OTW

May 11 2017

Thursday – Steady State

Every day is different this week. Today it was a nice 21 degrees and sunny. Krocan and I went out in singles and we did a long steady state row. It was choppy when we started and flat when we finished. In the chop, I rowed away from Krocan easily. On flat water, the difference was smaller. I worked on sending the boat at the finish, tapping down clean and keeping the wash metric low.

You can see how the total drive length has a much smaller spread than the effective length.

On rowsandall.com, the wash numbers always look a bit worse than what I expect from the numbers I see in the boat.

All this focus on “wash”. Does it really pay off? I decided to filter my rowsandall.com OTW rows on “Steady State” and look at the median value of Wash and its standard deviation. The result is sobering:

I added the average wind strength as reported by the Dark Sky network to the plot. It seems the wind (and probably chop) is the biggest factor influencing the Wash value and its spread.

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

May 11 2017

Two rest days and a hard session (lactate, lactate!)

Monday was a travel and tourism day, and tuesday was a very long day at work, and after the long weekend I was behind on a couple of important work related duties, as well as evening conference calls with final reviews of some project proposals, so I had to skip training. I didn’t mind much. I think a 2 day gap now and then, when life and work get in the way, is actually quite healthy and definitely not detrimental.

This also gave me a motivation to do a really hard training, although I chickened out of what our head coach had posted on the training plan board:

2x(7×50″/10″) @ 34-36 spm, 5 minutes rest between the 2 sets

That is like 30 strokes “on”, 3 strokes “rest”, for 7 minutes, at a stroke rate that I cannot hold for 4 minutes. Driving to the rowing club, I was thinking of what to do with these instructions. I was also curious to see how many of our Masters rowers would turn up on this Wednesday and what boat type I would row.

Turns out that through back injuries, work related duties, business travel, we had 4 rowers of our eight, plus 1 younger guy who rows with the Masters group occasionally. The issue, however, was that that one guy is not comfortable rowing a single, and one of the others is not a sculler. He only rows sweep. I got a little impatient when we hadn’t decided after 25 minutes so I announced that I would go in the single (which would also enable me to row my own session). The sweep rower Bulda teamed up with Krocan to take a pair, and the remaining two got out in a double.

We have the full Albano lanes out because of the International Youth Regatta of coming weekend, so I wanted to do 2x”something intensive at high stroke rates” in the 2k course. My training phase prescribes ANC training, which is short intervals with rest, and many of them, to get the body to produce lactate (as fuel, which I will condition the body to use in the subsequent phase).

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After 2k of warming up, I stopped to fiddle with my HR strap. I had the feeling that it was too lose and that I felt the strap on my back creeping down slowly. So I tried to adjust it back, which led to it snapping. The Wahoo Tickr straps connect with snap fasteners to the sensor “pod”. They call it the “two-snap” connection which is easy to get on and off. Well. It snapped. Under two layers of clothing (because it was cold), with me being in a single on cold water.

So I removed the upper part of my uni, clamped the scull handles between my belly and my legs, and tried to use two hands to snap on the HR strap. Initially, I failed, and I ended up holding only the sensor, with the strap being somewhere under my clothes, and discovering that my left blade had turned and was now perpendicular to the water, in flipping position. I corrected that, and proceeded to struggle. In the end I managed to snap everything back on and get my clothes in order as well. Without flipping.

Krocan proposed 20 strokes “on”, 10 strokes “off”, and that seemed a very good compromise. At this point, I was incorrectly remembering the training schedule and thinking that there were 3 series of 50″/10″, so I agreed with his proposal, thinking that we would 3 full 2k distances of them.

It was nice to row this next to the pair. I called out every eigth stroke of the paddle and grunted after the 20th (final) stroke of each interval. I managed to beat them by about a length over one entire 2k course. Looking at the graph, I see we did only 7 intervals per 2k. It felt more like 9 or 10. Anyway, after the first (headwind) and second (tailwind) 2k all three of us were so worn out that we couldn’t think of doing another series. So we just rowed the final 2k at steady state pace, followed by a cooling down.

During the intervals, I saw how I achieved fewer and fewer Watts as the intervals went on. Here, I am trying to see if that is a result of reduced force, length, stroke rate, or both. Stroke rate is excluded. You can already see from the overview chart above that the stroke rate didn’t drop. Here is a look at peak and average force.

In the these two plots, you can see that the effective drive length also drops, especially as I am shorter on the finish. I focused on not tapping down too late, because I noticed a very strong effect on “wash”, and also it makes it easier to keep the stroke rate high.

The next plot shows the same, but with effective drive length (taking into account slip and wash) instead of total drive length. I am running my effective drive length at 85% of total drive length. I would be interested to see the values of other people.

I also added a plot of the result, Work per Stroke, for the “on” intervals.

Here are some typical values according to Nielsen-Kellerman, compared to a summary for my “on” strokes. The values closest to my stroke are indicated with the colored cells. I guess I am just lacking in power and strength.

By sanderroosendaal • Uncategorized • 2 • Tags: ANC, ANC training, intervals, lake, OTW, rowing, single

May 8 2017

Stroke Analysis of my 1000m singles race

Race Analysis

In this post I am looking at a few detailed metrics of the Masters 1x 1000m race I rowed yesterday. Data were collected with a SpeedCoach GPS 2 combined with a NK Empower Oarlock.

Here is the overview plot of catch and finish angles for the entire outing, including warming up and cooling down. The actual race starts at 1200m. Interesting to see that I seem to suddenly take length about 400m before the finish line. This is exactly the point where I finally passed my opponent and actually started to row at a lower power.

Here is a close-up of catch and finish angle for the race segment. We’re talking a 1 degree difference, but still it looks pretty consistent and significant.

So here is the power and average drive force. The start strokes are always at high power and force, as you are starting from a stop and rowing short strokes at high rate. I think I did a pretty good job getting the average force down to an average value and holding that for the rest of the race. It is interesting to see the power drop about half way, while the drive force remains constant, and the catch angle actually increases. That means that I either started to row at a lower stroke rate, or the actual stroke was shorter despite the catch angle being longer.

The plot thickens when we look at the “Work per Stroke” which drops with the drop in power. So it looks like the stroke rate remained constant, but something else was changing.

Funny enough, both the absolute drive length and the effective drive length remain constant for the entire race and at pretty good values. So the shift in catch angle was actually me focusing on length (after I had passed my opponent) and tap-down (which makes the stroke slightly shorter at the finish). Should be visible from Wash values.

Looking at Wash and Slip values, I cannot see a big difference:

Finally, the solution to the riddle seems to be the Peak Drive Force:

Interesting! I hadn’t expected that. The stroke profile plot for the first half of the race:

And here is the second half of the race. Almost identical to the first half, but the tiny difference do lead to a drop in power, while my pace didn’t drop as much as that of my opponent.

Here are power and pace in one plot:

And finally, stroke rate and power:

Monday – Tourism and travel home

Today was a holiday, so we made a few stops on the way home. Here are a few pictures:

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By sanderroosendaal • Uncategorized • 0 • Tags: OTW, rowing, rowing analytics, single

May 8 2017

Sunday: Masters Racing in Piestany

Three races for me this Sunday. First, a mixed quad sprint (500m) at 9:35. Followed by what I considered to be the main event, the Masters C single, over 1000m, at 10:50. And finally the Masters C double at 13:50.

Masters Mix 4x-

I didn’t know about my start in the mixed quad until Saturday morning. It turns out the local team had been training this discipline, and had written up names of participants from other clubs to create some opponents. So on Saturday morning I discovered my name in the regatta program and my quad partners. Luckily we had a quad on our trailer. I rowed with Michal (the trainer of the boys), my wife Romana, and Michaela from the rowing club in Uherske Hradiste. We were up against the local team from Piestany and a mixed quad from Uherske Hradiste.

I am afraid we messed up the start a bit. We had done some pretty good practice starts during the warming up for the race, but we were not aligned when the referee announced (in Slovak) that he would start the race from the launch and that he would start immediately. As the stroke rower, I still had my blades flat on the water when the starter said “Attention”, and we definitely missed half a stroke.

Half a stroke is quite a lot on a 500m sprint on a fast flowing river. As was proven about 1 minute and 20 seconds later, when we crossed the finish line half a stroke behind the winning Piestany.

I had tried hard. The stroke rate had been in the high 30s for the entire minute and a bit, and my legs were exploding, but it wasn’t enough.

Masters C/D 1x

On to the main event. The Masters singles races were divided in two finals, one with the younger “A” and “B” rowers, and one with three “C” rowers and one “D” rower. In principle, I should win this race.

A few minutes before I wanted to launch, I was fiddling with my SpeedCoach and the single, when it started to rain. I turned around the single in the slings and reached our tent just in time before it started to rain really hard. I saw some of my competitors rowing to the start in the heavy rain. I checked the sky and decided to wait until the rain had completely stopped. It shortened the time before the start a bit, but there was still some reserve, and I figured it was better to arrive at the start line dry and not with a boat filled with water.

For me, the race was an experiment. With the power meter in the boat, I was torn between just rowing my usual race and trying to adhere to a certain power number and trying to flat pace. I guess the end result was a hybrid, but it was interesting.

The “ideal” pace was to row somewhere between 320W and 340W average on the SpeedCoach, 32spm, and try to ignore the other rowers.

I was second out of the start, with the guy from Bratislava a length ahead.

It is very hard for rowers to ignore other rowers in such a race situation. There is nothing better than being the first out of the start and to look at the competitors.

Still, I decided to go to slightly above sustainable pace (350W) but not much higher. So I ended up rowing about 400m behind this Bratislava guy, and then I finally started to move. Looking at the pace values in hindsight, I didn’t really speed up, but he was slowing down. During the race, I could also see that from the Power value, and I must say it was quite a nice feeling to hold 320W and see that I gained on him with every stroke. The passing took about 15 to 20 strokes. Then I was ahead of him and I decided to continue at 32-33spm and trying to hold 320W.

You can see from the power plot that I actually reduced the Power a bit after I had passed the competitor. I think it proves that going out too fast is a bad tactic.

That was a fast 1000m! Actually, it equals my erg PB. With a big help from the river Vah of course. Third win in a row for me in this race. I will do some detailed analysis in another blog post.

Masters C 2x

I spent the time between the singles race and the start of the doubles organizing a doubles partner. Originally, I was scheduled to row with the Boys trainer Michal, but his boys had a lot of starts around the 2x event, so he preferred to not row it. Finally, I found a guy from the Breclav rowing club wanting to row with me. I went around telling the main competitors so they wouldn’t be surprised and all was fine.

We took one of our club 2x boats, and I was surprised how low it was rigged.

Our main competitors were the double of Marko Milodanovic and Andreas Kral. Marko had won his singles race in a time 8 seconds faster than I. Kral and my partner Antonin were equally fast with 3:31. But of course Marko and Andreas train together regularly.

We rowed next to them for the first 500m. Then we got hit by a big wake, and the Austrians did a better job of rowing through it. In the final 200m we were trying to fight off Bratislava who were taking over. In the end they got us by 0.5 seconds.

After that it was time to help the coaches with their teams and to start preparing the trailer for the trip home. Around 3pm the “packing panic” started, which was worse than normal, because we were traveling with a lot of newby kids who didn’t know the drill, so boats arrived at the trailer in the wrong order, which created a traffic chaos, because the trailer parking was also the main through road from the race venue to the town.

I was glad when I could wave the trailer goodbye and get to my bike. We cycled back to our hotel. Romana and I took an hour of sauna and steam bath, and then we had a nice dinner. Monday would be a holiday, so we didn’t have to travel home immediately after the races.

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

May 8 2017

Friday & Saturday: Travel & Taking Pictures

Friday

Departed to Piestany in the afternoon. It’s a 2 hour drive but we got some heavy rain while we were crossing the White Carpathians on the border between the Czech Republic and Slovakia.

I had a chat with the race organizers, who told me they had almost canceled the race because of the high water and strong current.

In Piestany, I organized the kids to put up the tent and prepare all the boats. After that, it was time to go to our hotel. We had a nice dinner.

Saturday

My first task arriving at the race venue was to help my youngest son Robin and his doubles partner Vasek try out a borrowed double. When they were safely on the water, I launched my single. I wanted to row with them and try out the current. The river Vah was very high after rain earlier this week, and it didn’t look too safe.

All was well, but the pace and power curve of this short and easy row tells everything:

A 1 minute 20 per 500m difference between rowing against the stream and with the stream. Luckily, this was the strongest point, and during the weekend the water gradually calmed down.

The first race for our club was my son Robin (10) in the single. It was also his premiere. I must say I wasn’t too sure about putting him in the single.

The last picture was taken at the start of the race. Robin, with number 5 is trying to arrange his single in lane 5. Because of the strong current there were no buoys between the lanes and no start pontoons. So the task of the referees was to organize 6 10 or 11 year old boys in single simultaneously on the starting line on a fast streaming river.

Robin got orders to counter back (he was in the wrong lane) and then go to his lane. That was the moment when he flipped, which is not a nice moment to watch as a parent, especially knowing that the water was ice cold. Luckily, Robin grabbed his single which was upside-down in the water, and waited for the launch to pick him up, which took (only) about 30 seconds.

The launch delivered him and his boat on the bank and so Robin and I ran to the tent, where I got him some dry clothes. Then we rode the bike back to the hotel (2.5km) and I put him in a warm shower.

His doubles race was a complete one, including a fourth place.

My other son Dominik had a very nice row in his singles race and came in second place.

There were too many races to write about them all, and I was busy taking photographs (and tasting a beer now and then). So I will just put up a few pictures to convey the general atmosphere.

By sanderroosendaal • Uncategorized • 0 • Tags: OTW, races, rowing

May 4 2017

Mini taper for first sprint race

A 4x250m/250m is my traditional workout during the taper for a 1000m race. It is also the first workout I rowed when I got my SpeedCoach, in July last year, and the exported file from that workout is still one of the test files for rowsandall.com.

So I showed up at the rowing club after work, took my single for a quick spin, and then I prepared the boat for transport to Piestany in Slovakia.

During the warming up I did a few short 10 stroke intervals and test starts, building up the start with one more stroke at a time. First, one stroke. Then, two strokes. Etcetera.

It was quite choppy, and there were a lot of other boats on the lake. There was a sailing class with lots of sailing boats, and there were people windsurfing. In the end, I decided to do my first two 250m intervals between the buoys of the 2k course, in the headwind. Then turn around and do the other two in tailwind, like this:

Here’s the summary:

Workout Summary - media/20170504-175300-Sanders SpeedCoach 20170504 0520pmo.csv --|Total|-Total-|--Avg--|-Avg-|Avg-|-Avg-|-Max-|-Avg --|Dist-|-Time--|-Pace--|-Pwr-|SPM-|-HR--|-HR--|-DPS --|01000|03:52.0|01:56.4|338.7|31.9|174.0|181.0|08.1 W-|01000|03:53.0|01:56.5|338.8|31.9|174.0|181.0|08.1 R-|00000|00:00.0|00:00.0|000.0|00.0|000.0|181.0|00.0 Workout Details #-|SDist|-Split-|-SPace-|-Pwr-|SPM-|AvgHR|MaxHR|DPS- 00|00250|01:00.4|02:00.7|343.8|31.4|171.7|179.0|07.9 01|00250|01:02.2|02:04.5|334.2|31.6|175.9|181.0|07.6 02|00250|00:55.1|01:50.3|338.8|32.4|172.7|179.0|08.4 03|00250|00:55.3|01:50.5|338.5|32.2|175.8|180.0|08.4

Pretty happy with the result. It wasn’t nice clean flat water rowing. The chop made me concentrate and I didn’t look at the SpeedCoach display much. There was simply too much going on with the chop and the other traffic. I aimed for 320W average. In the end I managed a bit more.

Here are the metrics plots:

We’re leaving tomorrow afternoon. Monday is a holiday, so we plan to stay in Slovakia longer and hike to this castle, close to the town of Piestany where the races are held:

By sanderroosendaal • Uncategorized • 1 • Tags: lake, OTW, race preparation, rowing, single, sprint, taper

May 3 2017

Technique in the coxless four and the new Stroke Analysis plot

Technique in the 4-

Wednesday. The day when the CVK Brno Masters group tries to gather at 6pm and row the eight. Today, there was hope until 4pm. Then, there was an email that one of us had to urgently go to Prague for work.

In the end there were six of us. And it was raining hard, so “Pazdy”, who is recovering from a back injury, didn’t want to row outdoors and chose the indoor rower. I announced that I want to row something else than the single, so in the end “President” took the single, and “The mouth”, “Turkey”, “Bulldog” and I rowed the coxless four. We did mostly steady state but we tried a few 15 stroke intervals at a higher rate/pace. The intervals were not so good, but after we did a few minutes of square blade rowing and alternating square blade/squaring we finally got a bit of boat run.

Revamped Stroke Analysis plot

Today, I revamped the Stroke Analysis plot. This chart is similar to the “flex chart”, the Swiss Army Knife of rowsandall.com’s charting capabilities. Just as with the flex chart, you can chose any metric for the X axis and two other metrics for the Y axis. The difference is that the Stroke Analysis plot doesn’t relate to a single workout, but instead it plots all strokes for a certain time period.

That functionality has been part of rowsandall.com for more 8 or 9 months, but I restricted it to erg workouts. Today, I have added a selector where you can chose the workout mode (water, rower, slides, skierg, snow, etc) and added OTW rowing related metrics.

To show what is possible, I have plotted all rowing strokes between March 1 and May 4 and created various Stroke Analysis plots. Because I use Empower Oarlock related metrics, the data are self-selecting for the single. If you row a lot in different boat types, you will see them all in this plot. In the future I will build a boat type selector so you can filter focus on one discipline.

I also filtered out all “paddle” strokes by selecting strokes at 500 J/stroke and higher.

The effective length seems pretty consistent across the various stroke rates. If anything, I may have a slightly longer stroke at 30spm, and above that the length seems to decreate again. When looking at this metric in the boat, I like to see 90 degrees and higher.

Slip, a measure for how quick I load up the blade at the catch. This metric is clearly lower at higher stroke rates.

Catch angle vs stroke rate. I wonder what the group of strokes at the lower value is, but I suspect it is before I moved the footstretcher.

Wash, a measure for how long you keep the load on the blade before the tap down. Lower values are better. I have started working on this in the course of April. So if I select data from the second half of April to today, it should be better. Let’s check:

Hm. I guess there is work to do.

Finish angle. Again, there is a mix of footstretcher settings in this plot.

Work per stroke. Here I do include “paddle” strokes.

Average drive force. I seem to pull a little harder at the higher stroke rates.

And finally – the peak force angle, i.e. the angle at which I reach the maximum force during the stroke. Most of the data are centered in a 10 degree wide range around 25 degrees (before the pin).

And here is, finally, a power vs pace plot:

I have to adjust the units for pace. Currently, they are in milliseconds per 500m. Of course this plot is not normalized for head or tailwind, but still it is interesting.

How to use the Stroke Analysis

As with many things in data driven rowing, there is not a single answer to this. We are only starting to discover what is possible, and are exploring possibilities rather than focusing on what is useful. Still, I can imagine a few ways to use these data:

Think of the graphs as a fingerprint of a certain rower.
It will be interesting to see how the graphs vary between rowers.
Perhaps they can be used to do a first selection of matching rowers for a double or quad.
Look at time evolution of the graphs for a single rower.

Finally, above I have mostly put the stroke rate on the x axis. However, when you use Power instead, the graphs seem to start to make much more sense, even if you include “paddle” strokes. Just an observation.

For Wash, I know quite well what the blob above 20 degrees is. These are steering strokes where I reduce the force on my starboard scull.

Looking forward to discussing and finding more use of these plots. Please explore and share your thoughts.

By sanderroosendaal • Uncategorized • 0 • Tags: 4-, lake, OTW, rowing

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OTW

Thursday – Steady State

Two rest days and a hard session (lactate, lactate!)

Stroke Analysis of my 1000m singles race

Sunday: Masters Racing in Piestany

Friday & Saturday: Travel & Taking Pictures

Mini taper for first sprint race

Technique in the coxless four and the new Stroke Analysis plot

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