Leg fatigue after 180km Swift ride

I recently did a self supported full distance triathlon using Swift for the bike portion (180km). I did the ride at the same wattage and speed that I would outdoors. I have ridden and ran this distance multiple times before, however, this was my first time doing the bike portion on Swift. My legs were significantly more fatigued than after riding this distance outdoors and my marathon time was a full hour slower than what I would normally run. Has anyone else had the same experience? If so, why? Or am I just getting old and slow? Thanks!

I expect the issue is simply down to the physics of working on the trainer.
Outside you gain inertia and the effort required to maintain that intertia, despite you putting out the same power, is different.

On the trainer you are constantly fighting a fly wheel that want to stop, so you really have to stay on top of that power.

Outside you will also get some micro rests (cornering, over crests of hills, short descents etc) and these added up over time will reduce the overall workload.

I’m sure someone will weigh in and discount my theory though…


… not me - fully agree. If you compare a Zwift ride and a similar real world one, the real one will have a lot more variability in the power and cadence from moment to moment.

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Nope, I agree :slight_smile:

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Thanks! I feel better already. I will disregard any comments that contradict you. :grimacing:

Above is true, but some additional things:

  • Cooling
  • mental distractions
  • descents - only 50% replicated gradient so far less opportunity to freewheel, if you do at all
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