This is cool, we will play with it. We might do something more like this in the future.
So I am going to do something slighly non-traditional with regards to this. When uploading a GPX or TCX file, it will convert the power in the file to an ERG workout and also import the slopes. You will be able to ride this as an ERG or slope mode workout or hybrid of both but in this case if someone makes their workout public you will be riding the ERG like that person rode it, which is likely not the way you would ride it.
Now if you upload your own ride you can repeat it indoors. So that means 2 of the same routes can have two different sets of power targets. Now when riding in slope mode you will see the power targets but you can decide if you want to try to hit them or not. So this interesting from my perspective. A bit similar to Craigs nordic track in that he was not hitting the numbers exactly. It’s not ERG power it’s “ERG slope”
The second option is when you upload a route with no power data in it. In this case we will convert the slopes to standaridzed percent of FTP% which I took using some figures from my pro coach friend using average uphill speeds for both slow riders and fast ones (even pros). This is approximately what it will look like but we will probably use a flat line forumula. If you have a 20% grade it’s going to put that at 150% of your FTP, which a lot of people on a sustained 20% grade might start to walk. I realize the fastest riders (w/kg) it would not be 150% of FTP but there is no standardized way of converting slope to power and this seems reasonable for many riders on trainerday. If a rider wants to adjust this they can always push + -. @HighSpeed I would love to hear your thoughts on this. I reviewed your Nordic track conversion and although this seems different it seems inline with that.
Now finally you can create your own workouts manually with our editor and put both power and slope targets and completely design workouts exactly the way you want them with the power curves you want.
You made many great points Alex. Here are some comments:
… if you upload your own ride you can repeat it indoors.
This statement helps me understand your point of view much better.
My use cases for structured training don’t include simulating outdoor rides. Let me try to explain. In Erg mode, I enter target watts either by FTP percentage or directly in watts because that is the amount of work I want to do based on my training plan. The numbers are entered as line items in the workout sheet. There is no simulation software used here. We ask the bike to give us X erg watts and that’s what we get. If we want to compare riders, we apply watts/kg to the results.
When I do a resistance workout I still want to specify power targets. I would prefer to specify watts at 80 rpm. This gives me a predictable X watts @ 80 rpm, 1.2X watts @ 100 rpm and 0.8X watts @ 60 rpm. It is also easy to apply %FTP conversions. We record the results to measure the amount of work performed in watts/second, and all is good. We apply watts/kg to compare riders like usual. This is a good description of how the NordicTrack implements their resistance mode. You will also notice, everything centers around Watts. That’s what we ask for and that’s what we measure.
Slope mode is different. It’s a simulation function. The actual number of watts / second is determined by the bike vendor’s software. Specifying Slope is OK for resistance workouts. It is just not very predictable. Slope is weight based so we cannot use watts/kg to compare riders. This seems odd to me. Instead we will measure the watts / second that the bike produces, for each rider. We will never actually know what that number will be ahead of time because each bike vendor will produce different results for each rider, based its simulation software and hardware.
Summary: While I can get Slope to work with structured training, I would rather ask for a certain amount resistance (watts @ 80 rpm) based on my training plan and then get just it.
@Alex: You described the calculations you will need to import GPX/TCX files. I can see why slope is important here. If you want to simulate a real word ride, then you need slope to make the simulation feel right. I have always consider that to be a Zwift use case because it is a simulation game. I didn’t know this is a structured workout use case. Is replaying GPX/TCX files really something you want TrainerDay to do?
Thanks again for the detailed response. Yes I realize your goal is different and for example this
Is technically not possible. Meaning this is not how any trainers work. We could reverse engineer something but it would be very complex and may in the end not work how you like it. As I mentioned above for your trainer we can only specify watts in ERG mode or we can specify slope. That’s essentially how all smart trainers work although some support resistance also but not yours.
So again as I mentioned if you leave all these items the same in TrainerDay
You will get consistent pedal torque. Just pretend we don’t have a weight adjustment and you get what you want but you just can’t specify watts @ rpm, especially because this would be trainer specific as it would also need to factor in gear ratio which for each bike can be different and many people don’t want to try to figure out. There is really no way for us to do that. I do believe specifying slope will give you what you want or as close as we can get that is more universal for all users.
Again thanks for more clarification. It does help.
I was afraid of that. I have been careful to avoid saying that slope mode is bad. For me, a slope specification in my workout is simply inconvenient. There are simple workarounds, like you mention above, to convert slope requests into usable power metrics. Therefore, Slope specification is fine. If bike vendors don’t offer the APIs needed to build complete structured workouts, I am not surprised. It is fair to say that 90% of smart bike and smart trainer sales are targeted at Zwift users. Slope mode can be offered as proof. I’ll never be fully aligned with this since I have absolutely zero interest in Zwift. I am perfectly aware that makes me the outlier .
Let’s take a step back and consider “When is a slope mode structured workout better than an erg mode workout?” I can summarize in one word: Acceleration. Any riding - and especially racing - involves countless accelerations. Hills, sprints and breakaways all require somewhat intense accelerations. Riders with power meters on their road bikes know what these look like:
Massive increase in power. Even old guys like me go from 200 watts to 800 watts in a sprint.
Insane rate of change. Watch the track racers in the Olympics. These riders go from 0 to 2kw in half a pedal stroke.
When I move indoors, I want to train for acceleration. I will never do a 2 hour ride indoors, so LSD training will have to wait for me to get back outdoors. Short, hard efforts with rapid transitions is the training plan I want. They now call it HIIT. We called it “weekly team sprints” in the 1980s. It remains the best training tool I have ever used - even now 40 years later.
Erg mode is really “anti-acceleration” mode. Every attempt to accelerate is met with a corresponding decrease in resistance. You can only imagine how ex-sprinters like me curse erg mode. Just when the workout is getting interesting, the bike turns to mush.
I will use slope mode in preference to erg mode almost exclusively. I will keep rider weight and FTP constant so I can have maximum control over workouts. I already do this with FTP in erg mode. I never change FTP. Why? I don’t want rest interval power to change when I increase the peak intervals. Also, I like to vary the length of the recovery intervals based on fitness and load factors. This means I hand edit training plans almost everyday. I will likely do the same with slope training. I can’t wait to get started.
Yep, I like your statement ERG is anti-acceleration. Nice way to put it. Yes resistance mode is closer to what you want 1-100% of the trainers maximum resistance although most trainers support this most indoor bikes do not.
Yes I am excited to try this as well and fully agree long rides are better done outside. Thanks for the discussion you did inspire me here.
Fellow outlier. And fellow SB20. And fellow oldie.
Would love to see this ability to upload GPX/TCX from an outdoor ride and convert it to indoors. I’m really missing my local rides lately.
Jim ERG version is working now. See this post
Hi Craig, now you can use slope mode on your bike (assuming ble for SB20 is the same as our devices). It is available on iOS now and Android production version later today. It is in beta already for a few days.
See this post. Automated slope mode is working. I have tested it so it will be available soon as well
Awesome work Alex. I will enthusiastically start testing over the next couple of weeks
I am working on a new Medium article comparing different structured workout methods. Hopefully it be marginally useful after doing them for nearly 40 years. I show all examples in TrainerDay. With slope mode, it is now the most complete app available for building personalized structured training plans when you “know what you’re doing”. Let’s help more people to “know what they’re doing”
Cool, can’t wait to see the article. I agree, that is my goal is to people farther down with path of self-coaching or at the minimum helping them make better, more efficient and healthier choices. I also can thank you, I had thought of this idea, another customer talked about slope mode to re-create an outdoor and for a long time and wanted to do it but you were the one that got it prioritzed.
Here is a new article I was reading about 4-second HIIT intervals.
I was thinking this might be perfect for this slope mode but I want to try it. I have yet to really test out this automated slope mode training as I have been trying to recover from some longer lasting sickness, which is almost gone.
It is good to see this type of training get more notoriety. It is not new. Track riders - with their very tall fixed gears (60x11) ride this way every time they start: Four to eight pedal revolutions to achieve cruising speed at around 5 kilowatts! While few of us can generate this amount of short-term power, the training methods work for almost everyone.
In my competitive days (in the late 1970’s!), we had the perfect training tool: traffic lights The technique is hardly revolutionary. When the light turns green, you use your tallest road gear (53x11 back in the day) and get to maximum speed from a standing start (using a track stand of course) by the end of intersection. The more stop lights the better.
Here is the challenge for smart bikes and trainers: replicating not just resistance but acceleration in very short intervals. This means we need to increase resistance as the rider increases pedalling speed. It will be interesting to see if smart bikes or trainers can react fast enough and resist with enough force. The Car.ol bike claims to do it. Looking at the bike, it has a standard eddy current brake based on moving servo magnets (like the Peloton) instead of the faster responding and stronger electromagnet eddy current brakes used in the Kickr, Tacx and Stages smart bikes. The Carol Bike marketing is encouraging. Their hardware can’t actually deliver the goods since moving magnet brakes can only respond in seconds and not the milliseconds needed to replicate acceleration.
You are on top of things. I don’t know anyone else that has heard of a car.ol Interesting info on how the magnet brakes work. Do you know how the smart trainers work vs the bikes? This idea of increasing resistance as RPM increases is interesting. I can’t exactly imagine what that would feel like.
Yes I also do low rpm work (35-45 rpm) SFR (Salite-Forza-Resistenza) which is also been around a long time but rarely do “normal people” train this way but I am an experimenter more than a real athelete. I have never tried any accelleration or peak work inside. It seems to feel wrong. Probably better on your bike. I want to try these 4s intervals. My peak power was about 1300 watts last summer but it seemed like it was prematurely stretching chains (likely my imagination) so I backed off from doing that. Especially if you are saying these track guys can do 5k. I know the pros frequently do 2k+ but I was questioning why my chains were stretching after a year…
As I said I am mostly an experimentor. One of my great friends is a 30-year world tour coach and scientist so he and I are always exchanging ideas (mostly him providing me ideas…) so I was trying blood flow restriction. He and I have similar goals which is least amount of work, most amount of benefit and just learning/testing ideas in general…
Hey Alex. I tried Slope mode today. I couldn’t get it to behave any different than erg mode.
Settings for my Stages SB20
Power Match: off
Sim/Slope Mode: on
Everything else: off
I connect to the Stages SB20 head unit for bike control and the left Stages crank for power and cadence.
Here is the test workout I created.
When I run it, resistance for the slope intervals behaves like erg mode: the faster I pedal, the lower the resistance (watts) becomes. For slope intervals I expect watts to increase as I pedal faster - just like when climbing a hill. I specified 10% slope and pedalled at 120 rpm. I should have felt more resistance than at 80 rpm. I didn’t.
FWIW: I should be able to omit the slope value altogether. Trainer Day should be able to calculate slope based on the Watts and Cadence values provided. That’s a much easier way to create these types of workouts.
Hi there Craig. Actually we have not deployed automated slope mode to production yet. It is working but there are a few bugs. So creating a workout like that won’t work. What we do have is we have slope mode so you can manually switch to slope mode, by turning ERG off while riding
And then you can control slope at the bottom
If you install the beta version of our app, it does have this auto-slope mode but is not 100% stable yet. I hoped we would release it today to production but it looks like it might be a few more days.
Looks good. I will try manual slope. Thanks.
Ok new release finally got launched today with automated ERG. I am adding another post with an example workout I created using this. I have not had enough time lately to fully expore how to use it. We are finishing building a new house at the end of the month so hopefully life will get simpler soon.
Good luck with your house. Great work by everyone.
Excited to try this out soon . Going through a bit of sickness in my home but will have to take a try asap. Best of luck on the new home @Alex
Hi Jeremy is your oldest in kindergarten yet? We had 2-years of non-stop household sickness and still it’s pretty frequent. I hope you all recover quickly and thanks.