It’s a hard question to answer. “How fit am I?”
Lots of triathletes would say VO2 max and there are probably a million other ways than what I’m going to briefly talk about here.
Q: VO2 max – how do you measure it properly?
A: In a lab
So maybe it’s not so easy to measure the thing that is the best. And really anyway what we probably want to know is “How race ready am I…NOW. Yep right now.” And that needs to be based on the stats that I normally record because I can’t be bothered to do a special test (sound familiar? 🙂 )
So you need something that is fairly easily accessible ON A REGLUAR basis.
If you’ve read this blog before you’ve probably seen me go on about TRIMPs and TSB (CTL/ATL). They seem pretty good measures on the whole.
My A race was in June and I actually did about as well as I could expect for once. But what did the stats say? Well my race readiness (TSB) was FAR from what I had historically considered the best and my CTL and ATL were also not in a great place historically.
If I look instead at FirstBeat Athlete (link to download a trial version – I don’t get paid anything for that link). It produces a METmax measure of fitness (based on estimated VO2max and a few other things). That said that 5 days before my race I was at the best I’d been all year. So that appears to be right. However 5 days prior to my race I was already well into tapering and so taking it a bit easier. In fact the ideal scenario to record a proper METmax figure (apparently). So it peaked because for once I was doing the reading properly. Nevertheless I’ll watch this one from time to time. I’m also going to do a review of Firstbeat Athlete at some point as well. Watch this space.
My HRV figure from bioforceHRV showed a high readiness level but then again it does that fairly regularly as and when I have my rest days. So that might be a good indicator in the sense that if it is not at its best for a race then something is wrong.
Last Updated on 22 April 2026 by the5krunner
My favourite kit and nutrition
- Maurten — the race nutrition trusted by elite athletes. Gels and drink mix engineered to be easy on the stomach.
- Garmin 90-degree charging adapter — the small adapter that keeps your charging cable tidy at the stem. Essential for race day.
- Garmin charging puck — the fastest and most reliable way to top up your Garmin before a session.
- Ravemen FR300 — front light that mounts directly under your Garmin or Wahoo head unit. Keeps your bars clean and your beam pointed where it matters.
- Garmin Varia RTL515 — radar rear light that alerts you to vehicles approaching from behind. Pairs with your Edge or Garmin watch.
- Stryd — the footpod that brings running power to your Garmin. The single most useful running upgrade I have made.
- Favero Assioma Pro RS2 — the power meter pedals most serious cyclists end up choosing. Accurate, easy to move between bikes.
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tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. ID
