What is it?
Rowsandall.com is an online tool for rowers to analyze data from On The Water (OTW) and On The Erg (OTE) workouts. It accepts workout data from a diff --git a/rowers/templates/menu_workout.html b/rowers/templates/menu_workout.html index d8d4ceb6..edbdc5c6 100644 --- a/rowers/templates/menu_workout.html +++ b/rowers/templates/menu_workout.html @@ -76,28 +76,28 @@
How we calculate things
-How we calculate things
-You are reading this because you want to understand how the wind/stream conversion and the conversion from OTW pace to OTE pace works.
- -The conversions are done using a one-dimensional mechanical model that is -introduced here. -The model takes into account, among others, the following parameters: -
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You are reading this because you want to understand how the wind/stream conversion and the conversion from OTW pace to OTE pace works.
+ +The conversions are done using a one-dimensional mechanical model that is + introduced here. + The model takes into account, among others, the following parameters: +
- Stroke rate
- Stroke length
- Rigging parameters
- Rower and boat weight -
-Knowing boat type (rigging), pace and stroke rate, and taking into account -the influence of wind and stream (if provided), I am able to find the -mechanical power that you provide to the rowing system by a reverse -calculation. That is, I vary the input force until I find the one that -corresponds to your actual pace at that stroke rate. -
--Knowing the power, I can calculate how fast you would have gone without -external wind and stream influences by running the calculation in a forward -way, using the power and force profile found. This is the wind/stream -corrected pace, which I think is useful to know and be able to compare -from training to training and between different rowing venues. -
+ - Water Temperature
- Heavier/shorter/wider boats than the ones used by the elite
- Bungees, weed, or other artefacts slowing down the boat
- Boat stopping technique flaws
- Effect of wave height or cross-wind -
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Manual
--On top of that I am constantly comparing the model's results to my own sculling -and rowing, and I will be the first to admit flaws and correct them. So please -contact me if there are any inconsistencies, suspicions, questions or simply -if you want to chat about Rowing Physics. -
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+ Knowing boat type (rigging), pace and stroke rate, and taking into account + the influence of wind and stream (if provided), I am able to find the + mechanical power that you provide to the rowing system by a reverse + calculation. That is, I vary the input force until I find the one that + corresponds to your actual pace at that stroke rate. +
++ Knowing the power, I can calculate how fast you would have gone without + external wind and stream influences by running the calculation in a forward + way, using the power and force profile found. This is the wind/stream + corrected pace, which I think is useful to know and be able to compare + from training to training and between different rowing venues. +
+ ++ Using another algorithm to calculate total mechanical power on an erg, I can + calculate what the erg display would show you if you rowed on the erg with + the same average power, at the same stroke rate. The calculations are done + for a statical Concept2 erg with a fairly standard drag factor. I cannot + take into account the fact that you may use different technique or would + row at a different stroke rate on the erg. +
--Using another algorithm to calculate total mechanical power on an erg, I can -calculate what the erg display would show you if you rowed on the erg with -the same average power, at the same stroke rate. The calculations are done -for a statical Concept2 erg with a fairly standard drag factor. I cannot -take into account the fact that you may use different technique or would -row at a different stroke rate on the erg. -
- --It is important to understand that the Power display on the erg is not showing -you the complete picture. In my calculations, I use my proprietary algorithms -to calculate the additional power that goes into moving your body weight up -and down the slide on a static erg. To get the most accurate results, it is -important to be honest about your weight and set it independently for each -workout. -
- -Not taken into account are the following factors: -
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+ It is important to understand that the Power display on the erg is not showing + you the complete picture. In my calculations, I use my proprietary algorithms + to calculate the additional power that goes into moving your body weight up + and down the slide on a static erg. To get the most accurate results, it is + important to be honest about your weight and set it independently for each + workout. +
+ +Not taken into account are the following factors: +
+ I have checked the model both from a Physics perspective (I have a degree in + Physics, if you are interested) and compared with the data available. + An important data set has been published here by Dr Kleshnev. For sculling, + my algorithms are extremely close in reproducing that data set. For sweep + rowing, I am still fine tuning some parameters, but I am close for a pair and + a four. I had to make assumptions about Kleshnev's data, especially about the + stroke rate, but as I got realistic stroke rates (35 and higher) for world + record performance, I am quite confident. +
+ ++ On top of that I am constantly comparing the model's results to my own sculling + and rowing, and I will be the first to admit flaws and correct them. So please + contact me if there are any inconsistencies, suspicions, questions or simply + if you want to chat about Rowing Physics. +
--I have checked the model both from a Physics perspective (I have a degree in -Physics, if you are interested) and compared with the data available. -An important data set has been published here by Dr Kleshnev. For sculling, -my algorithms are extremely close in reproducing that data set. For sweep -rowing, I am still fine tuning some parameters, but I am close for a pair and -a four. I had to make assumptions about Kleshnev's data, especially about the -stroke rate, but as I got realistic stroke rates (35 and higher) for world -record performance, I am quite confident. -
+ +Manual
- -Here's the best way - in my mind - to use the Rowing Physics -functionality. I am assuming you have successfully uploaded or imported -a rowing workout. You must have position data (lat/long) with your row. A -TCX from CrewNerd or RiM or a workout imported from SportTracks or Strava -(where you see a map of your workout on those sites) should have those -data. I am working on adding the FIT file format that is used by SpeedCoach -GPS. For now, export the data to Strava and then import them here. -
- -Recipe for success: -
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- Click on the workout. This will bring you to the workout Edit view -
- Click on the "Advanced" button -
- Click on "Geeky Stuff" -
- Look for three buttons labelled "Edit Wind Data", "Edit Stream +
- Look for three menu items labelled "Edit Wind Data", "Edit Stream Data" and "OTW Power"
- If you have wind or stream data, click on the appropriate - button and enter your data. -
- If you have both wind and stream, click the shortcut button - on the respective page to take you to the other parameter + menu item and enter your data.
- Click on OTW Power
- Select the boat type and enter the average weight per crew member. Do not use the crew total weight.
- Click "Update & Run"
- Go do something else. You will receive an email when the calculations are finished. The calculation itself will take about 10 minutes for an -hour long row, but there may be other people's calculations in the queue, so + hour long row, but there may be other people's calculations in the queue, so it may take longer.
- Progress can be monitored by clicking on "here" in the message at the top of the page advising that the calculation has begun. -
- - When the calculation is complete, go back to the "Geeky Stuff" page - and click on "Corrected Pace Plot" to see the result. From here, you can re-run the calculation with different parameters. -
Here's the best way - in my mind - to use the Rowing Physics + functionality. I am assuming you have successfully uploaded or imported + a rowing workout. You must have position data (lat/long) with your row. A + TCX from CrewNerd or RiM or a workout imported from SportTracks or Strava + (where you see a map of your workout on those sites) should have those + data. I am working on adding the FIT file format that is used by SpeedCoach + GPS. For now, export the data to Strava and then import them here. +
+ +Recipe for success: +
+ Once you have run the calculation, the boat type, average crew weight, + Power and corrected pace data are stored permanently on the site. If you would + export the data to Strava or SportTracks now, those sites will have the + Power data. +
+ +Why does the calculation take so much time?
--Once you have run the calculation, the boat type, average crew weight, -Power and corrected pace data are stored permanently on the site. If you would -export the data to Strava or SportTracks now, those sites will have the -Power data. -
+I am running the calculations from a first principles base, so for + each data point that I am calculating, I am finding the stroke average + force, then calculating corrected pace (wind/stream) and finding the + corresponding erg power. I am not taking any shortcuts. The advantage + of this approach is that I can give you numbers irrespective of your + weight, speed, stroke rate, sex, etc. The model can deal with circumstances + it has not encountered before. The downside is that it takes time.
+ ++ A much faster approach would be to simply take pre-calculated data from + a table and interpolate. The advantage of this approach is is speed. The + disadvantage is that extrapolation outside the limits of the available + data is dangerous and will lead to erroneous results.
+ +Future versions of this site will use a hybrid approach + but only for pace/wind/stream/stroke rate/weight combinations that I consider + well validated. For that, I need to collect data, so keep the workouts coming! +
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-Why does the calculation take so much time?
+{% endblock %} -I am running the calculations from a first principles base, so for -each data point that I am calculating, I am finding the stroke average -force, then calculating corrected pace (wind/stream) and finding the -corresponding erg power. I am not taking any shortcuts. The advantage -of this approach is that I can give you numbers irrespective of your -weight, speed, stroke rate, sex, etc. The model can deal with circumstances -it has not encountered before. The downside is that it takes time.
- --A much faster approach would be to simply take pre-calculated data from -a table and interpolate. The advantage of this approach is is speed. The -disadvantage is that extrapolation outside the limits of the available -data is dangerous and will lead to erroneous results.
- -Future versions of this site will use a hybrid approach -but only for pace/wind/stream/stroke rate/weight combinations that I consider -well validated. For that, I need to collect data, so keep the workouts coming! -
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