determine BIKE FTP
The renowned physiologist Dr Andrew Coggan, defined the concept of Functional Threshold Power (FTP) as "the highest power a rider can maintain in a quasi-steady state without fatiguing for approximately 1 hour". Although different testing protocols will produce different results, and the precise range of watts will fluctuate from day to day, your FTP will typically coincide with what we term - the Anaerobic Threshold (AnT).
In the Tri-High Performance system, training levels for cycling are determined by percentages of your FTP. The more experienced you become as an athlete, the less you will need to perform assessments in order to determine this threshold. An experienced athlete can intuitively 'feel' when they are riding in a quasi-steady state they could maintain for approximately 60 minutes. However, less experienced athletes will often require frequent assessments to establish their hour power.
Unfortunately, it is not typically practical to execute an uninterrupted 60 minute TT on a regular basis. Therefore, we recommend choosing a shorter assessment duration that will be easily repeatable. Although a calculation based upon a shorter duration, will have a greater level of uncertainty, consistency from one assessment to the next, is far more important than absolute precision.
Below, you will find FTP calculations for any duration between 10 and 90 minutes. We have provided percentages beyond a 1 hour duration, solely to provide you with an appropriate calibration factor in case you wish to use power data from a recent TT which exceeded 60 minutes. However, I would typically advise against basing an FTP on a race duration greatly in excess of 70 minutes.
In the interests of minimising uncertainty and increasing repeatability - we recommend using a duration between 15 and 30 minutes. You may wish to choose a set assessment duration within the above time range, or perhaps use a set distance (such as 20km) in a Time-Trial race environment, that will be completed within the stated time range.
The choice is yours. Simply choose a repeatable assessment duration/distance that will motivate you to perform to the best of your ability. Unless you are performing a race-specific FTP assessment, the test should be performed where you do the majority of your training. Either indoors on a trainer, or outdoors on a relatively flat course (or moderate incline) that is free from interruptions or coasting opportunities.
Ensure that you are highly motivated, your power meter is charged and calibrated, you are well hydrated, and well fuelled on carbohydrates. Although I recommend that you weigh yourself on a daily basis anyway (primarily to monitor hydration levels), you must ensure that you weigh yourself prior to any FTP assessment. Without a record of your power to weight ratio for each assessment, we will never have a full picture of your fitness levels.
After you have completed your assessment, to establish your FTP, simply locate the duration of your assessment below and multiply your average power by the percentage alongside. For example, if you completed a 20 minute assessment, you would simply multiply your average power by 0.931. If your finish duration falls between two percentages, (although the difference will be negligible) by all means split the difference.
Please note, although you may have previously used 95% of 20 minute power as your FTP, in our experience, this calculation typically provides an inflated assessment of true 60 minute power. You may also have previously used multiple assessments to determine your Critical Power (CP) as an alternative measure of your Anaerobic Threshold. Although a CP assessment can certainly have merit when executed correctly, in my opinion, the potential for an erroneous result is far too great. For this reason, if required, I would always prefer my athletes to complete a single assessment protocol for FTP.