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What the SPI means ???
Posted: August 3rd, 2022, 5:20 am
by Titi
Hi,guys~
Here is a question,I found a data named SPI(Stroke Power Index) in reddit(
https://www.reddit.com/r/Rowing/comment ... spi_chart/)
They said it is watts per stroke.But I am not quite understand.
Is there anyone know something about it??
Re: What the SPI means ???
Posted: August 3rd, 2022, 6:17 am
by Citroen
It's a mostly meaningless value.
It can be used to tell you if you need distance vs speed training. But, nothing more than that.
It doesn't scale well as it ignores things like breathing and work vs recovery ratios.
Re: What the SPI means ???
Posted: August 3rd, 2022, 2:22 pm
by jamesg
SPI meant stroke power index and = Watts/Rating. Rating has dimension 1/T, so SPI is the Work done in each stroke, where Work = Force x Length.
This makes training very simple on the C2 erg. Just learn to pull a good stroke at low rate and forget everything else, for 10-15 minutes after warm-up every day.
Re: What the SPI means ???
Posted: August 3rd, 2022, 2:55 pm
by JaapvanE
James,
You beat me to it, those were my thoughts exactly: they are the Joules (Watts * Sec). An additional note, the PM5 actually records "strokeCalories" and reports them through the Bluetooth interface (for OpenRowingMonitor I had to find a way to calculate this metric, as we imitate a PM5's BT protocol to connect to EXR and the like). So somebody in C2 once thought it was a usefull metric.
Personally I am a bigger fan of Average and Peak force, and stroke length, as they provide better clues where you can improve, and combined amount to the same thing.