Jbobo
Watch it in real time (the first few seconds) several times.
http://www.bbc.co.uk/sport/0/rugby-union/31494355
Russell is already in the position he more or less ends up before biggar is even in the air (who is running full pelt but he's still on the ground just as he enters frame), he then jumps to grab the ball from above Russell and lands on top of him just to the pace he's moving at. Russell also clearly has his eyes on the ball and doesn't see Biggar coming.
He does attempt to duck slightly but to get out of the way is almost impossible.
He's not really guilty of anything as he is there to catch the high ball, clumsy to not see the welsh player and compete for it better but I wouldn't call it intentional in the slightest. Honestly I'd question a yellow card.
It's a question of whether he knew Russell was there, IF he did it certainly was wreckless as he knew he'd collide with him probably in a dangerous manner as Russel was in his path before he entered the air.
Technique has nothing to do with it, it's whether your wreckless in using that technique. If Russell wasn't in the way it would of been brilliant.
I've not seen it from an angle where you possibly know how aware Biggar was of Russell.
He didn't plough through Biggar, watch the incident (in real time) he barely moves just before and after Biggar enter the air. Biggar jumps into a space in which someone is already occupying, I'm just saying it's his own fault if he knew the other player was there.because he absolutely ploughed through Biggar..
GN10
Just want to clarify about 'trajectory' are you talking about the entire move or just when he enters the air?
Because personally if it's the latter looking at the footage I think Russell is there (or just about by fractions of a second) before Biggar enters the air.
My understanding is however that under current rules Russell doesn't have the right to occupy the space and has to get out the way or at least that's how the rule was being applied.