Random thought after Riot August talking about Knock-ups.

I often see people complain about knock ups and want tenacity to affect them. Know I was wondering if riot did that (pretty sure they wont) how would our favorite blind monks ult work?

Dragon's Rage TARGET RANGE: 375 COOLDOWN: 110 / 85 / 60

ACTIVE: roots the target enemy champion for 0.25 seconds after which he roundhouse kicks them dealing physical damage and Airborne icon knocking them back 1200 units over 1 second.

If you have 50% Tenacity would it change the 1200 units to 600 in .5, or would you fly the same Distance just in .5 seconds?