Update: Category Enforcement for Zwift Racing

August 25, 2022

LAST UPDATED October 17, 2023

UPDATE: Category Enforcement (CE) has evolved since this post. For all the current CE details, visit our canonical post: “All About Category Enforcement on Zwift.”

The first category enforcement test races on Zwift were announced in late February 2022, and the initial test was a success by anyone’s definition. For the first time in Zwift’s history, riders were restricted in their choice of race category based on their historic power data.

Since those early trials, Zwift’s Category Enforcement tools/features have been evolving, as has their documentation. We published this update in April 2022, and today we’re publishing this update thanks to some important category enforcement changes recently announced.

Usage

Back in April 2022, 23% of races were using category enforcement. Today, that number has doubled to 46%. (This is based on the next 7 days of events as of the date of this post. Currently there are 705 races happening in the next 7 days, with 327 of those races using the new category enforcement tools.)

This is especially impressive when you consider that category enforcement is still just an option for event organizers to use on request. It is not yet the default.

Latest Changes

Two Category Enforcement changes were recently announced by James Bailey on August 21:

Any ride that would cause an increase of 70% or more to a rider’s CP will not be included in the power curve used to assign a category. These are normally caused by a trainer miscalibration or someone sharing their account.
All category boundaries have been increased by 5%, to make the difference between Zwiftpower and CE less apparent and confusing (because Zwiftpower uses 95% of your best effort over 20 minutes).

How Category Enforcement Works

With the latest changes in mind, here is a summary explanation of how Zwift’s Category Enforcement currently functions.

Zwift uses your last 60 days of riding activity on the platform to build a 2-50 minute power curve profiling your fitness as a rider
This power data is used to compute your VO2max, Maximal Aerobic Power (MAP), and Critical Power (CP)
These three data points are then used to determine your minimum race category (see category boundaries below). When signing up for a race that uses Category Enforcement, you are only allowed to sign up for that minimum category or higher
New or returning Zwifters who don’t have enough recent activity data in their account are placed in the “E” category of Category Enforcement races so they won’t interfere with properly-classified riders
Any ride that would cause an increase of 70% or more to your CP is not included in your Zwift power curve, as it is assumed to be caused by a trainer miscalibration or someone sharing your account

Category Boundaries

Here are the boundaries currently used by Category Enforcement to determine the minimum race category for riders in open or “mixed” races (where both men and women can participate). Hitting just one of these thresholds will qualify you for that minimum category – you don’t need to hit all three.

Open Races	VO2max and Watts	MAP value and Watts	CP and Watts
Category A	≥60 and ≥250W	≥5.4W/kg and ≥250W	≥4.2W/kg and ≥250W
Category B	≥50 and ≥200W	≥4.1W/kg and ≥200W	≥3.36W/kg and ≥200W
Category C	≥45 and ≥150W	≥3.9W/kg and ≥150W	≥2.62W/kg and ≥150W
Category D	<45 and <150W	<3.9W/kg and <150W	<2.62W/kg and <150W
Category E	N/A	N/A	N/A

Race events that only allow women have their own set of boundaries:

Women Only Races	MAP value	zFTP
Category A	≥5W/kg	≥3.88W/kg
Category B	≥4.2W/kg	≥3.36W/kg
Category C	≥3.5W/kg	≥2.625W/kg
Category D	<3.5W/kg	<2.625W/kg
Category E	N/A	N/A

Next Steps

While Category Enforcement seems to be functioning quite well in terms of meeting its overall goal (stopping sandbaggers), there is still plenty of work to be done to make it a user-friendly feature. Zwift still needs to develop:

Support material explaining how CP, MAP, and VO2max are calculated
Better integration and visibility in ZwiftPower
Ability for event organizers to customize limits
Better information presented when signing up for an event, to explain why certain categories are unavailable to you

About Critical Power

The use of Critical Power (CP) instead of FTP is a smart move on Zwift’s part and one that will have reverberations throughout the cycling world just as Zwift’s focus on FTP has made it a more prominent metric. While CP and FTP are sometimes used interchangeably, they’re actually two very different metrics.

CP and FTP are typically within 10% of each other for any given cyclist, but they are calculated using very different inputs. While Zwift’s FTP estimation requires a 20-minute full gas effort, CP takes into account your best efforts from 2 minutes all the way to 50, which should (in theory) provide a more accurate fitness metric for classifying racers.

If you don’t know your CP, you might check out intervals.icu as a free service that can calculate your CP and many other metrics. Tip: find your CP by going to Power>Options, and choosing “eCP: Single max effort & Morton’s 3P” as the “power model used to estimate FTP”.

For a deep dive into all things CP, check out this post from Highnorth.

Finding Category Enforcement Races

Zwift has no easy search filter built into Companion, etc to list only those races using category enforcement. But ZwiftHacks, as always, comes to our rescue! Here’s a custom ZwiftHacks search showing all upcoming category enforcement races.

Category Enforcement FAQ

Zwift has been building out support documentation for their Category Enforcement features. If you still have questions about Category Enforcement, their Category Enforcement FAQ is a good place to start.