Using ST for Speedskating

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Using ST for Speedskating

Postby tndmbkr » Thu Dec 18, 2014 4:01 am

I am familair with ST+plugin for cycling and running.
But I do also speedskating on an indoor oval rink, or frozen waterways.
And I wonder how I can use ST+plugin for analyzing my efforts in this field.

Now I use a Garmin Edge to track heartbeat and time.
But I would also like to know the strokes per lap.

Swimmers use a watch to track the movements of their arms.
For instance a Garmin Forerunner920

My question: is it possible to fasten this Garmin watch on my leg, and tell the watch that I am doing a butterfly stroke, and count the number of strokes with my legs?

Or do I have to fasten a foot pod/accelerometer on my leg, and tell this watch that I am running.

At this moment I do not own a watch which can track swimming and/or running dynamics
So I cannot try it myself.
I wonder whether anyone has tried this before.
Thank you.
Last edited by tndmbkr on Sun Dec 28, 2014 2:11 pm, edited 1 time in total.
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Re: Using ST for Speedskating

Postby Stumpjumper68 » Thu Dec 18, 2014 7:22 am

Here's a link about actual fitness trackers maybe there's one which is able to count skating strokes.

http://www.bestfitnesstrackerreviews.co ... cises.html
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Re: Using ST for Speedskating

Postby dirk66 » Thu Dec 18, 2014 3:21 pm

Hi,

i'm also a speedskater and actualy even more an inline skater. But i don't ride much on a 400m oval. imo With the current garmin devices you can't measure the strokes. And for sure not with the devices i have (a forerunner 305 and a virb).

http://skatescience.nl/instrumented-skate-inzell/ and https://www.kickstarter.com/projects/1103510338/runscribe-wearable-for-the-data-driven-athlete/description are 2 sites where different types of devices which are probably more suitable for skating. However experimental.
The first is a scientific project of some of the dutch universities. The seccond a kickstarter project for runners but which imo also can be used for skating.

Regards
Dirk
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Re: Using ST for Speedskating

Postby tndmbkr » Fri Dec 19, 2014 4:19 am

Thank you.

I am glad to hear van der Kruk is still doing her research.
But in 2002 people were already talking and thinking over this subject
http://members.quicknet.nl/cvanstaaveren/schaatsen/article/ingenieur.html

I do not think running equipment will help me further.
Because foot pods and accelerometers only record shocks.
But a good skater keeps the upper part of his body motionless.
And he moves his legs without shocks, or sudden movements.

Of course the clapping of the blades of a klapschaats can be recorded.
But I am not willing to fasten a 400 dollar watch on the blades of a skate.

That is why I thought of swimming equipment.
But meanwhile I have learned from DC Rainmaker's reviews that his swimming watches are not accurate in a crowded swimmingpool.
The watches work OK as long as long as one maintains a steady rhytm.
And maintains this rythm not only indoor, but also outdoor, irrespective of the weather (nice sunny weather versus a fierce easterly wind)

Let alone that a skater does not make a sharp turn every 400 meter.
Last edited by tndmbkr on Fri Dec 19, 2014 12:24 pm, edited 1 time in total.
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Re: Using ST for Speedskating

Postby old_man_biking » Fri Dec 19, 2014 6:47 am

It can be understood that you're not keen on gluing your $400 watch to your skate blades.
How about trying to fix a bike cadence sensor to your skates?
All you'd need is a tiny magnet glued to the blade and a cadence sensor that's mounted on the shoe sole facing the magnet.
This would give an impuls whenever the blade of your clap skate "claps". A perfect cadence sensor.

Cheers,
OMB
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Re: Using ST for Speedskating

Postby tndmbkr » Sat Dec 20, 2014 4:47 am

Yes. That is a fine idea. I will sure try!!!!!
But you will have to wait until january for results

I had once an idea to fasten the magnet on one leg, and the sensor on the other leg.
But I did not always bring one leg enough close by the other leg.
That idea did not work.
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Re: Using ST for Speedskating

Postby tndmbkr » Mon Dec 22, 2014 3:58 pm

I could not wait. And already made a prototype today.

The position of the magnet in relation to the sensor appeared to be very important.
Only one of the poles of the magnet must be faced to the sensor.
The sensor cannot handle a magnet with two poles facing the sensor.

When I stretch my leg, and bring that leg up again, the magnet has passed the sensor twice.
Fortunately the sensor appears to measure only one pass of the magnet.
Every count corresponds to one gliding stride.

I fastened the magnet on the blade.
For that purpose I drilled a hole in the tube of the blade, and screwed a bolt in that hole.

I used a Speed+Cadence sensor, because I happen to own a GSC10.
The Edge500 is capable of handling a cadance only sensor (after you have changed the settings of the Edge).
See also DCRainmaker..

Image

Image

And this is a snapshot from a ST chart.
I have not analyzed the results yet.
Image

When one question has been answered, other questions arise.
On a bike the cadence for left and right leg are exactly the same.
But do I spent more/less time on my left leg, compared to the right leg, when skating ????
Last edited by tndmbkr on Wed Jan 07, 2015 3:10 am, edited 24 times in total.
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Re: Using ST for Speedskating

Postby texmurphy » Mon Dec 22, 2014 5:58 pm

tndmbkr wrote:...When one question has been answered, other questions arise.
On a bike the cadence for left and right leg are exactly the same.
But do I spent more/less time on my left leg, compared to the right leg, when skating ????

Effort to swap sensors is likely high from skate to skate, so get another sensor for left(?) skate.
Set up another profile on the Edge when you want left (or right) skate sensor.
Or get second Edge, record both at once.
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Re: Using ST for Speedskating

Postby dirk66 » Tue Dec 23, 2014 3:37 pm

Interesting!

To your new question. Of course you can put your GSC-10 on your other skate. But then you don't know, if there is a difference between left and right, it's because you stay longer on one of your feet by default or for instance it's because your are more tired during a training. So if you want to be sure you probably want to have one on both skates. My guess is, there will be a difference between left and right in a bend/curve on the track.
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Re: Using ST for Speedskating

Postby Stumpjumper68 » Sat Dec 27, 2014 4:01 pm

Here 's an intresting new gadget which offers a 9-axis analysis. If you'll contact the developers they maybe willing to adopt it to speedscating.

https://www.kickstarter.com/projects/11 ... en-athlete
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Re: Using ST for Speedskating

Postby tndmbkr » Sun Dec 28, 2014 9:33 am

texmurphy wrote:..... so get another sensor for left(?) skate. ....Or get second Edge, record both at once.

dirk66 wrote:..... So if you want to be sure you probably want to have one on both skates......

After some reflection I am sorry to say that we do not follow a right line of reasoning.
When a gliding stride with the right leg takes 2 sec, and a stride with the other leg takes 3 sec, the cadence = 60 / (2+3) = 12 rpm
The cadence is the same for either leg.
I cannot stretch one leg before I have brought the other leg up again.

In order to measure the left/right stride time, we need a stopwatch.
The gadget mentioned by Stumpjumper68 is worth examining.

===========================
Text added monday december 29th
I asked sunSkribe.
They answered the analysis algorithms specific to skating are different from the running motion.
They currentlly do not have a time line for when these would be available.
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Re: Using ST for Speedskating

Postby tndmbkr » Sat Nov 12, 2016 12:47 pm

A professoional coach in skating told me he used a phone to track his movements.
The precision of the accelerometer in a phone is satisfactory.
And Google Play Store offers plenty of apps which can produce a CSVfile for analysis.
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