Thrower’s Shoulder

Definition/Description

Wilk et al describe the thrower’s dilemma by defining the thrower’s paradox: the thrower’s shoulder must be loose enough to allow excessive external rotation yet stable enough to prevent symptomatic subluxation of the humeral head, thus requiring a balance between flexibility strike a delicate balance between and functional stability. This balance is often compromised and is thought to result in various types of injury to surrounding tissues. [1]

Due to the extreme angular velocities and the large amount of force transmitted through the glenohumeral joint and its surrounding structures, the tissues of these athletes must utilize tremendous stability. [1] Shoulder injuries in throwers are usually associated with a Inability to maintain functional stability and/or motion throughout the throwing motion with the following or more findings: Increased shoulder external rotation PROM Decreased shoulder external rotator strength Skeletal adaptation Scapular muscle imbalance Adverse postural changes Pitching Mechanics and Fatigue Pitching.

Epidemiology /Etiology

While many sports involve overhead pitches, baseball pitchers compromise multiple pitches and account for more than half of all pitches in baseball. [2]

The etiology behind throwing injuries can be analyzed by looking at the different stages of overhead throwing. The phases of an overhead throw include tightening the stride, jacking acceleration and deceleration phases. [3] Each phase will illustrate the definition of injury incidence, and finally pathological possibility. They are as follows:[3]

Wind up Phase

The tightening phase is defined as the initial movement of the striding leg to achieve maximum knee elevation. [3] In the initial motion, the pitcher raises his or her hands overhead and lowers them to chest level. In these simple movements, consider the muscles from proximal to distal. Electromyographic studies have shown that the The maximum voluntary isometric contraction (MVIC) of the trapezius is 18%, the serratus anterior 20% and the anterior deltoid 15%. During this phase, muscle activity is very low, so the risk of injury is also low. [3]

Stride Phase

The figure below depicts a top view of the body alignment during the acceleration phase of the throw. Note that the feet are at a 15-degree angle from the center of the mound. [4] The stride ankle is also usually about 10 cm from the same midline, some distance away from the ankle. Rubber makes up an average of 87 percent of a pitcher’s height. [4] Fleisig emphasizes the importance of these values by describing changes in shoulder strength when deviating from the norm. During the cocking phase, Fleisig reported that the forward force on the shoulder increased by 3.0N per pass For every 1 degree increase in foot angle, the forward force on the shoulder increases by 2.1 Newtons. Note that decreasing the distance from center or decreasing the angle does not increase the forward force on the shoulder. So due to the increased front force It can be hypothesized that over time the anterior ligamentous structures of the glenohumeral joint may become damaged. This finding is consistent with the anterior glenohumeral instability found in many throwers and highlights the importance of proper mechanics throughout the process Kinetic chain.[5]

Fleisig GS. Biomechanics of Baseball Pitching. PhD thesis. University of Alabama 1994.

Arm Cocking Phase

The arm lift phase can be defined as the onset of forefoot contact and the end of maximal external rotation of the shoulder. [3] A large amount of kinetic energy is transferred from the lower limbs and trunk rotation to the shoulders, accounting for approximately 80% of the body weight. due to circumstances The scapula and shoulder muscles are highly activated to facilitate and maintain shoulder movement, especially external rotation. Due to the high range of external rotation achieved at this stage, it is critical to pay special attention to frontal instability at this stage. [1][5] In a study of pitchers Chronic anterior instability stimulation of mechanoreceptors in the glenohumeral joint excites and/or inhibits certain muscles. The biceps and supraspinatus have been shown to be activated or excited by these mechanoreceptors and help prevent anterior instability. overtime Overuse of the biceps brachii may result in a superior labrum anteroposterior tear (SLAP). Simultaneously inhibits the pectoralis major, subscapularis and serratus anterior. During this phase, these muscles slow down the external rotation of the shoulder. When these actions cannot Prefabricated anterior glenohumeral joints have an increased likelihood of instability. [3]

Arm Acceleration Phase

The arm acceleration phase begins with maximal shoulder external rotation and ends with ball release. [3] During this phase, maintaining scapular stability is critical, as the forward acceleration of the arm corresponds to a peak pronation rate of approximately 6500⁰/sec Close ball release. Improper stabilization of the scapula may account for the increased risk of shoulder impingement at this stage. Combined with the arm erect phase, this phase is also hypothesized to increase the risk of various shoulder injuries due to the high kinetic energy generated from the lower extremities. [3] [5]

Arm Deceleration Phase

The arm deceleration phase begins with ball release and ends with maximum shoulder internal rotation. [3] Typically, the focus of this phase is to safely slow down the forward propulsion of the arm. According to Escamilla et al., produces a shoulder compression force slightly greater than body weight to resist shoulder decentration while generating a posterior shear force of 40-50% body weight to resist anterior subluxation of the shoulder. Due to the high forces generated during this phase, the posterior muscles are very susceptible to stretch overload The lower surface cuff tears the lip and biceps Pathological capsule damage and internal impingement. [3]

Risk factors for elbow and shoulder injuries in youth baseball pitchers:

Olsen et al surveyed 14-20 year old baseball players to identify risk factors for possible surgery in youth baseball pitchers. Ninety-five players were assigned to the injury group (66 elbows, 29 shoulders), and of the 300 prospects contacted for the control group, only 45 met the criteria.

Before the study, Baseball America’s Medical and Safety Advisory Committee issued recommendations for young pitchers: Pitched in more than 1 simultaneous season or pitched in more than 9 months of the year.

Compared with the control group, the shoulder injury group significantly increased the number of pitches per game per year and the number of warm-up pitches before games. These pitchers are used more frequently as starters and pitch in more shows. they voted Despite the fatigue, the speed is higher. They also used anti-inflammatory drugs more frequently to prevent injuries.

Four specific risk factors were identified:

1. 5x increase in pitchers who pitch more than 8 months per year. 2. Pitchers throw more than 80 pitches per game, a 4x increase. 3. Pitchers throwing 85mph or more increase their speed by 2.58 times. 4. There was a 36-fold increase in pitchers who pitched more often despite fatigue. [6]

Characteristics/Clinical Presentation

Introduction and Summary:

The ability to provide optimal physical therapy for throwing patients involves understanding the phases and biomechanics behind throwing. It’s important to note that when these athletes throw with their arms, they gain a significant amount of momentum and power through the use of their arms their legs and torsos. This section will deal primarily with the influence of the upper body on throwing.

There is no conclusive evidence on whether glenohumeral external rotation in the early stages of throwing (eg, striding foot contact) has a positive or negative effect on throwing kinematics or injury development. [5] Some studies claim that increasing external rotation increases risk of injury, while others counter the same. It has been hypothesized that total external rotation of the glenohumeral joint (PROM) predicts increased throwing velocity and increased risk of labrum and/or rotator cuff injury, especially when loss of The inner spin exceeds the outer spin gained. [5] The mechanism of labral tears may be caused by the decelerating force exerted by the attachment of the biceps tendon to the superior labrum.

The presentation of a thrower’s shoulder can be complex as it can manifest as pain, decreased mobility, or deficiencies in strength and/or range of motion. To properly assess and assess the thrower’s shoulder, understand the physical characteristics and clinical presentation Introduction is necessary. A structured approach to assessing a thrower’s shoulder is efficient and effective. Components of this approach should include assessment of joint range of motion and/or ligamentous laxity bony adaptations muscle strength postural and scapular Location. [1]

Range of Motion:

Athletes with throwing injuries typically exhibit increased shoulder external rotation and decreased shoulder internal rotation. Reduced shoulder internal rotation can be further defined as glenohumeral (GH) internal rotation deficit (GIRD). [1] Overhead range of motion The shoulders of throwers vary from researcher to researcher. External rotation provides 90o of active abduction in a range of 118o to 141o, with a passive range of 136.9o. Pronation is common at 40.1o. Discovery that total movement is a combination of external and internal rotation Roughly equal on the throwing and non-throwing shoulders of professional baseball pitchers. This shows that while motion is lost in one direction, it is gained in the opposite direction. [1]

Laxity:

Theoretically, changes in the histological structure of the anterior capsule of the GH joint are the largest factors that increase shoulder external rotation. Excessive movement in a thrower is further defined as “thrower’s laxity,” denoting slack Found in the anterior and inferior joint capsules of the GH joint. Controversial research has also shown that the posterior capsule is lax in throwers without anterior capsule problems and mixed range-of-motion deficits. Due to the circumstances, there is no clear conclusion that the anterior capsule Laxity is the only cause of hypermobility in the shoulders. [1]

Osseous Adaptation:

The most pronounced bony adaptation in throwers is increased retroversion of the humeral head in the glenoid. The posterior inclination of the humeral head can be determined from relative to the horizontal humeral head axis. [7] Increased retroversion of the humeral head indicates increased shoulder external rotation and decreased shoulder internal rotation. Chant et al speculated that the greater the posterior tilt of the humeral head Anterior to the anterior capsule and GH ligament constitutes the increase in external rotation of the shoulder. The reduction in shoulder internal rotation can be attributed to earlier exposure to the posterior capsule. [1] Whiteley et al. concluded that the reverse increase may in fact be a natural phenomenon Assists throwers with a wide range of motion. [5]

Muscle Strength:

A common strength deficit exhibited by throwers is weakness of the shoulder external rotators and strength of the shoulder internal rotators and adductors. The unilateral muscle ratio of the shoulder, and more specifically the antagonist-agonist muscle strength ratio, has been used to assess muscle balance Dynamic stability is required in the shoulders. The muscle strength ratios that require special attention are the external rotator/internal rotator ratio and the scapular extension/distraction and levator/inferior ratios. These muscle groups exhibit the greatest muscle activity Aids in mobility and stability of the humerus and scapula during EMG studies during all phases of throwing. Wilk et al concluded that in order to maintain stability during the throwing motion, the strength of the external rotators must account for 65% of the strength of the internal rotators, which Close to the best 66% to 75%. Studies have shown that baseball players in the throwing position have increases in the elevator and depressor muscles of the scapuloid quadratus compared with the non-throwing position. [1]

Posture and Scapular Position:

The shoulder blades play an important role in any movement of the arm, especially in overhead throws. A common problem faced by throwers is scapular dyskinesia, which is an altered movement of the scapula during joint scapular motion. In particular a type called “SICK” the scapula is a problem faced by throwers who have posture issues that basically damage the scapula. Signs and symptoms are as follows, most notably asymmetric drooping of the scapula, protrusion of the inferior medial border, coracoid process pain and misalignment, and dyskinesia Scapular movement such as scapular forward tilt results in decreased shoulder internal rotation. [1]

Differential Diagnosis 

• Rotator Cuff Tears
• Rotator Cuff Tendonosis/itis
• SLAP Lesions
• Subacromial Impingement
• Internal Impingement
• Primary Instability
• Osteophyte Formation
• Acute Traumatic Instability
• Improper Mechanics

Examination

The physical examination of an overhead thrower should include a thorough examination of the upper body, including the joints above and below the shoulder. These athletes suffer from a wide range of injuries that require an in-depth evaluation to tease out the pathology. Foundation The examination should include: Observation Palpation Range of motion assessment Flexibility testing Manual muscle testing Joint accessory movements and special tests. Comparisons should be made between the affected and uninvolved shoulders, looking for muscle hypertrophy or atrophy and total range of motion. Due to the complexity of the shoulder girdle examination in overhead throwers, the scapullothoracic rhythm and individual movements of the AC SC and GH joints should be examined. The anteroinferior and posterior portions of the joint capsule must Assess for hyperactivity or hypoactivity. The table below provides a sub-item inspection of the main points of the physical examination [9].

For these athletes, the next quarter of the exam is also essential. Reduction of knee flexion through striding foot contact during the release phase is associated with higher pitching velocities, so adequate knee strength and stability should be addressed. [5] Best hip alignment yet To be sure, it will vary depending on the type of pitch being thrown and the type of pitch the pitcher is using. However, stability, flexibility, strength, and endurance of the hip musculature (including the low back and abdomen) must be assessed to adequately examine and ensure The thrower is stabilized from the bottom up to prevent shoulder and even elbow injuries. [5]

Essential UE Exam Essentials for Overhead Throwers

Capsular Mobility Assessment [9]

Subacromial Impingement TIC:[9]

Biceps Load II Test Shoulder Inhibition Test

(for labral tears involving the biceps)[9] (anterior subluxation or dislocation)[9]

[10]

Medical management (best current evidence)

While preventive and conservative treatment are the most critical components of rehabilitation from common injuries affecting throwers, concomitant medical management is required in some cases. The following medical advice should be considered:

NSAIDs and corticosteroid injections: These medications are used primarily in the early stages of shoulder lesions to reduce pain and inflammation. [11][1] recommend initially combining NSAIDs with physical rehabilitation prescriptions and thermotherapy agents. [11] If the athlete does not respond well to this combination therapy, intraarticular corticosteroid injections may be considered while continuing treatment. Corticosteroids have been shown to be effective in reducing short-term pain in subacromial impingement and rotator cuff Tendonitis, but showed long-term pain relief and continued poor function. [12] It should be noted that corticosteroid injections are known to cause adverse events such as transient pain (10.7%) and skin changes (4.0%) after injection as well as harmful connective tissue The effect of repeated use. [12] Historically, corticosteroid injections may have been selected based on season time and player performance needs rather than NSAID use. Treatment considerations of affected tissue should guide treatment and return-to-play decisions, as ROM and strength are Properly restored.

Imaging Issues: Failure to show significant progression within 3 months or return to asymptomatic competition within 6 months, requiring imaging if not already available. In addition, sharp imaging is required if more significant dysfunction or mechanical abnormalities are suspected. [11]

• In young throwers, especially those aged 13-16 years, radiographic images may help rule out a stress fracture of the proximal humeral epiphysis. Known as “Little League” syndrome, this condition can manifest as side shoulder pain, usually only when throwing hard Movement, but may progress to include a dull ache at rest. [11] Adequate rest from exercise followed by a progressive rotator cuff strengthening and recovery throwing program has proven beneficial in this case.
• Radiographic evidence of humeral torsion (retroversion) in the dominant arm of throwing athletes is a normal and benign finding regardless of age, sex, or sport. This presence has actually demonstrated favorable mechanical efficiency and may account for part of the contralateral limb Rotate the measurement difference. [13]
• Imaging may be helpful in detecting bone changes or osteophyte formation, especially in older throwers due to repetitive trauma. The condition usually responds well to supervised rehabilitation, but may require surgical resection if conservative management is ineffective (see Internal shock). [1]

Imaging is also used to detect the type and severity of other conditions, such as SLAP injuries, rotator cuff injuries, and rotator cuff tears.

SLAP Injuries: Of the four main types of SLAP injuries, throwers typically present with type II tears that, in addition to labral involvement, include complete or partial detachment of the biceps tendon from its attachment to the upper lip. This injury is caused by repeated stretching and the twisting force produced by external rotation in the late tilt phase, and the eccentric biceps contraction produced by deceleration. Types II and IV SLAP tears typically do not respond well to physical therapy or corticosteroid injections. Arthroscopic debridement and suture reduction is The preferred method of rehabilitation, being able to achieve success and return to previous levels of play, has a success rate of between 70-87% for throwers and over 90% for the general population. [14][15] A supervised physical rehabilitation program is essential for full recovery after SLAP surgery repair.

Rotator cuff injury: Injury to the rotator cuff muscles or biceps tendon may result from primary or secondary impingement of the subacromial structures. Although primary impingement is rare in throwing athletes, both conditions usually respond well to conservative treatment. the most common The mechanism of secondary impingement of the rotator cuff muscles is joint instability and laxity, most commonly a lack of adequate scapular control. Surgical examination and debridement of involved tissue is required only after attempts at appropriate conservative management have failed Because there is no strong evidence to support surgery for this condition. [1][16]

Rotator Cuff Tears: Full or partial thickness tears of the rotator cuff should attempt no less than two sessions of physical therapy for the entire shoulder joint followed by an intermittent throwing program. [1] Corticosteroid injections can then be performed as a viable trial. Current research Throwing athletes, especially baseball pitchers, who have undergone surgery for total rotator cuff tears have shown very poor return-to-game outcomes. For only 15% of baseball players, neither arthroscopic nor small incision repair yields acceptable full-thickness results and 8% of athletes returned to competition respectively. [1][17]

Acute Traumatic Instability: While most conditions associated with the dominant shoulder in throwing athletes are classified as injuries resulting from overuse or repetitive trauma, the occurrence of acute traumatic instability or dislocation most often indicates surgical management. Recurrent dislocation rates have been found to be as high as 94.5% in young athletes treated non-surgically and as high as 4% in young athletes treated surgically. [18] Arthroscopic procedures using absorbable sutures have not shown a significantly greater benefit than nonabsorbable sutures. [19]

See this Physiopedia link for surgical information on internal shoulder impingement.

Physiotherapy management (best current evidence) [8][11]

A pitcher can choose to pitch from either an extended position or a tucked-in position. What matters is that they are happy with both deliveries and that the two are mechanically similar in subsequent stages. [5]

“The Stretch” vs. “The Wind-up”

Wilk Meister and Andrews defined 4 phases of rehabilitation for throwing athletes: acute intermediate advanced reinforcement and recovery throwing. [8] They also discuss more specific rehabilitation principles for injuries common to overhead throwers. The details of these rehabilitation will be in the Chart below. [8]

[1]

Throwers ten exercise programme

The Thrower’s Ten Exercises Program is a long series of scrubs designed to prepare the shoulders for throwing (related video and PDF). An extension to the standard thrower’s ten-exercise program was proposed by Wilk et al. in 2011 [20].

Youtube video showing ten throwing practice programs.

Restoration Throwing Interval Program – Developed by: Raymond Smokey Kubacak PT

10 Guidelines to Follow:

1. Perform a proper full body warm-up
2. Use proper stretching techniques
3. Throw with proper mechanics
4. The throw must be made on a line (minimize the arc of the ball’s trajectory)
5. Throwing needs to be painless before moving on to the next level
6. Take a day off between steps to ensure adequate tissue recovery
7. Use legs and trunk during throwing
8. Crow Hop Crow Hop Video at 60 Feet or More
9. General soreness is to be expected – severe pain and swelling are unusual – contact an appropriate medical professional before proceeding with the protocol
10. You may take a more conservative approach based on how you feel

31-day plan:

Lyman et al. made the following recommendations for teenage pitchers [21]:

Injury Prevention and Strengthening

Pre-game tubing warmup for pitchers:

• Fingertip level @ fully flexed arm (shoulder flexion) using tube on fixed object (pole or fence)

o Shoulder extension

o Throwing Acceleration

• Use tube in anatomical position @ height from floor equal to athlete’s fingertip

      o Shoulder Flexion

o Throwing slow

o Abduction 90o External Rotation

      o Scapular Punch

      o Low Scapular Rows

• Recommended warm-up dose is 1 set of 30 repetitions per exercise

• These 7 exercises were selected based on EMG results from a set of 12 showing greater than 20% of maximal voluntary isometric contraction in at least 11 of the 13 tested shoulder muscles. [twenty two]

Ballistic Six Exercise Program

6 Exercises:

1) Elastic External Rotation

2) Elastic 90o/90o external rotation

3) Overhead Soccer Throw

4) 90/90 External Rotation Side Throw

5) Deceleration Baseball Throw

6) Baseball Throw [23]

Ballistic Six Practice Progression [23]

The Ballistic Hexagram is designed to reproduce the conditions under which the shoulder girdle musculature must control the humeral head on the glenoid during an overhead throw motion. The sets and progression of the ballistic six-form training program were developed as Follow the SAID principles of progressive resistance training and tax the pitcher’s anaerobic and aerobic systems in a pattern similar to the game of baseball. Exercise 12456 is performed unilaterally, while Exercise 3 is performed with both hands. [twenty three]

Key Research

Whiteley’s review titled: Baseball Throwing Mechanics in Relation to Pathology and Performance – Based on a study of more than 100 articles, a review does an excellent job of relating the biomechanics of throwing to physical therapy. Physiotherapists can use this information to educate Athletes and their coaches better protect and/or recover throwers. [5]

In the article: “Risk Factors for Elbow and Shoulder Injuries in Youth Baseball Pitchers,” Olsen et al. focus on the scant clinical evidence surrounding current safety recommendations for minor league pitchers. By conducting a retrospective survey, they were able to identify four Important risk factors surrounding teenage pitchers who require elbow or shoulder surgery versus those who do not. Identifying these factors can help minor league coaches and associations determine rules and regulations to further protect youth pitchers. [6]

The purpose of this article: “Shoulder Injuries in Overhead Athletes” is to discuss the physical features and nonsurgical and postoperative treatments of common pathologies in overhead athletes. found that the thrower’s shoulders must be sufficiently slack Allowing excessive external rotation yet sufficiently stable to prevent symptomatic subluxation of the humeral head requires a delicate balance between mobility and functional stability. They determined that frequent injuries can be successfully treated with a well-structured and carefully implemented approach Non-surgical rehabilitation program. [1]

Resources

ChrisOleary.com Pitching Mechanics Review. This site has great pictures and media related to the wrong pitching mechanism.

Clinical Bottom Line

Throwing athletes generate tremendous power through highly skilled and complex shoulder movements. [1] Despite meticulous research on the biomechanics of throwers and the forces exerted on surrounding tissues, high-level evidence for therapeutic interventions is lacking. current Evidence points to the need for a comprehensive workup to differentially diagnose multiple deficiencies that may arise from the large repetitive forces on the thrower’s shoulder complex.