Jumping high and low

There has been a special issue of J. Sports Engineering and Technology devoted to rowing technology, and it’s available on-line. It’s a very interesting read! While I was reading through that, I realized I had never thought about muscular strength and muscular power before. What force can a human leg produce? What power can a human sustain? These will be important input parameters into a model of rowing.

The Concept 2 ergometer readings are in Watts, but it is averaged over the entire stroke, including the recovery. How strong is a man? I didn’t know.

So I bought a book on sports physiology. A very nice book indeed, with good reviews on Amazon. The edition I got even has a cover with a very strong looking German race rower. I learned a lot about muscle biology and muscle chemistry, but not a single mention of a number. Not in Newtons, not in Watts.

I ended up jumping up and down in my living room. I managed to move my center of mass vertically by about 90cm. The motion included leg extension and some funny looking and very short flying in the air. So, I managed to increase my potential energy by 680 J (and now you know my weight). I did this by a leg push of 60cm. So, as energy is force times distance, the average force must have been 1131 N.

Later I found this to be a pretty standard test. You can search the internet for Sargent jump, but usually the result is measured in inches or cm.

I could have jumped much higher of course, if my ceiling allowed it. However, I am not so sure if I could perform these jumps for seven minutes to mimic a rowing race.

Anyway, 500N to 1000N seems a good range to use once I have my model developed. And how does that translate to blade force? I’ll discuss that another time.