Hello,
Didn’t find anything related to this so hence proposing here.
For those who run with power meter, one of the main metrics to look after is the efficiency index. Which translates to speed per watt,
The formula for this metric is pretty straightforward as per Jim Vance’s book Run with power 
EI=avg speed/ avg power
Where avg speed is expressed as average pace or speed in meters per minute.
Can this be added to running activities with a power meter? 
Hmm there is already “Efficiency” which is normalised power / average HR and “Power/HR” which is average power / average is HR. So maybe it should be called “Speed/w”? Then I need to try find somewhere to fit it in!
I also need a blob post or similar to reference. Have found these but maybe someone has something better?
Also is this relevant to any other sports?
AFAIK this is only for running, as Cycling with a power meter measures only the work that is applied to the pedals in order to move forward, vs running where a slightly change in running technique/form can either result in using more or less watts for going over the same distance in the same period of time.
This metric was coined by Jim Vance I think, so not sure if there are many references out there other than his book “Running With power”, Efficiency Index is only the term he used in this book, we can name it whatever we want, but the metric is interesting and I think it’ll add to the training analysis after the fact, meaning comparing similar runs and seeing if any technique or form changes resulted in a more efficient ratio of speed per watt.
Hope others find it useful and start looking and tracking this.
This is now available as a custom field, thx to the creator 
Hi @herlas where do you see that field?
I searched the forums to ask for the same metric (EI) after reading the same book (Run with Power by J. Vance). But I do not how to add it to my activities.
Thanks.
On your activity screen, follow these Screenshots and add it to your activities. I’ve only managed to get a value for the new activities after I added the custom field, not sure if there’s a way to fill for previous ones.
Hope this helps.
Thank you so much! you made my day. (I was trying to find it using the “Fields” menu).
Oz.
If you reprocess the activity EI should show. You might need to refresh the page.
