Looks more like the Daytona 500 variation on a "bluff charge" than an "attack". Like anything to do with bear attacks, there is controversy on the subject of bluff charges, I am basing my comments on my own experience with a bear in Mount Rainier NP that charged me - he stopped when I picked up a baseball bat sized stick and wielded it in my best cave-man fashion while yelling "BACK OFF!" at the top of my lungs, but I am pretty sure that he was just trying to make me move away, as I had been running down some switchbacks when I intersected his path. Of course, this was a black bear, not a griz.
Kinda reminds me the way my Staffordshire Terrier would run around the living room when she was in "attack" mode, bouncing off the walls, door, and the back of the couch. Great display of physical agility ( and definitely worth a biscuit).