The field of
biomechanics works at improving athletic performance and reducing
injury. Today there is a concern about maximizing performance at
the sake of causing injury. It is definitely possible to push an
athlete past the limits of her body in order to improve her
pitching performance. There is one element of the pitch, however,
where improving performance and reducing the chance of injury go
hand in hand. Proper arm motion during the windmill pitch will
maximize pitching efficiency and reduce elbow and shoulder stress.
In terms of pitching performance, a
"windmilling" motion of the arm at the side of the body
so that the arm brushes the head and hip, is ideal (assuming that
all of the other pitching components are correct). Keeping the arm
in the plane results in a built-in accuracy mechanism for
windmillers. If the arm circle is performed so that the arm passes
behind or far away from the head, chances are that the arm will be
far from the hip at ball release. Ball control will be compromised
as a result.
Pitchers who windmill the arm close to
the body tend to have better control. An extreme example of this
is a slingshot pitcher whose arm passes behind her body during the
windup. Because it is difficult to move the arm and ball in the
same plane so that the release point is consistent, young
slingshotters tend to have more control problems than windmill
pitchers.
The chance of arm injury is also reduced
with an arm circle that is close to the body. A windmilling motion
with the arm at the side creates a significant amount of stress to
the shoulder joint. Moving the arm out of the plane that would
cause the arm to brush the head and hip, places an even greater
load on the pitching arm. Although I do not agree with the common
myth that the windmill motion is a "natural" one, I do
agree that the arm circle close to the side of the body is more
natural than passing the hand behind or far away from the head.
Shoulder joint stress will be less with proper arm rotation
because the joint is placed in a better position.
Another important ingredient in arm
rotation is keeping a "long arm." Maintaining a
relatively straight arm throughout the pitch results in a long
lever. Greater ball speed is afforded by greater leverage. The
longer the lever, the less force. Also, a straighter arm places
the fingers at a greater distance from the shoulder-joint. Points
further away from an axis of rotation (in this case, the shoulder
joint) have greater linear speeds.
A "longer" arm also helps
reduce the stress on the throwing shoulder and elbow. Many
pitchers who bend their elbows too much (short arm) tend to get
their arms out away from the body during the downswing. This
requires an abnormal rotational component of force on the upper
arm in order to deliver the ball.
This rotation causes unnecessary torque
on the elbow and shoulder. A straighter arm, on the other hand,
tends to result in greater degrees of elbow and shoulder flexion.
Since this is the strongest motion at both joints, it is more
advantageous to keep a "longer" arm because of both
force production and stress reduction. Note: The longer arm should
feel comfortable, natural, and may not/should not be forced
perfectly straight.
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A biomechanics specialist, Sherry L.
Werner has her doctorate from Pennsylvania State University and
has had many articles published in the former FastPitch World
magazine
Utilizing
Proper Arm Motion in Pitching