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help & physics

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Sander Roosendaal
2018-10-09 13:03:50 +02:00
parent 8b5a0f2e5c
commit a5e98dd69c
5 changed files with 155 additions and 145 deletions
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rowers/templates/help.html
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<h1>Welcome to Rowsandall.com</h1> <h1>Welcome to Rowsandall.com</h1>
<ul class="main-content"> <ul class="main-content">
<li class="grid_2"> <li class="grid_2">
<h2>What is it?</h2>
<p> <p>
Rowsandall.com is an online tool for rowers to analyze data from On The Water 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 (OTW) and On The Erg (OTE) workouts. It accepts workout data from a
rowers/templates/menu_workout.html
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<label for="group-chart">Static Charts</label> <label for="group-chart">Static Charts</label>
<ul> <ul>
<li id="chart-time"> <li id="chart-time">
<a href="/rowers/workout/{{ workout.id }}/addtimeplot"> <a href="/rowers/workout/{{ workout.id }}/addstatic/1">
<i class="fas fa-stopwatch fa-fw"></i>&nbsp;Time <i class="fas fa-stopwatch fa-fw"></i>&nbsp;Time
</a> </a>
</li> </li>
<li id="chart-distance"> <li id="chart-distance">
<a href="/rowers/workout/{{ workout.id }}/adddistanceplot"> <a href="/rowers/workout/{{ workout.id }}/addstatic/2">
<i class="fas fa-ruler fa-fw"></i>&nbsp;Distance <i class="fas fa-ruler fa-fw"></i>&nbsp;Distance
</a> </a>
</li> </li>
<li id="chart-powerpie"> <li id="chart-powerpie">
<a href="/rowers/workout/{{ workout.id }}/addpowerpiechart"> <a href="/rowers/workout/{{ workout.id }}/addstatic/13">
<i class="far fa-chart-pie fa-fw"></i>&nbsp;Power (Pie) <i class="far fa-chart-pie fa-fw"></i>&nbsp;Power (Pie)
</a> </a>
</li> </li>
<li id="chart-hrpie"> <li id="chart-hrpie">
<a href="/rowers/workout/{{ workout.id }}/addpiechart"> <a href="/rowers/workout/{{ workout.id }}/addstatic/3">
<i class="fas fa-heartbeat fa-fw"></i>&nbsp;Heart Rate (Pie) <i class="fas fa-heartbeat fa-fw"></i>&nbsp;Heart Rate (Pie)
</a> </a>
</li> </li>
{% if workout|water %} {% if workout|water %}
<li id="chart-otwpower"> <li id="chart-otwpower">
<a href="/rowers/workout/{{ workout.id }}/addotwpowerplot"> <a href="/rowers/workout/{{ workout.id }}/addstatic/9">
<i class="fas fa-chart-area fa-fw"></i>&nbsp;OTW Power <i class="fas fa-chart-area fa-fw"></i>&nbsp;OTW Power
</a> </a>
</li> </li>
rowers/templates/physics.html
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{% extends "newbase.html" %}
{% block title %}About us{% endblock title %}
{% block main %}
{% extends "base.html" %} <h1>How we calculate things</h1>
{% block title %}About us{% endblock title %}
{% block content %}
<div class="grid_6 alpha"> <ul class="main-content">
<h3>How we calculate things</h3> <li class="grid_2">
<p>You are reading this because you want to understand how the wind/stream conversion and the conversion from OTW pace to OTE pace works.</p> <p>You are reading this because you want to understand how the wind/stream conversion and the conversion from OTW pace to OTE pace works.</p>
<p>The conversions are done using a one-dimensional mechanical model that is <p>The conversions are done using a one-dimensional mechanical model that is
introduced <a href="https://sanderroosendaal.wordpress.com/index/">here</a>. introduced <a href="https://sanderroosendaal.wordpress.com/index/">here</a>.
The model takes into account, among others, the following parameters: The model takes into account, among others, the following parameters:
<ul> <ul>
<li>Stroke rate</li> <li>Stroke rate</li>
<li>Stroke length</li> <li>Stroke length</li>
<li>Rigging parameters</li> <li>Rigging parameters</li>
<li>Rower and boat weight</li> <li>Rower and boat weight</li>
</ul> </ul>
For this site, we use "standard" rigging parameters, blade shapes, and FISA minimum boat weights. For the eight, I add the weight of a cox (at the FISA minimum weight). The stroke length is also set at a fixed value, but in the future I For this site, we use "standard" rigging parameters, blade shapes, and FISA minimum boat weights. For the eight, I add the weight of a cox (at the FISA minimum weight). The stroke length is also set at a fixed value, but in the future I
will allow you to adjust to your own stroke length. will allow you to adjust to your own stroke length.
</p> </p>
<p> <p>
Knowing boat type (rigging), pace and stroke rate, and taking into account 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 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 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 calculation. That is, I vary the input force until I find the one that
corresponds to your actual pace at that stroke rate. corresponds to your actual pace at that stroke rate.
</p> </p>
<p> <p>
Knowing the power, I can calculate how fast you would have gone without 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 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 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 corrected pace, which I think is useful to know and be able to compare
from training to training and between different rowing venues. from training to training and between different rowing venues.
</p> </p>
<p>
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.
</p>
<p> <p>
Using another algorithm to calculate total mechanical power on an erg, I can It is important to understand that the Power display on the erg is not showing
calculate what the erg display would show you if you rowed on the erg with you the complete picture. In my calculations, I use my proprietary algorithms
the same average power, at the same stroke rate. The calculations are done to calculate the additional power that goes into moving your body weight up
for a statical Concept2 erg with a fairly standard drag factor. I cannot and down the slide on a static erg. To get the most accurate results, it is
take into account the fact that you may use different technique or would important to be honest about your weight and set it independently for each
row at a different stroke rate on the erg. workout.
</p> </p>
<p> <p>Not taken into account are the following factors:
It is important to understand that the Power display on the erg is not showing <ul>
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.
</p>
<p>Not taken into account are the following factors:
<ul>
<li>Water Temperature</li> <li>Water Temperature</li>
<li>Heavier/shorter/wider boats than the ones used by the elite</li> <li>Heavier/shorter/wider boats than the ones used by the elite</li>
<li>Bungees, weed, or other artefacts slowing down the boat</li> <li>Bungees, weed, or other artefacts slowing down the boat</li>
<li>Boat stopping technique flaws</li> <li>Boat stopping technique flaws</li>
<li>Effect of wave height or cross-wind</li> <li>Effect of wave height or cross-wind</li>
</ul> </ul>
The water temperature has a small but measurable effect on the water density The water temperature has a small but measurable effect on the water density
(and thus on the drag). I am using the value at 20 degrees C, which is a (and thus on the drag). I am using the value at 20 degrees C, which is a
good average over the OTW season for a lake in a temperate climate. All good average over the OTW season for a lake in a temperate climate. All
the other elements result in an equivalent erg pace that is probably slower the other elements result in an equivalent erg pace that is probably slower
than what you can achieve on the erg. So look at it as an incentive to than what you can achieve on the erg. So look at it as an incentive to
improve your technique (big effect) and/or buy a faster boat (minor effect). improve your technique (big effect) and/or buy a faster boat (minor effect).
If your OTW to OTE pace conversion results in numbers close to what you If your OTW to OTE pace conversion results in numbers close to what you
normally achieve on the erg, you are rowing like an elite rower (but possibly normally achieve on the erg, you are rowing like an elite rower (but possibly
at a lower power)! When I get around it, I will try to model the effect of cross-wind. at a lower power)! When I get around it, I will try to model the effect of cross-wind.
</p> </p>
<p>
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 <a href="http://www.biorow.com/RBN_en_2007_files/App2007RowBiomNews08.pdf">here</a> 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.
</p>
<p>
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.
</p>
<p> </li>
I have checked the model both from a Physics perspective (I have a degree in <li class="grid_2">
Physics, if you are interested) and compared with the data available. <h2>Manual</h2>
An important data set has been published <a href="http://www.biorow.com/RBN_en_2007_files/App2007RowBiomNews08.pdf">here</a> 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.
</p>
<p> <p>Here's the best way - in my mind - to use the Rowing Physics
On top of that I am constantly comparing the model's results to my own sculling functionality. I am assuming you have successfully uploaded or imported
and rowing, and I will be the first to admit flaws and correct them. So please a rowing workout. You must have position data (lat/long) with your row. A
contact me if there are any inconsistencies, suspicions, questions or simply TCX from CrewNerd or RiM or a workout imported from SportTracks or Strava
if you want to chat about Rowing Physics. (where you see a map of your workout on those sites) should have those
</p> 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.
</p>
</div>
<div class="grid_6 omega"> <p>Recipe for success:
<h3>Manual</h3> <ol>
<p>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.
</p>
<p>Recipe for success:
<ol>
<li>Click on the workout. This will bring you to the workout Edit view</li> <li>Click on the workout. This will bring you to the workout Edit view</li>
<li>Click on the "Advanced" button</li> <li>Look for three menu items labelled "Edit Wind Data", "Edit Stream
<li>Click on "Geeky Stuff"</li>
<li>Look for three buttons labelled "Edit Wind Data", "Edit Stream
Data" and "OTW Power"</li> Data" and "OTW Power"</li>
<li>If you have wind or stream data, click on the appropriate <li>If you have wind or stream data, click on the appropriate
button and enter your data.</li> menu item and enter your data.</li>
<li>If you have both wind and stream, click the shortcut button
on the respective page to take you to the other parameter</li>
<li>Click on OTW Power</li> <li>Click on OTW Power</li>
<li>Select the boat type and enter the average weight <li>Select the boat type and enter the average weight
per crew member. per crew member.
Do not use the crew total weight.</li> Do not use the crew total weight.</li>
<li>Click "Update & Run"</li> <li>Click "Update & Run"</li>
<li>Go do something else. You will receive an email when the calculations are finished. The calculation itself will take about 10 minutes for an <li>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.</li> it may take longer.</li>
<li>Progress can be monitored by clicking on "here" in the message <li>Progress can be monitored by clicking on "here" in the message
at the top of the page advising that the calculation has at the top of the page advising that the calculation has
begun.</li> begun.</li>
<li> </ol>
When the calculation is complete, go back to the "Geeky Stuff" page </p>
and click on "Corrected Pace Plot" to see the result. From here, you can re-run the calculation with different parameters.</li>
</ol> <p>
</p> 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.
</p>
<h2>Why does the calculation take so much time?</h2>
<p> <p>I am running the calculations from a first principles base, so for
Once you have run the calculation, the boat type, average crew weight, each data point that I am calculating, I am finding the stroke average
Power and corrected pace data are stored permanently on the site. If you would force, then calculating corrected pace (wind/stream) and finding the
export the data to Strava or SportTracks now, those sites will have the corresponding erg power. I am not taking any shortcuts. The advantage
Power data. of this approach is that I can give you numbers irrespective of your
</p> weight, speed, stroke rate, sex, etc. The model can deal with circumstances
it has not encountered before. The downside is that it takes time.</p>
<p>
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.</p>
<p>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!
</p>
<img src="/static/img/validation.png" width="450">
</li>
</ul>
<h3>Why does the calculation take so much time?</h3> {% endblock %}
<p>I am running the calculations from a first principles base, so for {% block sidebar %}
each data point that I am calculating, I am finding the stroke average {% include 'menu_help.html' %}
force, then calculating corrected pace (wind/stream) and finding the {% endblock %}
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.</p>
<p>
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.</p>
<p>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!
</p>
<img src="/static/img/validation.png" width="450">
</div>
{% endblock content %}
rowers/urls.py
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@@ -270,7 +270,6 @@ urlpatterns = [
), ),
url(r'^physics$',TemplateView.as_view(template_name='physics.html'),name='physics'), url(r'^physics$',TemplateView.as_view(template_name='physics.html'),name='physics'),
url(r'^partners$',TemplateView.as_view(template_name='partners.html'),name='partners'), url(r'^partners$',TemplateView.as_view(template_name='partners.html'),name='partners'),
url(r'^workout/(?P<id>\d+)/$',views.workout_view),
# keeping the old URLs for retrofit # keeping the old URLs for retrofit
url(r'^workout/(?P<id>\d+)/addtimeplot$', url(r'^workout/(?P<id>\d+)/addtimeplot$',
views.workout_add_chart_view, views.workout_add_chart_view,
rowers/views.py
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@@ -6717,6 +6717,7 @@ def workout_undo_smoothenpace_view(
request,id=0,message="",successmessage="" request,id=0,message="",successmessage=""
): ):
row = get_workout(id) row = get_workout(id)
r = getrower(request.user)
if (checkworkoutuser(request.user,row)==False): if (checkworkoutuser(request.user,row)==False):
message = "You are not allowed to edit this workout" message = "You are not allowed to edit this workout"
@@ -6737,7 +6738,12 @@ def workout_undo_smoothenpace_view(
row.write_csv(filename,gzip=True) row.write_csv(filename,gzip=True)
dataprep.update_strokedata(id,row.df) dataprep.update_strokedata(id,row.df)
url = "/rowers/workout/"+str(id)+"/advanced" url = reverse(r.defaultlandingpage,
kwargs = {
'id':id,
}
)
return HttpResponseRedirect(url) return HttpResponseRedirect(url)
@@ -6747,6 +6753,8 @@ def workout_undo_smoothenpace_view(
def workout_smoothenpace_view(request,id=0,message="",successmessage=""): def workout_smoothenpace_view(request,id=0,message="",successmessage=""):
row = get_workout(id) row = get_workout(id)
r = getrower(request.user)
if (checkworkoutuser(request.user,row)==False): if (checkworkoutuser(request.user,row)==False):
message = "You are not allowed to edit this workout" message = "You are not allowed to edit this workout"
messages.error(request,message) messages.error(request,message)
@@ -6776,7 +6784,11 @@ def workout_smoothenpace_view(request,id=0,message="",successmessage=""):
row.write_csv(filename,gzip=True) row.write_csv(filename,gzip=True)
dataprep.update_strokedata(id,row.df) dataprep.update_strokedata(id,row.df)
url = "/rowers/workout/"+str(id)+"/advanced" url = reverse(r.defaultlandingpage,
kwargs = {
'id':id,
}
)
return HttpResponseRedirect(url) return HttpResponseRedirect(url)