What is Axle stall?

A skateboarding trick where you go up to the coping on minipipe, turn 90 degrees, and lean back on your heels, therefore ending up with both trucks on the coping, and being stationary. To get out, lift up your front truck, lean forward, and pivot back 90 degrees, and come back down in the stance you came in. These are also the base for a 50-50 on a minipipe.