Setting up a step test

The step test is the standard method in lactate diagnostics. It is not rocket science, but it does not forgive sloppiness with the protocol. This chapter shows you how to set it up and gives you ready-made protocols to work with.

The principle

You run, cycle or row at a fixed workload, hold it for a few minutes and then increase it by a fixed increment. At the end of each stage, a drop of blood is measured and the heart rate noted. This is how your lactate curve takes shape, point by point.

Why stages and not a steadily rising ramp? Lactate needs time. After a change in workload, it takes 3 to 5 minutes for the level in the blood to settle. In a ramp, lactate lags behind the workload. In a step test, each workload has exactly one lactate value.

The five variables

1. Starting load

Start so easy that you could hold a conversation. The first two to three stages should be clearly below your aerobic threshold. Only then does the curve show where lactate begins to rise. If in doubt, start one stage lower.

2. Stage increment

The increment from stage to stage depends on the sport and your performance level. It stays the same throughout the test. Increments that are too large give too few points on the curve; increments that are too small make the test unnecessarily long.

3. Stage duration

At least 3 minutes; 3 to 5 minutes is usual. The duration has consequences for the analysis: the shorter the stages, the lower the lactate values at the same power output. That is why every threshold model comes with a protocol that suits it. More on this in Chapter 5.

4. Break

When running, you need a short break for blood sampling. It should last about 30 seconds and be the same length at every stage. On an ergometer, samples can be taken from the earlobe without interruption.

5. Number of stages

Plan for at least 5 stages, preferably 6 to 8. If your test has fewer, the start was too high or the increment too large.

Ready-made protocols

The following protocols are proven starting points. Choose the start and the increment so that you end up with 6 to 8 stages.

Treadmill

Treadmill gradient 1%, break for blood sampling about 30 seconds.

Track and field test

On a 400-metre track you run a fixed distance per stage. With 1,200 metres, i.e. three laps, even the fastest stage still lasts long enough. You set the pace using the lap time, a GPS watch or a pacing bike.

Times rounded to whole seconds. Alternatively, you run every stage for the same length of time, for example 3 minutes, and note the distance. In the field, the rule is: flat course, little wind, same conditions as in the last test.

Bike

Keep your cadence the same throughout the test. Your own pedals, your usual riding position and a fan help.

Rowing

The same rules apply on the rowing ergometer: start at 75 to 100 watts, or at 150 watts for trained athletes, then 25 to 50 watts more per stage, 3 minutes per stage.

What a record sheet looks like

The header of the sheet contains name, date, time, location, sport, meter, sampling site, temperature and body weight. Below that comes one row per stage. Here is a completed running test as an example.

Example values, lactate in mmol/L. If someone stops early in the last stage, you note the time reached. The stage is only included in the analysis if at least half of it was completed.

It is normal for the second value here to be slightly below the first. In well-trained athletes, lactate often drops slightly at the beginning before it rises.

Preparation

• Start healthy: Only test when you feel healthy. If you have pre-existing conditions or risk factors, a medical examination should come before your first exercise test.
• Two days before: no competition, no hard training, eat normally, drink enough.
• On test day: eat as you normally do and rich in carbohydrates, with the last meal two to three hours before the test. After that, water only.
• What to bring: your usual shoes or your own pedals, a heart rate chest strap, the record sheet from your last test.
• Room: 18 to 22 °C and a fan are ideal.

The procedure on test day

1. Measure the resting value

   Sit for a few minutes, then note your resting lactate and resting heart rate.

2. Complete the stages

   Set the workload, hold it for the whole stage, take the drop of blood and the heart rate at the end, then move on to the next stage. How to take a clean sample is explained in Chapter 3.

3. Stop

   The test ends when you can no longer hold a stage. For guiding your training, you do not have to go to complete exhaustion.

4. Measure recovery

   Spin your legs or walk easily and measure again after 1, 3 and 5 minutes. After you stop, lactate initially keeps rising and then falls.

5. Analyse

   The values go into the Lactate Express App or into WinLactat.

Typical mistakes

• Started too high: The curve begins when lactate is already rising, and the aerobic threshold cannot be determined.
• Stages too short: Lactate has not settled, and the thresholds appear to shift upwards.
• Uneven breaks: 20 seconds one time, a minute the next. That shifts the values.
• Too few stages: A reliable curve cannot be fitted to three or four points.
• Protocol changed: A test with 3-minute stages and one with 5-minute stages are not comparable.
• Lactate in a ramp test: For lactate thresholds you need stages.

Repeating and comparing

A single test shows where you stand. Only the next one shows whether your training is working. To be able to compare tests, you keep everything the same: protocol, time of day, preparation, sampling site, meter. For triathletes there is one more rule: each discipline is tested separately. Thresholds and heart rate values from the bike cannot be converted to running.

The protocols are examples from diagnostic practice and are no substitute for individual advice. If you have no experience with exercise tests, it is best to gain it first with a qualified performance diagnostics provider.