Kickass Science

Performance diagnostic parameters – these values determine metabolic endurance capacity

Florian Heck • 05. March 2021 • 4 Min.

Measuring endurance performance based on an arbitrarily determined threshold and specifying training ranges based on percentages of these is simply inadmissible and only leads to insufficient progress. A measure that is more efficient is the metabolic profile of each athlete, it is determined on the basis of several parameters and tells us much more for individualisation of each training plan. With the right parameters individual training ranges and specific training targets can be set and a training goal can be defined. When selecting and carrying out performance diagnostics, care should therefore be taken to determine several parameters for determining the metabolic profile.

The following parameters are indispensable for classifying endurance performance of each athlete:

1) Maximum oxygen uptake – VO2max 

Colloquially referred to as the “size of the engine”, VO2max indicates the maximum amount of millilitres of oxygen the body can utilise per minute, it provides information about the aerobic capacity of each individual. Several processes are involved in this utilisation: From the pure supply of oxygen from the air via the respiratory organs, via transport in the blood, via the cardiovascular system to the utilisation of oxygen in the working muscles. VO2max decreases systematically from the age of 30 (Shvartz & Reibold, 1990), but can be increased at any age with the appropriate training. A high VO2max is desirable for every endurance athlete. Accordingly, an increase in the maximum oxygen uptake in the training process should be aimed for.

Comparative values VO2max:

Professional endurance athlete:
70 – 85 ml/min/kg

Good amateur athlete:
55 – 65 ml/min/kg

Recreational athlete:
45 – 55 ml/min/kg 

Non-trained man:
30 – 40 ml/min/kg 

Non-trained woman:
28 – 35 ml/min/kg

„Die VO2max ist als das Bruttokriterium der Ausdauerleistungsfähigkeit anzusehen und sollte daher im Training große Beachtung finden.“

2) Maximale Laktatbildungsrate – VLamax

In addition to “engine”, VLamax can be colloquially referred to as “fuel consumption”. Metabolically, the VLamax indicates how many carbohydrates per second can be used for energy production and represents the anaerobic capacity. When evaluating and training the lactate formation rate, the requirement profile of the sport practised and the objective must also be taken into account. For example, a high VLamax is advantageous for short, intensive exertions, as a lot of energy has to be provided in a very short time. This is done by metabolising carbohydrates (glycogen) in the anaerobic metabolism. However, since the carbohydrate storage is emptied quickly, this is rather counterproductive for long-term endurance exercise where a high amount of energy is required over a long period of time. For these requirements, a rather low lactate formation rate should be aimed for in order to preserve the carbohydrate stores for as long as possible.

Low VLamax

  • Slow energy supply during intense exercise
  • Low carbohydrate consumption during low-intensity exercise
  • To be aimed for during long-term endurance exercise

High VLamax

  • High carbohydrate consumption + lactate accumulation even at low loads
  • Poorer fat burning 
  • Good power production during short, intensive efforts 
  • Goal during short, intensive workouts

3) Anaerobic Threshold

This is the most widespread but least understood term in performance diagnostics. In metabolic terms, it represents the highest power output at which the concentration of lactate in the blood reaches a state of equilibrium. This state is also referred to as the Maximum Lactate Steady State (MLSS). The MLSS corresponds to the highest intensity of exercise at which the blood lactate concentration increases by less than 1 mmol/l in the last 20 minutes of a 30-minute sustained exercise (Heck, 1990).

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4) Ventilatory threshold 1 – VT1

Ventilatory threshold 1 “occurs during increasing exertion as a consequence of the first rise in blood lactate concentration above the baseline value” (Meyer, 2007). The lactate produced is buffered in the body via bicarbonate. This leads to an increase in ventilation and an increased release of carbon dioxide (CO2). Metabolically, VT1 marks the transition from aerobic to aerobic-anaerobic metabolic range and is therefore interesting for determining the basic endurance range. 

In practice, VT1 can be determined very accurately if the test is carried out carefully.

5) Ventilatory Threshold 2 (VT2) / Respiratory Compensation Point (RCP)

Referred to as VT2 or the RCP, depending on the author. Both values are characterised by “disproportionate ventilation as a result of increasing metabolic acidosis” (Westhoff, Rühle, Greiwing, Schomaker, Eschenbacher, Siepmann & Lehnigk, 2013). The buffering of the accumulating lactate can no longer take place sufficiently, resulting in a drop in the pH value in the blood with a simultaneous disproportionate increase in ventilation. From a metabolic point of view, the point of maximum lactate steady state is exceeded and a further increase in intensity leads to metabolic acidosis. The VT2 is therefore usually slightly above the anaerobic threshold. 

The determination of VT2 requires a lot of experience and may not always be unambiguous.


Heck, H. (1990). Laktat in der Leistungsdiagnostik. Schorndorf: Hofmann.

Meyer, T. (2007). Belastungsuntersuchungen: Praktische Durchführung und Interpretation. In W. Kindermann (Hrsg.), Sportkardiologie. Körperliche Aktivität bei Herzerkrankungen (S. 39-66)Darmstadt: Steinkopff. 

Shvartz, E., Reibold RC. (1990) Aerobic fitness norms for males and females aged 6 to 75 years: a review. Aviat Space Environ Med 61 (1): 3-11

Westhoff, M., Rühle, K.H., Schomaker, R., Eschenbacher, H., Siepmann, M. & Lehnigk, B. (2013). Ventilatorische und metabolische (Laktat-) Schwellen – Positionspapier der Arbeitsgemeinschaft Spiroergometrie. Deutsche Medizinische Wochenschrift 138 (6): 275-280

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