graph showing power produced during a cycling workout on a smart trainer outside or ERG mode

What is ERG mode?

Smart trainers include a feature called “ERG mode”. When turned on, ERG controls the load on the trainer to match a prescribed intensity (power target) during a workout. In other words, no matter what cadence you use or how hard you turn the pedals, the trainer adjusts the load so that your output in watts is exactly the number prescribed on your intervals/workout. All you have to do is pedal. No shifting, no change in cadence.

Why some cyclists prefer to train in ERG mode

Some cyclists believe that hitting power targets is the most important part of a workout (specially if their workouts ignore the importance of cadence changes, transitions, etc.), so they use ERG mode as a way to force them to hit the watts. Other riders don’t want to have to do any “thinking” or shifting during workouts. And many never even thought about the topic, or bought a smart trainer and assumed that ERG mode is simply how all workouts are done.

Reasons for not using ERG

For all the athletes I coach, and for my own training, I never use ERG mode. Here’s why.

Control and muscle activation

Training to control your efforts with your own legs, instead of having the trainer do it for you, is a valuable skill in cycling. Without ERG, you have to work to maintain the power within the target power zones by engaging more muscles in your legs, and by learning to apply and develop torque to be in control.

Control is also important to avoid big power spikes as you transition to a higher power zone, and to avoid power dips as you transition to lower power zones. Learning to hold the tension on the chain with your muscles to control the power as you do these transitions will help you do it on your own when you are not on the trainer, be in at a race, event, or outdoor ride.

Why is it important to avoid these spikes and dips? Because both translate in unnecessary waste of energy. You might think this is small, but in the course of a ride/event/race, it adds all up. By a lot.


Not using ERG makes you aware of how you generate power in the workouts. You practice shifting, changes in cadence, transitions, and body position, all of which are fundamental to performance and speed.

Our workouts incorporate many important skills that translate into more efficient riding (i.e., more power transfer to the pedals), including changes in cadence (low, medium, high) and power, fast and quick changes requiring a fast reaction, etc. ERG would make these very difficult or even impossible to accomplish because of how ERG works.

Lastly, being fast in cycling is not simply about the power you produce. It is about the technique required to produce it. Cycling is a sport, and if you think about any other sport out there, there is always a lot of work on technique (e.g., how to kick, how to throw, etc.) Cycling is no different, so why use an artificial environment that impedes the development of these techniques?

But isn’t ERG mode the reason for buying a smart trainer?

No. Smart trainers are not useless if you do not use ERG. They exist to simulate the changes in terrain when riding a virtual course. These changes are very valuable for when you ride outside and deal with “real” terrain.

If you do workouts in Zwift, for example, and use “workout mode”, all roads will be “flat”. That’s unfortunate, but it is still better than using ERG, because you are still in control of your efforts. I have a Tacx Neo and do all my workouts outside of “workout mode” and outside of ERG, just like I do them outdoors, using the changes in terrain to control the efforts and cadence, while changing body positions (seated vs. standing, etc.)

Give it a try and see the positive changes!

Hope this sheds some light as to why I recommend not using ERG. If you haven’t tried doing workouts outside of ERG, give it a try! Stay with it and be patient as you learn to be in control of your efforts and you will notice the difference in your performance. As our athletes can attest, it is worth it and it has real results!


  1. Thanks for the help article Theia, I find ERG mode also a bit mindless when in a workout. I prefer to shift when I feel it’s needed and I have no problems matching the prescribed wattage. ERG mode seems like a ruthless coach at times, applying more pressure because I allowed my cadence to drop. That added pressure, especially if I’m not feeling my best, only makes matters worse and instead of letting me spin a smaller gear I feel like I am now climbing Alpe D’Huez. I am 60 and have been riding for over 34 years and I know best what I need when training not the computer. Thanks again for the article, now I don’t feel like it’s just me!

  2. Theia, Great article. I’ve just noticed my lack of skills after getting my first power meter that’s not associated with my smart trainer. I’m new to structured training and have only done workouts inside of zwift using erg. After installing my pedal based power meter I actually thought it was broken due to inconsistent power. I just haven’t allowed my self to develop the skills you mentioned due to only using erg. I’ll definitely be giving your suggestions a try.


    • Hi Nick, thank you for your comment. Yes, please give it a try. It will be a little frustrating at the beginning, but just like developing any new skill, you will get better by practicing, and I am confident you will see improvements.

  3. Hi Theia, this is really useful and helpful.
    I’ve been undertaking indoor structured training for a number of years always using ERG mode to dictate efforts. I’d been seeing good numbers and was generally happy with progress, however after starting to race more on Zwift I’ve been finding that even maintaining a ‘consistent’ power at say 340w during a race or time trial is far harder than the same length effort at 340w in ERG mode. Would you suggest this is a consequence of the reasons you list above? even trying to balance my power output during a time-trial leaves me absolutely cooked but I can hit the same watts/interval length in ERG with relative ease! I’m fairly experienced at racing and time trialling in the ‘real’ world so don’t think my overall measure of my pacing is completely off but where you talk about ‘spikes’ and ‘dips’ that all add up I suspect this could be a contributing factor?

    Thanks, Luke

    • Hey Luke, this is Drew (the other half). I’m sure she will respond this AM. Power control is such an important “skill” in cycling. It’s something you need to train, think about, and practice always. It’s possible that lots of ERG training could make the same effort feel harder in a race on Zwift due to the variability. In Today’s Plan we can measure standard deviation of an effort. You could test this theory by looking at the Std Dev. In ERG your Std. Dev. for 340 must be very low. Sub 10%. Without ERG on an undulating course sub 10% is hard to do but very possible with training. So you could compare two efforts with and without ERG at the same average power and compare Std. Dev. If the higher Std Dev. at 340 feels harder then the theory could accurate. I suspect Normalized Power could get you similar results. Either way, I highly recommend that you control the power yourself. It will not only make you a better cyclist, it will force you to change gears, stand, sit, and use your brain more. You will engage more when riding inside, making the workouts more enjoyable. Killing ERG was a game changer for me.

  4. Not sure about this article.

    Firstly ERG is not an acronym for ergonomic, ergonomic means something else entirely.

    Secondly, the statement that fast cycling is not all about power. I am not claiming to be a coach, but fast cycling is ALL about power.

    • Thanks for pointing that out. I just corrected it. In the “real” world (outside of Zwift) many factors affect speed. Power, cadence, body position, wind, positioning, etc… all impact speed. A rider putting out 300w in an aero position can generate more speed than a rider putting out more power while riding in the hoods. So a huge “watt club” does not always generate more speed. But using a watt club correctly with the right body position, cadence, and accelerations at the right spot can be very effective in generating speed.


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