It’s been ten weeks since I last posted about Zwift Insider’s VO2sday races, so I figured it was time for an update. Keep reading to learn all about our “Structured Workout Races”!
The VO2sday concept is simple, but not easy: 5 all-out 4-minute efforts, with 6 minutes of recovery between each race. If you do it correctly, you’ll accumulate 5×4=20 minutes of quality VO2 max work by the end of the last race. But it’s done in a motivating and engaging race setting, which makes the suffering much more bearable. Here are two live streams from last week’s races:
August 25 Race Details and Signup
Tomorrow’s races feature the first 5 routes of the new Zwift Shorts challenge. As long as you complete a full lap of the route, you’ll get credit toward the challenge, which means bonus XP! (Pro tip: most riders cover around 3km of distance in a 4-minute VO2sday race on flat roads. So you may need to keep spinning after the race ends in order to finish the lap and get credit toward the Zwift Shorts challenge.)
- Downtown Dolphin (2km)
- Macaron (2.6km)
- LaGuardia Loop (4.3km)
- Glasgow Reverse (4.1km)
- Neokyo Crit Course (4.6km)
Races are held at three different times each Tuesday:
- Zone 1: 11am UTC/7am UT/4am PT
- Zone 2: 5pm UTC/1pm ET/10am PT
- Zone 3: 11pm UTC/7pm ET/4pm PT
Click the banner to sign up:
Sign up at zwift.com/events/tag/vo2sday >
Time-Based Races, Distance-Based Results
VO2sday Micro Races aren’t your typical Zwift race. These are time-based races finishing at the 4-minute mark instead of finishing at a particular point on the course.
The win goes to whoever rides the furthest in 4 minutes. And the overall rankings across the 5 races are based on the total distance you cover across all 5 races.
ZwiftPower can’t handle time-based race results, so our results are hosted by our friends at LeadoutEsports.com. This week’s results will be found at https://leadoutesports.com/vo2sday/17.
Be sure to register at Leadout and link up your Zwift account so your name is included in the race results (here’s a shot of last week’s B category leaderboard):

Structured Workout Racing
I’ve set up these races with a very unique structure, with the goal of delivering an event that is engaging and fun while delivering a proper VO2 max session:
- 5x 4-minute V02 max efforts: That’s 20 minutes of solid VO2 max interval work in just 44 minutes.
- Recovery time: Races are 10 minutes apart, so a 4-minute race leaves you with 6 minutes of recovery before the next interval.
- Drafting is disabled: These are effectively time trials, so you’ll want a fast TT setup. Turning off the draft moves us from the “sit in then sprint” mindset to “hold steady high power for the duration” mode.
- Mass start: While riders are broken into categories for results, these are mass-start events with all categories starting together, so everyone has riders ahead to chase. (Remember, the goal is to push as hard as you can for the duration of the race. There is no “sitting in the pack and conserving” on VO2sday!)
- Mix of courses: Each week we mix up the courses a bit to keep things interesting, but they’re all some mix of flat, rolling, and even downhill parcours.
- Compound Score categories: Since results are driven by your power numbers, riders are categorized by compound score, not Zwift Racing Score. This takes into account your 5-minute power and body weight.

Questions or comments?
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