It avoids the issues of having an exact power target for efforts than can vary quite a bit.
You basically have to assume that it’s going to be correct every time vs adjusting throughout the workout to target maximizing time at vo2 max vs time at a specific power target.
100% ERG mode for me. I like being pushed along and having to “keep up” with the preset wattage. With a little practice you get used to timing your spin up for huge jumps in watts for those sprint bursts in some workouts. Tricky at first but you’ll get the hang of it.
At this point I have pretty much completely surrendered my training to TR and the watts I’m putting out seem to be climbing steadily. ERG mode is an extension of that for me. Once the workout starts I’m damn well doing these watts whether I want to or not. I get to pick the cadence but not the wattage. I have always perform better when I have no option but everyone is different and you should definitely do whatever works for you.
Yeah. Lots of anti-ergites. For trainer workouts, I’m all ERG, which I was first introduced to on Computrainers back around 2010. I love that it’s a merciless taskmaster. I can’t ease up even a little on hard intervals, which is too easy to do resistance mode. Anyway, I get plenty of non-erg riding outdoors, which I do far more of then riding the trainer.
Having used TR for a few months I use ERG all the time now. Initially I struggled with VO2 efforts but seem to have trained myself to manage it, plus got a little fitter in that zone
Another long-time ERG user for all my indoor interval workouts. What I don’t use it for though are endurance rides - for these, I much prefer just free-riding in Zwift and having to manually keep the power in check makes it more mentally engaging.
ERG, forever. Since 2018.
plus YT, Netflix or Disney.
I tend to keep all my workouts in ERG mode. Occasionally I’ll do endurance workouts in resistance mode but that’s rare. I prefer to just lock in and not think about the power.
Sometimes if I’m really struggling with a later threshold interval or VO2 I’ll put it in resistance just to complete the workout.
I feel like I have no issue pacing efforts out in the real world. My body knows what each zone feels like and can get that same power out. I think this is often an area people over inflate the issue with ERG and think it’s a major non factor.
I started training under a coach in 2016, way before I joined TR and he advised against ERG, when I upgraded from an Elite Muin to a Smart trainer (Elite Suito) so Ive kinda got in the habit of resistance mode. Since I left him, I’ve had brief flurries with ERG but I don’t like how the Suito handles it (ERG is probably better with other trainers). When I was running a single sided power meter it seemed to be a constant drag (pulling me into the spiral of death eventually) perhaps the power drop outs and it would often hang up at a high power target when it should be a recovery target. (Ive tried ant + on an extension cable and bluetooth its made no difference). With a double sided power meter (Assimoa Pro RS-2) it seems to less of a drag (power drop outs still occur but I think the other side kicks in faster) but now things seems to bottom out just below the target when I have a little more in the tank. The power hang ups still occur though.
My experience is from a Kickr and if you take advantage of the flywheel 150w to 500w instantly is no problem even in ERG-mode depending on how “instantly” you want it to be. I have no problem accelerating from 100w to 600-700w in 2-3 seconds. Start in a low cadence and just explode. When the rpm’s get high enough just shift up to a harder gear and keep at it. I understand your point if you just wait for the trainer so adjust the power, but why not work around it’s limitations?
I’m guilty of not bailing soon enough sometimes. The Suito just seems particularly bad for hang up beyond an interval, power drop outs etc, perhaps you have a higher end Elite trainer and its more on the ball.
I also use ERG for all my workouts on a Kickr Core. For me the question is for which I use the TR app and which I do in Zwift. General rule for me: Shorter than 2 minute intervals → TR; 2 min. and above: Zwift.
Reason being the slower adjustments on Zwift. Made a comparison back in the day:
The difference is probably not significant for your training effect, but it’s for my peace of mind 
Before I had a PM, my vo2 max target was based on HR and feel. I would get my HR about 10-12 beats below TH, hit the timer, increase effort and try to get above TH in 30 sec or so. Then stay above TH for the duration.
On the smart trainer the first vo2 interval doesn’t feel quite as hard as that, but they eventually do. The interval starts when I’m still in Z1 or Z2, so I get some amount of time before the o2 deficit catches up to me.
So the erg gives precisely increasing watts and duration progression, and just feeling the intervals puts the focus on the physiological response?
I’m all erg since starting TR. Don’t know if one is better than the other across the board.
Confirmed tonight during my SS workout why I dont like the Suito’s management of ERG. At a high cadence for me (90-95rpm) I would exceed the target. At still a high cadence for me (90rpm) I would track around the target but depressingly just below it. At what is a more natural cadence for me in the heat of the house (80-85rpm) I’d sit comfortably below the target and resistance never seemed to be upped by the Suito’s ERG. I’m using a double sided power meter now; when I was using a single sided power meter the Suito’s ERG seemed to up the resistance too quickly dragging me into the spiral of death. I want a half way house :-/
Reminds me of a friend’s complaint that zwift ranks her short interval workouts a failure because zwift’s own slew rate is too slow & so isn’t actually serving her up the proper intervals. I told her to come across to TR. 
I use Erg on Zwift and have no issues with a mismatch of power. Maybe it is an issue with some combo of turbo/powermeter.
I have a Tacx Neo 2T and use P2 Pedals for power.
Recently experienced with this. Last vo2max interval was definitely better for me in “resistance mode” going all out but was still able to complete the workout. Much harder and much more power instead of ERG.
today I did mixed intervals threshold workout. Started out in resistance mode but It’s hard for me to hit the exact target. First 2 sets was in resistance mode. I struggled much in the final 6 mins of set 2. Switched to ERG mode and it got much easier and I was able to complete it.
I use virtual shifting and it does take about 30 secs for me to change ecears and ramp up the effort and set power correctly when I’m in resistance mode, usually start out with higher power and then fall down to target. So ERG mode for me hits the correct power much faster.
I continue to practice using resistance mode. Atleast for vo2max and AC workouts. But I would like to be better at it, as it should in theory also make you better adjusted for outside and races?
but no 1 prio for me is to complete the workouts I guess. Guess it’s just practice.
100% agree with when to use the TR app vs Zwift.
I got a bit fooled on my last workout, Lion Rock -4. This one had a few 15-30 second accelerations where I wish I when with the TR app, Zwift just felt too slow for those short acceleration.
May even been the reason I didn’t get full credit for the workout. Live and learn.
I’m on a Kickr V5 using the Power data from the trainer.
Yeah, sometimes it’s a tricky decision to make. I guess also in your case it doesn’t really make a difference, but it triggers the perfectionist in me
Had an edge case workout yesterday as well, with interval durations of 2 minutes. Did it in Zwift, but adherence to the power targets was so-so:
Especially the lengthy ramp-up slighly triggers me. Overall, the last of the 4 intervals was only 2.5 % below target, but still I know it would be closer in TR. But it’s a trade-off I’m willing to take considering the better distraction and the - for me - more motivating finishing arches of the intervals compared to the blue graph.
Was this with external power source? Those wattages look really jumpy? I find ERG mode ok just using trainers powermeter. TR app is better handling ERG nomatter what though
No, it’s from a Kickr Core without power smoothing. But I guess the scale can be deceiving, as the intervals are only 2 minutes and with them being at 115 & 125 % FTP, I’d expect them to be a bit more jumpy than - for example - Sweet Spot or Threshold
