Many of the stunts or tricks that snowboarders usually do involve spinning or twisting in the air. The physics principle that goes to aerial spinning and twisting can be related to the conservation of angular momentum. The angular momentum of the snowboarder is usually determined at the takeoff of the jump once the snowboarder is in the air it can not be changed. To make the twists in the air the snowboarder has to give himself an initial twist when he is about to takeoff. In order to maximize his number of spins while in the air, the boarder wants to maximize his angular velocity, so he will spin faster. Since momentum cannot be changed mid-air, he must decrease his rotational mass in order to increase his angular velocity. To increase his angular velocity the snowboarder tucks in his arms.