Timmy: Shoulders
The shoulders need to stay closed for as long as possible throughout the delivery. The shoulder girdle should be launched at the target by the stretch reflex traveling up to the shoulders from the core. There are myriad ways to keep your shoulders closed, but here are the best way’s that I have heard — and some that I currently use — to keep the shoulders closed in order to have complete control over the knuckleball.
Shoulders Mechanics
#1: Look At Target Over Back of Front Shoulder.
This adjustment rides right alongside the tucked pelvis. What most MLB pitchers and you’ll see both a tucked pelvis and ribs down. That’s because we know that the force of the throw will put your rib cage and butt into extension, so we want to start in the opposite position so that there’s room for your body to move. You don’t want to start ribs up because that’s the ending position and you don’t want to start from the end. You won’t get any energy that way.
#2: Drive Ribs At Target.
You don’t want your shoulders to open weakly. You want them to pop open to the plate with force. Now, most of this force comes from the ground through the movements of your legs and through the stretch reflex created by hip-to-shoulder separation through your core. But can choose to drive your drive-side ribs cage to the plate to accentuate the proper movements of the shoulders and to get extension on the pitch.
#3: Initiate Throw With Back Shoulder.
This one might seem simple but it has huge impact on the quality of your knuckleball. You need to begin the rotation of your shoulders with the drive-side shoulder. You cannot allow your front shoulder to open first. That will cause early torso rotation which will cause you to lose all the energy coming up the kinetic chain below.