It's probably worth noting that that sample was taken at night with a flash strobe, allowing you greater "freezing power" if you wanted it. From the dust flying around the left side of the frame and the rim light on the pillars' left side (not to mention the actual flash at the bottom left of the frame), I would say this shot was backlit, possibly with a speedlite and using the camera's high speed shutter sync.
The hair is still kind of blurred though (a good thing in my opinion), so it might've been under 1/200th of a second. You usually don't want a FROZEN frozen shot, which would take away the feeling of motion. But you might, it's photography and art, so its your choice, haha. I wanted a blur on this person's jacket so that you would FEEL the jacket flying but not so much it would distract you from the cosplayer's performance. So I didn't use a super high shutter speed.
As for the hair motion itself, I've never worked with hair that long before, but playing with wigs where it was clearly not real hair, I doubt using a head flick would be feasible in creating big motion with hair that long and stiff. For this martial arts shot I actually spent like half an hour inserting wire hangers through the chain whips so that when we shot it, he was just holding it up in place. The sense of motion comes from a little motion blur in photoshop. Same for the girl. I had her jump straight up in place holding the swords that way and in post, I tilted her body to add a sense of motion and added the water streaks to the weapon to simulate a swing.