Overhand throwing places extremely high stresses on the shoulder and to the elbow. In throwing athletes, these high stresses are repeated many times and can lead to a wide range of overuse injuries. In fact, there are some injuries that may occur in a thrower’s shoulder and elbow that simply do not occur in the shoulders and elbows of non-throwers. The constant, repetitive overhead throwing motion imparts high, outward, extension loads to the athlete’s shoulder and elbow. This can lead to either a progressive structural change, or a chronic or acute injury.
The shoulder and elbow are inextricably intertwined with each other and to the joints and muscles of the trunk and lower extremities (hip, back, knee, ankle). Therefore, in order to maintain painfree throwing, potential causes of altered throwing kinematics must be prevented with a balanced training program and treated appropriately when identified.
It must be pointed out; however, that continuation of overhead throwing most often results in subsequent injury and symptom recurrence in the competitive athlete.
Repetitive Throwing Injuries in Youth
According to Sports Medicine Specialists, they are seeing an epidemic of elbow and shoulder injuries in youth, usually due to overuse, poor training, improper throwing mechanics, and fatigue.
If a young athlete is throwing too hard, too much, too early, and without rest, a serious elbow or shoulder injury may be on the horizon. If the athlete complains of elbow or shoulder pain the day after throwing, or movement of the joint is painful or restricted compared to the opposite side, contact OrthoLive, to find a physician familiar with youth sports injuries immediately.
The dreaded injury to the ulnar collateral ligament (UCL) is usually caused by excessive pitching. If the UCL is injured, it can sometimes be difficult to repair or rehabilitate and may require the so-called Tommy John procedure in order to return to competitive pitching. The surgery is named after Tommy John, the first baseball pitcher to undergo successful UCL reconstruction surgery in the 1970’s.
Other common throwing-related injuries include Little League shoulder, which occurs when the growth plate of the humerus (arm bone) becomes inflamed by the excessive forces produced by repetitive throwing. Similarly, Little League elbow involves injury to the growth plate along the inner portion of the elbow.
In addition to acute injuries, repetitive activities such as throwing can lead to physical changes in the development of growing bones and joints. Significant amounts of pitching during adolescence can change the rotation and shape of the shoulder which may leave the player vulnerable to shoulder injury and arthritis in adulthood.
Studies show that children and adolescents who pitch competitively for more than 8 months in a year are the most prone to injury. Throwing more than 80 pitches per game, a fastball that consistently exceeds 85 mph, or pitching while fatigued are also risk factors for injury.
According to one study, pitchers who pitched more than 100 innings in a calendar year were 3.5 times more likely to sustain serious injuries requiring elbow or shoulder surgery or retire due to the injury. This is why USA Baseball and Major League Baseball now recommend that youth pitchers of all ages and abilities take a minimum four month break from overhead throwing, with at least two months off consecutively.
However, athletes and their parents should be reassured that numerous studies have shown that kids who are exposed to a range of sports that utilize different muscle groups and mechanical skills have greater overall success in athletics than those who specialize early on. In addition, they are less prone to injury and burnout than those who focus on a single sport exclusively.
Prevention of Repetitive Throwing Injuries in Youth
- Warm up properly by stretching, running, and easy, gradual throwing
- Rotate playing other positions besides pitcher and catcher
- Concentrate on age-appropriate pitching
- Adhere to pitch count guidelines, such as those established by Little League Baseball
- Avoid pitching on multiple teams with overlapping seasons
- Don’t pitch with elbow or shoulder pain. If the pain persists, see a doctor
- Don’t pitch on consecutive days
- Don’t play year-round
- Never use a radar gun
- Communicate regularly about how your arm is feeling and if there is pain
- Develop skills that are age appropriate
- Emphasize control, accuracy, and good mechanics
- Master the fastball first and the change-up second, before considering breaking pitches
- Speak with a sports medicine professional or athletic trainer if you have any concerns about injuries or prevention strategies
Source: Baseball Injuries Sports Tips: http://www.stopsportsinjuries.org/baseball/
The parts of the shoulder that keep the shoulder stable that may be effected in a repetitive throwing injury are the ligaments, the rotator cuff, and the muscles in the upper back. Each of these play and important role and function as the foundation for the shoulder joint.
Although throwing injuries in the shoulder most commonly occur in baseball pitchers, they can be seen in any athlete who participates in sports that require repetitive overhand motions, such as volleyball, tennis, and some track and field events.
Common throwing shoulder injuries include labral tears, bursitis, tendonitis, rotator cuff tears,biceps tendon injuries, capsular contractures, and shoulder blade (scapula) dyskinesis (abnormal movement) or true winging. A common condition in which throwing athletes develop loss of internal rotation from scarring of the joint capsule, scapula dyskinesis, labral tears, and rotator cuff tears is known as GIRD or glenohumeral internal rotation deficit. It is the most common condition affecting the throwing shoulder.
When athletes throw repeatedly at high speed, significant stresses are placed on the anatomical structures that keep the humeral head centered in the glenoid socket.
Causes of Repetitive Throwing InjuriesThe phases of pitching a baseball. Reproduced and adapted with permission from Poss R (ed): Orthopaedic Knowledge Update 3. Rosemont, IL. American Academy of Orthopaedic Surgeons, 1990, pp 293-302.
Of the five phases that make up the pitching motion, the late cocking and follow-through phases place the greatest forces on the shoulder.
- Late-cocking phase. In order to generate maximum pitch speed, the thrower must bring the arm and hand up and behind the body during the late cocking phase. This arm position of extreme external rotation helps the thrower put speed on the ball, however, it also forces the head of the humerus forward which places significant stress on the ligaments in the front of the shoulder. Over time, the ligaments loosen, resulting in greater external rotation and greater pitching speed, but less shoulder stability.
- Follow-through phase. During acceleration, the arm rapidly rotates internally. Once the ball is released, follow-through begins and the ligaments and rotator cuff tendons at the back of the shoulder must handle significant stresses to decelerate the arm and control the humeral head.
When one structure — such as the ligament system — becomes weakened due to repetitive stresses, other structures must handle the overload. As a result, a wide range of shoulder injuries can occur in the throwing athlete.
The rotator cuff and labrum are the shoulder structures most vulnerable to throwing injuries.
Common Throwing Injuries in the Shoulder
SLAP Tears (Superior Labrum Anterior to Posterior)
In a SLAP injury, the top (superior) part of the labrum is injured. This top area is also where the long head of the biceps tendon attaches to the labrum. A SLAP tear occurs both in front (anterior) and in back (posterior) of this attachment point.
Typical symptoms are a catching or locking sensation, and pain with certain shoulder movements. Pain deep within the shoulder or with certain arm positions is also common.(Left) The labrum helps to deepen the shoulder socket. (Right) This cross-section view of the shoulder socket shows a typical SLAP tear.
Bicep Tendinitis and Tendon Tears
Repetitive throwing can inflame and irritate the upper biceps tendon. This is called biceps tendinitis. Pain in the front of the shoulder and weakness are common symptoms of biceps tendinitis.
Occasionally, the damage to the tendon caused by tendinitis can result in a tear. A torn biceps tendon may cause a sudden, sharp pain in the upper arm. Some people will hear a popping or snapping noise when the tendon tears.(Left) The biceps tendon helps to keep the head of the humerus centered in the glenoid socket. (Right) Tendinitis causes the tendon to become red and swollen.
Rotator Cuff Tendinitis and Tears
When a muscle or tendon is overworked, it can become inflamed. The rotator cuff is frequently irritated in throwers, resulting in tendinitis.
Early symptoms include pain that radiates from the front of the shoulder to the side of the arm. Pain may be present during throwing, other activities, and at rest. As the problem progresses, pain may occur at night, and the athlete may experience a loss of strength and motion.
Rotator cuff tears often begin by fraying. As the damage worsens, the tendon can tear. When one or more of the rotator cuff tendons is torn, the tendon no longer fully attaches to the head of the humerus. Most tears in throwing athletes occur in the supraspinatus tendon.Rotator cuff tendon tears in throwers most often occur within the tendon. In some cases, the tendon can tear where it attaches to the humerus.
Problems with the rotator cuff often lead to shoulder bursitis. There is a lubricating sac called a bursa between the rotator cuff and the bone on top of your shoulder (acromion). The bursa allows the rotator cuff tendons to glide freely when you move your arm. When the rotator cuff tendons are injured or damaged, this bursa can also become inflamed and painful.
During the cocking phase of an overhand throw, the rotator cuff tendons at the back of the shoulder can get pinched between the humeral head and the glenoid. This is called internal impingement and may result in a partial tearing of the rotator cuff tendon. Internal impingement may also damage the labrum, causing part of it to peel off from the glenoid.
Internal impingement may be due to some looseness in the structures at the front of the joint, as well as tightness in the back of the shoulder.The muscles and tendons of the rotator cuff. Reproduced with permission from JF Sarwark, ed: Essentials of Musculoskeletal Care, ed 4. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2010.
The following illustration shows the infraspinatus tendon caught between the humeral head and the glenoid.
REPRODUCED WITH PERMISSION FROM JF SARWARK, ED: ESSENTIALS OF MUSCULOSKELETAL CARE, ED 4. ROSEMONT, IL, AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS, 2010.
Shoulder instability occurs when the head of the humerus slips out of the shoulder socket (dislocation). When the shoulder is loose and moves out of place repeatedly, it is called chronic shoulder instability.
In throwers, instability develops gradually over years from repetitive throwing that stretches the ligaments and creates increased laxity (looseness). If the rotator cuff structures are not able to control the laxity, then the shoulder will slip slightly off-center (subluxation) during the throwing motion.
Pain and loss of throwing velocity will be the initial symptoms, rather than a sensation of the shoulder “slipping out of place.” Occasionally, the thrower may feel the arm “go dead.” A common term for instability many years ago was “dead arm syndrome.”
Glenohumeral Internal Rotation Deficit (GIRD)
As mentioned above, the extreme external rotation required to throw at high speeds typically causes the ligaments at the front of the shoulder to stretch and loosen. A natural and common result is that the soft tissues in the back of the shoulder tighten, leading to loss of internal rotation.
This loss of internal rotation puts throwers at greater risk for labral and rotator cuff tears.
Scapular Rotation Dysfunction (SICK Scapula)
Proper movement and rotation of the scapula over the chest wall is important during the throwing motion. The scapula (shoulder blade) connects to only one other bone: the clavicle. As a result, the scapula relies on several muscles in the upper back to keep it in position to support healthy shoulder movement.
During throwing, repetitive use of scapular muscles creates changes in the muscles that affect the position of the scapula and increase the risk of shoulder injury.
Scapular rotation dysfunction is characterized by drooping of the affected shoulder. The most common symptom is pain at the front of the shoulder, near the collarbone.
In many throwing athletes with SICK scapula, the chest muscles tighten in response to changes in the upper back muscles. Lifting weights and chest strengthening exercises can aggravate this condition.
Common injuries that are usually encountered in the throwing elbow include ulnar neuritis, ulnar collateral ligament tears, flexor-pronator muscle strain or tendonitis, valgus extension overload syndrome with olecranon osteophytes, medial epicondyle apophysitis or avulsion, olecranon stress fractures, osteochondritis dissecans of the capitellum, and loose bodies.
However, significant advantages in recent arthroscopic surgical techniques and ligament reconstruction have markedly improved the prognosis for a healthy return to competition for the extremely motivated athlete.
When athletes throw repeatedly at high speed, the repetitive stresses can lead to a wide range of overuse injuries. Problems most often occur at the inside of the elbow because considerable force is concentrated over the inner elbow during throwing.
Repetitive throwing can irritate and inflame the flexor/pronator tendons where they attach to the humerus bone on the inner side of the elbow. Athletes will have pain on the inside of the elbow when throwing, and if the tendinitis is severe, pain will also occur during rest.
Ulnar Collateral Ligament (UCL) Injury
The ulnar collateral ligament (UCL) is the most commonly injured ligament in throwers. Injuries of the UCL can range from minor damage and inflammation to a complete tear of the ligament. Athletes will have pain on the inside of the elbow, and frequently notice decreased throwing velocity.
Valgus Extension Overload (VEO)
During the throwing motion, the olecranon and humerus bones are twisted and forced against each other. Over time, this can lead to valgus extension overload (VEO), a condition in which the protective cartilage on the olecranon is worn away and abnormal overgrowth of bone — called bone spurs or osteophytes — develop. Athletes with VEO experience swelling and pain at the site of maximum contact between the bones.
The abnormal bone growth of VEO is apparent in these illustrations of the back of the elbow and inner side of the elbow.
Reproduced with permission from Miller CD, Savoie FH III: Valgus extension injuries of the elbow in the throwing athlete. J Am Acad Orthop Surg 1994; 2:261-269.
Olecranon Stress Fracture
Stress fractures occur when muscles become fatigued and are unable to absorb added shock. Eventually, the fatigued muscle transfers the overload of stress to the bone, causing a tiny crack called a stress fracture.
The olecranon is the most common location for stress fractures in throwers. Athletes will notice aching pain over the surface of the olecranon on the underside of the elbow. This pain is worst during throwing or other strenuous activity, and occasionally occurs during rest.
When the elbow is bent, the ulnar nerve stretches around the bony bump at the end of the humerus. In throwing athletes, the ulnar nerve is stretched repeatedly, and can even slip out of place, causing painful snapping. This stretching or snapping leads to irritation of the nerve, a condition called ulnar neuritis.
Throwers with ulnar neuritis will notice pain that resembles electric shocks starting at the inner elbow (often called the “funny bone”) and running along the nerve as it passes into the forearm. Numbness, tingling, or pain in the small and ring fingers may occur during or immediately after throwing, and may also persist during periods of rest.
Ulnar neuritis can also occur in non-throwers, who frequently notice these same symptoms when first waking up in the morning, or when holding the elbow in a bent position for prolonged periods.
Cause of Repetitive Throwing Injuries to the Elbow
Elbow injuries in throwers are usually the result of overuse and repetitive high stresses. In many cases, pain will resolve when the athlete stops throwing. It is uncommon for many of these injuries to occur in non-throwers.
In baseball pitchers, rate of injury is highly related to the number of pitches thrown, the number of innings pitched, and the number of months spent pitching each year. Taller and heavier pitchers, pitchers who throw with higher velocity, and those who participate in showcases are also at higher risk of injury. Pitchers who throw with arm pain or while fatigued have the highest rate of injury.
Symptoms of Repetitive Throwing Injuries to the Elbow
Most of the above conditions initially cause pain during or after throwing. They will often limit the ability to throw or decrease throwing velocity. In the case of ulnar neuritis, the athlete will frequently experience numbness and tingling of the elbow, forearm, or hand as described above.
Prevention of Repetitive Throwing Injuries to the Elbow
As mentioned for the shoulder, proper conditioning, technique, and recovery time can help to prevent throwing injuries in the elbow.