70.3 & Ironman Metabolic Testing – FAQs

This page answers the most common questions about metabolic and performance testing for long-course triathlon, including 70.3 and Ironman racing. If you’re unsure whether testing is right for you, start here.

What is metabolic testing for 70.3 and Ironman athletes?

Metabolic testing identifies how your body produces and sustains energy over long durations. For 70.3 and Ironman racing, performance is limited less by peak fitness and more by:

  • Aerobic capacity

  • Fatigue resistance

  • Lactate production vs clearance

  • Sustainable bike power and run pace

Our testing quantifies these factors so training can be built around your true physiological limits, not estimated zones.

How is this different from FTP or standard VO2max testing?

ingle-metric tests (FTP, ramp tests, time trials) provide one snapshot of performance.

Metabolic and PPD testing:

  • Models your entire power– or pace–duration profile

  • Separates aerobic limitations from lactate limitations

  • Explains why you fatigue, not just when

  • Identifies what training adaptations will actually improve durability

This is critical for long-course racing, where pacing errors compound over hours.

Do you test both bike and run for Ironman athletes?

Yes — bike and run are tested individually.

Many athletes are:

  • Aerobically strong on the bike but limited on the run

  • Or metabolically inefficient on the bike, which compromises the run

Testing both disciplines provides the most complete picture, but testing a single discipline can still deliver meaningful training insights.

Is bike and run testing done on the same day?

No. Bike and run testing are not performed on the same day.

  • For in-person testing, bike and run are completed as separate bookings

  • Athletes may choose:

    • Two in-person lactate tests, or

    • One in-person lactate test and one remote PPD test

For remote PPD testing, separate test files are provided for bike and run. We recommend a minimum of 48 hours between tests to ensure full recovery and high-quality data.

What’s the difference between in-person lactate testing and remote PPD testing?

Both routes provide the same physiological outcomes and training guidance.

The difference is how the data is collected — not what we can determine from it.

What equipment do I need?

Bike testing

  • A power meter (crank, pedal, or smart trainer)

  • A head unit or watch capable of recording .FIT files

  • Indoor trainer or suitable outdoor route

Run testing

  • GPS watch with 1-second recording

  • Flat route or athletics track

  • Track Run mode recommended if available

All in-person testing equipment is provided.

What does the testing actually tell me?

Testing allows us to accurately determine:

  • VO₂max – your aerobic ceiling

  • VLamax – how quickly you produce lactate

  • MLSS / Threshold – maximal sustainable bike power and run pace

  • Fatigue resistance – how performance decays over time

  • Athlete phenotype – aerobic-dominant vs glycolytic-dominant

Together, this explains:

  • Why you fade late in races

  • Why current training may not be working

Can this testing help with fuelling strategy?

Yes.

By understanding:

  • Intensity relative to threshold

  • Lactate accumulation behaviour

  • Aerobic efficiency

We can make more informed decisions about carbohydrate requirements, pacing, and intensity control, particularly for long-course racing where fuelling errors are costly.

What happens after the test?

You receive:

  • A full metabolic and performance profile

  • Clearly defined training intensities

  • Identification of your key performance limiter

  • A 1-to-1 results consultation

  • Clear guidance on how to structure training differently

You are not left alone with the data.

Yes and often even more valuable.

First-time athletes commonly:

  • Overbike

  • Run too hard early

  • Underestimate metabolic cost

Testing provides objective limits that help you execute a controlled, sustainable race.

Is this suitable for Ironman first-timers?

Testing is most effective:

  • Early in a training block

  • When progress has stalled

  • Before a key build phase

  • Or closer to a race to refine pacing and priorities

It can be repeated later to track adaptation.

How do I book?

Book Metabolic Performance Testing

When is the best time to do this testing?

Yes.

Many athletes share their results with their coach to:

  • Improve training accuracy

  • Clarify intensity distribution

  • Align expectations around pacing and durability

Is this useful if I already have a coach?