Running cadence only half most of the time. Running steps incorrect, too

juhis70

My Suunto 5 records my running cadence wrong, and also running steps. No problems in walking/hiking. For example today’s run:

And here comes the reason for those numbers:

Cadence shows only half most of the time. And that really is exactly half of the correct value, not just any random reading, and this could be corrected by software.

Real avg cadence for this run was 87 rpm and steps around 14349.

I’m posting here to see if anyone else has the same problem.

Bulkan

Just running? No poles?

Egika

@juhis70 Cadence in Suunto world is rpm (revolutions per minute) - in the sense of revolutions. One revolution would be a left plus a right foot stride.

I know others count each foot separately. Where do you get your “real” values from?

Dimitrios Kanellopoulos

Steps are not part of the cadence just FYI

juhis70

@Bulkan
just running, no poles

@Egika
I’m aware of Suunto using rpm instead of spm. Easy way to get “real” steps is from a wrist band that calculates steps.

@Dimitrios-Kanellopoulos
Well, they may be handled separately in watch, and that really does not matter. But by definition running average cadence = (running steps) / (running minutes) spm. Divide that by 2 and you get rpm. But as I said, that does not matter. Both are wrong and quite insane values (and cadence graph, too).

Dimitrios Kanellopoulos

@juhis70 yeah I see the insanity for sure…

Does this happen all the time? Is the watch “not wobbling on wrist”?

juhis70

@dimitrios-kanellopoulos Yes this happens on every run. Sometimes it “locks” more to the correct cadence, sometimes more to the “half-cadence”. Watch is quite firmly on my left wrist.

Dimitrios Kanellopoulos

@juhis70 has it been link this all the time ?

This smells HW

juhis70

@dimitrios-kanellopoulos All the time, from the first run. And not just that. I sent my (first) watch to Suunto as they suspected HW problem. They replaced the watch with a new (or refurbished?) one.

And it has exactly the same problem! Actually this new watch locks to the half cadence more easily.

It might be that HW+SW is not compatible with my arm swing. However this could be corrected by SW perfectly.

I can download the .FIT, then go through the cadences, every time watch gives cadence <= 55, multiply it by two (just quick and dirty solution, not checking speed for example). And here’s the resulting graph from today’s run:

(as I’m a programmer, I’ve already automated the steps from FIT to corrected grapg)

The watch could do this with more logic (check speed to see if I walk or run). Now it gives FIT records where speed > 10 km/h and cadence < 55, which is not possible, unless you’re 4 meters tall. And the watch knows I’m not.

Others have had similar problems, so I’m not completely alone. Here’s an ancient but exactly the same problem with Ambient 2: https://www.watchuseek.com/threads/suunto-ambit-2-cadence-problems.2189745/

Also with Garmin:
Forerunner 745: https://forums.garmin.com/sports-fitness/running-multisport/f/forerunner-745/248630/why-my-cadence-suddenly-drop
Forerunner 245: https://forums.garmin.com/sports-fitness/running-multisport/f/forerunner-245-series/213605/cadence-randomly-drops

(so I’m not switching to Garmin, if this is not solved)

Dimitrios Kanellopoulos

@juhis70 that is strange. Tbh first time I see this also for ambit and Garmin.

What is the pace of the workout if I may ask ?

juhis70

@dimitrios-kanellopoulos Workout data (most of it) is in the first post. Average pace was 5’52/km.

Dimitrios Kanellopoulos

@juhis70 very strange. I am out of clues.

Perhaps some other test? For example to wear the watch higher in the arm (almost at the bicep level) ?

@juhis70 you mentioned that when walking/hiking the cadence is okay. You could try to run with one of those sport profiles and see what cadence it results or do a short walk with the running profile, whichever you prefer.

juhis70

@andrasveres A walk in running mode gives correct avg cadence and a cadence graph that is next to perfect. Counted steps are low though, I don’t have a walking stride length of 2,275 meters (3760 meters/3305 steps = step length, x 2 gives stride length). It is more like 1,6 meters. But I don’t really care about the steps, I care about the cadence bug.

Dimitrios Kanellopoulos

@juhis70 so it looks like something bounces more in running mode to me , right ? Because from walking to running that is one bug parameter change , g force I think (maybe I am wrong ).

@juhis70 would be interesting to see the results of a running with the walking/hiking mode too. Just out of curiosity, do you wear anything near your watch that could interfere with it?!

juhis70

Today’s run

The SW makes here a bad (wrong) choise selecting the “half cadence” frequency from all the possibilities, considering for example speed.

Look at four record pairs (8 records), that is four consequent seconds, from .FIT file, especially cadence and speed:

record

cadence: 88 [rpm] <— ALL GOOD EVERYTHING
distance: 2.661 [km]
heart_rate: 121 [bpm]
speed: 10.296 [km/h]
vertical_speed: -0.072 [km/h]

hrv

time: (0.496, 0.49) [s]

record

cadence: 87 [rpm] <— ALL GOOD EVERYTHING
distance: 2.664 [km]
heart_rate: 122 [bpm]
speed: 10.296 [km/h]
vertical_speed: -0.072 [km/h]

hrv

time: (0.498, 0.496) [s]

record

cadence: 44 [rpm] <— WHAT JUST HAPPENED? WRONG CHOICE!
distance: 2.667 [km]
heart_rate: 120 [bpm]
speed: 10.296 [km/h] <— SAME SPEED! 44 IS IMPOSSIBLE CADENCE
vertical_speed: -0.072 [km/h]

hrv

time: (0.495, 0.491) [s]

record

cadence: 44 [rpm] <— WE’RE SCREWED
distance: 2.67 [km]
heart_rate: 122 [bpm]
speed: 10.296 [km/h]
vertical_speed: -0.072 [km/h]

If I take the FIT data and manipulate it, I can reconstruct a good cadence graph, and calculate correct average cadence. Here’s the cadence graph overlayed with my corrected graph:

I could wear the watch on my bicep or my leg or something, but I don’t want to. It may be bad sensor, but then it is already second in row, which would be bad quality. And to me, the sensor seems to give good values but the SW chooses wrong. To me this is not a HW bug but a SW bug.

Dimitrios Kanellopoulos

@juhis70 said in Running cadence only half most of the time. Running steps incorrect, too:

To me this is not a HW bug but a SW bug.

Lets investigate that.

I ll need the workout id (SA link share) to get the raw data and check.

That said , if its SW we should have some more users with the same issue.

Also just making sure you are using Android Suunto app right?

@dimitrios-kanellopoulos said in Running cadence only half most of the time. Running steps incorrect, too:

That said , if its SW we should have some more users with the same issue.

That’s why I suggested to try different sport profiles to rule out a corrupted profile case (aka software issue).

juhis70

@dimitrios-kanellopoulos It may be a very rare problem, like 1/100 or 1/1000, people have different arm swings and running styles. It may also be more common, but many people don’t look the average cadence or don’t find the cadence graph from SA (you have to swipe it). All watch owners don’t run.

It may even be a newish bug, like someone “simplified” or “optimized” the code handling accelerate sensor data or something. (I’m a developer myself…)

I’ve have run with default running sports mode, and a custom sports mode (based on running). And I’ve done that with two watches already, with same problem. The chances of both having similarly corrupted sports profiles are so slim. I did try walking with Running profile yesterday, and that was ok.

I’m using Android SA. I just clicked “send logs to Suunto” in Suunto App and it did something.

Is the ID (60c9975495d42602d25bedcb) enough or do you need the full link?