Thanks for the detailed answer PS. Not sure if I'm right, but when I clicked on the video off of your finis link, I thought the swimmer wasn't breaking his elbow for the EVF- it seemed more like the arm was quite straight. I watched that other video earlier today funny enough.
I think I will persist with EVF development for now, just learn a bit more about it first. I really felt the shoulder loading, but the improvement in speed was massive. It's like having the car that you've gotten used to, then fitting a turbo to it. Instant power increase.
I came across some info from Sheila Taormina about the EVF. I followed this up with the obligatory Amazon/ Youtube research combo.
As a member of the church of 'Swim Smooth', I'm torn They think it's putting a lot of pressure on the shoulder and advocate a more modest version of it, whilst Taormina's book is more 'go for it' (from what I can gather).
I tried it out this morning and the difference in speed is huge. I did tire out quite quickly though. Can you help me make sense of this discovery? What are your thoughts/ experiences of the EVF?
I'm declaring today a 'no lurking' day, so If you've read this far, you're morally obliged to comment