focusing on aerobic and anaerobic threshold first, then adding VO2 max and peak power later.
How do these markers change with training?
All of them can improve, but the rate and amount of improvement depends on your training history and what you emphasize. Threshold work tends to move the middle markers more than the very top end.
Can I estimate these without a formal test?
You can get rough ideas from how efforts feel and from workout data, but a structured test gives you clearer, more repeatable numbers to work with.