OTW

Apr 14 2016

Windy Intervals – and a small step towards quantitative rowing

Wind predictions (from windfinder.com) for the Brno lake for today:

Morning: 5 m/s (max 11) – 3 Beaufort

Afternoon: 8 m/s (max 10) – 5 Beaufort

So the decision was easy, given that our lake can be choppy already at 2 m/s, depending on the wind direction. I will row in the morning. Today’s session was a 24×45″/R60″ at 29-30spm.

Indeed, when I arrived there was a fierce wind blowing down the lake. Chop was not too bad though.
Workout Summary - 2016-04-14-0718.CSV --|Total|-Total-|--Avg--|Avg-|-Avg-|-Max-|-Avg --|Dist-|-Time--|-Pace--|SPM-|-HR--|-HR--|-DPS --|07703|37:02.0|02:14.2|28.3|167.8|174.7|08.7 Workout Details #-|SDist|-Split-|-SPace-|SPM-|AvgHR|MaxHR|DPS- 01|02015| 11:01 |02:44.0|18.3|145.0|156.0|10.0 | Warming Up 02|00200| 00:45 |01:52.5|29.4|153.0|170.0|09.1 | Tailwind 03|00198| 00:45 |01:54.0|28.0|168.0|174.0|09.4 04|00200| 00:45 |01:52.4|29.4|170.0|176.0|09.1 05|00196| 00:45 |01:55.1|30.7|168.0|175.0|08.5 06|00199| 00:45 |01:52.8|29.4|169.0|176.0|09.0 07|00200| 00:45 |01:52.4|30.6|171.0|178.0|08.7 08|00173| 00:45 |02:10.5|29.3|168.0|176.0|07.9 | Headwind 09|00177| 00:45 |02:06.8|29.4|171.0|178.0|08.0 10|00174| 00:45 |02:09.5|28.0|174.0|179.0|08.3 11|00175| 00:45 |02:08.6|28.0|174.0|178.0|08.3 12|00178| 00:45 |02:06.5|29.3|174.0|179.0|08.1 13|00181| 00:45 |02:03.9|30.7|174.0|180.0|07.9 14|00197| 00:45 |01:54.2|29.4|169.0|177.0|09.0 | Tailwind 15|00000| 00:45 |0000:00|30.6|172.0|176.0|00.0 | GPS error 16|00000| 00:45 |0000:00|24.0|170.0|174.0|00.0 | GPS error 17|00193| 00:45 |01:56.5|29.4|164.0|173.0|08.8 18|00194| 00:45 |01:56.0|29.3|169.0|177.0|08.8 19|00186| 00:45 |02:00.6|28.0|169.0|174.0|08.9 20|00169| 00:45 |02:12.9|28.0|165.0|174.0|08.0 | Headwind 21|00177| 00:45 |02:06.9|29.3|172.0|176.0|08.0 22|00176| 00:45 |02:07.9|28.1|171.0|176.0|08.4 23|00173| 00:45 |02:10.1|28.0|170.0|177.0|08.2 24|00174| 00:45 |02:09.1|29.3|170.0|176.0|07.9 25|00179| 00:45 |02:05.2|30.7|173.0|179.0|07.8 26|01619| 08:01 |02:28.8|20.1|150.0|158.0|10.1 | Cooling Down

It was a nice session. In interval 15, the XGPS160 decided to stop. This external GPS is nice. It saves phone battery power, is more accurate and has a higher data rate than the in-phone GPS, but it has it’s glitches. In interval 16, I got massively waked by a bunch of water quality scientists in a fast motor boat. I saw them launching on the bank when I turned after interval #7. When I rowed down the lake again, they were speeding up the lake. They take water quality and other scientific measurement at various buoys on the lake, but they clearly don’t understand how to be a good skipper.

Here are the graphs. They are slightly different today.

What’s going on? I have added some rowing physics to the python plots to create a Power plot. The power plot takes into account the wind direction and strength, and that also enabled me to calculate what pace I would have had in windstill conditions. The whole thing is massively experimental, but so far it works. To get the wind effect, I had to estimate the drag factor of a rowing shell. I used these data from Kleshnev:

They are fits to a very old data set collected by Klaus Filter. I couldn’t find the original data. Some more data (or perhaps the same data in a different representation) were found on the Australian Nielsen Kellerman website. I used that to tune the drag constant to achieve realistic results in my calculations. Here is the reproduction of the top left picture of Kleshnev:

I had to create a shielding equation for the bigger boats. My data will be more reliable for the single. Anyway, you can see very clearly what every rower knows. Headwind slows you down more than tailwind speeds you up.

I did my calculation using an average wind direction and speed for the entire outing. If I mounted a wind meter on the boat, I could even have processed instantaneous wind.

For now I had to rely on data from nearby weather stations. It was interesting to see that those that are closest to the lake reported windstill (less than 1 m/s) weather for the time of my row. I definitely know that this is not the case. Here is the SportTracks report:

I suspect those people have their weather station in their nice garden surrounded by trees. Definitely not representative for what happens on a large body of water.

At the same time Brno airport (LKTB) reported about 6 m/s, but that was on the other side of the town. But it is in line with the wind prediction by windfinder.com.

In the end I did my calculations for a 2.5 m/s wind and a wind direction of 290 degrees. Produced credible results, given that I estimate that the headwind cost me about 10 seconds of pace.

Anyway, all this is just theoretical rambling. I would have to get a wind meter, mount it on my boat, and start measuring. Not sure if I will do that … they already consider me a nutcase right now.

I just find it interesting … and I like Physics.

By sanderroosendaal • Uncategorized • 8 • Tags: intervals, lake, OTW, rowing, training, wind

Apr 12 2016

OTW Steady State

Mirror flat water this morning. I copied the workout from yesterday, but for time reasons I had to skip the final 12 minute interval.

A little problem with the XGPS160. I have noticed that it works perfectly if you switch it on while CrewNerd is already running. My natural behaviour is to attach the XGPS160 to the boat and switch it on while still on the dock. I only switch on CrewNerd when I am already sitting in the boat and on the water. I need to remember to do it in the right order. This led to noisy data and suspicious pace values in the first two intervals (especially in the second one, which apparently I had rowed in 1:56 average pace.

I also suspect that the system doesn’t work well when other apps using GPS position are running in the background (like Waze, in this case).

Workout Summary - 2016-04-12-0726.CSV --|Total|-Total-|--Avg--|Avg-|-Avg-|-Max-|-Avg --|Dist-|-Time--|-Pace--|SPM-|-HR--|-HR--|-DPS --|13271|59:52.0|02:16.7|19.1|148.2|157.2|11.5 Workout Details #-|SDist|-Split-|-SPace-|SPM-|AvgHR|MaxHR|DPS- 01|01345| 05:55 |02:11.6|17.8|125.0|139.0|12.8 | warming up 02|02721| 12:00 |02:12.3|18.9|149.0|160.0|12.0 | interval 1 03|03089| 12:00 |01:56.4|19.7|156.0|166.0|13.1 | suspicious 04|02502| 12:00 |02:23.9|20.3|160.0|167.0|10.3 | interval 3 05|02513| 12:00 |02:23.2|20.1|159.0|166.0|10.4 | interval 4 06|01101| 05:57 |02:41.9|17.8|140.0|145.0|10.4 | cooling down

Here is a map of the row from Strava, from the CrewNerd app:

You can see the straight line for the third and fourth intervals, after I had reset the XGPS160, and the wobbly line from the first and second intervals, before the reset.

Here is the same segment as recorded by the Garmin Forerunner:

The colorful plots:

First 30 minutes suspicious pace data – rest is OK

By sanderroosendaal • Uncategorized • 3 • Tags: lake, OTW, rowing, single, steady state, training

Apr 7 2016

Taper Race Day minus Two

The workout

My plan for today was to do a 50 minute row, and have one “lake” of 30 sec / 60 sec rest at race pace.

Arrived at the club. Had a nice chat with the head coach. He saw the Holland Acht (Dutch 8+) training in Gavirate, and expects them to be very good at the Olympics. Nice. I casually asked him what his guys were doing today. “One lake at 22spm, then one lake 30″/60″ rest”, he answered.

Typical.

So it must be a good training to do two days before the race.

Workout Summary - C:Downloads2016-04-07-1545.CSV --|Total|-Total-|--Avg--|Avg-|-Avg-|-Max-|-Avg --|Dist-|-Time--|-Pace--|SPM-|-HR--|-HR--|-DPS --|04020|18:08.0|02:13.9|28.7|162.9|173.4|09.2 Workout Details #-|SDist|-Split-|-SPace-|SPM-|AvgHR|MaxHR|DPS- 01|03008| 13:38 |02:16.1|22.5|160.0|171.0|09.8 | 3km 02|00124| 00:30 |02:00.7|28.0|150.0|165.0|08.9 03|00000| 00:30 |0000:00|30.0|165.0|173.0|00.0 | GPS failure 04|00125| 00:30 |02:00.1|30.0|156.0|171.0|08.3 05|00124| 00:30 |02:01.3|28.0|163.0|174.0|08.9 06|00125| 00:30 |02:00.2|28.0|166.0|175.0|08.9 07|00127| 00:30 |01:58.3|28.1|166.0|174.0|09.1 08|00128| 00:30 |01:57.5|30.0|166.0|175.0|08.5 09|00128| 00:30 |01:57.3|30.0|165.0|176.0|08.5 10|00131| 00:30 |01:54.9|32.0|172.0|180.0|08.2

The lake was super flat. One would think there was no wind. I thought so. I thought so during the warming up, and during the first 3km stretch at 22spm. I was really excited to see my average split drop below 2:20 for that part. (By the way, I rowed this as a CrewNerd set course, with start and finish lines that you can define in Google Earth and then upload to CrewNerd. Nice feature.)

But when I turned, I quickly realized that there had been a very light breeze pushing me.

On to the 30 second intervals. My GPS device stopped during the second interval and I had to reset it. That causes the peaks in the graph and the absence of data in interval #3.

Otherwise, it was nice. I know what to focus on to row my best head race stroke, so I tried to focus on that, and I think it works. Keywords: Length. Reach. The Distance-per-Stroke (DPS) parameter is what I monitor.

Programming fun

Just for fun, I wrote to Concept2 for the API to the Concept2 logbook. I got an answer today with a link to a description and a form to fill out and get an API key. So, in principle it is possible to change my Python code so it uploads much more row data to the Concept2 logbook, including splits, so the logbook can create the nice graphs that you get with ErgData.

I am very unexperienced with HTTPS requests (in any programming language), so I am probably not going to do this.

What it tells me is that C2 logbook integration is doable. Painsled, CrewNerd, NK, others: You can do it! I would love to see this integration, as well as direct upload to Garmin, Strava, SportTracks, and of course CSV and TCX downloads. That would be very cool.

By sanderroosendaal • Uncategorized • 0 • Tags: head race, lake, OTW, rowing, single, taper, training

Apr 7 2016

Race Day Logistics for a LW Masters rower

I will race in 2 days. In the elite Light Weight category. Just because there is no Masters category on this race.

So this will be one of the few rowing races this year (perhaps the only one) where I will have to make weight. My natural weight oscillates around 72kg, so it should not be a big problem. The challenge is always that I am a few kilograms more on January 1. Well. who isn’t? Here is how my weight has been going in the past few months:

The blue symbols are measurements. Always measured first thing in the morning, after a visit to the bathroom. The fat orange line is the line I need to be under on Saturday. The blue line is a linear fit to the trend in the data, and the thin orange line is the moving average with a window size of 5 measurement points.

A few things. You can see that the day to day oscillations are big. Almost 2kg sometimes. I strongly suspect that that is mostly water. I was happy I knew this and didn’t worry about those oscillations too much between January and now. The consequence, of course, is that I want to be well under the limit approaching race day, or otherwise I will have to dehydrate myself.

By the way, I didn’t do anything special to lose the weight. Regular exercise, of course. And no fizzy soft drinks. Beer and wine limited to the weekends, with the exception of business dinners.

On race day, I need to make weight between one and two hours before the race start time. After that, there is time for a quick snack and some drinking. I need to buy some bars and sports drinks for that time window. Also, there are no shops in the starting or finish area. In the starting area, there is nothing. In the finish area you can buy softdrinks and grilled sausages. :-/ So, I need to plan carefully and take all my food and drinks with me.

So that was the easy logistics challenge.

This year, my daughter is racing as well in the Girls 15/16 category, and that will make it really interesting. Almost as if I am doing two races. Why?

Here’s is the starting list and time order:

http://www.veslo.cz/17-mistrovstvi-cr-na-dlouhe-draze-s-mezinarodni-ucasti/25043315/startovni_listina_horin_2016.pdf

Lenka’s start is at 13:08. My start is at 14:33, and that is the time when the officials start my race clock, even when I actually pass the starting line later. There is 85 minutes between that. Let’s say Lenka’s race takes 30 minutes. That leaves 55 minutes to

Take the single out of the water and load it on the trailer. This will involve carrying it through the finish area crowds, because I doubt we will be able to get the trailer any closer than 500m to the finish line. This will take at least 15 minutes.
Drive 10km to the starting area. This will take 15 minutes.
Change footstretcher setting. Launch. This will take 10-15 minutes.
Row to the start line. This will take 5-10 minutes.

There is very little slack in this schedule. 🙁

Luckily I can put the single on the top level of the trailer without actually removing the wing rigger.

Here’s a map of the race. The green polygon is the approximate position of the start line. The red one is the finish. The yellow ones are boat/trailer areas. The race is 6 km long.

Oh boy. I will have to have a very relaxed attitude to all this, and take it with some lightness. If I miss the start time, I will miss it. Will measure my real time on CrewNerd and then check where I would have been in the results if …

By sanderroosendaal • Uncategorized • 2 • Tags: head race, OTW, race prep, rowing, single

Apr 5 2016

Taper intervals

With all the python stuff I forgot to spend some time on Sunday to plan this week’s training plan in detail.

So in the morning I drove to the club with only a vague notion. I wanted to test a bit at race pace, but have a short training. One, it’s taper week. Two, I was late and needed to be at work in time. I contemplated 500m intervals at race pace.

At the club I met the head coach, and I asked him what he was planning for his team (the men). They were doing

5x(5min)/R4 at 22/24/26/28/30 spm

That was an interesting session. Good training at race pace, but it starts slower, so you can focus on technique and build up to the race pace. I was sold, but I made it slightly lighter:

4x(4min)/R4 at 22/24/26/28. Last minute in last interval to be at 30spm

Here is how I executed it:

4x4min. Third interval in headwind. Massive wake a few meters into the last interval

Workout Summary - C:Downloads2016-04-05-0730.CSV --|Total|-Total-|--Avg--|Avg-|-Avg-|-Max-|-Avg --|Dist-|-Time--|-Pace--|SPM-|-HR--|-HR--|-DPS --|03727|16:00.0|02:08.8|24.9|165.5|172.2|09.4 Workout Details #-|SDist|-Split-|-SPace-|SPM-|AvgHR|MaxHR|DPS- 01|00912| 04:00 |02:11.6|21.5|156.0|161.0|10.6| 22spm, tailwind 02|00950| 04:00 |02:06.3|24.2|166.0|172.0|09.8| 24spm, tailwind 03|00884| 04:00 |02:15.7|25.7|171.0|177.0|08.6| 26spm, headwind 04|00981| 04:00 |02:02.3|28.0|169.0|179.0|08.8| 28spm, tailwind

Actually, the 26spm and 28spm felt more comfortable than the 22spm and the 24spm. I guess that is good. I also used stroke counting on those sessions, so maybe it is just a psychological thing. The 4 minutes seem to pass faster when you count to 100.

By sanderroosendaal • Uncategorized • 1 • Tags: lake, OTW, rowing, single, taper, training

Apr 2 2016

A 6km with competition

Today we planned to row a 6k. On our lake, this has to be a 6k with a turn in the middle. When we arrived to the lake, there was mirror flat water. Even when we pushed off, the water was flat. During the warming up, the wind started to blow and within ten minutes there was a nasty chop, which, as the 6k progressed, turned into a very nasty chop. I had a sweater in the bottom of the cockpit, which was completely soaked after the row.

A measured 6k. Three boats. A youth 15/16 single, a youth 15/16 pair, and me. We started with 1 minute intervals, first the young single, then the young pair, and finally me. I argued a bit with the youth trainer about the location of the start of the 6k. He has been timing 6k all his life with a starting point at a certain cliff. I have measured out the 6k with a GPS and I told him we had to start at the red buoy, which is about 150 m earlier. In the end I gave in and started from the “traditional” starting point, but when I passed the finish line, CrewNerd told me I still had 300m to go, so I kept going to complete the 6k.

Final result according to the trainer, who subtracted 30 seconds for the turning:

Youth single in 25:02
Me in 25:05
Youth paid in 25:10

Not sure about the absolute times, but I believe the order is ok. I tried to row towards the pair but couldn’t get closer to them. I guess they tried to row away from me and couldn’t increase the distance.

The row was slow and nasty. I should have put my oarlocks a bit higher. I was slamming into the chop. In the first half, the head wind slowed me down significantly at times. In the second half, with tailwind, I didn’t manage to rate up as much as I wanted. It started fine with paces around 2:02 – 2:05, and I had hope that I would get the average pace down to 2:13. I didn’t.

I have been a minute faster on this course, but that was with flat water.

Workout Summary - 2016-04-02-1008.CSV --|Total|-Total-|--Avg--|Avg-|-Avg-|-Max-|-Avg --|Dist-|-Time--|-Pace--|SPM-|-HR--|-HR--|-DPS --|06000|27:22.0|02:17.0|26.6|175.0|180.0|08.2 Workout Details #-|SDist|-Split-|-SPace-|SPM-|AvgHR|MaxHR|DPS- 01|06000| 27:22 |02:16.8|26.6|175.0|180.0|08.2

Overall summary:
Workout Summary - 2016-04-02-1008_data.CSV --|Total|-Total-|--Avg--|Avg-|-Avg-|-Max-|-Avg --|Dist-|-Time--|-Pace--|SPM-|-HR--|-HR--|-DPS --|10465|65:23.0|03:07.4|21.6|157.4|180.0|07.4

By sanderroosendaal • Uncategorized • 2 • Tags: OTW, rowing, single, training, trial

Apr 1 2016

Long Reach (not Long Beach)

Again a quick row between meetings. Raced to the lake. Rowed. Raced home to dial in to the first call of the afternoon.

The session was again a 10 strokes on/10 strokes off, but I changed it and dialed up an old workout: 3x(5x30sec)/8min with 30 seconds of rest in the first set, 45 seconds in the second set and one minute in the final set. I didn’t go above 30 spm and tried to reach long. I noticed that this has a big influence on my boat speed so I want to ingrain this habit firmly.

It was a choppy business on the lake, so I first rowed up to the castle on the river, to seek quiet water. Did the first two intervals there and the final one on the lake with tailwind and stronger and stronger chop, the closer I got to the bottom of the lake. You can see the “lap” points on this little map:

Here are the pretty plots. I am starting to miss having to mess with excel. Now I have the python command line tool it has become a very quick process. The only hassle is having to email the files to myself to get them off the iphone:

Tomorrow, I will row a “sharp” 6k against some of the junior pairs. Race is in 8 days …

Here are the stats for the intervals:Workout Summary - 2016-04-01-1301.CSV --|Total|-Total-|--Avg--|Avg-|-Avg-|-Max-|-Avg --|Dist-|-Time--|-Pace--|SPM-|-HR--|-HR--|-DPS --|01895|07:30.0|01:58.7|29.5|163.5|170.7|08.6 Workout Details #-|SDist|-Split-|-SPace-|SPM-|AvgHR|MaxHR|DPS- 01|00117| 00:30 |02:07.9|28.0|144.0|161.0|08.4 - 30 sec rest & headwind 02|00114| 00:30 |02:11.1|28.0|164.0|169.0|08.1 03|00120| 00:30 |02:04.6|28.1|164.0|170.0|08.6 04|00123| 00:30 |02:02.6|27.9|166.0|172.0|08.8 05|00121| 00:30 |02:03.6|28.1|168.0|173.0|08.6 06|00128| 00:30 |01:57.4|29.9|157.0|167.0|08.5 - 45 sec rest & tailwind 07|00128| 00:30 |01:56.6|30.0|163.0|170.0|08.5 08|00130| 00:30 |01:55.1|30.0|168.0|175.0|08.7 09|00122| 00:30 |02:02.6|30.0|167.0|171.0|08.1 10|00130| 00:30 |01:55.9|29.9|167.0|174.0|08.7 11|00132| 00:30 |01:53.8|29.9|158.0|167.0|08.8 - 60 sec rest, tailwind 12|00133| 00:30 |01:52.9|30.0|166.0|172.0|08.9 13|00132| 00:30 |01:53.6|30.1|164.0|170.0|08.8 - increasing chop from here 14|00133| 00:30 |01:52.3|32.1|167.0|174.0|08.3 15|00132| 00:30 |01:54.0|30.0|169.0|175.0|08.8

Overall summary:

Workout Summary - 2016-04-01-1301_data.CSV --|Total|-Total-|--Avg--|Avg-|-Avg-|-Max-|-Avg --|Dist-|-Time--|-Pace--|SPM-|-HR--|-HR--|-DPS --|11943|64:34.0|02:42.2|20.0|150.7|176.0|09.2

In the mean time, my PM5 is now unstuck from customs, where it was stuck over the long Easter weekend. The parcel is now traveling to my local post office. Knowing the Czech Post, they will try to deliver on Monday or Tuesday. However, I will not be at home, so they will just drop me a note and then I will pick up the parcel at the post office on Tuesday or Wednesday. I need to be patient.

By sanderroosendaal • Uncategorized • 0 • Tags: intervals, lake, OTW, river, rowing, single, training

«< 38 39 40 41 42 >»

OTW

Windy Intervals – and a small step towards quantitative rowing

OTW Steady State

Taper Race Day minus Two

Race Day Logistics for a LW Masters rower

Taper intervals

A 6km with competition

Long Reach (not Long Beach)

Calendar

Tags