How To Prevent

Pitching Arm



Recognizing Pitching Faults and Injury Patterns
Coach Bill Thurston

At the college level, the pitcher is the most often injured
player, nearly twice as often injured as a position player, and
the throwing mechanism, (shoulder, elbow, forearm, and wrist)
suffers the highest rate of injury of any of the various body

At a high level of play, it is important that a coach is able to
recognize various faults, and identify the point of origin of the
fault, then know how to teach the proper technique.

Of course many injuries to the throwing arm are caused by factors
other than mechanical faults. I believe we can divide the causes
of pitching arm injuries into 3 categories:

A. Conditioning Factors
B. Fatigue, Overuse, or Overload Factors
C. Mechanical Throwing Faults

A. Conditioning Factors

1. Lack of being properly conditioned; lack of total body
2. Lack of a long-term progressive throwing program.
3. Improper strength or weight work, which restricts upper body
4. Over-stretching the shoulder joint causing too much laxity.
5. Lack of a proper stretching and warm-up program.
6. Pitching competitively too soon; i.e., attempting to throw
at maximum velocity too early, over exertion.

B. Fatigue, Overuse, or Overload Factors

1. Throwing too many pitches during one outing.
2. Throwing when experiencing muscle fatigue or tightness.
3. Lack of adequate rest or recovery time for the throwing
4. Lack of an active in-season maintenance program ensuring
flexibility, strength and stamina.
5. Playing (or practicing) at other positions between pitching
turns, lack of recovery time.
6. Strength work too strenuous between pitching turns.
7. Attempting to pitch through pain caused by joint or muscle

C. General Mechanical Faults

1. Balance, alignment, or transfer of weight faults.
2. Throwing arm action faults.
3. Stride problems; direction, lack of balance, alignment, or
4. Cocked position faults. Improper position during the maximum
cocking phase - poor balance and stability, poor alignment of the
body and arm, improper arm angles and positions.
5. Trunk rotation faults or trunk flexion faults.
6. Acceleration and release phase faults.
7. Deceleration phase problems.


Most of the stresses that cause pitching arm injuries occur
during the acceleration, release and deceleration phases, but the
stress may be caused by an improper technique that was used
earlier in the motion. The arm, or body segments, could have been
placed in a position where it could not function efficiently.
Since there is a cause and effect relationship, it is important
to identify and adjust the original improper technique.

I am now going to address various faults that cause undue stress
on the shoulder joint and musculature.

Faults Which Cause Stress on the Shoulder

A. Arm Action Faults
* 1. Long arming (stiff arming) the back swing
* 2. Arm out of alignment (flailing)
3. Wrist hooking
* 4. Elbow lifts higher than the pitching hand into the cocked
5. Hand rolls under the ball vs. the fingers staying on top of
the ball
6. Overly short-arming the back swing (infielders technique)
Note: Improper timing of the hand separation causes many arm
action faults.

B. Stride Faults
1. Direction problems; too closed, too open, too short
* 2. Lands on heel, foot flies open
* 3. Leg and foot are not firmly planted and stable. Could be a
lack of leg strength.
4. Stride leg does not brace
Note: A long stride is good if the pitcher can get up over the
braced stride leg since the ball comes out of the hand as it
crosses over the stride foot.

C. Trunk and Upper Body Faults (out of sequence)
1. Rushes motion; body out ahead of the arm
2. Upper body instead of the front hip leads, dives into the
* 3. Front side flies open before stride foot plants
* 4. Upper body flexes forward before the torso squares to the
5. Shoulders and hips not squared to the plate
Note: Rotational forces are a major contributor of pitch

D. Cocked Position Faults
* 1. Elbow and hand too low
* 2. Elbow too high at stride foot plant
* 3. Early external rotation of the shoulder
* 4. Improper lead-arm action and position, flying open early
5. Head not in the top center of the triangle
6. Wrist flexed vs. extended back
7. Elbow flexed too much; hand too close to head
8. Palm faces forward too much
9. Head, shoulders, and hip line not relatively level; front
side elevated
10. Arm and hand straight back, stiff arms


E. Acceleration and Release Phase Problems
* 1. Arm slot too high, too close to the head
* 2. Arm slot too wide, too low - hand and fingers outside or
under the ball
* 3. Hand and elbow come forward in an upward vs. a downward
* 4. Trunk not squared to the plate; upper torso flexes forward
too early
5. Elbow leads and continues forward too long on fastball, a
dart thrower

F. Deceleration Faults
* 1. Head and shoulders do not come down over a braced stride
leg. (Hips stay behind the stride leg and the body recoils back.)

* 2. Arm and hand cut across the body vs. a good long arc of
deceleration down outside the knee of the stride leg
* 3. Arm extends outward towards the plate vs. in a downward
plane. Does not finish off the pitch.

* Major faults

Of course not all pitchers throw exactly the same way, they have
their own style, but through the critical phase of throwing (the
early cocking phase through release) most overhand pitchers use
the same techniques.

Bill Thurston has been at Amherst College in Massachusetts for
37 years and has won nearly 65% of all games played (667-389).
Since 1990, Thurston has served as the pitching consultant for
the American Sports Medicine Institute in Birmingham, Alabama.
Bill has conducted baseball clinics in over 25 states and five
provinces of Canada and was inducted into the American Baseball
Coaches Association Hall of Fame in 1997. He was a standout
player at the University of Michigan and later served as the NCAA
Baseball Rules Editor for 14 years. He is a nationally known
clinic speaker, and many of his instructional materials have been
published and videotaped

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