Locus pro 3.18.1 and new track statistics

sl91 shared this question 4 years ago
Answered

Hi


First of all, thank you so much for this new version. One can feel the intensive work which is behind. I have recorded today a track between home and work. The length is a little bit more than 10 kms. I have used several ant+ sensors. All of them are from Garmin. A HR SS3 sensor, a cadence sensor and a speed sensor. The data have been recorded using LocusPro 3181 installed on a samsung Galaxy S7 smatphone. I have also recorded these data on my Garmin Forerunner 230 watch connected to the same sensors. This is a big advantage of ant+ sensors compared to the Bluetooth ones. My profil is correctly entered on both sides. Here are my results. One can observe some significant differences:


1. HR max - FR230: 181 ; LocusPro 3181: 180

2. HR avg - FR230: 138 ; LocusPro 3181: 139

3. Energy - FR230: 269 Cal ; LocusPro 3181: 455 Cal (this is a huge difference)

4. Cadence (max) - FR230: 95 rpm ; LocusPro 3181: 95 rpm

5. Cadence (avg) - FR230: 68 rpm ; LocusPro 3181: 55 rpm

6. Altitude (min) - FR230: 49m ; LocusPro 3181: 46m

6. Altitude (max) - FR230: 90m ; LocusPro 3181: 90m


This is my own experience. Any comments ?


Best regards,


sl91

Comments (7)

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Hello sl91,


this is very very nice test, thanks for it. Even if Garmin values may not be 100% correct, I think we may use them as some kind of standard ... at least everyone will expect same results.


Firstly, may I ask you for export of your recorded track to GPX 1.1 format and share it with me, so I may test it directly on track, where I know expected values.


Difference in energy is interesting and together with average cadence values, these are "only" values that has big difference. In case of cadence, it is a big surprise as it looks for me like quite logical method how I compute this average value.

In case of energy: there is not a lot known methods how to compute energy based on heart rate. In the end, I found only one. Anyway I may optimize some parameters in this method and reduce computed values.

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Well, I think that Garmin has a long experience with this kind of data. Do you want the file recorded by LP3181 or that one exported from Garmin Connect and recorded from my FR 230 ? May be both ?


Best regards,


sl91

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If you may share both with me, it will be perfect. I may at least compare data from both sources if they match. Thank you.

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OK. Both files are ready. Please tell me how to transfer them in a private way.


Regards


sl91

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Use my work email jiri.mlavec@asamm.com, thank you!

If you also privately write me your personal values needed to compute energy, it will be even better so I may check exact expected value. Anyway not absolutely necessary.

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Hello,

firstly thanks for the files.


About cadence: interesting thing is, that Garmin recorded 125 points with cadence equal 0 and 22 points do not have cadence at all. Where Locus has only 48 points with 0 cadence value and no points without cadence value.


Problem here is that Locus use only two states - no cadence at all (then there is no record in exported file) or any cadence (in this case I mean any value, also a 0 which is valid cadence value). And final cadence value is then computed as sum of measured RPM values over certain time. When any point has recorded 0 value, then it dramatically reduce final average.

I do not want to discuss why are there these 0 values (probably some downhill ride), but rather what value you expect: average value over whole ride even a downhill, where there were no movement OR really average value just when you were trample with foot?


And energy: here it will be more complicated.

Anyway try for example this web page I quickly found: http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.shtml . After insert of your values, I get almost 500 kcal so even more then in Locus.


My wife is a nutritionist and she computed for me expected energy requirements for average speed cycling, based on your values you send me and values from imported files, and her software say it should be around 300 - 400 kcal.


Another case: http://keisan.casio.com/exec/system/1350958587 , here you get 250 kcal.


Anyway ... in case, you have measured HR values, Locus use these values to get more precise results. When you do not have recorded HR values, Locus use own system to compute energy values based on selected activity and speed.


I've just send you GPX file of your track, with removed all lines with HR values. Try to import it into Locus database. Then open this track and on first page select your activity. Then check value on second page in statistics ... well? :)

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Hello Menion,

you asked what value you expect: average value over whole ride even a downhill, where there were no movement or really average value just when trampling.

First of all, you need to know that I am no expert. But to me, as a non-talented but enthousiastic biker, it makes sence that the values only be measured and counted when trampling.

Why? I try to maintain a higher cadance as an indicator of "good biking". For me, this is over 90. Reason: the quicker you turn the longer you can last, the experts say. Under 80 my legs get tired much quicker.

So a high average tells me I will last longer beacause I give my energy to the right action (high instead of low cadance).

Down hill, or just behind my pal, I have the nice moments to rest - to spare energy. In those moments I do not waist my energy to the heavy duty such as a climb - which go with low cadance normally. So to me cadance zero should not disturb my high cadance average and should not be calculated!

I hope you understand my motivation. Sorry for my bad English.

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Good day Tom,

thank you for your opinion. After some thinking, I agree that zero values should not disturb average cadence as well. I've changed this in Locus and in case of sl91 track, average cadence changed from original 55 to new value 65 rpm. So it's almost same as in case of Garmin, which is fine as it indicates that they compute average cadence also only form non-zero values.


So this will be changed in next version.

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One more note: seems that Locus do not use measured HR values to compute your calories. Good information for me as well. In your case, it makes really big difference.

To be true, your HR values are quite high, so expect you will need more energy then some programs which do not use HR values, display.

From my point of view, all is correct. What you think?

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Yes, this is quite consistent. When training, my HR goes quite high compared to average people. My rest HR is about 50 and the max one is 195. This means that in my case the most reliable results are obtained with taking into account HR .


regards,


sl91

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Damn I wanted to write "seems that GARMIN do not use measured"!


Because of this, computed value is very close to values computed on web pages, that do not consider average HR - and also to values you should get with modified file I've send you!


Pages that use also average HR values has results very close to Locus - to your recorded file with Locus itself.


Higher HR for certain activity compare to others is not problem, but it means that you just need more energy on this task. And only usable method is use measured HR values or at least average HR.

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Hi,


Many thanks for all these explainations. During my tour I made two short stops, at 16':03" and 17':39" because I was following some diesel cars (this is France !) on a hilly part. I a have imported the file you sent me by email. It gives an energy value of 53 Cal. This is too low . Isn't it ?


Regards


sl91


PS: I will do the same test while hiking on next sunday

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You are welcome. For me this is also benefit as this helps to check if computed values make sense.

And "too low value" :) ... you missed this info I wrote before: open this track and on first page select your activity

Locus currently display very low value if no activity is selected (this happen only when no HR values are recorded). I have to improve this somehow

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Yes indeed ! The value is now...256 Cal


Thanks,


sl91

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Hi Menion,


I have recorded a set of data from my today's hiking tour. All the relevant values are in the table attached to this reply. The previous values (from last cycle tour) are there also. I have several remarks:


- I don't know if the speed values are deduced from the GPS log or from the Ant+ sensors on both sides (i.e. Garmin and Locus). This is absolutely not clear for me. May be this is the reason why the speed max value is so different on each side.

- It seems that locus take into account only "one foot". I assume that is why the walking cadence is almost half for LP3182

-The walking cadence is displayed with rpm units in the LP statistics page !!! this is quite strange...

-Is it possible to display the total number of step in the LP statistics page ?


Best regards


sl91

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Hello,

thank you very much for a field testing. Very interesting.

- speed in latest 3.18.2 version is always from a measured values, so it is simply difference in distance / difference in time, between current and previous point. Difference in values in both cases are quite high, but I believe you may know if you had such values or not. Mainly on bike ... did you ride almost 50 km/h in any moment?

- cadence - not sure where is a problem here. "One foot" problem is possible, but I'm not sure about it. Compute of average cadence is now little bit improved, so average value won't be probably half of Garmin value. May you please export for me your hiking trip? I'll check this as well as maximum speed.

- same with "rpm" units - you expect some "steps / min" units, but Locus has registered only a "cadence", but do not know if it is cadence on bike or steps. Do you think that value without units will be better?

- and total number of steps - to be true, I'm not sure. Hard to test without a sensor ...

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Hi Menion,


Thanks for your answer.


-I don't think that I have reached 50 km/h with my heavily loaded trekking bicycle even if there was a downhill part. The values given by Garmin seem to be more realistic and maybe extracted from the speed sensor (not 100% sure).

-I am almost quite sure that you should do a x2 operation in order to get realistic step per minute or total step number values. During my last hiking tour, Locus Pro 3182 has displayed realtime total strep number values and those numbers where almost equal to the ones given by the Garmin FR230 divided per 2. However, after ending and recording the tour, this number (total step value) was not displayed anymore on the stat page.


-For the unit issue (rpm vs step per minute), my suggestion is to use the (minute to the power minus one unit), i.e. min-1 . After all, only the time is a true unit, round or step are not.


I will send you my last two gpx log corresponding to the hike tour and recorded using Garmin FR230 and LocusPro3182 by email to your email adress.


Best regards,


sl91

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Hello,

- hmm if you do not reached 50km/h, then Locus value is correct ;). Locus compute speed in these cases from dDistance/dTime. Anyway in next version, I've added support for speed from sensors, so it will be used instead.


- number of strides . You are correct! I did deeper into Ant+ documentation and there is really wrote "This value is incremented once for every two footfalls". So I'll increase two times in next Locus version.


- units for cadence > thanks, good idea


- number of steps added to track statistics


And finally thanks for a file. I've realized that number of steps is not exported to GPX. Anyway I'll check them tomorrow, mainly because of weird speed values

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