Running a steady-state test

Applies to every Range Freely app that shows DFA α1. Last updated 28 October 2026.

A ramp test sweeps through your threshold too quickly for α1 to settle at each level. A steady-state test holds one effort long enough for the reading to settle, and does it at several levels, so you can see where α1 crosses 0.75. This is a guide to setting one up. It is not a medical test.

Before you start

• Be fresh. Fatigue, a hard day before, heat and dehydration all move α1.
• Prepare the strap. Wet the electrodes, wear it snugly, and check the signal is clean before you begin. A few missing beats spoil a reading.
• Hold the effort in one place if you can. A trainer, indoors, is best: no coasting, terrain or surges. Outdoors on a flat, steady road also works.
• Pick one way to hold the effort constant: power, pace, or heart rate. Power is the steadiest. Heart rate lags effort, so it is the hardest to hold truly steady.

Warm up first

Ride or run easily for 10 to 15 minutes, building gently. Early in a session your heart rate is still catching up with the effort, and α1 in those minutes is not representative.

Setting the steps

Set the steps as a percentage of your threshold effort. For cycling that is a percentage of your FTP. Use a workout on your trainer or head unit that holds each step constant (ERG mode does this), or hold it yourself.

• Where to look: start in the range you could ride for hours, and step up towards the point where the effort begins to feel like work. For most trained riders that is roughly 55 to 80 percent of FTP.
• Size of step: about 5 percent of FTP per step, or about 5 beats per minute if you are holding heart rate. Three to five steps is enough.
• How long: about 5 minutes a step once you are warmed up. The reading needs a couple of minutes to catch up after each change, so the last two or three minutes of a step are the stretch to read. Four minutes works if you read only the value at the end of the step. Go longer if the numbers are still moving.
• Sweet spot is not the place to look. Sweet spot is a training zone, roughly 88 to 94 percent of FTP. For most riders α1 has already fallen well below 0.75 there. It is a useful second test of how the number behaves at hard, steady effort, but it will not show you where the aerobic threshold is.
• No power meter, or a different sport: use heart-rate steps, or pace steps for running, in the same pattern: easy, then up in small even steps.

Trainer files

These load into any trainer app that opens .zwo workout files, including Zwift. They hold a 12-minute warm-up, then five steps at 60, 65, 70, 75 and 80 percent of FTP, then an easy finish. Set your FTP in the trainer app first: the files use percentages, so they scale to you.

• Steady-state test, 5-minute steps
• Steady-state test, 4-minute steps

Hold, then stop climbing

Go up the steps in order. Once α1 has dropped clearly below 0.75 and stays there, you have crossed it: stop climbing. Once α1 has fallen well below 0.75 it stays suppressed until you have recovered, so a step taken straight after a hard one will read low whatever the effort is.

If you want to repeat a step, recover first. Ride easily until α1 has climbed back toward its easy-effort level, near 1, which can take several minutes. Then go again.

Reading the result

• For each step, look at the steadiest stretch after the reading has caught up, not at the instant it first crosses a line.
• Note the power, pace or heart rate of the step where α1 is nearest 0.75.
• Do the test again on another day. A cluster of results that agree is worth far more than one crossing.
• Compare with how it felt. At the aerobic threshold most people can still talk in full sentences, and effort starts to feel noticeably harder just above it.

What spoils a test

• Surges, standing, coasting and big changes of cadence or gear in the middle of a step.
• A loose or dry strap, which makes beats go missing or arrive late.
• Starting tired, hot or under-fuelled.
• Treating the first minutes after a change as if they were the settled reading.
• Expecting the group figure to be your figure. It may not be.

Exercise carries risk. Stop any test if you feel unwell.

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