Double Fun and Double Analysis, or how to prove that your wife is perfect

The title of this post is Double Fun because I had a lot of fun rowing doubles last week, and Double Analysis because there will be two in-depth boat acceleration analyses done using Quiske pods. And both rowing and analysis is ufn, so that’s double too.

First, a summary of a week of training:

Monday, June 17th

A weights session.

Tuesday, June 18th

Romana and I did a short steady state row in the double. It was very nice. We did the long full lake stretches as rate ladders. Power is estimated.

Wednesday, June 19th

Wednesday is eights day. By the way, here are a few new pictures from our last race in the eight. One of the photos shows us protesting (or were we waving to our fans on the bank?).

We did steady state with a few short bursts at higher power. I was pulling OK but we’ve had better sessions.

Thursday, June 20th & Friday, June 21st

We had a long day at work. Visitors from overseas. Visitors from the Middle East. Workshops. Demos. It was good, long, fulfilling, interesting, and everybody was happy in the end, and there was no time to go out and row.

Saturday, June 22nd

It was a warm, humid day, and I was hesitating if I should do this workout. In the end I did it: 5x1500m at 26spm, in the single. And it went much easier than I thought.

The lower power bits in the third interval are caused by steering. In the fourth interval it’s more about fatigue, and in the final interval it’s steering + fatigue. I was using Quiske with the pod on the oar.

In the data, I selected the fastest bits of each interval as well as the slowest bits. The left chart collects all the “fast” sections, while the right one summarizes boat acceleration and oar angle speed for the slow bits. I think the biggest difference is in how effective (and fast) I am around the catch. You can see it both on the oar angle velocity chart (bottom) as well as on the boat speed chart (top).

I had a great swim in the lake after the row.

Sunday, June 23rd

No training. We had family visits in “nearby” Pardubice (2 hour drive).

Monday, June 24th

This was going to be the day. I was going to measure seat speed for the bow and stroke seat of my mixed double. Finally, we would be having data to see where we can further improve.

It was not going to happen. I had everything: Two phones, two pods, seat pads. I forgot the second phone holder.

So we rowed “unplugged” (NK SpeedCoach only) and did a short session of 1 minute on / 1 minute off.

Heart rates are high, because it was well over thirty degrees Celsius when we rowed. The lake has turned into a giant open air swimming pool as well. Romana and I played around with the stroke rate a bit. That is why the two final intervals of each of the two series is rowed at 30spm instead of race stroke rate. It seems that it didn’t impact the pace too much.

Workout Summary - media/20190624-1720490o.csv
Workout Details

Pace is not exactly where we want it to be, but it was hot, and we rowed after a long work day.

Tuesday, June 25th

This was going to be the day. I was going to measure seat speed for the bow and stroke seat of my mixed double. Finally, we would be having data to see where we can further improve.

This time I succeeded in getting us all hooked up. It was a very hot evening again. We rowed steady state and a few twenty stroke intervals at 24, 28, 32spm (in headwind) and 32, 38spm (in tailwind) to collect good race pace data.

So here is us at 24spm:

The top chart is boat acceleration, and the bottom one is seat speed. The chart start on the left at a point just after the catch (point of lowest boat acceleration) and finishes on the right after an entire stroke cycle. The two acceleration and speed curves are slightly different, because we are using two different phones (with differently sensitive accelerometers), and because speed is the integration of acceleration data, and (I suspect) a naive algorithm is used so cumulative errors cause the differences. Also, I had to hand select the data for this chart from two different “sessions” on the Quiske portal, so it may be that we are comparing two slightly different sets of strokes from the same interval.

The bottom chart is what we are after. This is the seat speed. You can see that seat speed increases after the catch and reaches a maximum (leg part of a sequenced stroke), and then decreases during the back swing and becomes zero at the arms pull, remains zero at arms away and back swing, and then slowly increases as we are sliding towards the catch during the recovery phase.

You can see that bow (green) has a slightly less sequenced stroke than stroke seat (blue). Her seat is moving slowly during the back swing and arms phase. In this sequence, we are slightly asynchronous, especially during the recovery phase. Let’s take a look at 28spm:

Well, the picture doesn’t change much, but the differences are smaller. Let’s take a look at 32spm:

Again, tiny differences, but I think this is a pretty good match. Finally, let’s look at the last interval at race pace:

This interval wasn’t really great. We were waked, tired, hot, and distracted. So I am not surprised we see some bigger differences here. Especially on the recovery, bow seat starts rolling the seat a bit earlier than stroke seat. Stroke than slides slightly faster.

But how serious are these differences? Let’s take a look at another double:

I think Romana and I should be happy with the synchronicity that we achieve. Here is data from another boat:

From this instagram post (click on the image to see the video on Instagram):

So we used a “random” sample of other published curve sets to say that we are already very good.

Mission failed: Romana and I didn’t find anything to improve.

Relationship saved, of course: As stroke seat and husband, I would find it hard to tell my bow seat and wife that she is less than perfect. Turns out we have data to prove she is perfect.

We also had a really good swim in the lake, after the session.

Wednesday, June 26th

Another Wednesday evening row in the eight. Today, the thermometer reach 37 degrees C and it was really hot. We did a short outing, but we did do some speed work in the eight. My heart rate band misbehaved a bit, I think:

In the first 10 minutes of this chart, only the seats 5 to 8 are rowing. From about 10 to 16 minutes into the session, seats 1 to 4 (including me on 2 seat) are paddling. The main purpose of this session was to get some time in at high stroke rates.

We had a long team swim after the row. The lake water was fantastic!

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