please consider this:
1. ALL pitches utilize IR*. (yes, even "hello elbow" pitchers...)
2. For a Change-up, the important thing is WHEN IR occurs.
To take velocity away from the pitch, IR needs to occur a lot earlier than with, say, a drop ball or fastball.
With "fast" pitches, IR is delayed as long as possible, to occur just before release (rapid sequence: IR>>humerus deceleration>>forearm pronation/acceleration>>finger-pressure/release).
With "slow" pitches, IR is rushed to occur earlier in the sequence, usually just after the ball clears the top of the arm circle (12:00). This makes it very difficult to achieve any amount of significant "arm whip" and thus yields a slower pitch.
* = IR, or "internal rotation" describes the pronation of the humerus (or "upper arm").
1. ALL pitches utilize IR*. (yes, even "hello elbow" pitchers...)
2. For a Change-up, the important thing is WHEN IR occurs.
To take velocity away from the pitch, IR needs to occur a lot earlier than with, say, a drop ball or fastball.
With "fast" pitches, IR is delayed as long as possible, to occur just before release (rapid sequence: IR>>humerus deceleration>>forearm pronation/acceleration>>finger-pressure/release).
With "slow" pitches, IR is rushed to occur earlier in the sequence, usually just after the ball clears the top of the arm circle (12:00). This makes it very difficult to achieve any amount of significant "arm whip" and thus yields a slower pitch.
* = IR, or "internal rotation" describes the pronation of the humerus (or "upper arm").
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