Sprint: Do you have to Hold the Button?

I plan on using Recon control style and I was wondering if I would have to hold X to sprint, or would I just have to press it while running forward to sprint?

If anyone here played the game at E3 or know someone who played it at E3 or whatever, I would like an answer.

I’ve been wondering this too… IMO it should be like in Reach. Tap the button and guy starts running (and breathing like a dog) and when you press it again or lower you speed with LS you stop sprinting.

Control scheme would be better if they switched sprint and reload; reload on X, sprint on right bumper. How hard is that to figure out?