Train.Red Looks at my attempt at a Wahoo 4DP Test

Train.Red Looks at my attempt at a Wahoo 4DP Test

More: detailed Train Red Review – FYER & Plus

As part of my look at several of the Muscle Oxygen Sensors this year, Train.Red kindly offered to analyse my Wahoo 4DP Test (formerly from Sufferfest). This is an extremely hard test if done properly and it assesses the strength and weakness of your ability to produce power for different durations – hence all energy production systems are tested in 60 minutes of unpleasantness!

Why Train.Red?

  • It uses a current-generation gold standard sensor from Artinis.
  • It takes deeper, more frequent readings than other sensors – you can see individual muscle contractions
  • Live Muscle ‘states’ are reported (Like supersapiens glucose, SmO2 does not have zones)
  • When cycling, 300w now is not the same as 300w in 60 minutes. Even if you took into consideration W’, I would expect that Muscle Oxygen states better reflect your ability to perform as that workout continues. (FTP tests tend to overestimate MLSS) More: science stuff from Jem Arnold
  • Supports: Garmin data fields, ANT+ compatibility with Muscle Oxygen Profile (Wahoo, Garmin), Bluetooth link to smartphones and web platforms.


Train.Red’s app has been evolving significantly over the last few months and is now in a good place with significant new features released and a few more to follow. The Garmin CIQ data field works but needs enhancement.

SmO2 readings can vary depending on sensor placement. I like Moxy’s shorts that have an inbuilt, fixed position on the quads for its sensor. Or put another way, I moved the Train.Red sensor during the test 🙂

Thierry at Train.Red helpfully told me to try harder next time! He also commented about my inability to correctly perform the last 1-minute part of the due to muscle exhaustion might mean that the test does not correctly determine anaerobic capacity. I seem to recall that Wahoo/Sufferfest tried to take this into account in the design and interpretation of the test.

NNOXX One analysed my half marathon effort – here is exactly what they found

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