Tuesday, August 4, 2015

An Overview of New Metrics in WKO4

WKO4 New Metrics - Peaks Coaching Group

Much of coaching and training comes down to measuring changes to find the answers to important questions. Does one training strategy work better than another? Do workouts with one version of intensity create better results than another version? Does focusing on longer intervals instead of shorter ones help achieve the goal of training?

WKO4 and its new Power Duration Model have supplied coaches and athletes with some exciting new metrics to expand and deepen data analysis allowing a coach or athlete greater insight into these questions through the ability to view training results more specifically and view micro changes in these specific types of fitness.

WKO4 New Metrics - Peaks Coaching Group
Pmax and Functional Reserve Capacity are related but separate measurements
of capabilities and fitness that can give us insights into performance.


Pmax is the maximum amount of power that can be generated for a very short period of time (at least a full pedal revolution with both legs). Units are watts (W) or watts per kilogram (W/kg).

Pmax Standards

Pmax typically ranges between 676 and 1299 watts for women, and 939 and 1483 watts for men, with an average of 988 and 1211, respectively.

WKO4 New Metrics - Peaks Coaching Group

Pmax over Max Power

Pmax is more stable and a bit less prone to measurement error than Max Power since the model utilizes all data. This provides a “cleaner” metric when compared to Max Power, while giving us better insight into a true maximal effort than MeanMax five-second power.
  • Pmax vs. Max Power. Pmax is derived from at least one full pedal stroke, measuring the contribution of both legs (both released and absorbed). This gives us a cleaner look at maximal power as we effectively apply it to the bike, as it is less subject to erroneous data.
  • Pmax vs. MeanMax Five Seconds. Because Pmax is model derived, it is a truer determination of maximal power when compared to five-second max, as it reduces the effect of fatigue.

How we use Pmax

  • To measure the increase or decrease in maximal power outputs over the course of training (or de-training)
  • To determine the maximum rate of FRC consumption (more below)
  • To develop and implement race strategies

Functional Reserve Capacity (FRC)

FRC is the total amount of work that can be done during continuous exercise above Functional Threshold Power (FTP) before fatigue occurs. Units are kilojoules (kJ) or kilojoules per kilogram (kJ/kg). This effort is related to your ATP-PC energy system, but other energy contributions need to be considered.

The simplest explanation is to think of it as your anaerobic battery. If you have a low FRC, you have a smaller battery, and if you have a high FRC, you have a big battery. However, we also have to think about FRC in relationship to Pmax, maybe like this:

High Pmax / High FRC: Great long sprinter or lead-out rider
High Pmax / Lower FRC: Great short sprinter but needs support to the line
Lower Pmax / Higher FRC: Long attacker, punchy short climbs, good pursuer
Lower Pmax / Lower FRC: Good stage racer

FRC Standards

FRC typically ranges between 6 and 24 kilojoules for women and 9 and 35 kilojoules for men, with an average of 13.2 and 18.2 kJ, respectively.

WKO4 New Metrics - Peaks Coaching Group

FRC Converted to Watts

A kilojoule is simply a thousand joules, and a joule is equal to watts multiplied by seconds (J = W x s). So when you do 400 watts for 5 seconds, you’ve used 2,000 joules, or roughly 2 kJ.

An Example of FRC

Let’s say you have a Pmax of 1,000 watts (just to keep the math simple) and an FRC of 11kj. If you sprint at Pmax, you’ll burn 1,000 joules per second (J = W x s) for 11 seconds before you run out of fuel.

How we use FRC

  • To measure the increase or decrease in the amount of continuous work an athlete can do over modeled Functional Threshold Power (mFTP, defined below)
  • To improve understanding of an athlete’s abilities
  • To understand an athlete’s burn rate
It’s easy to figure out burn rate at Pmax; we just do the math. Below that it gets tricky, since other systems do contribute, but we can use the Power Duration Curve to help make that determination.

WKO4 New Metrics - Peaks Coaching Group
Tracking micro changes in Pmax and FRC gives us faster insight into training
effectiveness and helps adjust training and performance strategies.

Modeled Functional Threshold Power (mFTP)

mFTP is the model-derived highest power a rider can maintain in a quasi-steady-state without fatiguing. When power exceeds FTP, fatigue will occur much sooner; if power is just below FTP, it can be maintained much longer. FTP is the single most important physiological determinant of performance in events ranging from as short as a 3-kilometer pursuit to as long as a 3-week stage race.

You can read up on Functional Threshold Power here to better understand the concept.

How we use mFTP

  • To measure the increase or decrease in FTP as based on modeled estimates, giving better insight into training effectiveness or ineffectiveness
  • mFTP can support the accuracy of your FTP management system (testing, predicting…) and allow you to set zones based on percentages of FTP.
  • mFTP can be used as the basis for numerous analytics in WKO4 to better help diagnose and prescribe workouts.
Analytics can supply answers. The focus of WKO4 and the new Power Duration Model is to supply coaches and athletes with new metrics and robust analytics to better determine training strategies and to better (and more quickly) measure their effectiveness.

Want to give it a try? Download the fully functional 14-day free trial here: http://home.trainingpeaks.com/products/wko4.

Author Tim Cusick

Contributions and standards by Dr. Andrew Coggan  

1 comment:

  1. IN WKO4 on the Hero mFTP is displayed as 239 (which I understand is calculated as an average over the last 90 days. In the PD History Metrics graph - selecting 90days in RHD - my first mFTP reading is 227 and may last is 253. Considering my sFTP would it be reasonable to enter 253?