Stand facing a large tire, feet shoulder-width apart, holding a sledgehammer.
Grip the handle with one hand near the bottom and the other hand higher up.
Lift the sledgehammer diagonally overhead, sliding the top hand towards the hammer head.
Swing the sledgehammer down forcefully in an arcing motion, sliding the top hand down to meet the bottom hand.
Strike the tire with maximal force.
Control the rebound and repeat, alternating sides or performing sets on each side.