3. Minimize Your Upper Body Rotation
Since you ride sideways in snowboarding, it's only natural to think that your body is facing sideways when on the slopes right?
Ordinarily however, humans face forward, living their day to day lives.
Since facing forward is human's natural posture, most snowboarders face forward without thinking about it when on the slopes.
Since humans live their lives facing forward, it is optimal for our bones, muscles, etc. to face the front when moving.
Because of this, a posture in which the whole body faces forward makes it easy for us to maintain balance and be able to use muscle effectively.