Training Zones

Training zones are the performance bands between recovery and maximal effort, defined as a percentage of a threshold or by measured physiological markers.

Definition

Training zones are the performance bands the body passes through between active recovery and maximal effort. They are defined either as a percentage range of a previously established reference (e.g. FTP, lactate threshold) or by measured physiological responses (e.g. the ventilatory thresholds VT1 and VT2). Zones are used to prescribe sessions and to evaluate them afterwards.

There is no international standard. Accordingly, many zone models exist with three to seven bands and sometimes contradictory names (see Names and Models). The table below shows the widespread six-zone model as used in cycling after Coggan and, in similar form, in running.

Zone	Physiological description	Share of threshold (FTP)	Typical duration	Purpose
1 – Active recovery	purely aerobic, fat metabolism dominant, hardly any lactate rise	< 55 %	30–90 min	regeneration, blood flow
2 – Endurance	aerobic, below VT1, calm breathing, conversation possible	56–75 %	1–6 h	mitochondria, fat metabolism, base
3 – Tempo / development	between VT1 and VT2, lactate rising but still stabilising	76–90 %	20–90 min	intensive endurance, durability
4 – Threshold	around VT2 / lactate threshold, maximal lactate steady state	91–105 %	8–30 min per interval	raise threshold power
5 – VO2max	above VT2, oxygen uptake near maximum	106–120 %	3–8 min per interval	maximal aerobic capacity
6 – Anaerobic / maximal	anaerobic lactic to alactic, open-ended	> 120 %	10 s – 2 min	anaerobic capacity, sprint

The zones in detail

Zone 1 serves active recovery: movement promotes regeneration without setting a training stimulus.

Zone 2 is where ideally most of the training takes place. The effort feels easy, the metabolism is trained gently and the base is built on which higher intensities later rest.

Zone 3 trains intensive endurance and durability; for long distances, race intensity often lies here. At the same time the load is above average without the stimulus being as specific as in zone 4 or 5. Spending too much time here leads to a plateau despite hard training, known as «zone 3 stagnation».

Zone 4 contains, in most models, the intensive performance thresholds: Critical Power, Functional Threshold Power, lactate thresholds and ventilatory thresholds.

Zone 5 targets maximal oxygen uptake. Models with only five zones, typically heart-rate models, label this band directly as the maximal zone.

Zone 6 is open-ended and describes the absolute maximum. Heart rate is useless as a control metric here because it lags the effort.

Why it matters

Training zones translate an abstract goal («build base», «raise threshold») into concrete targets in watts, pace or heart rate. Without them you can neither plan an intensity distribution nor check afterwards whether a session delivered the intended stimulus.

That only holds if the zones fit the body, though. When a threshold is set as the 100 percent mark and the zones are derived by percentage arithmetic, the model says nothing about oxygen uptake, metabolism or energy supply. Without measuring these responses, calculated zones are at best an estimate; two athletes with the same FTP can have VT1 at 65 or at 80 percent.

How obseed measures it

obseed distinguishes two levels of quality. If only field-test values are available (FTP, rFTP, CSS, HRmax), the zones are derived as percentages of that reference; this is a usable starting point but explicitly an approximation.

If a metabolic performance test is available, obseed sets the measured thresholds VT1 and VT2 directly as zone boundaries. The zones then correspond to the person’s actual physiological transitions rather than a statistical average. obseed recommends this route for anyone serious about steering their training, and the analysis shows which data basis the zones rest on.

Training zones should not be confused with training intensities, which offer a three-tier classification (LIT, MIT, HIT) for prescription and analysis.

Example

A cyclist reaches 280 W in a 20-minute field test; the estimated FTP is 0.95 × 280 = 266 W. Arithmetically this gives zone 2 from 149 to 200 W and zone 4 from 242 to 279 W.

A subsequent metabolic test measures VT1 at 185 W and VT2 at 255 W. His endurance zone therefore ends 15 W lower than calculated, and his threshold sits 11 W below the estimated FTP. Had he trained by the percentage model, his «easy» rides at the upper end would regularly have drifted into the band between the thresholds, with higher fatigue but without the intended base stimulus.

References

Allen, H., Coggan, A.: Training and Racing with a Power Meter. VeloPress.
Seiler, S. (2010): What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance.