VO₂ Max vs. Threshold — Which One Predicts Marathon Performance Better?
When it comes to running long-distance events like the marathon, every athlete wants to know "How fast can I go?"
Thanks to advancements in wearables and performance testing, two metrics often dominate the conversation—VO₂ Max and Threshold (also called lactate threshold or functional threshold pace/power). But what's the difference between them, and which one actually matters when it comes to predicting race-day performance?
VO₂ Max vs. Threshold: What's the Difference?
| Metric | VO₂ Max | Threshold |
|---|---|---|
| Definition | The maximum amount of oxygen your body can use during intense exercise | The highest pace or power you can sustain for ~45-60 min |
| Think of it as | The size of your engine | Your sustainable race speed |
| Trainability | Partially limited by genetics | Highly responsive to consistent training |
Which Metric Predicts Marathon Performance More Accurately?
Threshold is a better predictor of marathon performance than VO₂ Max.
- VO₂ Max tells you how much oxygen your body can process—it's an indicator of potential.
- But threshold tells you how efficiently your body can operate at submaximal effort, which is exactly what you need for a marathon and ultra-distance running.
A marathon isn't run at your VO₂ Max. It's typically run at 75–85% of it (higher for competitive and elite athletes). So, knowing your VO₂ Max doesn't tell you how long you can hold a fast pace before falling apart.
Real-World Example
Runner A: VO₂ Max: 65 ml/kg/min, Threshold Pace: 4:30 min/km, Likely Marathon Time: ~3:10
Runner B: VO₂ Max: 65 ml/kg/min, Threshold Pace: 5:00 min/km, Likely Marathon Time: ~3:30
They have the same VO₂ Max, but Runner A can sustain a faster pace for longer. That's the power of threshold fitness.
Why VO₂ Max Can Be Misleading
- You can have a high VO₂ Max and still blow up halfway through a marathon.
- VO₂ Max doesn't account for fatigue resistance, fuelling strategy, or mental strength.
- Most importantly, it doesn't reflect how well-trained you are to run at race pace.
What Should You Focus On?
- Train to increase your threshold pace or power (using specific sessions)
- Use tools like Stryd or lactate testing to measure progress.
- Prioritise sustainable endurance over maximal bursts.
- Build long runs at or just below threshold to improve fatigue resistance.
Final Takeaway
In endurance running, VO₂ Max sets the potential, Threshold shows the reality.
You don't win marathons with a big engine—you win them by using your engine smartly and efficiently over 42.2 kilometres.
At A-Team Coaching, we analyse your VO₂ Max, power zones, threshold metrics, and real-world training data to build you a performance-driven plan. Sign up with A-Team Coaching