That tingling sensation

[Furbz]

This is a question I've been struggling to find an answer to.

When I put in a really hard effort, somewhere in the middle of the effort I get a very brief strange pins and needly feeling that runs through my legs, and something my entire body.

It's not every effort, it's only when putting in really all out efforts anywhere between 3-10 minutes.

And pretty much only happens once in a ride.

It only happens for a brief moment, like maybe a second if that.

 

Anyone have any ideas?