U15 boys game last weekend, reasonably skilled teams. White challenged red for the ball and popped it loose, no foul so far. Both players half fall down (hands on the ground). However, in the aftermath, white's foot hooked red's foot, preventing red from moving towards the ball. Red was actively trying to break loose and get to the ball, but was unable to do so. At that point I blew a foul and awarded a free kick to red. My thought was that this was holding, rather than tripping, and thus a DFK was proper. However, I wondered if this was more properly impeding, for an IDFK. White, of course, thought it was nothing. Any thoughts on whether this sort of action should be considered impeding or holding? ...or nothing at all?