The most common causes of pitching arm injuries to high school, college and professional pitchers are overload, overuse, lack of proper conditioning, and improper throwing mechanics.

Overload is the result of throwing too many pitches during one outing. Maximum pitch counts for various age groups, or for an individual pitcher’s normal strength and stamina, are effective in preventing overload.

Overuse is the result of pitching too often and not having an adequate recovery time or a good arm maintenance program (stretching, running, strengthening, throwing) between pitching assignments. Coaches and trainers should be aware that each individual pitcher varies in arm strength, arm fatigue, arm tightness and soreness and require different recovery time needs. Make certain you provide your pitcher with a good active recovery program between pitching assignments.

Proper conditioning involves the entire body; the legs and core muscles as well as the throwing arm. Coaches should supervise a proper stretching and warm-up procedure that is performed daily before throwing a ball.

Pre-season is one of the most frequent times for arm injuries. Pitchers throw too much and too hard, too early. Also, they have not ingrained their normal rhythm and often are attempting to learn new techniques or new pitches.

Another major factor of injury during pre-season is that pitchers are not working with a normal in-season rotation schedule and do not get enough recovery time from a lot of necessary drill work that involves throwing (pick-offs, defensive plays, etc.).

Improper throwing mechanics. If a pitcher has improper throwing techniques, with the body or arm, there is a great chance of early fatigue of the throwing mechanism, and of course injury. The more power and force generated, the greater the chance of injury.

In a competitive situation, most pitchers will not admit they are fatigued, experiencing minor pain or have a minor injury. It is important that you, a coach, trainer or physical therapist be able to recognize changes in the pitcher’s mechanics, performance, or mannerisms.
Recognizing Pitching Arm Fatigue

Besides the loss of control (command of his pitches), and some loss of velocity, a pitcher will often change his throwing motion to compensate for the loss of arm strength and hand speed, or he will change to protect his arm from further stress and pain. Be alert for:


  1. The pitcher rushes his motion trying to generate more power with the body and reduce the stress on his arm. This action actually causes more stress because the arm drags behind the normal throwing rhythm. The pitcher will have a greater loss of hand and pitch speed.
  2. The pitcher may shorten his arm deceleration path and follow-through. He will lose his normal arm extension during the release and deceleration phases.
  3. The pitcher takes more time between pitches, walks around the mound, etc.
  4. The pitcher stretches, shakes, or swings his arm or shoulder more between pitches.
  5. The pitcher may not get his hand and elbow up to the normal height in the cocked position. It will appear that he has lowered his elbow during his motion and is accelerating in more of an upward plane.
  6. The pitcher grimaces (flinches) during the release and deceleration phases.
  7. Between innings, the pitcher may massage his elbow (lower biceps) or top of the shoulder (biceps tendon) area. With arm fatigue, a pitcher’s hand often trembles.
  8. Between pitching assignments, the pitcher is reluctant to throw, or throw properly during defensive drill (PFP) work. He is protecting a stiff or sore arm that needs more recovery time.
  9. Many pitchers will not admit to their coach that they are overly sore or have a minor injury. They will see the trainer or team physician if they believe the medical person will not tell the coach. There needs to be a good open communication, in confidence, between medical personnel and coaches.
  10. At higher levels of baseball, your opponent’s hitters will show you that your pitcher has fatigued and lost some command and velocity. They will take better swings and hit the ball harder more frequently.

In addition to changes in a pitcher’s mechanics, there are often some noticeable physical signs, which indicate muscle, tendon, or ligament strain around the shoulder, elbow, forearm or wrist.

  1. Redness, discoloration, or internal bleeding in the area.
  2. Swelling, puffiness, stiffness, extreme tightness.
  3. A burning sensation upon movement.
  4. Sharp pain versus a normal dull ache.
  5. Lack of grip strength.
  6. Loss of extension, flexion, or normal range of motion.

When a coach or trainer observes some of these signs, stop the pitcher from throwing, apply ice to the injured area, and allow him more recovery time from drill work, throwing and a pitching assignment. Have the pitcher do a lot of running and cardiovascular work, but limit his throwing.

If there is little improvement (recovery) after rest within his normal recovery time frame, the player should be seen by a physician to learn the extent of the injury. The pitcher may have to be closed down and go through a throwing rehab program before pitching competitively again.

I believe the best way to develop arm strength, arm stamina, andpitch velocity while avoiding arm injury is to throw a baseball, throw often over a long period of time, and throw bio-mechanically correct. Long term, consistently successful pitchers develop a repeatable, rhythmic and efficient motion.

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.