Sitting up on trainer outputs tons more wattage?

I have been really getting into Zwift but I have been noticing that I can typically pump out 150w or more above my “hard” efforts by sitting straight up in the saddle without holding my handlebars (without standing or doing anything crazy). When I lean down and cycle in a typical cycling position I cant get myself to output anywhere near that wattage consistently. Is this just a typical thing on trainers that I am only noticing because I am zwifting so much?

I’ve noticed similar things, although I’d say the increased power output effect is short-lived when shifting positions.
If you are able to consistently put out far more power from the sitting-up position than when sitting forward in the drops or on the hoods, my first thought is that you could benefit from modifying your position on the bike, probably through a bike fit.
So, no, it’s very probably not so much trainer-related as position-on-the-bike-related.

i can’t say that I have ever had this experience. Can you tell us more about your trainer setup? If issuing a wheel-on trainer, I am wondering if sitting up, and therefore putting more weight onto your rear wheel, might be keeping the tire from slipping on the roller. If a direct-drive trainer I have no idea.

It’s a wheel-on wahoo kickr! It’s probably a a fit issue, sitting up in that position is just not something I have been able to do or try in my many years of outdoor cycling.

It sounds to me that you are engaging your glutes when sitting upright but your bike fit is wrong and unable to let you engage your glutes in a normal position

I highly recommend a professional bike fit. Not from a guy with a tape measure and plumb bob in a bike shop, but something like the Retul system or one of the other types that professionals will use. Some people think that they can’t justify the cost of this but will happily justify bike upgrades that cost way more and have way less benefit.

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sounds a bit WTF to me :smiley:

You would notice the same on a real bike. But only for a short time, because with your full body weight above your feet you can press more power at a lower cadence.

Hey, @All-weather-danny, I thought I’d come back to your thread in more detail after having posted quickly late last night.

As Tante_Lotte alludes to, it’s probably thanks to the power reading in Zwift and our otherwise static position on the trainer that we can observe this phenomenon so easily.

I’m an inveterate tinkerer with my position on the bike. When I first got back into cycling through Zwift about three years ago after a decade or more off, I didn’t go in for a professional bike fit, but decided to DIY it on the trainer, benefiting from having the tools and the time.
Over these years, I’ve changed my position quite radically as my cycling ability has progressed and my core body strength has increased. When I first started experimenting with stem length/height and saddle position, I gravitated to an undemanding position with a shorter stem and the saddle quite forward. (A professional bike fitter would probably have steered me away from that immediately, but hey – no one got hurt.) This position was easier to hold for long periods, but, I found, also limited the power I was able to put out when on the hoods or in the drops. Like you, I noticed that when sitting up I was able to put out a lot more power. In addition, I found it particularly uncomfortable to transition from sitting up to the drops, feeling little control during the move. Like Tante_Lotte described above, there would be a brief but considerable peak in the power as I shifted position.

As my core strength has increased (and my weight has dropped) I have found that I’m now more comfortable putting my saddle much further back and having a longer stem. This stabilises my position on the bike overall, allowing me to go from the drops to sitting up and back again without huge spikes in power to the pedals, and feeling much more in control, while developing more power.
After a while, I realised that I should use the technology available and I started filming my self on the trainer side-on using my phone, while experimenting with position. Quite an eye-opener! That helped even more and I then went down the rabbit hole of changing crank length, experimenting with cleat positioning, etc. It’s lots of fun for me, but most people would probably prefer to get an experienced fitter’s opinion: far quicker, though likely even more expensive.

Everyone is at a different point in their cycling life. Perhaps you’re a far more experienced cyclist with a great position already and your issue comes from something else. However, examining bike fit and perhaps having someone else observe yours could provide a shortcut to a better overall riding experience for you, on and off the trainer.