The CP analytic is a method to evaluate your cycling performances using mean maximal powers (MMPs) between 5-seconds and 60-minutes.
Based on the fitted MMP curve; we can obtain some relevant cycling performance parameters.
Sprint capacity: Pmax vs. Tau
The ability for winning a sprint is evidently indicated by the maximal power at extremely short times i.e. by Pmax. However this maximal power can be maintained only for a very limited time and it will decline after one or two seconds. Sprinting success thus depends also on the rate of decline of this high power. The longer the time constant Tau, the longer a high sprinting speed can be sustained.
- So called "power sprinters" may have a slightly lower Pmax but a long sprinting time Tau.
- Conversely a sprinter with a short time constant Tau may have a "cat-like" jump but may not have the ablility of winning a 200 m side by side sprint.
Considering that a mass sprint takes only 10 - 11 seconds, slight changes in the time constant Tau may have huge effects on sprinting success.
Endurance capacity: MAP, P20, P60
- MAP (maximal aerobic power) is the highest aerobic power one can develop at the end of a short intense burst of power of a few seconds, such as a sprint or at the end of an all-out break-away of a few minutes.
- P20 is the highest power one can develop during 20-minutes.
- FTP is the highest power one can develop during 60-minutes.
- CP is the maximum rate of work that can be sustained for a very long time without theoretical fatigue
- Weff is the total amount of work that can be produced until fatigue at any level above CP. The highest value of Weff for all intensities up to the super critical power SCP is indicated as AWC.
Value of the CP concept
Critical power analysis allows one to determine whether it is chances in anaerobic capacity (Weff) or aerobic capacity (CP) accounting for any changes in performance.
It provides a very good conceptual framework for understanding the most basic factors determining exercise performance/power output (i.e., anaerobic and aerobic energy production), and how the contribution of each varies as a function of time.
In modern cycling the anaerobic component is more important than generally accepted. Also, little is known about the influence of modern anaerobic training. By offering coaches and athletes a new instrument to monitor CP and AWC, iQO2 wants to be a pioneer in optimizing performance with legal techniques.
Example - based on a study of Grand Cycling Tour winners by Prof. C. Dauwe
Analysis of CP and AWC calculations on MMP data could give some remarkable insights. We try to show you some of these insights based on a study of the CP and AWC of Grand Cycling Tour Winners by Charles Dauwe - Dept. Physics and Astronomy, Ghent State University, Belgium.
We see that of all these grand tour champions, Contador (2009) presents the highest CP of 5.42 W/kg, while Hesjedahl had 4.82 W/kg in his winning Giro in 2012.
|Froome||Contador 2009||Contador 2013||Hesjedahl|
|AWC (kJ/kg)||1.58 ± 0.04||1.81 ± 0.04||0.86 ± 0.14||1.42 ± 0.21|
|CP (W/kg)||5.16 ± 0.02||5.42 ± 0.01||5.20 ± 0.07||4.82 ± 0.13|
Tabel 1. Compilation of CP and AWC of some top-riders
More interesting are the CP values of Froome and Contador in the TDF 2013. They have identical values within the margins of error. The main difference between Froome and Contador in the TDF2013 is their AWC, 1.58 kJ/kg for Froome and barely half as much for Contador. Could Froome have won the TDF of 2009 against Contador? Absolutely not because in 2009 both CP and AWC of Contador were much higher than Froome’s in 2013. Although Contador had to concede time to Froome on every climb in the TDF 2013 they had a almost identical CP from which it is clear that superior aerobic (endurance) power cannot be considered to be the only physiological quality of the grand tour winners. The secret, if any, of the supremacy of Froome over Contador in the TDF 2013 lies in his higher AWC, 1.58 kJ/kg for Froome versus 0.86 kJ/kg for Contador.
We also have to observe an enormous difference between the performances of Contador in his winning tour of 2009 and in the tour 2013. His CP was a full 4.25 % higher in 2009, and most notably his AWC in 2009 was more than double of his AWC in 2013! Because AWC is related to the ability of maintaining a higher speed than his adversaries, it seems that Contador’s best weapon in 2009 had become his greatest weakness in 2013.
Hesjedahl has the lowest CP, but he combines this with a high AWC. This could be the result of his past as a MTB rider.
Learn more how to analyze the CP charts.
- How to work with the CP charts?
- Critical power: how do I analyze the P(t) relationship?
- Critical power: how do I analyze the P(1/t) relationship?
- Critical power: how do I analyze my Anaerobic work capacity (AWC)?