Actually there was a previous episode where he used them in offence:
https://www.youtube.com/watch?v=HV0ugSBay2U
@0:48
Kept Atom Smasher at a stand still, and we know he could keep up with Barry when he was chasing after him. I'm sure Barry wasn't running away at full speed, but it was still impressive either way. So to keep him from stomping his away to him was pretty impressive.