When I was brand new to Zwift and started experimenting with the workouts, I noticed a little setting that was checked called ERG Mode. I left it on not really knowing what it was. If you are like I once was, this post will attempt to explain.
ERG mode effectively turns your bike attached to a smart trainer into an exercise machine you would use in a gym. No changing your gears. No worrying about the terrain in the game. You just pedal and Zwift will have your trainer force you to output the required power target during the workout and, this is key, no matter how fast or slow you pedal or what gear your bike is in.
This is where I screwed up in the past and I’ve seen friends new to Zwift doing the same. During my workouts, I would shift gears and/or pedal faster or slower (adjust cadence) depending on the power target. I’d be struggling to keep consistent. It was a mess. Essentially, I was in a tug-of-war with Zwift and frankly mislead by the on-screen prompts. (With ERG mode on, the game should be prompting people to pedal at a certain cadence, but that’s a discussion for another day.) Once I understood what ERG mode does, I stopped trying to meet the power target and focused solely on keeping my cadence as smooth as possible.
Take a look at the time line below from a Sweet Spot Training session. The SST target is to work at near your Functional Threshold Power. You can see my power output in black and my cadence in blue on the graph. Notice the relatively steady cadence around 90 rpm and yet my power changes for each interval. That’s because Zwift was adjusting my trainer’s resistance to match my cadence and set my power output to the target.
This is why ERG mode is so cool. You get exactly the workout you expect from Zwift. You’re not shifting gears or trying to find the right cadence at a specific gear to get to the power target. You focus simply on managing your cadence and getting through the suffering! 🤣 Maximum efficiency workout for your precious time!