This is an article from the NPA saying that 80% of MPH comes from Hip/Shoulder seperation and that 20% of mph comes from legs or direction.
Also this is a short part of the article.
[b]Our research has indicated 80% of ball velocity is generated by rotational momentum when:
Hips and shoulders separate between 40� - 60� around an upright spine.
Hips and shoulders maintain their angle of separation as long as strength and flexibility will allow while total body tracks forward into landing foot.
Throwing shoulder/glove shoulder delay rotation until hips have slowed/stopped their rotation.
Scapular “loading” is allowed to be an unconscious accommodation that helps the throwing shoulder to stabilize and compensate for the weight of the throwing arm/ baseball as they change direction and snap from external rotation into release point.
Our research has indicated 20% of ball velocity is generated by directional momentum when:
Total body tracks head and spine on line in the exact direction created by shifting weight from posting foot to landing foot.
Low back/spine hyperextend to keep torso upright and stacked as shoulders square up and track into a flexed and firm front leg.
Glove swivels and stabilizes over front foot as throwing arm lays back in external rotation.
Low back/spine goes into flexion just before throwing forearm snaps straight into release point. [/b]
Tell me what you think.
Also I have one question
Mound vs Flat ground what mechanics would have greater Hip/Shoulder separation I have all way’s wanted to know.