Ergomo Pro and sprinting power

Dave K said:

I understand that the older Ergomo Sport had an issue where each data record was really a 5-second rolling average, but wasn't the Ergomo Pro designed to make this configurable? I have my Ergomo Pro set to record data every second and the display refresh is set to one second. It seems that when the data is recorded each second, that record is still a rolling five seconds worth of data. Thus, when I do a sprint, my max recorded power seems to actually be my best five-second power. Here's an example of what I would typically see in Ergoracer (I'm not near the computer that has Ergoracer installed, so these are ficitious numbers) if I started the sprint at 00:30:00:

Time Watts Speed
00:30:00 150 12
00:30:01 180 15.5
00:30:02 350 19
00:30:03 650 22
00:30:04 920 25
00:30:05 1150 27
00:30:06 1200 29

There seems to be no way I could possibly be accelerating that much 2 or 3 seconds into the sprint if I was only putting out 350 watts. Does anyone else with an Ergomo Pro see this behavior? Is there any way to correct it? This behavior makes it difficult to do a true power profile unless I simply interpret my max recorded power for 1s as my best true 5s power.

I do not have an ergomo pro but I do plenty of sprint training. With that said, let me tell you that I routinely go from 0 watts to over 1500 in 3.5 seconds. So my comment on your experience is that it is most definitely possible to go from 350 watts to well over 1000 in 2-3 seconds.

Good luck with your ergomo and with sprint training - my favorite! 🙂

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Sprints are most definitely fun to do, even though my sprint has severely deteriorated over the last couple of years! I guess the point I was trying to make in my original post is that I believe the Ergomo is misrepresenting the true power output early in a sprint. To go from 15.5 to 19 MPH in around a second (again, fictitous numbers just to illustrate my point) takes considerably more wattage then the reported 350 watts. I would imagine that my true power output at that point in time is well in excess of 1000 watts, so my issue is with the variance between my true power output and the power that is recorded/displayed on my Ergomo. The values that show on the display for any given second are identical to the values that appear in Ergoracer after the download. Just wondering if this is "normal" Ergomo Pro behavior or not.

Ok, I see what you are saying Dave.

I have to think that the power required to go from 15.5 to 19 mph in the span of one second, could be calculated.

Perhaps taking into the account the change in work versus the change in time. Maybe someone who is more interested in such calculations can contribute.

That's definitely a 5 second average. If you weigh 75 kg+10 kg bike, I calculate the power needed to accelerate that mass is over 1100 watts to go from 15.5 mph (6.8m/s) to 19.5 mph (8.5 m/s) during the first second. That number doesn't include drag from air or rolling resistance.

That sounds pretty good to me, if your sprint has deteriorated than you must have been a good sprinter before.

Does this complete discussion mean that the ergomo puts out inaccurate watts for accelerations?

I'm really keeping track of all the ergomo threads cuz I'm thinking of getting one instead of using the Polar Power Meter which I have on 4 bikes already.

JTE83 said:

Does this complete discussion mean that the ergomo puts out inaccurate watts for accelerations?

I'm really keeping track of all the ergomo threads cuz I'm thinking of getting one instead of using the Polar Power Meter which I have on 4 bikes already.

Doesn't the polar average over 5 seconds as well? For sprinters I think SRM or PT is best option. Ergomo is only measuring one leg, not sure how it handles standing starts and negative torque.

My polars gives watts every second or so during a ride, but the smallest recording interval is 5 seconds. Good thing about the Polar is the left / right pedaling balance info, and the multiple workout files.

I heard that the ergomo has a complex formula for estimating the power of the right leg and it's not just doubling the power of the left leg.

Well, from all the complaint threads about the Powertap and how they often have to send it for servicing it's either the ergomo or Polar for me. SRM is too expensive and I've only raced twice.

Can't wait to put a power meter on my 6th road bike, a CF Soloist!

The Ergomo Pro has a lot of positives. The display is great. They obviously put a lot of thought into it. It shows you all of the information you need to see at any one particular time (ex, interval mode shows current power, average power, RPM, heart rate and interval time), it calculates NP, TSS and IF on the fly, has a backlight, etc. The altitude feature is a lot handier than I would have thought. It's very easy to use, comes with Ergoracer software (which is basically CyclingPeaks). Also, Ergomo has the ability to tweak the behavior of the unit through firmware patches/upgrades. It's possible that they could one day release an update that corrects this very issue of all data being recorded as a five-second rolling average.

With all of that being said, I think I will be selling my Ergomo Pro. Its one weakness, for me at least, is a big one - showing and recording true power output. Even aside from this sprinting issue, there's just too much variation in the power readings from one day to the next. I'm not sure if I favor one leg over the other differently from one ride to the next, or if there's a flaw in the particular bottom bracket I have (which is being serviced right now), or what it is, but if I put it up against a Powertap or Computrainer multiple days in a row, I will get different results. I've re-installed it a couple of times, but to no avail. Since there is no true way to calibrate the Ergomo (I don't consider running the offset procedure "calibrating"😉, there's is no way to determine if its power output is correct from day to day. Maybe the newly-serviced BB will improve things, but up to this point, I've been rather disappointed. I never know if 300 Ergomo watts is really 290, 300, or 320. Kinda defeats the whole purpose of training with power!

JTE83 said:

I heard that the ergomo has a complex formula for estimating the power of the right leg and it's not just doubling the power of the left leg.

No, it just doubles your left leg power. You can prove this to yourself by pedaling a trainer at a constant speed, first using both legs and then using just your left leg. If you really keep the speed constant (and the trainer and tire are at a stable temperature), the reading of the Ergomo won't change.

Alex Simmons said:

Doesn't the polar average over 5 seconds as well? For sprinters I think SRM or PT is best option. Ergomo is only measuring one leg, not sure how it handles standing starts and negative torque.

I see no reason that the ergomo should have any problem handling negative torque just because it only measures power from one leg (assuming that you pull up equally hard with each leg!)

GettingFaster said:

I see no reason that the ergomo should have any problem handling negative torque just because it only measures power from one leg (assuming that you pull up equally hard with each leg!)

My question on negative torque is unrelated to the measurement from one leg issue. I simply don't know how it handles negative torque (which you don't get on a free wheel but will get a lot of on a fixed gear). e.g. on a PT - you need to change the CPU set up for that specifically.