It’s all about the start: Here’s how many watts it takes to win a Zwift race
What does it take to win a Zwift race? Power, obviously, but that’s not all. Stay with me.
While Zwift may be more of a watts-per-kilogram (W/kg) contest than real-world racing, there is an art to W/kg utilization when it comes to deciding the virtual podium. Just because you’re the strongest doesn’t mean you are going to win. You certainly won’t be able to ride everyone off your wheel unless you’re climbing the Alpe du Zwift, where the punishing gradient almost nullifies the benefit of a slipstream – not unlike the real world.
When the top 10 results pop up on the screen after confetti shoots across the Zwift finish line, the W/kg are never in order from biggest to smallest. So what does it take to win a Zwift race? How do you know when matches are worth burning and which are a waste of time? And how strong do you actually need to be in order to win?
I set out in search of as many Zwift race files as I could, including those from professionals and amateurs in races ranging from 13 minutes to 50. I ignored the cheaters and weight-dopers to find riders who are legitimately among the strongest in the world. What I found isn’t all that surprising – you need to be strong in order to win a Zwift race – but after sifting through the details, I realized that Zwift is far more complicated than a simple power-to-weight ratio.
For the purposes of this article, we will focus on the power-based demands of Zwift racing. We recognize that factors such as power-ups, in-game equipment, and team tactics still matter, but here we will be focusing on the most important factor: watts per kilo.
Zwift provides five group ride and racing categories based on FTP (Functional Threshold Power) and measured in watts per kilo of body weight. These categories are:
A: 4+ W/kg
B: 3.9-3.2 W/kg
C: 3.1-2.5 W/kg
D: 2.4-1 W/kg
E: Open W/kg
Users can measure their FTP with an in-game FTP test which takes “95% of the average power exerted during the 20-minute test block,” according to Zwift. FTP can be also estimated automatically based on in-game power data. It is important to note that the user can select any race category they please, regardless of their FTP. For example, a new user with an unmeasured FTP can jump into an “A category” (A) race if they are confident enough.
The Start (is really hard)
Once you’ve entered a Zwift race, you can join the holding pen up to 30 minutes before the start. Avatars pedal on fluorescent trainers as their real-life counterparts warm up their legs, and a countdown is displayed at the top of the starting banner.
My first ride on Zwift was about one week before this article was written. But as a numbers nerd, I had been following pro and amateur Zwift racing for a while. So I thought I knew what to expect from my first (A) race.
The rumor mill had told me that the start of a Zwift race is hard. Really hard. It’s anyone’s guess as to why this is, but my hypothesis is that start intensity and race duration are inversely correlated. In other words, the shorter the race, the harder the start, and vice versa. Most Zwift races are between 20 minutes and an hour, which are just a fraction of what we expect from real-life road racing. Thus, based on my hypothesis, I could expect a very hard start for this race of only 15.4 km.
Common advice included: “Do 500 W right before the start,” or “Sprint as hard as you can off the line,” and “Do 400 W for the first three minutes or you will get dropped.”
I took some of the advice and spiked my power up to 500 W as the countdown approached zero. After the first few seconds at 450 W, I saw my avatar moving through the front third of the field. That’s good enough, so I eased off the pace to 350 W. Suddenly my avatar was dropping through the field like a rock. I went from 20th place to 50th, then 80th, and I realized that I was at the back of the field, still doing 350 W!
I surged again, back up to 450 W and I could see my avatar moving up the pack. It took nearly five minutes for the race to “settle down” – meaning I could ride at 4.0 W/kg and not get dropped – and up to that point I had averaged over 400 W (~5.4 W/kg). These races are legit.
Over the course of this 19-minute race, I had to surge over 6 W/kg a total of 16 times. I never attacked or sprinted unnecessarily – this is what it took to stay with the front group which had whittled down to nine riders with 1 km to go. We were racing on the 2019 UCI Road Worlds circuit in Harrogate, which meant that the last ~600 metres was a mostly uphill drag to the line. For the last minute I averaged 510 W (6.8 W/kg) and I got dropped. I finished sixth, but still lost a handful of seconds to the podium in those final few hundred metres.
After sifting through races and power files from amateurs and pros alike, I can confidently say that my first Zwift race was not too dissimilar from all the others. I spent a few hours compiling the data, and I can say that the typical pattern for a Zwift (A) race is this:
– 5-6 W/kg for the first three to five minutes, including 6-7+ W/kg for the first 30 seconds.
– 4-5 W/kg for the majority of the race (sitting in the pack).
– 3-4 W/kg on downhills or when the group bunches up.
– 6-7+ W/kg surges on major climbs. Depending on the course, climbs can range from 20 seconds to 10 minutes.
– Sprinting is … complicated (more on that in a second)
– Finish with an average power of >5 W/kg for if you want to make the top 10.
These figures can be roughly applied to the other categories as well. If the B category is marked 3.2-3.9 W/kg, you’ll have to do 4-5 W/kg, minimum, for the first few minutes. This is ignoring any blatant sandbaggers or folks with impossible power profiles.
“Pro” Zwift Races
British Cycling recently launched an eight-race series of short, criterium-like races for the strongest riders on Zwift. Take a quick look at the power files from any one race and it is obvious just how hard the first few moments can be. In less than 30 seconds, the field goes from a standstill to over 50 km/h, quickly leaving behind anyone who was hoping to ease off the line. As in most Zwift races, most riders are pushing 6 to 7+ W/kg straight out of the gate.
After just 20-30 minutes of explosive racing, a reduced group sprints to the finish line at over 60 kph. As the leaderboard flashes up on the screen, it’s clear that only the strong have survived. Throughout the entire top 20, average powers range from 5.0 to 5.9 W/kg. When you factor in the countless surges of a chaotic Zwift race, riders are pushing a normalized power of close to 6 W/kg for over 20 minutes.
There are countless other examples, but the bottom line is this: Zwift categories are accurate for those who are content with holding on for dear life and finishing mid-pack. But in order to finish in the top 10, on the podium, or even take the win, you need to be at or above the top end of your category’s W/kg range. While prestigious race events such as the British Cycling Race Series may be punching slightly above their category, the requirements for your typical Wednesday night Zwift race are not that far off.
The Final Sprint
I began this article by saying that we were going to focus only on the power-based aspect of Zwift racing. But when it comes to sprinting on Zwift, it is hard to ignore the significance of positioning, drafting, and power-ups when riders are separated by hundredths of a second.
It is impossible for me to tell you how many watts it takes to win a sprint on Zwift – every sprint finish is different, just like in real life. How hard has the race been up until the final 500 metres? How many riders are left – 10 or 100? And what is the finishing straight like – is it fast and flat, uphill for the entire final kilometre, or downhill for the last 200 metres?
All of these factors make each sprint so wildly different that, with the added complications mentioned above, it is impossible to say what numbers it takes to win. With that said, I have seen riders win a sprint by doing 8.5 W/kg for the final 40 seconds, 16 W/kg for the final nine seconds, or by riding everyone off their wheel by doing 7 W/kg for the final minute and a half. All that matters is who crosses the line first.
Power does matter, but winning a Zwift race is more complicated than producing the highest watts per kilo.
You need to be able to start hard — 5-6 W/kg for the first couple of minutes in the A races, and 1-2 W/kg higher than the stated average for other categories. Then you need to be able to sit at 4-5 W/kg for the majority of the next 20 to 40 minutes. Practice training your sweetspot.
Rest on the downhills when you can, but don’t expect to be coasting for more than a few seconds, if at all. And when the road kicks up, get ready for a 6+ W/kg surge that will keep everyone honest.
When the dust finally settles and you hit 1 km to go, get ready to go all-in. It may be just a few seconds, or it could be over a minute. Get ready to grit your teeth and use whatever power(-up) you have left and empty the tank all the way to the line.
About the author
Zach Nehr is a Level 3 USA Cycling coach, a Cat 1 cyclist and a graduate from Marian University where he received a Bachelor’s Degree in Exercise Science and Psychology. He is currently undertaking a Masters degree in Physiology.