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 parts.

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 fitness.
2.  Lack of a long-term progressive throwing program.
3.  Improper strength or weight work, which restricts upper body flexibility.
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 mechanism.
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 stiffness.

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 stability.
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 theacceleration, 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 theoriginal 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 position
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 pitch
* 3.  Front side flies open before stride foot plants
* 4.  Upper body flexes forward before the torso squares to the plate
5.  Shoulders and hips not squared to the plate
Note: Rotational forces are a major contributor of pitch velocity.

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 plane
* 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 ThurstonBill Thurston has been at Amherst College in Massachusetts for 42 years and his teams have won nearly 65% of all games played (771-441). Bill is a full-time tenured professor of physical education at Amherst and he is widely respected as a teacher of baseball skills and techniques.Prior to coaching, Thurston starred in baseball at the University of Michigan and later played three years with the Detroit Tigers organization. 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 also served as the NCAA Baseball Rules Editor for 14 years.

Thurston is a nationally known clinic speaker, and many of his instructional materials have been published and videotaped. He is an expert on proper pitching mechanics, video analysis of the pitching motion, proper care of the pitching arm and prevention of arm injuries. His DVD, Common Mechanical Pitching Faults, is available at for only $39.95.