First thoughts

All novice rowers are taught not to race the recovery. Many rowers and rowing coaches develop a sense of “good” rowing. It is a question of balance, rhythm, power, ease of motion, yin and yang, feeling for the water, etc. We immediately recognize the skilled rower, and by teaching our pupils we pass on the art of rowing from generation to generation. So, all rowers are taught not to race the recovery, and for a skilled rower, it just ‘feels’ wrong, and it hurts to see a novice rower race the recovery.

We know when the rowing feels good, when the stroke feels light and we let the boat run easily through the water. We don’t waste energy to move the boat. No, we almost effortlessly and oh so playfully persuade our shell to slide through the water. We are using the right rhythm. We are rowing in sync with the rest of the crew. We are one with the elements, with the crew, with the boat.

Not racing the recovery is where it all starts. So I had this all rationalized: Conservation of momentum tells us that if we race the recovery, we force a sudden increase in the shell speed, which is a very bad idea because the shell’s drag resistance scales with the square of the shell velocity. On the other hand, doing a really slow recovery is not smart either, because the drag force would decelerate the boat, and one would need a very strong stroke to compensate. So, by hand-waving arguments I had concluded that there must be an optimum stroke-recovery ratio! All I needed now was the back of a napkin to jot down a few equations and voila!

The back of the napkin turned into a notebook full of notes, which then turned into a numerical model. So is there an optimum stroke recovery ratio? Perhaps. Let’s see.

Is racing the recovery a bad idea? You bet!

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2 thoughts on “First thoughts

  1. Martijn

    You conclude that racing the recovery is a bad idea. But, you also made one argument that the recovery should not be slow either. So, should a proper recovery be fast?

    This makes me wonder about a semantic problem. How is ‘racing the recovery’ defined? If it is defined as ‘a recovery fast enough to be bad’ than it is obvious that ‘racing the recovery’ is bad by definition and the final conclusion would be a bit platitude.

    1. sanderroosendaal Post author

      Beste Martijn,

      In my post, I was referring to it in the blurry definition of most rowing coaches. In that definition, it is bad if it is not right, and it is a plattitude indeed.

      Somehow, as I hope to show in following blog entries, the duration of the stroke is more or less defined (by boat speed and blade force). The free recovery can be chosen by the stroke to be of shorter or longer duration. Think of it as a ratio of stroke/recovery durations which according to the imaginary typical rowing coach’ knowledge is ideally somewhere between 0.5 and 0.8.

      Another way to think of it is of the ideal rating for each pacing. (Native speakers of English, please help me here: am I correct assuming that rating is what is measured in strokes per minute, and pacing in m/s?) At a pace of 5 m/s (1:40 per 500m), most rowers row 30 and up. However, what our crew did in the eight yesterday seemed definitely wrong: we rowed a 1000m race in 44 strokes per minute. It was difficult to pull hard at this rating, and at the same time we became tired very fast. Perhaps we could have been faster in 36, and perhaps the numerical modelling of rowing physics can help us understand this.

      Sander

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