Concept2 Forum

That would be an upgrade I'm interested in.

crbrownlee wrote:That would be an upgrade I'm interested in.

Since it stores both the times and the Cal/hour, there is no point to showing the total, since the calculation is trivial.

Bob S.

Bob S. wrote:

crbrownlee wrote:That would be an upgrade I'm interested in.

Since it stores both the times and the Cal/hour, there is no point to showing the total, since the calculation is trivial.

Also the calories are calculated from watts with such an odd approximation there's little point in even recording them as (K)Cal/hr.

Displaying total calories would be useful to many of the people who use a C2 in their local gym. Most of these people care about calories burned. (I look at the display settings left by the previous user) There is no way most people could look at 680 cal/hr and 17:38.2 and do the arithmetic for total calories in their heads. C2 uses the calories as another view of watts rather than a cumulative number like time or distance. I think displaying total calories would be welcomed by most casual users.

Please excuse this newbie question, but does anyone from C2 ever reply to these feature requests and decides whether they get implemented or not? I'm no programmer, but it seems like a rather trivial task to add this to the firmware. There are companies that are grateful for user requests and implement them in a matter of days and weeks, because they ultimately make for a better product. So I'm just wondering, what the procedure is like with C2 and what might be possible hold-ups.

You may do better by sending an email to rowing@concept2.com

Some of the C2 engineering folks follow the forum, but only intermittently. I'd also guess they're busy right now preparing for the British Indoor Rowing Champs next weekend (some of the C2 USA folks normally turn up in Birmingham).

For casual users, I think it's actually a bad idea to show total calories (at least from a usage/marketing perspective). Most gym members are used to using a bike or elliptical machine for 30 minutes and seeing wildly inflated calories-burned (i.e. my wife regularly comes home saying she burned 800 calories in half an hour). On a rower, a casual gym user probably cannot row as long, or does so at such a slow pace that the # of calories burned just isn't comparable (and may result in frustration with the rower).

To use my wife as an example again, she tried rowing tonight and came upstairs all disappointed - "I rowed as hard as I could for 20 minutes and only burned 200 calories!" Now she'll probably only use the rower if she has no other option. If the rower had incorrectly informed her that she burned 600 calories (as the elliptical would have for the same period of time), she'd probably would use it every day.

Another issue regarding calories burned is an individuals efficiency. Net watts produced can result from a human eff. anywhere from high teens to as much as 25% of the internal power. Total calories burned is not a realistic number that can be given by the Performance Monitor. Power produced can be accurate. Calories burned relates to internal energy as a function of eff. while split times and watts on the PM relate to net power generated. Just another complicating point of interest.

Any idea on how big the margin of error might be? Is it +/-5%, +/-10%, +/-20% or more?

The simple view of the formula is 300 Cal + real calories at the wheel. The 300 Cal is the estimation of how many calories it takes an average person to push themselves back and forth with no effort put into spinning the fan. It does not take into account body weight, so it would underestimate for a heavy person and overestimate for a light weight person.

MarkusC2forum wrote:Any idea on how big the margin of error might be? Is it +/-5%, +/-10%, +/-20% or more?

Short of a lab testing, the best estimate that I can come up with is using my Suunto (or Polar) R-R type Heart Rate recording and get my Firstbeat Athlete (FBA) calibrated to the Suunto Running Guide page 47 chart. If I get this right producing the correct EPOC for my heart rate over a set time, then I think the estimate from FBA probably will be typically within 10% (Page 45) but the guide gives an example in the footnotes of that table of an average size man exercising for 45 minutes with an estimated error less than 5% on energy consumption which is good enough for me.

The Suunto Running guide can be Googled and useful for anyone in any sport. I highly recommend this pdf for anyone. I think Eddie Fletcher was one of the primary authors of the guide. He can be Googled as well for his articles on indoor rowing on his website. These articles are very informative and sport specific as well.

I also highly recommend a book called: The Heart Disease Breakthrough by Thomas Yannios, M.D. and especially chapter 14 which is the most dense set of pages on exercise and its impact on the body I have ever read. This one chapter has more info than any other book I have ever seen on this subject. I bet I have read this chapter at least a dozen times still gleaning more understanding from it every time I read it.