• Mark Turnbull

What is INSCYD PPD Critical Power Test?


The INSCYD PPD is unique by way of being a lab accurate a critical power test which the rider can do outdoors using their own bike, a power meter or indoors on a smart trainer. One of several performance metrics determined is critical power. This can then be used in conjunction with anaerobic threshold to measure and control training intensity.


What is the critical power

Critical power (CP) - describes the maximum possible power over a certain period of time. Think of it as a “personal best” over a certain number of minutes. For example, a CP20 is referred to as the maximum possible output over 20 minutes. The CP3 would indicate your maximum power over 3 minutes and can be used as measure of a riders VO2. The CP60 is therefore often used as a synonym for anaerobic threshold or FTP.


The original CP is a modeled value which theoretically could be driven "infinitely". From a physiological point of view, this construct can be compared with other concepts of a physiological equilibrium, such as the maximum lactate steady state or, in other words, the anaerobic threshold.


Once you go beyond the CP, it becomes “critical” and you have to stop the exercise prematurely. How quickly the performance fails depends of course on how far you go (beyond the critical power) into the red area and how high the "reserves" are above the CP (expressed as W 'in the original context).


How does the Critical Power Test work?

In the classic critical power test, you drive a series of all-out loads on different days, e.g. within a week. In this way you “draw” several points on an xy diagram (power/time), which can be “plausibly connected” with a curve (interpolated). The more points you have “collected” through various tests, the more precise the curve will be. The classic 20min FTP test is basically just a single point on the line (which is also the reason why it cannot predict the full range of services on its own ).


The critical power curve then depicts the complete time-power structure . This means that, in principle, you can read off how high a maximum power would potentially be over a period x, even if you have never actually driven it. The curve thus ultimately predicts all possible best performances .


How can a critical power test derive physiological findings?

The Inscyd Critical Power Test also uses a number of different maximum intervals. You can do this on the street or on your roller trainer. The only important thing is not to vary the conditions.


The intervals to be driven were specially selected for the targeted analysis of a physiological profile. In the complex interplay, the resulting data from the individual tests make it possible to “calculate” the complete physiological behavior of an organism and thus to simulate all conceivable stresses.



Part 1: The maximum rate of lactate formation VLamax - A measure of "liveliness"

The maximum rate of lactate formation or VLamax describes the ability of an organism to produce a maximum amount of energy in the shortest possible time. This makes it the determinant of explosiveness, speed and general “liveliness”.


The Inscyd Power Performance Decoder uses one or more maximum 15-20 sec sprints in its critical power test to estimate the maximum lactate formation rate VLamax. The resulting maximum power and the drop in power alone give an idea of ​​how this parameter should be represented. Above all, it is important that you DO NOT do ANY ACTIVITY before the sprint, i.e. a complete rest phase of at least 90 seconds in order to exclude the aerobic system as an energy source.


INSCYD Power Performance Decoder Sprint test to determine the VLamax


Part 2: The maximum oxygen uptake VO2max - The "displacement" of your aerobic system

The maximum oxygen uptake or VO2max for short is pre-estimated in the Inscyd Power Performance Decoder using a 2.5 min all-out interval . Studies have shown that the performance of a uniformly controlled, maximum 2.5 - 3min interval is perfect to stimulate the aerobic system to the maximum. Shorter interval times often break off before reaching VO2max. Longer intervals have to be completed with lower loads, which are often not sufficient to access the maximum oxygen uptake.



Part 3: The Anaerobic Threshold - The Counterpart to FTP

The anaerobic threshold has been known as a physiological balance since the 1970s. In principle, the anaerobic threshold describes a maximum balance between the two systems, anaerobic and aerobic. If you drive a performance above the anaerobic threshold, the anaerobic component predominates and leads to a higher lactate production compared to the lactate breakdown. The Inscyd Power Performance reveals this parameter via a smart test: You start in a 3 - 4 minute interval with full power , i.e. sprinting. As you get exhausted, you try to drive as hard as you can. After the anaerobic system is "exhausted" (after approx. 2 - 2.5 minutes), only the aerobic part remains, so to speak, and you level off at a performance close to the anaerobic threshold. This type of test has already been used in some scientific studies.



Part 4: Cross-validation of the three parameters

In principle, all variables are only estimated in advance by the INSCYD Power Performance Decoder up to this point and the performance curve is supplemented by means of a few additional load segments, as in the Critical Power Test. The three variables are then compared and fitted with an algorithm. The three variables must therefore match each other in a regressive relationship in such a way that all measured values ​​match the curve! This is the strength of the INSCYD Power Performance Decoder and makes the data evaluation really robust.


INSCYD Cross Validation of the parameters VO2max, VLamax and anaerobic threshold

Can a Critical Power Test replace laboratory performance diagnostics?

In the original version, the Critical Power Test is quite meaningful with regard to the predictability of various services. But it cannot give any well-founded statements about physiological values.


With the INSCYD Power Performance Decoder it is possible for the first time to read out a physiological profile including the VO2max, VLAMax and anaerobic threshold from a modified form of the critical power test . This allows a well-founded analysis of the data and, above all, an explanation of the background. This makes the test more than a simple measurement of pure performance , but rather a complex performance diagnostic tool.


Jones, AM, Vanhatalo, A., Burnley, M., Morton, RH and Poole, DC Critical power: implications for determination of VO2max and exercise tolerance. Med Sci Sports Exerc. 42 (10): 1876-1890, 2010.


Mattioni Maturana, Felipe & Keir, Daniel & Mclay, Kaitlin & Murias, Juan. (2016). Can measures of critical power precisely estimate the maximal metabolic steady state ?. Applied Physiology, Nutrition, and Metabolism. 41.10.1139 / apnm-2016-0248.


#coachingworks #coachingwithsparks #indoorcycling #periodisation #sparksintolife #inscydppd #coaching #cyclecoaching #cycling #fatloss #weightloss #endurancetraining