rowing stroke data analysis

The rowing stroke “sweet spot” for head racing

Sander Roosendaal is on a mission to find the optimal pace for his single scull when doing head races.  In this article he explains how he is experimenting with his working hypothesis that the ideal stroke is in a sweet spot where three parameters (power, force and stroke length) are optimised, a bit like in the following picture:

rowing stroke data analysis

Rowing stroke ‘sweet spot. optimal power and rate

His workout plan was Warming up. 4km 10 strokes on / 10 strokes off. Then Steady state.  Here is how he worked out the sweet spot for himself.

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.

He explains his reasoning behind choosing these parameters

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.

The readouts he selected to display

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.

As a coach and an athlete I found this statement the most important.

For rowing data analytics, we must focus on metrics that are easy to communicate, meaningful (as in influencing boat speed) and actionable.

There’s a balance between what you can quickly read off a small display while racing and whether you have the brain-space to interpret it and make a change to your rowing.  As a coach, I like to recommend which data points to display – one very useful data point is distance moved per stroke, especially for long pieces.

Which are your top 3 racing data points?

COMMENTS (4)

  1. Mike

    Very interesting article! The availability of real-time power data could be putting us on the verge of a whole new paradigm for strategizing race plans?

  2. Alastair Isherwood

    Ultimately distance per stroke (DPS) is the most actionable metric to use. It is a reflection on your work per stroke but reflects the effectiveness of the drive and the efficiency of the recovery, thus encapsulating the entire stroke cycle and conveying it in an “actionable” format. You then have the option of increasing power but maintaining the same rate to increase DPS, you can increase rate and maintain DPS to increase boat speed, or you can maintain intensity and rate and try and interact more efficiently with the boat/oars to increase DPS – or as Sander alludes to you can find the optimum compromise between all three depending on your race distance. The New Zealand men’s pair (6:08 world best time!!) are a great example of a crew that found the sweet spot and had the confidence to pace their way over 2000m despite any attempts by their competition to unsettle them in the first 500m – their splits were remarkably consistent, often negative splitting their way to Gold. Focussing only on work per stroke ignores the time when the blades are not in the water. We all know that ergos don’t float so why ignore the elements of the stroke cycle that contribute to less powerful/more efficient athletes wining races. DPS is all-encompassing.

  3. Pingback: Masters: Pacing a 1000m single scull row with a power meter – Rowing Analytics

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