czechoslovakia1956

Mar 5 2017

Short Intervals & The Rowsberry Pi project

First, a cool photograph that I came across today. It is totally unrelated to the post, but I like it, and I find my “feature image” featuring charts and graphs a bit boring:

Czechoslovakia, 1956

There are five people on the photograph.

Today’s row was the short interval session that I had planned for this week. It is not part of my club’s training program, but I have decided to go hybrid. I have planned out my training periodization and the type of workouts I will do in each period. On Monday, when I receive the coach’s training plan, I will plan out the rest of the week, adhering as much as possible to his sessions, but making sure I remain close to my planned periodization, and thus adding, replacing or adapting sessions where needed. It allows me to join the group erg sessions on the club but still understand what the purpose is of each session.

After lunch, I played a bit with the Raspberry Pi, for the “Rowsberry Pi” project. The idea is to create open source software that can be loaded on a Raspberry Pi, turning it into a low-cost data logger for erg sessions. I started with PyRow and I adapted it slightly to capture some extra stroke stats, like drive length, work per stroke, etc. It took a few iterations to get that to work, so my family saw me running back and forth between the rowing basement and the living room.

The basic idea is as follows:

  1. One or more ergs connect to a Raspberry Pi through the USB cable
  2. The Pi just listens to the ergs. When a workout is programmed and started, it starts recording automatically.
  3. At the end of each workout, the Pi saves the stroke data to a CSV file. If configured with an email address, the workout is uploaded automatically to rowsandall.com. Otherwise, the data are available on a shared drive on the network

It should really be a plug-and-row solution. Here’s a picture of my “test lab”:

The Pi is connected to the network through Wifi, and has a network address rowsberrypi1.local. It is connected to the erg through USB. I still have to manually start the program before each workout, and get the results from the Pi by FTP. So there is still some work to do. Also, the recording of the interval session failed. I manually started the session, then programmed it on the PM. I believe that the Pi thought that the session ended at that point.

So, lots of fun details to get right. But imagine being able to install a few Pis in the rowing club ergroom and just silently log all the data … or have your own Pi for recording sessions while traveling. With the network access, even more can be done. A coach can set up all ergs to the same workout remotely through the network.

So here is  my traditional warming up with a few hard strokes, as recorded with Painsled and processed on Rowsandall.com:

And here are a few quick graphs from excel, from the CSV file produced by the Pi. Same warming up as above:

And here is the main session. I did 15 intervals of 40″ on, 1 minute off:

Finally, I did a 3km cooling down.

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1920juniori

Mar 4 2017

Saturday – OTW in the single

A jedeme v tom zas. #cvkbrno #czechrowing #loveit

A post shared by Leňaa (@lenka_roosendaal) on

This morning I drove to the lake to pick up another batch of singles and pairs. In the erg room I saw Eda, who just finished his first set of 10 500m pieces (see yesterday’s blog). He was rowing them in 1:42-1:44 pace, but rating around 28spm instead of the prescribed 26spm.

Took the boats to the Pisarky (river) club house. Then quickly hopped in the single for a short row, knowing that Lenka would be around in 45 minutes for her row.

I had to reset the SpeedCoach after 1800m. I was rowing with Slip and Catch angle values on the bottom row of the screen. Suddenly there were no values any more. First I tried switching off and on the oarlock. That didn’t help. Then I reset the SpeedCoach, which solved the issue.

First part:

Workout Summary - media/20170304-102315-Sanders SpeedCoach 20170304 0927amo.csv
--|Total|-Total-|--Avg--|-Avg-|Avg-|-Avg-|-Max-|-Avg
--|Dist-|-Time--|-Pace--|-Pwr-|SPM-|-HR--|-HR--|-DPS
--|01839|09:26.0|02:33.9|159.2|21.0|150.9|166.0|09.3
W-|01839|09:26.0|02:33.9|159.2|21.0|150.9|166.0|09.3
R-|00000|00:00.0|00:00.0|000.0|00.0|000.0|166.0|00.0

Second Part:

Workout Summary - media/20170304-102435-Sanders SpeedCoach 20170304 0938amo.csv
--|Total|-Total-|--Avg--|-Avg-|Avg-|-Avg-|-Max-|-Avg
--|Dist-|-Time--|-Pace--|-Pwr-|SPM-|-HR--|-HR--|-DPS
--|07351|38:53.0|02:38.7|147.4|20.7|161.4|172.0|09.1
W-|07351|38:53.0|02:38.7|147.4|20.7|161.4|172.0|09.1
R-|00000|00:00.0|00:00.0|000.0|00.0|000.0|172.0|00.0

I had moved the seat rails a bit sternward to allow for full reach with the new foot stretcher settings.

I was watching slip and catch angle for most of the workout. Only in the last leg did I change it to wash and catch angle.

It’s a great spring day today. I had to interrupt sitting in the sun in the garden to write up this training log. I guess the Rowsberry Pi work will have to wait until tomorrow.

Adding two pictures from an old album about our club.

The juniors (1920)
A party at the rowing club (1936)

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myimage (21)

Mar 4 2017

Friday – a lot of 500m

This is the mirror post to this one, so I suggest you read Greg’s observation first. The training was 2x10x500m/80″, with 4 minutes between the sets of 10. And with a rate cap of 26spm.

This was on my training plan and Greg agreed to do it as well, so we could test some of the new “team” functionality on rowsandall.com.

I will go straight to the results.

Set 1:

Workout Summary - media/20170303-1700260o.csv
--|Total|-Total-|--Avg--|-Avg-|Avg-|-Avg-|-Max-|-Avg
--|Dist-|-Time--|-Pace--|-Pwr-|SPM-|-HR--|-HR--|-DPS
--|07000|29:39.0|02:07.1|205.9|24.0|159.7|175.0|09.8
W-|05000|18:40.0|01:52.1|253.1|25.8|161.2|175.0|10.4
R-|02000|11:00.0|02:45.0|098.1|19.8|156.2|175.0|08.8
Workout Details
#-|SDist|-Split-|-SPace-|-Pwr-|SPM-|AvgHR|MaxHR|DPS-
00|00500|01:51.4|01:51.4|245.8|25.6|150.0|165.0|10.5
01|00500|01:52.5|01:52.5|256.6|25.7|158.6|170.0|10.4
02|00500|01:51.5|01:51.5|253.3|25.8|158.2|168.0|10.4
03|00500|01:52.0|01:52.0|257.7|26.3|162.4|171.0|10.2
04|00500|01:53.1|01:53.1|251.3|25.7|160.3|172.0|10.3
05|00500|01:52.6|01:52.6|255.4|25.9|162.0|174.0|10.3
06|00500|01:52.1|01:52.1|248.4|26.1|164.1|174.0|10.2
07|00500|01:52.3|01:52.3|252.0|25.7|165.1|174.0|10.4
08|00500|01:51.5|01:51.5|258.1|25.9|164.4|174.0|10.4
09|00500|01:51.8|01:51.8|252.6|25.8|166.7|175.0|10.4

Set 2:

Workout Summary - media/20170303-1700240o.csv
--|Total|-Total-|--Avg--|-Avg-|Avg-|-Avg-|-Max-|-Avg
--|Dist-|-Time--|-Pace--|-Pwr-|SPM-|-HR--|-HR--|-DPS
--|07000|29:32.0|02:06.6|206.4|24.2|162.6|179.0|09.8
W-|05000|18:13.0|01:49.4|264.2|26.2|163.7|179.0|10.5
R-|02000|11:19.0|02:49.8|080.8|19.9|160.2|179.0|08.9
Workout Details
#-|SDist|-Split-|-SPace-|-Pwr-|SPM-|AvgHR|MaxHR|DPS-
00|00500|01:50.3|01:50.3|253.2|25.9|154.6|171.0|10.5
01|00500|01:50.1|01:50.1|259.2|26.4|162.0|174.0|10.3
02|00500|01:50.0|01:50.0|261.0|26.2|163.7|174.0|10.4
03|00500|01:50.1|01:50.1|258.1|26.2|162.9|175.0|10.4
04|00500|01:49.9|01:49.9|257.8|26.2|163.6|174.0|10.4
05|00500|01:49.6|01:49.6|265.8|26.2|165.6|175.0|10.5
06|00500|01:50.0|01:50.0|259.9|25.9|164.4|176.0|10.5
07|00500|01:49.7|01:49.7|263.1|26.0|164.6|175.0|10.5
08|00500|01:47.6|01:47.6|276.7|26.2|167.3|177.0|10.6
09|00500|01:46.7|01:46.7|288.0|26.3|168.5|179.0|10.7

And the graphs:

It was a doable workout. On paper it looks very brutal, but I didn’t have any problems rowing it. Hence I accelerated in the second set, by focusing on long strokes.

While rowing, I was wondering how Greg was doing. I imagined 1:44 pace. After we both uploaded our workouts to rowsandall.com, we could compare:

So you can see that we were really close in terms of heart rate and power. On the dynamic, Greg upped the stroke rate a bit.

Here are the metrics plots, just because I have them. Nothing special to observe, except that I did a good job holding length.

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myimage (16)

Mar 1 2017

Steady State in the single (and more empower thoughts)

The clouds looked like they contained either rain or snow, but luckily they were just very threatening.

The training plan said “45 minutes of swimming”, but I went to back to the single again. Moved my footstretcher sternwards to try and get a bit more catch angle. Feels heavy.


Workout Summary - media/20170301-185315-Sanders SpeedCoach 20170301 0421pmo.csv
--|Total|-Total-|--Avg--|-Avg-|Avg-|-Avg-|-Max-|-Avg
--|Dist-|-Time--|-Pace--|-Pwr-|SPM-|-HR--|-HR--|-DPS
--|10552|55:58.0|02:39.1|150.1|20.5|156.7|179.0|09.2
W-|10552|55:58.0|02:39.1|149.9|20.5|156.5|179.0|09.2
R-|00000|00:00.0|00:00.0|000.0|00.0|000.0|179.0|00.0
Workout Details
#-|SDist|-Split-|-SPace-|-Pwr-|SPM-|AvgHR|MaxHR|DPS-
00|02200|11:36.3|02:38.2|162.0|19.9|150.8|166.0|09.5
01|02200|11:05.3|02:31.2|159.3|20.9|160.6|176.0|09.5
02|02200|11:47.5|02:40.8|156.6|21.3|162.4|179.0|08.8
03|02200|11:19.9|02:34.5|151.2|20.8|160.1|177.0|09.3
04|01752|10:09.2|02:53.9|116.5|19.3|147.9|164.0|09.0

I set the bottom left part of the screen to “Work per stroke” and left it there. Indeed, technically good strokes on straight bits of the river came in between 450 and 600J. Paddling and turning was below 450J.

Catch angle today: -60 +/- 4 degrees

Catch angleMonday: -58 +/- 4 degrees

Finish angle today: 44 +/- 4 degrees

Finish angle Monday: 45 +/- 4 degrees.

These are median values (not averages). I will explain the reason for that below. Slip and wash nearly unchanges as far as average values were concerned. Two remarks, though:

  1. In the first 2km I had catch angle on the display and I do believe I saw values between 60 and 65 degrees consistently. This is also confirmed by the catch angle plot. What is less satisfactory is that the effect went away as soon as I started monitoring a different metric.
  2. Looking at slip, I could consciously get the number down to 5 degrees and I like how I was rowing when I achieved that.
Monitoring catch angle in first 2km. You can see the effect ebb away after that.
Slip values – I could work on it consciously and get the lower values
Wash. I didn’t monitor this so the values are “as is”.

The Wash graph is also interesting for two reasons. First, I didn’t monitor “wash” during the row, so you can see a natural spread of finish angles (lean back?) and wash values. It is clear that a better lean back lowers the Wash values (which is better). It is also clear that on the long rows you cannot average over the entire row. The sloppy strokes (paddle strokes) all are biased to low values of finish angle and high values of wash. This distorts the average if you don’t look at a specific interval. The median value of 44 degrees is much more representative.

The two charts above show this well for the slip parameter. I plotted it against Work per Stroke (left) and Power (right). Good strokes are above 500 J per stroke. So that brings me into the slip values of 6-7 degrees. And as said, working on technique brought that down, which illustrates how this tool can help you work on technique.

Here are the overview plots of the workout:

And here is the full set of metrics plots:

Here is the row on Strava:

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Rowingchat-logo-on-soundcloud

Feb 28 2017

3x20min at the rowing club

I got up very early. We took the 6:07 train to Prague, for another visit to the embassy, this time with the kids, to get the documents for the rest of the family in order. I spent a few hours in the train updating the rowsandall.com site with some advanced filtering of Empower Oarlock data.

The training plan was clear and this is a training I recognize.

3x20min / 4 min rest. Alternate 20 and 22 spm each 2 minutes

I rowed this at the rowing club and the turnout was great. We Masters occupied 5 ergs. Doing the rate stuff in a row of five ergs is interesting when you sync your strokes, as we did.

I was on the erg next to the wall, and I did notice that air circulation is a lot worse there. I am used to my cold rowing basement and I did have a lot of trouble rowing in this hot, humid environment.


Workout Summary - media/20170228-1920230o.csv
--|Total|-Total-|--Avg--|-Avg-|Avg-|-Avg-|-Max-|-Avg
--|Dist-|-Time--|-Pace--|-Pwr-|SPM-|-HR--|-HR--|-DPS
--|15791|72:00.0|02:16.8|190.0|21.2|000.0|000.0|10.3
W-|14649|60:00.0|02:02.9|189.3|21.4|000.0|000.0|11.4
R-|01146|12:00.0|05:14.1|188.7|21.9|000.0|000.0|00.2
Workout Details
#-|SDist|-Split-|-SPace-|-Pwr-|SPM-|AvgHR|MaxHR|DPS-
00|04900|20:00.0|02:02.5|190.5|21.4|000.0|000.0|11.4
01|04883|20:00.0|02:02.9|189.8|21.3|000.0|000.0|11.5
02|04866|20:00.0|02:03.3|187.6|21.4|000.0|000.0|11.3

I was the slowest of the lot, but I think I am the only one who knows about a polarized training plan. I tried to explain that this should be rowed at “conversation” pace, but the others wanted to pull faster splits than their neighbors.

I am happy to report that my Sunday hour of updating firmware was successful. I have the full metrics from Painsled now.

No heart rate data. I recorded that separately on the Garmin, but I haven’t finished my Data Fusion functionality on rowsandall.com yet.

Oh and I should mention that you can listen to my on Sunday 8pm UK time, when I will be in the RowPerfect Rowing Chat: https://www.rowperfect.co.uk/rowingchat/

You can also download the podcast afterwards and listen to it later.

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corr

Feb 27 2017

First Empower Connected Row

So today I had a long gap between a busy first half of the working day and the evening series of conference calls, which was ideal to drive to Pisárky and do a longish outing in the single. This time I did pay attention to switching on the SpeedCoach correctly.

I did three “rivers”, i.e. rowing up to the hydro plant in Komín and back. That is a little over 2km per stretch of river, 4.4km per loop, and the total workout duration was 13km.

Rowing on a river is interesting for me as a lake dweller. There is much more waterfowl and bird life to watch during the row. Except for two mean looking swans that is really a plus. The other difference is how close you are to people walking on the banks. Mothers with prams and small children. People relaxing on park benches. People standing on bridges, just staring at the water. And most of those people smiled at me, which is great.

I played with the SpeedCoach settings. With the Empower oarlock, there is a whole set of new parameters to watch during as well as after the workout. The “classic” screen looks like this:

You set up the top row before the outing, but you can very easily switch what is displayed on the bottom row at the turning points. I was running the Garmin Forerunner in backup mode, so I didn’t need to see heart rate.  Here are the settings I chose:

  • Average Power & Instantaneous Power
  • Catch angle & Slip (a measure of how quickly you take pressure on the blade, after the catch)
  • Finish angle & Wash (a measure of how much the force drops off in the second half of the drive)
  • Total drive length (catch to finish) and effective drive length (taking slip and wash into the equation)
  • Max Force and Average Force
  • Max Force Angle & Work per Stroke

I found the effective drive length a really interesting metric to display during the row. I have to work on my sequencing, and when I do this right, I see that I maintain the effective length well above 85 degrees. When I become lax, it drops quickly. Average power seemed to be more relevant when you do pieces. I couldn’t relate much to the force numbers. I also liked to watch “work per stroke” but it isn’t entirely clear to me how to use it. Perhaps when you do rate ladders, you can try to keep this value constant when you go up the ladder.

Talking about all those metrics, here is what rowsandall.com had to say about correlations. Mind you, this is for a single row and I mainly rowed at 20spm.

Interesting that “wash”, which has to be low, strongly correlates with Peak force, power, drive length, finish angle. The only concern I have here is that with the twisty river, there were a lot of strokes where I was steering. Especially on the turns to starboard, where I row a slightly shorter, weaker stroke with my starboard scull, this may lead to a relatively large portion of “non-relevant” strokes.

Export to Strava, now with real power values:

Here are the big plots:

Classic OTW plot
With power plot

And here are the metrics plots:

I leave them without comments for now.

Now that I am a first-hand user of the Empower, I already discovered a couple of improvements that I need to implement on rowsandall.com. Also, I am suspicious of the drive length. Probably a small mistake in a calculation I made. I like how the SpeedCoach talks about drive length in degrees and I like the “effective drive length” parameter. To make this maximally effective, I will add these parameters exactly as they are represented during the row. That makes it easier for coaches and rowers to analyze the training and then transfer the lessons learned to the next practice.

Next time I will try out the “skill” screens of the SpeedCoach.

http://www.nkhome.com/rowing-sports/empower-oarlock

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IMG_1359

Feb 26 2017

Exciting and disappointing at the same time

So I had an exciting morning. I drove to the lake to pick up the trailer with three singles. As you can see, the lake was still frozen and it will take another few weeks before it will be rowable.

Frozen Brno lake

We took the singles to the place where our rowing club started 105 years ago, which we still own, even though most of the buildings are in bad need of renovation.

There, it didn’t take us long to get two single ready and we headed out on the water. My first row with the Empower Oarlock, so I badly wanted to record it. Unfortunately, I made a critical mistake. After a few months without using the SpeedCoach, it’s user interface managed to confuse me. Seeing the message “stop”, I figured it was running and recording, and I could “stop” that by pressing the “back” button.

So I happily selected which parameters to watch and went off rowing, already looking forward to taking a critical look at the data.

Unfortunately, as I just found out, you have to set it to “ready” and not to “stop”. All I have is a 27m segment when I was fiddling with the setup! 🙁

Other than that, the row was fun, and luckily I had the Garmin Forerunner running in parallel, so I do have heart rate and pace.

The rowable part of the river is about 2.5km long, between two sluices. It is quite windy.

In the first 2.5km, I selected stroke rate/pace/power/catch angle. I started with arms only, then arms and back, and then to half slide, three quarter and on to full slide. It was fun to watch the catch angle go up. If I remember well, I ended up around 61 degrees.

Power was around 180W. It dropped down to 120 when I was turning to starboard, and went up to 220W when I was turning to port. And as this is a windy river, there was a lot of turning.

At one point, I ran into a thin sheet of ice. Luckily, no scratches on the boat.

At another point, I surprised a few swimmers. I didn’t expect swimmers. I should have known better, with the Czech Republic the world center of cold water swimming. The girls were splashing in the ice cold river while Eda and I rowed by, and only on our second loop they were back on the shore. Amazing!

I experimented a lot with the third and fourth metric to watch, so on the first return leg I looked at slip and average power. Average power stayed at zero. (I know understand why, but it didn’t occur to me then.) Slip was around 4 to 7 degrees. Then I looked at wash and total stroke angle, with wash around 11 degrees, and total stroke angle around 107 degrees, if I remember correctly. And finally, back to power and finish angle. All very exciting. If only I had all the data afterwards. Well, I guess it’s my fault.

It was also fun to watch how my power remained consistently oscillating around 180W, while pace varied with the stream and wind.  I am already looking forward to training for the 6km head race and figuring out what power I can sustain over that distance. I plan to spend some time doing that, and then on race day I can just hold that power for 4 or 5km, and then go for it. Having power feedback available during a row is perfect. Really perfect.

I guess only in the turns, the power value can be deceiving.

After the row, I took a few pictures of our river rowing venue.

After the row I drove the trailer back to the lake venue. I took a shower there and replaced batteries and did firmware upgrades on 8 of the club ergs. After that I drove over to the electronics store to pick up a new Raspberry Pi for my little rowing data logger project.

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