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Mar 30 2017

Dream on, Sander & Rowsberry Pi

How many times have I made this mistake? Many times.

Actually, I was fully aware that I was making this mistake when I made it. But I guess this is how I am wired. I was going to try anyway.

This is the failure mode:

  1. Go on a business trip
  2. Return late in the evening
  3. Have a busy day at work catching up with all the stuff of running a research department
  4. Plan to row an erg test (a 6k this time) in the evening
  5. Fail

Our coach wanted us to row the spring 6k test a week ago, but I was in Racice rowing on the water. This week I was on a business trip. Today I was doing item 3 above, with on top of that a key meeting where I had to announce a major course change to a project team, as well as two technology demonstrations to our CTO. So it was quite a busy day,

Oh, and I hadn’t slept too well. Some stuff related to growing up children that kept me awake. I guess the usual stuff parents go through.

But I still wanted to give the 6k a try (and at the same time record a time for the 5142 meters CTC challenge). So I dialed up a 6k.


Workout Summary - media/20170330-2015100o.csv
--|Total|-Total-|--Avg--|-Avg-|Avg-|-Avg-|-Max-|-Avg
--|Dist-|-Time--|-Pace--|-Pwr-|SPM-|-HR--|-HR--|-DPS
--|06000|24:10.0|02:00.8|203.8|24.0|163.9|178.0|10.3
W-|06000|24:10.0|02:00.9|201.9|23.9|163.9|178.0|10.4
R-|00000|00:00.0|00:00.0|000.0|00.0|000.0|178.0|00.0
Workout Details
#-|SDist|-Split-|-SPace-|-Pwr-|SPM-|AvgHR|MaxHR|DPS-
00|01500|05:32.6|01:50.9|254.5|26.6|166.2|178.0|10.2
01|01500|06:15.8|02:05.3|187.8|23.8|161.4|178.0|10.1
02|01500|06:09.1|02:03.0|188.0|22.7|163.1|168.0|10.7
03|01500|06:12.7|02:04.2|182.9|22.7|165.0|170.0|10.6

So you can see that I gave up after 2000m and made this an ordinary steady state row.

Well, I guess I will always dream.

Rowsberry Pi

Talking of dreaming. The Rowsberry Pi is going well. I have a quickly hacked version that logs my workouts automatically and sends each workout to a configured email address when you press the Menu button on the PM.

Rowing with the iPhone running Painsled, it was kind of cool to see emails coming in immediately after I pressed the menu button.

This project is now officially Open Source and it lives on Github. One developer has joined me and is doing a fine job of decluttering and refactoring the code.

The end goal should be an easy to use software that you can burn to a microSD disk and use with a Raspberry Pi. The software should be used as a datalogger, and will then be expanded to be much more than that.

Any rowing Software developers skilled in Python out there? Come and join the effort. I guess this is a dream project in a way … so if you like to do things that can’t be done, and you are a rower … come join!

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Mar 29 2017

Wahoo! Hotel room fitness

Tuesday evening: Business dinner. It was quite late when I arrived back in my hotel room. In the morning, I snoozed the alarm and prioritized an additional hour of sleep over a full workout.

Still, I was interested to explore use of my new Wahoo Tickr X heart rate strap in combination with the iPhone and a hotel gym/hotel room.

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First I headed to the gym on the 8th floor. It was very hot in the gym, but I grabbed a treadmill and opened the Wahoo app.

But which app? Wahoo has an entire suite of apps but to me they all seem to be very overlapping in functionality. First I tried “Wahoo Fitness” but I couldn’t even get the app to connect to the Tickr X. It saw the Tickr, but it got stuck on “connecting”. I tried Wahoo RunFit, with the same result.

Only when I stopped recording on my Garmin Forerunner watch, I succeeded in pairing the strap to the phone. That was a bit disappointing. With the SpeedCoach and with CrewNerd, I was able to successfully pair with the phone through Bluetooth and with the Garmin through ANT+.

Now I had the RunFit app open so I continued on the RunFit. I wanted to see the special running metrics that I was promised, stride rate and running smoothness. The values were “–“. Only when I picked up the phone from the treadmill and held it in hand, was I able to get some parameters. Apparently this works with the motion sensors in the phone, not the motion sensors in the strap.

It was very hot and I also wanted to do some strength exercises, so I headed back to the hotel room.

I changed the RunFit app to the “7 minute workout” (again, I struggled a bit with the connection but succeeded in the end), and got started.

But this was fun! I am the type of “athlete” who has no difficulty to run or row for hours, but I do have issues doing circuits or strength training on my own. I need supervision there. The iPhone gave me instructions, and using the motion sensor in the Tickr X counted the number of push-ups, lunges and other exercises. Also, I think the 7 minute circuit is a nice mix of body weight exercises. (The only think you need is a chair). I did the circuit twice, before I had to get ready to go to my meetings. In the second round, the app reminded me of my best effort (from the first round). I really feel the iPhone voice giving instructions and counting the repeats with me was enough “supervision” to get me to do these circuit trainings properly.

What was also neat was a color coding on the phone. The app background was blue if you did the exercise “so-so” and green if you did it better (deeper push-ups, less body movement during plank, etc). I like that.

I was excited to see sharing functionality with Strava in the FitRun app, but unfortunately it only syncs heart rate and time. I was hoping that the number of repeats for the different exercises would at least be captured in the Notes section.

Here are a few screenshots:

The March CTC effort (a full out 5143m on the erg) is at risk of not being done. It will depend on how Thursday goes, but as we have a visit of our CTO, so I have little hope of carving out time and being rested enough to do the CTC.

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Mar 28 2017

Monday – Guest row with the double

Arjan is my old training partner when we were both studying in Utrecht and rowing for Orca. He is over in Vienna for a week long conference, decided to fly in half a day earlier and hop on the train to Brno. I picked him up at the railway station at the end of the afternoon and we headed to the lake.

We took the double “Orca” for a tour of the lake. We rowed up to the castle and then crossed the lake. This was a steady state session so we did most of it at 20spm, with an occasional excursion to 22spm. Arjan really enjoyed the scenery. In Weert and Eindhoven they are rowing on narrow canals in an industrial setting, so being in the middle of a forest, in a canyon, between rocks, was quite a change for him.

He also needed some time to get used to navigating on the lake.

Then we went to my place to have dinner, chat a bit, and at in the end I brought him to the last train to Vienna.

This morning the alarm clock rang at 5AM. At 5:30 the driver was already waiting. I hopped in the car and headed to the Vienna airport. I took the flight to Brussels. First time I flew on a Sukhoi SSJ100 aircraft, operated by City Jet for Brussels airlines. Lots of leg space!

Tomorrow morning: Hotel gym workout.

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Mar 26 2017

Technique row in the 2x

A short outing with Romana, just to check that our double “Orca” is in good shape. She is.

Lots of technique drills and footstretcher adjustments.

The water was a bit “bumpy” today. Sunny but not so warm.

Tomorrow: A 6k row on the erg. Tuesday travel / rest day and wednesday hotel fitness circuit.

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Mar 25 2017

Sunny Steady State Session (SSS session)

This was just a very nice morning at the rowing club. Arrived at 9:30, in time for my son’s training time. Lenka helped me swap the oarlock pins on my single for better ones. Since I have backstays, I need the screw-thread on the top of the pin to be longer for all the bolts to fit on nicely. So that is now the case.

Then I took the single for this year’s first row on the lake.

Here is the graph from rowsandall.com:

During the row, I had set the SpeedCoach monitor to the most basic parameters you can have: Stroke Rate, Pace, Distance and Elapsed Time. I just focused on rowing. It was nice weather. This was a 12km steady state. I was tired from the week in Račice, and I didn’t feel like focusing on complex parameters.

The Empower Oarlock magnet moved a bit during the row. Even though I had screwed it tight. I suspect that the new pins are a bit greasy. This made the catch and finish angle measurements unusable, but all the other metrics are still valid. I leave it as an exercise to the reader to spot the headwind and tailwind segments. As a hint, the nearest airport (16km) reported 3kt wind from the North.

After the row, I took out our double and rigged it. It was nice to stand in the sun, mess around with a double, and chat with the other rowers.

I fell asleep in my chair while trying to process my workout. I guess I have some lack of sleep and accumulated fatigue.

I hope to persuade Romana to go for a technique outing in the double, followed by a sauna session. By the way, Romana was in Pardubice today to do rowing trainers’ exams. She passed. Yay! Now she is officially certified.

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Mar 24 2017

The Proof of the Pudding – a 6k head race test with power meter

So yesterday I had some theories about how you can use the metrics of a power measuring oarlock (the NK Empower Oarlock in this case) to find an optimum race strategy and keep an eye on technique during the race.

This morning I tested some aspects of this theory. This is part of the philosophy I have for the rowsandall.com rowing data analytics site. I will try to test as much as I can so that you, the users, can be sure that what we recommend has been tried and tested. We (that is I and our alpha and beta testers) use all the apps that the site is compatible with and we make quick adjustments when something doesn’t work.

Back to the 6k test now. First, I did a 2k warming up:

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After that is was time for the proof. I set the SpeedCoach display as follows:

  1. Top Left: Stroke Rate
  2. Top Right: Instantaneous Power (Watts)
  3. Bottom Left: Effective Stroke Rate (degrees)
  4. Bottom Right: Work per Stroke

For (4), you could argue that I should have chosen maximum or average force, but the problem was that I didn’t have a feel for the data. This is partly my own fault. On the site, I am using pounds, a horrible American unit, while the SpeedCoach uses the perfectly sound Newton. I need to convert the site to Newtons. I don’t think anyone will object. For now I use work per stroke, though, because I feel I shouldn’t go above 550 J or below 500 J.

The effective stroke length is the stroke length minus slip and wash, so it is the arc through which you are effectively pulling. Stroke rate was there to check that when the other metrics tell me to lighten up and rate up, I am actually achieving that goal.

So, no pace information? No distance? Correct. As I was rowing on a 2k FISA compliant race course, I had enough visual clues about my position, with a sign every 250m, and a sequence of buildings as you approach the finish line. And pace? I decided that pace was irrelevant. (I did cheat a little, because my Garmin watch on the scull provided pace in time per km, so a division by 2 would give me the infamous pace per 500m.

There was a light wind, which would be a headwind in the first and last 2k sections. After each 2k section, I would have to quickly turn. I contemplated setting the row up as a 3x2km workout with 1 minute rest, but decided I wouldn’t do that. I rowed it as a Just Row.

Here are the results:


Workout Summary - media/20170324-083240-SpdCoach 2136923 20170324 0726amo.csv
--|Total|-Total-|--Avg--|-Avg-|Avg-|-Avg-|-Max-|-Avg
--|Dist-|-Time--|-Pace--|-Pwr-|SPM-|-HR--|-HR--|-DPS
--|06117|27:20.0|02:14.1|225.9|26.3|173.9|185.0|08.5
W-|05908|25:36.0|02:10.0|232.8|26.4|174.0|185.0|08.7
R-|00211|01:44.0|04:06.0|099.1|24.0|171.9|185.0|00.0
Workout Details
#-|SDist|-Split-|-SPace-|-Pwr-|SPM-|AvgHR|MaxHR|DPS-
00|01968|08:33.0|02:10.3|234.7|26.4|167.0|177.0|08.7
01|01976|08:34.0|02:10.0|231.0|26.1|175.4|181.0|08.8
02|01963|08:29.2|02:09.7|232.7|26.8|179.6|185.0|08.6

In graphs:

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I wasn’t entirely sure about the ideal Power value, but I guessed that 250W would be too much, and I took Monday’s 4x2km at 211W as the lower boundary. In the end that worked out to 233W average. During the row I saw it vary between 210W and 250W. Some of that was due to course corrections (the wind was a headwind but also a slight crosswind). I was worried about the low stroke rate, but I also know it takes a few of these trials to get the stroke rate higher. I decided to stop worrying about it and focus on length, power, and work per stroke.

The effective length was a bit lower than I had hoped, and I consciously worked to get the values above 90 degrees. But then, I didn’t want to look at the SpeedCoach for each and every stroke, so the values slipped a bit as I got tired. I think you can also see that my effort was quite constant in the end.

The question is always if I could have gone faster. In a 6k race, on race day with the adrenalin, and without the turns, I think I could. But still it will be a smart strategy to stick to these values for the first 4.5km, and only go faster in the final stretch.

bokeh plot (12)

Drive length oscillating around 89 degrees (would have liked to see a bit more there).

 

bokeh plot (11)

Catch and finish angles in a pretty narrow range.

 

bokeh plot (10)

It looks like work per stroke and power are mainly determined by the drive length.

 

bokeh plot (9)

 

bokeh plot (8)

Pretty constant in the average drive force. This tells me that most of the Work per Stroke variations are from the effective drive length.

 

bokeh plot (7)

Not sure what the big differences in catch angle mean.

 

bokeh plot (6)

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Mar 23 2017

Thursday – Racice day 4 – finding the sweet spot

The training plan said:

Warming up. 4km 10 strokes on / 10 strokes off. Then Steady state.

And that is almost exactly what I did. I kept the stroke rates in check in the “on” intervals, because I am looking for that ideal 6km head race stroke.

Still, looking at Power, I went way above 300W. On Monday’s 4x2km training, I only managed 211W average. So clearly 300W is not sustainable. Even if I take into account that on Monday I was still recovering from the week in the US.

I set the SpeedCoach to show stroke rate, pace, as well as Work per Stroke and Power, and looked at the Work per Stroke numbers at steady state pace. Then I did 250m intervals at higher stroke rate, but keeping the Work per Stroke around the same number. That way, I found this perfect light 30spm stroke which I think may be sustainable. I will check tomorrow.

I have this working hypothesis that the ideal stroke is in a sweet spot where three parameters are optimized, a bit like in the following picture:

The ideal power is given by the length of the race, so it has a narrow range where you can slightly negative split over the entire length of the course.

The ideal stroke length (given optimal foot-stretcher setting) is given by a minimum catch angle to work in the effective range, and the maximum catch angle that you can achieve. Arguably you should use “effective stroke length”, which gives you an additional penalty for slip and wash.

The ideal stroke (average) force has an upper bound. If you cross that, muscle fatigue will slow you down even when your fitness would allow you to continue at given power.

If you pick power, stroke length and average force, you basically have fixed stroke rate, stroke rhythm, and all the other parameters.

Of course, for sprint races, a similar diagram can be drawn but the values will be somewhere else.

It’s just a theory. And there may just as well be three other parameters to look at. During the row, I looked at Work per Stroke (which is stroke length times average force) and Power.

The nice thing about these metrics is that they are actionable. In the middle of a race, you can actually monitor these parameters on the SpeedCoach, and when they are not in the right range, you know exactly what to do. If I had to monitor “check” or some other complex parameter, I would find it difficult to act if the metric was outside the optimum range. I personally think this is extremely important. For rowing data analytics, we must focus on metrics that are easy to communicate, meaningful (as in influencing boat speed) and actionable.

So here is today’s training:

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Zooming in to find that Sweet spot:

bokeh plot (3)

 

Drive length is nearly constant, but effective drive length increased with stroke rate. Not sure if that is good, but it is probably also a consequence of how “slip” and “wash” (and thus effective drive length) are defined in the NK world.

The left-hand side plot shows power and average drive force. The right-hand side plot show work per stroke and stroke rate. The green area shows where I tried to find the sweet spot (in terms of work per stroke). The blue dots that are higher are from the 10/10 stroke intervals, where I pulled too hard.

That was my training.

The canal was really busy today. In the morning, there was a FISA visitation related to the upcoming European Rowing Championships. Then Czech TV arrived and started filming. “Our” girls Lenka and Iva even gave interviews for the TV. After that, there was a press conference.

In the afternoon I swapped the Empower Oarlock to Iva’s boat and set her up to monitor Finish Angle and Wash. I told her to keep finish angle at 40 degrees (which she did) and wash below 20 degrees, or as low as she could (which she didn’t). This shows how we have to learn to work with the oarlock as a technique tool. I forgot to tell her what the number is, and how she could work on reducing it (because it was clear in my mind). So the metric was not really actionable for her.

So in the end she didn’t improve too much, even though visually it looks like her layback has improved over the week. I took a closer look at her rowing and I think there is also an element of “blades popping out of the water” in the last part of her stroke. Even with a slightly less exaggerated lean back, there just isn’t a lot of power in the last part her stroke. After the row, we showed the data to her again, and I told her she can go a lot further on every stroke if she finishes strong. It will be interesting to see if that sticks.

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