Lactate step test, Trained cyclist (example)

Since the first test: LT1 +27 W, LT2 +74 W

5 tests from 14 Jan 2019 to 21 Aug 2024, with LT1 as Bsln + 0.5 and LT2 as ModD_max. A threshold also moves when fitness does not, so a change counts only when it is larger than the noise of the method.

Every lactate curve: the latest test in blue, the first in dark gray, the tests between in light gray; then the heart rate of the stages in the same colors, with LT1 and LT2 as filled points, and below them the five training zones of each test up to its highest stage, with LT1 and LT2 at their boundaries; dashed lines: 2 and 4 mmol/L.

Test by test

Test	LT1, Bsln + 0.5 (W)	LT2, ModD_max (W)	Heart rate at LT2 (bpm)	Peak (W)	Peak lactate (mmol/L)
14 Jan 2019	257	290	176	360	6.4
26 Jun 2019	272	328	173	400	8.2
25 Jan 2022	236	270	165	360	10.5
22 Feb 2024	269	325	176	400	6.3
21 Aug 2024	284	364	179	440	8.0

The latest test against the one before (22 Feb 2024)

	22 Feb 2024	21 Aug 2024	Change	90% interval	Change ÷ noise	Against the noise
LT1, Bsln + 0.5	269	284	+15 W	−36 to 66	0.5	within the noise
LT2, ModD_max	325	364	+39 W	1 to 78	1.7	beyond the noise

The noise is what two tests of this method usually differ by when nothing changed. A change is beyond the noise when its whole 90% interval lies on one side of zero (a change of more than 1.6 times the noise); a change within the noise may still be real: one pair of tests cannot tell.

The latest test (21 Aug 2024)

A cycling step test of 9 stages, up to 440 W.

LT1, Bsln + 0.5

284 W

65% of peak

1.6 mmol/L · 159 bpm

5 first-rise methods: 221 to 307 W

LT2, ModD_max

364 W

83% of peak

4.0 mmol/L · 179 bpm

8 second-rise methods: 298 to 364 W

Peak

440 W

8.0 mmol/L · HR_max 189 bpm

Five training zones from these two thresholds

Domain			Intensity (W)	Heart rate (bpm)	Lactate (mmol/L)
Moderate	Zone 1	below LT1	< 213	< 139	< 0.8
	Zone 2		213–284	139–159	0.8–1.6
Heavy	Zone 3	LT1 to LT2	284–364	159–179	1.6–4.0
Severe	Zone 4	above LT2	364–402	179–184	4.0–5.8
	Zone 5		> 402	> 184	> 5.8

What to double-check

9 of 10 checks of the data passed.

Early lactate dip

The first stage is 0.2 mmol/L above the lowest later stage; it shapes Dmax and Bsln+. Check warm-up and sampling.