TL;DR
🔹 Your Power-Duration Curve (PDC) shows the power you can achieve for different durations
🔹 It’s personal, based on your workouts, and needs maximum effort runs at a few different durations to be accurate
🔹 It contains your Critical Power (CP) – a measure of your current metabolic fitness that can be used to set target effort levels
🔹 It also shows your Time To Exhaustion (TTE) – a trackable measure of your fatigue resistance for shorter duration runs
🔹 The left end of the curve is your Reserve Work Capacity (RWC) – used to estimate how long you might take to run a race up to 40-45 minutes
🔹 The right end can be used to find your Riegel Exponent – used to estimate how long you might take to run a race longer than 40-45 minutes
Questions about your PDC? Ask them in the from1runner2another Facebook group.
What is a PDC?
Your Power Duration Curve is modelled based on your recent power-based workouts – usually the last 90 days, sometimes with older runs having less “weight” than a more recent workout.
An accurate curve usually needs a minimum of 4 maximum effort runs, each at a different duration – for example: 20 seconds; 2 minutes; 10 minutes; 20 minutes.
Note that the curve doesn’t show what you have achieved – it shows what you could achieve
What is my CP? What is my FTP?
Critical Power (CP) and Functional Threshold Power (FTP) are a power-based measure of your metabolic fitness – how efficiently your muscles use fats and carbohydrates to produce energy when you run.
They are calculated differently, but often end up at around the same number.
If this sounds complicated, then think of CP or FTP as numbers you use to track your fitness and that you can use to set workout targets when you train and power targets when you take part in an event.
What is my TTE?
Time To Exhaustion (TTE) measures how long you can maintain your CP or FTP power before you need to slow down.
It’s a way to track your fatigue resistance for shorter durations and can be improved through power-based training.
What is my RWC?
Think of your Reserve Work Capacity (RWC) as a barrel of water.
When you run at a power above CP/FTP, you’re draining the barrel; at a power below CP/FTP, the barrel is being refilled (by internal metabolic processes).
If you empty the barrel, you have no choice but to slow down.
RWC is important for races that last up to your TTE, and can be used to predict how long it might take you to run that shorter race.
What is my Riegel Exponent?
The Riegel Formula works well for races that last longer than your TTE, and can be used to predict how long it might take you to run that longer race.
The original formula worked with distance and duration (speed) – there’s a modified version that works with power and duration.
Part of the Riegel Formula is an exponent that can be derived from your PD Curve, enabling the formula’s predictive capability to be applied to individual runners.
Why is it so complicated?
Where can I see my PDC?
Stryd PowerCenter
- An online website free to anyone with a Stryd account
Stryd accounts are free (optional subscriptions too) - PowerCenter plots mean-max power (MMP) and “models” a PDC across the top of MMP maximums
- It only calculates CP, but TTE and RWC can be derived
- Your workouts can be automatically synced to PowerCenter
WKO
- Paid PC-based software from Training Peaks
Training Peaks accounts are free (optional subscriptions too) - WKO plots mean-max power (MMP) values and “models” a best-fit PDC
- It calculates FTP, TTE and FRC
- Your workouts can be automatically synced via Training Peaks
Golden Cheetah
- Free PC-based software from GoldenCheetah.org
- Golden Cheetah plots mean-max power (MMP) and “models” a PDC across the top of MMP maximums
- It calculates CP and W´, but does not calculate TTE (although it has an “endurance index”)
- Your workouts must be manually downloaded / imported
Download pictures as a PDF
The pictures above are available as a downloadable PDF
Feedback? Questions?
If you have questions or recommendations – things that have worked for you – come and share them with us!
Join the discussion in the from1runner2another Facebook group.
