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Critical Power Profiling

Personalised Performance Training for ALL

Model and Calculation

The Critical Power model determines your overall performance above lactate threshold, and serves to quantitate energy expenditure with the view to prescribing custom interval sessions. Critical power is theoretically defined as the highest, continuously sustainable power output which a cyclist is capable of producing. The critical power calculation complements the Lactate Threshold Profile (the applied aerobic power at the physiological threshold) by measuring the strength of a cyclist’s total anaerobic capacity (energy production without sufficient oxygen). This includes the work done at VO2max, as this occurs above threshold. Maintaining an optimal level of anaerobic capacity is critical for performance success in any type of cycling.

The actual amount of energy available to a cyclist is important when riding at intensities above their critical power is termed the Anaerobic Work Capacity (AWC) or more recently known as W’ (W prime). The AWC (or W’) is an important training tool for designing optimal interval sessions unique to any individual cyclist to specifically target and improve the maximal capacity of both aerobic and anaerobic systems. Therefore the critical power calculation provides a full picture of your current physiological condition and is a valuable basis for formulating personalised training schedules for progression with your training.


The strength of your anaerobic work capacity can predict the type of rider you are, with sprinters having a significantly larger anaerobic capacity compared with time-trialists or rouleurs who have a higher critical power or threshold.

Using this information is important when assessing:

  • Weaknesses in your power profile.
  • Prescribing specifically personalised interval sessions for optimal training.
  • Remote testing and benchmarking for anyone with a power meter.


The critical power assessment involves conducting a series of variable maximal and sub-maximal time-trials between 1 – 10 minutes, performed at random. The test is performed under stringently controlled conditions with specific periods of recovery between each effort, and is blinded to reduce the possibility of bias. After your test data has been analysed and processed, we will provide a series of interval sessions specific to your physiology, maximising exposure to the relevant intensities necessary to evoke adaptations in your weaknesses, and balance your strengths.

The Critical Power widget below lets you visualise the results from an assessment performed with us.

This interval session will strengthen the riders capacity to improve upon the amount of work tolerable at these wattages and lower, after a period of recovery and biogenetic adaptation over a few weeks.

The visit for the Critical Power Assessment should take no more than 1.5hrs.

Download our complimentary info PDF on Perfect Intervals