Hey guys

I was chatting to one of my friends about our workouts, and he told me he's developed a split bicep. Now I was under the impression that this was a question of genetics.

A few points to take into account:
*He's quite ripped. His bf% hasn't increased past 12% in the last year and a half.
*With that in mind, he initially did not have a split in his bicep.
*The split began like any other cut. Initially it was barely noticable but now it stands out like dogs balls.

Another thing we discovered is that the split only began appearing when he changed his bicep routine to incorporate incline curls. The one's where your grip is underhand throughout the whole movement.

I suppose the only way to test this is for me to incorporate it and see what happens. Anyone know anything about this?