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THE AMERICAN JOURNAL OF SPORTS MEDICINE, Vol. 30, No. 1
© 2002 American Orthopaedic Society for Sports Medicine

Current Concepts

Current Concepts in the Rehabilitation of

the Overhead Throwing Athlete
Kevin E. Wilk,*† PT, Keith Meister,‡ MD, and James R. Andrews,§㛳 MD

From *HealthSouth Rehabilitation Corporation and American Sports Medicine Institute,

Birmingham, Alabama, 㛳Tampa Bay Devil Rays Baseball Team, Tampa Bay, Florida,
‡Department of Orthopaedics, Division of Sports Medicine, University of Florida, Gainesville,
Florida, and §Alabama Sports Medicine and Orthopaedic Center, Birmingham, Alabama

ABSTRACT tion and neuromuscular control, and efficiently return-

ing the athlete to competitive throwing.
The overhead throwing motion is an extremely skillful
and intricate movement that is very stressful on the
shoulder joint complex. The overhead throwing athlete The repetitive microtraumatic stresses placed on the ath-
places extraordinary demands on this complex. Exces- lete’s shoulder joint complex during the throwing motion
sively high stresses are applied to the shoulder joint challenge the physiologic limits of the surrounding tis-
because of the tremendous forces generated by the sues. Frequently, alterations in throwing mechanics, mus-
thrower. The thrower’s shoulder must be lax enough to cle fatigue, muscle weakness or imbalance, and excessive
allow excessive external rotation, but stable enough to capsular laxity may lead to tissue breakdown and injury.
prevent symptomatic humeral head subluxations, thus These injuries frequently involve the glenohumeral cap-
requiring a delicate balance between mobility and func- sule, glenoid labrum, and the rotator cuff musculature.
tional stability. We refer to this as the “thrower’s para- It has been our experience that most injuries to the
dox.” This balance is frequently compromised, which thrower’s shoulder can be effectively treated with a proper
leads to injury. Numerous types of injuries may occur nonoperative rehabilitation program. Generally, the reha-
to the surrounding tissues during overhead throwing. bilitation program consists of activity modification, flexi-
Frequently, injuries can be successfully treated with a bility exercises, strengthening exercises, and a gradual
well-structured and carefully implemented nonopera- return to throwing activities. In part one of his “Current
tive rehabilitation program. The key to successful non- Concepts” series, Meister 64 described a four-group classi-
operative treatment is a thorough clinical examination fication system to categorize shoulder injuries in the over-
and accurate diagnosis. Athletes often exhibit numer- head throwing athlete. We will discuss the rehabilitation
ous adaptive changes that develop from the repetitive program for each of the classifications. Bison and An-
microtraumatic stresses observed during overhead drews10 have also offered a classification system for inju-
throwing. Treatment should focus on the restoration of ries to the thrower’s shoulder. Each of these abnormalities
these adaptations during the rehabilitation program. In develops because of unique etiologic factors. On the basis
this article, the typical musculoskeletal profile of the of these etiologic factors and the clinical examination, a
overhead thrower and various rehabilitation programs proper rehabilitation program can be developed for each
for specific injuries are discussed. Rehabilitation fol- category. The key to effective treatment is a thorough
lows a structured, multiphase approach with emphasis clinical examination and appropriate differential diagno-
on controlling inflammation, restoring muscle balance, sis. In this article, we will discuss a typical nonoperative
improving soft tissue flexibility, enhancing propriocep- rehabilitation program for various shoulder injuries that
have been discussed in the previous two articles.

† Address correspondence and reprint requests to Kevin E. Wilk, PT, REHABILITATION OVERVIEW
HealthSouth Rehabilitation Corporation, 1201 11th Avenue South, Suite 100,
Birmingham, AL 35202.
No author or related institution has received financial benefit from research Before the specifics of the rehabilitation program can be
in this study. discussed, a thorough understanding of the clinical exam-

136
Vol. 30, No. 1, 2002 Rehabilitation of the Overhead Throwing Athlete 137

ination of the shoulder joint complex must be established.

The evaluation of the thrower’s shoulder has been dis-
cussed in part two of the series by Meister.63 The physi-
cian must evaluate the thrower to establish a differential
diagnosis, then the physical therapist or athlete trainer
must evaluate the thrower to establish a list of physical
limitations or problems that may be contributing to or
resulting from the disorder. The rehabilitation specialist
must evaluate range of motion, muscle strength, laxity,
and proprioception. In addition, the rehabilitation special-
ist should address the athlete’s throwing program, exer-
cise schedule, and throwing mechanics. Once these areas
have been assessed, a comprehensive rehabilitation pro-
gram can be established. Furthermore, during the evalu-
ation process, the clinician must have an understanding of
what is considered to be the “normal” or acceptable phys-
iologic characteristics for the overhead throwing
population.
The purpose of the following sections is to convey to the
reader the typical physical characteristics of the overhead
throwing athlete. Specific range of motion, strength, lax-
ity, and proprioceptive characteristics exhibited in throw- Fig. 1. The total motion concept: ER ⫹ IR ⫽ total motion.
ing athletes will be discussed. The clinician must possess ER, external rotation; IR, internal rotation.
a complete understanding of what is typical for this
unique athletic population so that abnormalities or differ-
ences can be appropriately identified and addressed. the greatest total arc of motion; that is, external and
internal rotation at 90° of abduction, followed closely by
Range of Motion catchers, then outfielders, and finally infielders. Further-
more, when comparing left-handed with right-handed
Most throwers exhibit an obvious motion disparity pitchers, the left-handed throwers exhibit approximately
whereby external rotation is excessive and internal rota- 7° more external rotation and 12° more total motion when
tion is limited at 90° of abduction.8, 15, 47, 92 Several inves- compared with right-handed throwers. These findings
tigators have documented that pitchers exhibit greater were statistically significant (P ⬍ 0.01).
external rotation of the shoulder than do position play-
ers.8, 47, 93 Brown et al.15 reported that professional pitch- Laxity
ers exhibited 141° ⫾ 15° of shoulder external rotation
measured at 90° of abduction. This was approximately 9° Most throwers exhibit significant laxity of the glenohu-
more than the nonthrowing shoulder, and approximately meral joint, which permits excessive range of motion. The
9° more than the throwing shoulder of position players hypermobility of the thrower’s shoulder has been referred
measured in 90° of abduction. Recently, Bigliani et al.8 to as “thrower’s laxity.” 92 The laxity of the anterior and
examined the range of motion of 148 professional players. inferior glenohumeral joint capsule may be appreciated by
The investigators reported that the pitchers’ external ro- the clinician during the stability assessment of the over-
tation at 90° of abduction averaged 118° (range, 95° to head thrower’s shoulder joint. Some clinicians have re-
145°) in the dominant shoulder, whereas the position play- ported that the excessive laxity exhibited by the thrower is
ers’ dominant shoulder averaged 108° (range, 80° to 105°). the result of repetitive throwing and they have referred to
In an ongoing study of professional baseball players, this as “acquired laxity” (J. R. Andrews, unpublished data,
Wilk and Arrigo (unpublished data, 2000) assessed the 1996), while others have documented that the overhead
range of shoulder motion of 372 professional baseball play- thrower exhibits congenital laxity.8
ers. We have noted that pitchers exhibit an average of Bigliani et al.8 examined laxity in 72 professional base-
129.9° ⫾ 10° of external rotation and 62.6° ⫾ 9° of internal ball pitchers and 76 position players. The investigators
rotation when passively assessed at 90° of abduction. In noted a high degree of inferior glenohumeral joint laxity,
pitchers, the external rotation is approximately 7° greater with 61% of pitchers and 47% of position players exhibit-
in the throwing shoulder when compared with the non- ing a positive sulcus sign in the throwing shoulder. Addi-
throwing shoulder, while internal rotation is 7° greater in tionally, in the players who also exhibited a positive sul-
the nonthrowing shoulder. In addition, the total motion cus sign in the dominant shoulder, 89% of the pitchers and
(external rotation and internal rotation added together) in 100% of the position players exhibited a positive sulcus
the throwing shoulder is equal (within 5°) when compared sign in the nondominant shoulder. Thus, it would appear
with the nonthrowing shoulder. This was consistent in all that some baseball players exhibit inherent or congenital
372 baseball players. We refer to this as the “total motion laxity, with superimposed acquired laxity, as a result of
concept” (Fig. 1). We have also noted that pitchers exhibit adaptive changes from throwing.
138 Wilk et al. American Journal of Sports Medicine

TABLE 1 the external rotator muscles should be at least 65% the

Glenohumeral Muscular Strength Values (in percent) in strength of the internal rotator muscles.94 Optimally, the
Professional Baseball Playersa
external-to-internal rotator muscles strength ratio should
180 deg/s 300 deg/s 450 deg/s be 66% to 75%.91, 94, 96 This provides proper muscle bal-
Bilateral comparisons ance. Table 1 illustrates the expected muscle strength
External rotation 95–109 85–95 80–80 values of professional baseball players.
Internal rotation 105–120 100–115 100–110 Magnusson et al.60 used a hand-held dynamometer to
Abduction 100–110 100–110
study the isometric muscle strength of professional pitch-
Adduction 120–135 115–130
Unilateral muscle ratios ers and compared it with strength of a control group of
External/internal 63–70 65–72 62–70 nonthrowing, nonathletic persons. In pitchers, the su-
rotation praspinatus muscle was significantly weaker on the
Abduction/adduction 82–87 92–97 throwing side compared with the nonthrowing side; this
External 64–69 66–71
rotation/abduction was tested by performing an isometric manual muscle test
Isokinetic torque/body of the empty can maneuver. Additionally, pitchers were
weight ratios weaker than the control group of nonbaseball players for
External rotation 18–23 15–20 shoulder abduction, external rotation, internal rotation,
Internal rotation 27–33 25–30
and muscle strength of the supraspinatus muscle.
Abduction 26–32 20–26
Adduction 32–36 28–33 The scapular muscles play a vital role during the over-
a
head throwing motion.26 Proper scapular movement and
Data condensed from Wilk et al.94,96
stability are imperative for asymptomatic shoulder func-
tion.48, 49 These muscles work in a synchronized fashion
Muscle Strength and act as force couples about the scapula, providing both
movement and stabilization. Wilk et al.97 documented the
Several investigators have examined muscle strength pa- isometric scapular muscle strength values of professional
rameters in the overhead throwing athlete with varying baseball players. The results indicated that pitchers and
results and conclusions.1, 7, 15, 20, 22, 39, 89, 91 Wilk et al.89, 91 catchers exhibited a significantly different strength in-
performed isokinetic testing on professional baseball play- crease of the protractor and elevator muscles of the scap-
ers as part of their physical examinations during spring ula when compared with position players. All players (ex-
training. The investigators demonstrated that the exter- cept infielders) exhibited significantly stronger depressor
nal rotation strength of the pitcher’s throwing shoulder is muscles of the scapula on the throwing side compared
significantly weaker (P ⬍ 0.05) than the nonthrowing with the nonthrowing side. In addition, we believe that
shoulder, by 6%. Conversely, internal rotation strength of the agonist/antagonist muscle ratios are important values
the throwing shoulder was significantly stronger (P ⬍ when considering how the scapula provides stability, mo-
0.05), by 3%, compared with the nonthrowing shoulder. In bility, and symptom-free function. Table 2 illustrates the
addition, adduction strength of the throwing shoulder is scapular muscle strength values in the overhead throwing
also significantly stronger than in the nonthrowing shoul- athlete.
der, by approximately 9% to 10%. We believe that an
important isokinetic value is the unilateral muscle ratio,
which describes the antagonist/agonist muscle strength Proprioception
ratio. A proper balance between agonist and antagonist
muscle groups is thought to provide dynamic stabilization Proprioception is defined as the conscious or unconscious
to the shoulder joint. To provide proper muscle balance, awareness of joint position, whereas neuromuscular con-

TABLE 2
Scapular Muscle Values and Their Unilateral Ratiosa
Scapular muscle values (in foot-pounds)

Protraction Retraction Elevation Depression

D ND D ND D ND D ND

Pitchers 71 ⫾ 10 74 ⫾ 13 62 ⫾ 8 60 ⫾ 7 83 ⫾ 14 84 ⫾ 5 22 ⫾ 6 18 ⫾ 5
Catchers 68 ⫾ 10 73 ⫾ 10 63 ⫾ 5 59 ⫾ 7 88 ⫾ 15 85 ⫾ 8 21 ⫾ 4 16 ⫾ 5
Position players 58 ⫾ 10 58 ⫾ 11 57 ⫾ 6 56 ⫾ 6 65 ⫾ 12 66 ⫾ 11 19 ⫾ 5 18 ⫾ 5
Unilateral muscle ratios (in percent)

Protraction/Retraction Elevation/Depression

D ND D ND

Pitchers 87 81 27 21
Catchers 93 81 24 19
Position players 98 94 29 27
a
D, dominant; ND, nondominant.
Vol. 30, No. 1, 2002 Rehabilitation of the Overhead Throwing Athlete 139

trol is the efferent motor response to afferent (sensory) TABLE 3

information.53 The thrower relies on enhanced propriocep- Rehabilitation of the Overhead Thrower—Phases and Goals
tion to influence the neuromuscular system to dynami- Phase one—acute phase
cally stabilize the glenohumeral joint in the presence of Goals
significant capsular laxity and excessive range of motion. Diminish pain and inflammation
Normalize motion
Allegrucci et al.2 tested the shoulder proprioception in 20 Retard muscular atrophy
healthy overhead throwing athletes participating in vari- Reestablish dynamic stability (muscular balance)
ous sports. Testing of joint proprioception was performed Control functional stress/strain
on a motorized system with the subject attempting to Exercises and modalities:
reproduce a specific joint angle. The investigators noted Cryotherapy, ultrasound, electrical stimulation
Flexibility and stretching for posterior shoulder muscles
that the dominant shoulder exhibited diminished propri- (improve internal rotation and horizontal adduction)
oception compared with the nondominant shoulder. The Rotator cuff strengthening (especially external rotator
investigators also noted improved proprioception near the muscles)
end range of motion when compared with the starting Scapular muscles strengthening (especially retractor,
protractor, depressor muscles)
point. Dynamic stabilization exercises (rhythmic stabilization)
Blasier et al.12 reported that, in persons with clinically Closed kinetic chain exercises
determined generalized joint laxity, the laxity is signifi- Proprioception training
cantly less sensitive during proprioceptive testing. Wilk et Abstain from throwing
al. (unpublished data, 2000) studied the proprioceptive Phase two—intermediate phase
Goals
capability of 120 professional baseball players. The inves- Progress strengthening exercise
tigators passively positioned the player’s arm at a docu- Restore muscular balance (external/internal rotation)
mented point within the player’s external rotation range Enhance dynamic stability
of motion. The athlete was then instructed to actively Control flexibility and stretches
Exercises and modalities
reposition the shoulder in the same position. The re- Continue stretching and flexibility (especially internal
searchers noted no significant difference between the rotation and horizontal adduction)
throwing shoulder and nonthrowing shoulder. In addition, Progress isotonic strengthening
Wilk et al. (unpublished data, 2000) compared the propri- ● Complete shoulder program
oceptive ability of 60 professional baseball players with ● Thrower’s Ten program
Rhythmic stabilization drills
that of 60 nonoverhead throwing athletes. The investiga- Initiate core strengthening program
tors noted no significant differences between baseball Initiate leg program
players and the others. However, baseball players exhib- Phase three—advanced strengthening phase
ited slightly improved proprioceptive abilities at external Goals
Aggressive strengthening
rotation end range of motion compared with nonoverhead Progress neuromuscular control
athletes, but these results were not significantly different. Improve strength, power, and endurance
Initiate light throwing activities
Exercises and modalities
THE REHABILITATION PROGRAM FOR THE Flexibility and stretching
OVERHEAD THROWER Rhythmic stabilization drills
Thrower’s Ten program
The nonoperative rehabilitation program used for treat- Initiate plyometric program
ment of shoulder injuries to the overhead thrower involves Initiate endurance drills
a multiphased approach that is progressive and sequen- Initiate short-distance throwing program
Phase four—return-to-activity phase
tial. The specific goals of each of the four phases of the Goals
program are outlined in Table 3. Each phase represents a Progress to throwing program
progression from the prior phase: the exercises become Return to competitive throwing
more aggressive and demanding, and the stresses applied Continue strengthening and flexibility drills
Exercises
to the shoulder joint gradually increase. We will briefly Stretching and flexibility drills
discuss the specific rehabilitation exercises and drills that Thrower’s Ten program
we use to treat the overhead throwing athlete. Plyometric program
There are 10 rehabilitation principles that we follow Progress interval throwing program to competitive
when treating a throwing athlete. These principles are throwing
shown in Table 4.

Phase One—Acute Phase modalities such as ice, ultrasound, and electrical stimula-
tion. In addition, the athlete’s activities (such as throwing
The primary goals of the initial rehabilitation phase are to and exercises) must be modified to a pain-free level. The
improve flexibility, reestablish baseline dynamic stability, thrower is often instructed to abstain from throwing until
normalize muscle balance, and restore proprioception advised by the physician or rehabilitation specialist. Ad-
without causing shoulder irritation or pain. One of the ditionally, active-assisted motion exercises have been
goals—to diminish the athlete’s pain and inflamma- shown to assist in reducing the athlete’s pain.69
tion—is accomplished through the use of local therapeutic Another essential goal during the first phase of rehabil-
140 Wilk et al. American Journal of Sports Medicine

TABLE 4
Principles of Rehabilitation in the Thrower
1. Never overstress healing tissue
2. Prevent negative effects of immobilization
3. Emphasize external rotation muscular strength
4. Establish muscular balance
5. Emphasize scapular muscle strength
6. Improve posterior shoulder flexibility (internal rotation
range of motion)
7. Enhance proprioception and neuromuscular control
8. Establish biomechanically efficient throwing
9. Gradually return to throwing activities
10. Use established criteria to progress

itation is to normalize shoulder motion, particularly

shoulder internal rotation and horizontal adduction. It is
common for the overhead thrower to exhibit a significant
loss of internal rotation. This may be due to soft tissue Figure 2. Internal rotation stretch: the arm is placed in the
tightness, which may be from muscle inflexibility due to throwing position and passively stretched into internal rota-
significant and repetitive eccentric muscle forces during tion to stretch the external rotator muscles.
arm deceleration. If the posterior soft tissue structures
such as the infraspinatus and teres minor muscles are
tight, increased anterior translation of the humeral head
may result.35 Therefore, the thrower should perform spe-
cific stretches and flexibility exercises for the benefit of
the posterior rotator cuff muscles.
We believe that the loss of internal rotation is due to
osseous adaptation of the humerus and posterior muscle
tightness.21 We do not believe that the loss of internal
rotation is routinely due to posterior capsular tightness. It
appears that most throwers exhibit significant posterior
laxity when evaluated.21 Thus, to improve internal rota-
tion motion and flexibility, we prefer the stretches illus-
trated in Figures 2 and 3. These stretches are performed
to maintain the flexibility of the posterior musculature,
which may become tight because of the muscle contraction
during the deceleration phase of throwing. We do not
recommend performing stretches for the capsule unless
Figure 3. To improve posterior shoulder flexibility, the hori-
the capsule has been shown on clinical examination to be
zontal adduction stretch can be performed at 90° of shoulder
excessively hypomobile.
abduction. The arm is horizontally adducted while the scap-
The rehabilitation specialist, in addition to helping re-
ula is stabilized to enhance the posterior shoulder stretch.
store glenohumeral motion, should assess the resting po-
sition and mobility of the scapula. Frequently, we have
seen overhead throwers who exhibit a posture of rounded specialist should carefully assess the position, mobility,
shoulders and a forward head. This posture may lead to and strength of the overhead thrower’s scapula. We rou-
muscle weakness of the scapular retractor muscles due to tinely have throwers stretch their pectoralis minor muscle
prolonged elongation or sustained stretches. In addition, and strengthen the lower trapezius muscle and scapular
the scapula may often appear protracted and anteriorly retractor and protractor muscles.
tilted. An anteriorly tilted scapula has been shown to Additional primary goals of this first phase are to re-
contribute to subacromial impingement.58 In overhead store muscle strength, reestablish baseline dynamic sta-
throwers, we have seen this scapular position abnormality bility, and restore proprioception. In this early phase of
correlate to pectoralis minor muscle tightness and lower rehabilitation, the goal is to reestablish muscle bal-
trapezius muscle weakness. Tightness of the pectoralis ance.94, 96 Therefore, the focus is on improving the
minor muscle can lead to axillary artery occlusion and strength of the weak muscles such as the external rotator
neurovascular symptoms such as arm fatigue, pain, ten- muscles, the supraspinatus muscle, and the scapular mus-
derness, and cyanosis.6, 70, 75, 78 The lower trapezius mus- cles.94, 96 The scapular muscles we routinely focus on in
cle is an important muscle in arm deceleration in that it rehabilitation are the trapezius, serratus anterior, and
controls scapular elevation and protraction.26 Weakness rhomboid muscles. If the injured athlete is extremely sore
of the lower trapezius muscle may result in improper or painful, submaximal isometric exercises should be em-
mechanics or shoulder symptoms. Thus, the rehabilitation ployed; conversely, if the athlete exhibits minimal soreness,
Vol. 30, No. 1, 2002 Rehabilitation of the Overhead Throwing Athlete 141

then lightweight isotonic exercises may be safely initiated.

Additionally, during this phase we use rehabilitation exer-
cise drills (see the next paragraph) that are designed to
restore the neurosensory properties of the shoulder capsule
that has experienced microtrauma and to enhance the sen-
sitivity of the afferent mechanoreceptors.53, 55
Specific drills that restore neuromuscular control dur-
ing this initial phase are rhythmic stabilization and recip-
rocal isometric muscle contractions for the internal/exter-
nal rotator muscles of the shoulders. Additionally,
proprioceptive neuromuscular facilitation patterns are
used with rhythmic stabilization and slow reversal hold to
reestablish proprioception and dynamic stabiliza-
tion.51, 53, 55, 79, 93, 96 The purpose of these exercise drills is
to facilitate agonist/antagonist muscle cocontractions. Ef-
ficient coactivation assists in restoring the balance in the
force couples of the shoulder joint, thus enhancing joint
congruency and joint compression.37 Padua et al.71 used Figure 4. External rotation with a dumbbell, with the patient
proprioceptive neuromuscular facilitation patterns for 5 lying on his side, is one of the exercises to increase external
weeks and significantly improved their subjects’ shoulder rotation strength.
function and enhanced functional throwing performance
test scores. Uhl et al.83 reported improved proprioception The scapula provides proximal stability to the shoulder
after specific neuromuscular training that challenged the joint, enabling distal segment mobility. Scapular stability
glenohumeral musculature. is vital for normal asymptomatic arm function. Several
Other exercise drills commonly used during this first authors have emphasized the importance of scapular mus-
rehabilitation phase include joint repositioning cle strength and neuromuscular control in contributing to
tasks52, 53, 54 and axial loading exercises (such as closed normal shoulder function.23, 48, 49, 72 Isotonic exercise tech-
kinetic chain). Active joint compression stimulates the niques are used to strengthen the scapular muscles. Fur-
articular receptors.19, 52 Thus, axial loading exercise drills thermore, Wilk and Arrigo93 developed specific exercise
such as weight shifts, weight shifting on a ball, wall push- drills to enhance neuromuscular control of the scapulotho-
ups, and quadruped positioning drills are beneficial in racic joint. These exercise drills are designed to maximally
restoring proprioception.90, 92, 95 challenge the scapulothoracic muscle force couples and to
stimulate the proprioceptive and kinesthetic awareness of
Phase Two—Intermediate Phase the scapula. These scapular neuromuscular control drills
are illustrated in Figure 6.
In phase two of the rehabilitation program, the primary Another popular exercise used by athletes is the “empty
goals are to progress the strengthening program, continue can” exercise (Fig. 7). With this exercise movement, the
to improve flexibility, and facilitate neuromuscular con- arm is placed in the scapular plane with the hand placed
trol. During this phase, the rehabilitation program is pro-
gressed to more aggressive isotonic strengthening activi-
ties with emphasis on the restoration of muscle balance.
Selective muscle activation is also used to restore muscle
balance and symmetry. In the overhead thrower, the
shoulder external rotator muscles, scapular retractor
muscles, and protractor and depressor muscles are fre-
quently isolated because of weakness. We have estab-
lished a core exercise program for the overhead thrower
that specifically addresses the vital muscles involved in
the throwing motion.90, 98 This exercise program was de-
veloped on the basis of the collective EMG research of
numerous investigators,11, 24, 30, 38, 45, 46, 56, 65, 66, 73, 81 and
is referred to as the “Thrower’s Ten Program㛳.”90 Sidely-
ing external rotation (Fig. 4) and prone rowing into exter-
nal rotation (Fig. 5) have been shown to elicit the highest
amount of EMG activity of the posterior rotator cuff
muscles.30

㛳 To request a copy of this four-page illustrated program, please write to the Figure 5. Prone rowing into external rotation is another
corresponding author. exercise to enhance external rotation strength.
142 Wilk et al. American Journal of Sports Medicine

Figure 7. The empty can exercise movement. This exercise

can produce pain in some athletes. For this exercise, the
subject elevates the arm in the plane of the scapula with the
thumb pointed downward. The hand position appears to
resemble that of emptying a can, hence comes the name of
the exercise.

90° to 120°, which places the upper extremity into an

impingement type of position.81 Blackburn et al.11 noted
that the position with the patient lying prone and with the
Figure 6. Neuromuscular control exercise drill for the scap-
arm abducted to 100° and full external rotation (Fig. 8)
ular muscles: the athlete lies on his side with the hand placed
produced the highest EMG activity in the supraspinatus
on the table (A) and the clinician applies manual resistance to
muscle, compared with the empty can position. This
resist scapular movements (such as protraction and retrac-
exercise maneuver, advocated by Blackburn et al.,11 has
tion) (B). The athlete is instructed to perform slow and con-
been substantiated by Malanga et al.61
trolled movements.
Many times when athletes perform the empty can exer-
cise they complain of shoulder pain during this maneuver.
in full internal rotation (thumb down).44 Originally, Jobe We believe the shoulder pain may be occurring because of
and Moynes44 reported high levels of EMG activity in the superior displacement of the humeral head due to weak-
supraspinatus muscle during this exercise. Recently, sev- ness of the external rotator muscles. Overhead throwing
eral investigators have tested the efficiency of this exer- athletes often exhibit external rotator muscle weakness;
cise. Townsend et al.81 reported that the best exercise to thus, we advocate the “full can” exercise (Fig. 9) instead of
activate the supraspinatus muscle was the military shoul- the empty can exercise in an attempt to avoid the possi-
der press, but this exercise is not recommended for the bility of causing superior humeral head displacement,
overhead throwing athlete. Furthermore, the investiga- which may lead to pain and inflammation.
tors noted that the empty can exercise produced high Also during this second rehabilitation phase, the over-
EMG activity but only when the arm was elevated from head throwing athlete is instructed to perform core
Vol. 30, No. 1, 2002 Rehabilitation of the Overhead Throwing Athlete 143

Figure 8. Prone horizontal abduction at 110° of shoulder

abduction and full external rotation. This exercise produces
high levels of EMG activity of the posterior rotator cuff, su-
praspinatus, and lower trapezius muscles.
Figure 10. Rhythm stabilization exercise drill: the subject
throws a 2-pound Plyoball (Functional Integrated Technolo-
gies, Watsonville, California) against the wall, at the end-
range of external rotation (late cocking).

strengthening exercises for the abdomen and lower back

musculature. Plus, the athlete should perform lower ex-
tremity strengthening and participate in a running pro-
gram, including jogging and sprint timing. Upper extrem-
ity stretching exercises are continued as needed to
maintain soft tissue flexibility.

Phase Three—Advanced Strengthening Phase

In phase three, the advanced strengthening phase, the

goals are to initiate aggressive strengthening drills, en-
hance power and endurance, perform functional drills,
and gradually initiate throwing activities. During this
phase, the athlete performs the Thrower’s Ten exercise
program, continues manual resistance stabilization drills,
and initiates plyometric drills. Dynamic stabilization
drills are also performed to enhance proprioception and
neuromuscular control. These drills include rhythmic sta-
bilization exercise drills by throwing a ball into a wall
(Fig. 10), push-ups onto a ball (Fig. 11), and ball throws.
Plyometric training (described in the next paragraph) may
be used to enhance dynamic stability, enhance propriocep-
tion, and gradually increase the functional stresses placed
on the shoulder joint.
Plyometric exercise employs three phases, all intended
to use the elastic and reactive properties of the muscle to
Figure 9. The full can exercise movement. This exercise is generate maximum force production.13, 16, 18 The first
performed in the plane of the scapula. The subject elevates phase is the eccentric phase, where a rapid prestretch is
the arm with the thumb pointed upward, as if not to spill applied to the musculotendinous unit, stimulating the
contents of an imaginary can, stopping at 90° of elevation. muscle spindle. The second phase is the amortization
144 Wilk et al. American Journal of Sports Medicine

Figure 13. A plyometric exercise drill: a two-handed over-

head soccer throw.

Figure 11. Rhythm stabilization exercise drill: the subject

performs a push-up into a Plyoball. At midrange, the subject
holds that position.

Figure 14. A plyometric exercise drill: a two-handed side

throw using an 8-pound Plyoball. Note the use of the lower
extremity and hips to produce trunk and shoulder rotation.-

Figure 12. A plyometric exercise drill: a two-handed chest

pass using an 8-pound Plyoball that is thrown into a Plyoback
(Functional Integrated Technologies).

phase, representing the time between the eccentric and

concentric phases. This time should be as short as possible
so that the beneficial neurologic effects of the prestretch
are not lost. The final phase is the resultant concentric
contraction. Wilk et al.88, 98 established a plyometric exer-
cise program for the overhead thrower. The initial plyo-
metric program consists of two-handed exercise drills such
as a chest pass, overhead soccer throw, side-to-side
throws, and side throws (Figs. 12 through 14). The goal of
the plyometric drills is the transfer of energy from the legs
and trunk to the upper extremity. Once these two-handed Figure 15. A plyometric exercise drill: a one-handed base-
exercise drills are mastered, the athlete is progressed to ball throw with use of a 2-pound Plyoball.
Vol. 30, No. 1, 2002 Rehabilitation of the Overhead Throwing Athlete 145

one-handed drills. These drills include standing one- program is designed to gradually increase the quantity,
handed throws in a functional throwing position (Fig. 15), distance, intensity, and type of throws needed to facilitate
wall dribbling, and plyometric step and throws. Swanik et the gradual restoration of normal biomechanics.
al.80 reported that a 6-week plyometric training program Interval throwing is organized into two phases: phase I
resulted in enhanced joint position sense, enhanced kin- is a long-toss program (from 45 to 180 feet) and phase II is
esthesia, and decreased time to peak torque generation an off-the-mound program for pitchersa.90 During this
during isokinetic testing. Fortun et al.32 noted improved third rehabilitation phase, we usually initiate phase I of
shoulder internal rotation power and throwing distance the interval throwing program at 45 feet and progress to
after 8 weeks of plyometric training in comparison with throwing from 60 feet. The athlete is instructed to use a
conventional isotonic training. crow-hop type of throwing mechanism and lob the ball
Additionally, muscle endurance exercises should be em- with an arc for the prescribed distance. Flat ground, long-
phasized for the overhead thrower. Recently, Murray et toss throwing is used before throwing off the mound to
al.67 documented the effects of fatigue on the entire body allow the athlete to gradually increase the applied loads to
during pitching using kinematic and kinetic motion anal- the shoulder while using proper throwing mechanics. In
ysis. Once the thrower was fatigued, shoulder external addition, during this phase of rehabilitation, we routinely
rotation decreased and ball velocity diminished, as did allow the position player to initiate a progressive batting
lead knee flexion and shoulder adduction torque. Voight et program. We routinely use a program that progresses the
al.86 documented a relationship between muscle fatigue athlete from swinging a light bat, to hitting a ball off a tee,
and diminished proprioception. Chen et al.17 demon- to soft-toss hitting, to batting practice.
strated that once the rotator cuff muscles are fatigued, the
humeral head migrates superiorly when arm elevation is Phase Four—Return-to-Throwing Phase
initiated. Recently, Gladstone et al. (unpublished data,
1996) documented that once the shoulder musculature Phase four of the rehabilitation program, the return-to-
fatigues in professional baseball pitchers during game throwing phase, usually involves the progression of the
situations, the humeral head translates superiorly. Fur- interval throwing program. For pitchers, we progress the
thermore, Lyman et al.59 reported that the predisposing long-toss program to 120 or 145 feet, whereas position
factor that correlated to the highest percentage of shoul- players would progress to throwing from 180 feet. Once
der injuries in Little League pitchers was complaints of the pitcher has successfully completed throwing from 120
muscle fatigue while pitching. Thus, the endurance exer- or 145 feet, the athlete is instructed to throw 60 feet from
cise drills described here appear critical for the overhead the windup on level ground. Once this step is successfully
thrower. completed, phase II, throwing from the mound, is per-
Specific endurance exercise drills we use include wall formed. Position players continue to progress the long-toss
dribbling with a Plyoball (Functional Integrated Technol- program to 180 feet, then perform fielding drills from their
ogies, Watsonville, California), wall arm circles, upper specific position. While the athlete is performing the in-
body cycle, or isotonic exercises using lower weights with terval throwing program, the clinician should carefully
higher repetition. Other techniques that may be beneficial monitor the thrower’s mechanics and throwing intensity.
to enhance endurance include throwing an under- In a study conducted at our biomechanics laboratory, we
weighted or overweighted ball (that is, a ball that is objectively measured the throwing intensity of healthy
either less than or more than the weight of an official pitchers. When pitchers were asked to throw at 50% effort,
baseball).14, 18, 25, 27, 57, 84 These techniques are designed radar gun analysis indicated that the actual effort was
to enhance training, coordination, and the transfer of ki- approximately 83% of their maximum speed. When asked
netic energy. Fortun et al.32 noted an increase in internal to throw at 75% effort, the pitchers threw at 90% of their
rotation strength and power after an 8-week plyometric maximum effort.31 This indicates that these athletes
training program using a weighted ball. Most commonly, threw at greater intensities than were suggested, which
the underweighted ball is used to improve the transfer of may imply difficulty of controlling velocity at lower throw-
energy and angular momentum.25, 27, 84 Conversely, the ing intensities.
overweighted ball is generally used to enhance shoulder In addition, during this fourth phase the thrower is
strength and power.25, 27, 84 instructed to continue all the exercises previously pre-
Also, during this third rehabilitation phase an interval scribed to improve upper extremity strength, power, and
throwing program may be initiated. Before initiating such endurance. The athlete is also instructed to continue the
a program, we occasionally suggest that the athlete per- stretching program, core exercise training, and lower ex-
form “shadow” throwing or mirror throwing, which is the tremity strengthening activities. Lastly, the athlete is
action of mimicking the throwing mechanics into a mirror, counseled on a year-round conditioning program based on
but not actively throwing. This is designed to allow the the principles of periodization.85 Thus, the athlete is in-
athlete to work on proper throwing mechanics before structed when to begin such things as strength training
throwing a baseball. The interval throwing program is and throwing.96 To prevent the effects of overtraining or
initiated once the athlete can fulfill these specific criteria:
1) satisfactory clinical examination, 2) nonpainful range of
motion, 3) satisfactory isokinetic test results, and 4) ap- a
To request copies of the phases of the interval throwing program, please
propriate rehabilitation progress. The interval throwing write to the corresponding author.
146 Wilk et al. American Journal of Sports Medicine

Figure 16. The concept of periodization for the overhead Figure 17. Rhythmic stabilization drills to enhance dynamic
throwing athlete. The graph illustrates that volume, intensity, glenohumeral joint stability. The athlete is instructed to max-
and technique should be adjusted based on the time of the imally externally rotate, then perform reciprocal isometric
year (that is, preseason, in-season, and postseason). (From contractions to enhance dynamic joint stability. The goal of
Wilk et al.90) this exercise is to maintain a specific joint angle.

throwing when poorly conditioned, it is critical to instruct

ing of the posterior rotator cuff to reestablish muscle bal-
the athlete specifically on what to do through specific
exercises throughout the year (Fig. 16). This is especially ance and improve joint compression abilities.
critical in preparing the athlete for the following season. The scapular muscle must be an area of increased focus
Wooden et al.99 demonstrated that performing a dynamic as well. Restoring dynamic stabilization is an essential
variable resistance exercise program significantly in- goal to minimize the anterior translation of the humeral
creases throwing velocity. head during the late cocking and early acceleration phases
of throwing. Exercise drills such as proprioceptive neuro-
muscular facilitation patterns with rhythmic stabilization
SPECIFIC REHABILITATION GUIDELINES are incorporated.92, 94 Also, stabilization drills performed
at end-range external rotation are beneficial in enhancing
To successfully rehabilitate the overhead thrower, an ac- dynamic stabilization (Fig. 17). Perturbation training of
curate differential diagnosis is imperative. Once the diag- the shoulder joint is performed to enhance proprioception,
nosis is established, an appropriate rehabilitation pro- dynamic stabilization, and neuromuscular control. We be-
gram can be formulated. Often, the previously mentioned lieve that this form of training has been extremely effec-
program must be modified based on the specific disorder tive in treating the thrower who has posterior/superior
exhibited by the thrower. In this section, we will discuss impingement.
the rehabilitation guidelines for several common injuries Once we have restored posterior flexibility, normalized
that occur in the overhead thrower. glenohumeral strength ratios, enhanced scapular muscle
strength, and diminished the patient’s symptoms, an in-
Posterosuperior Glenoid Impingement terval throwing program may be initiated. Jobe40 sug-
gested abstaining from throwing for 2 to 12 weeks before
Posterosuperior glenoid impingement, often referred to as
the throwing program, depending on the thrower’s symp-
internal impingement, is one of the most frequently ob-
served injuries to the overhead throwing athlete (Refs. toms. Once the thrower begins the interval throwing pro-
3–5, 40 – 42, 62, 87; J. R. Andrews, unpublished data, gram, the clinician or pitching coach should observe the
1996). We believe that one of the underlying causes of throwing mechanics frequently. Occasionally, throwers
symptomatic internal impingement is excessive anterior who exhibit internal impingement will allow their arm to
shoulder laxity. One of the primary goals of the rehabili- lag behind the scapula, thus throwing with excessive hor-
tation program is to enhance the athlete’s dynamic stabi- izontal abduction and not throwing with the humerus in
lization abilities, thus controlling anterior humeral head the plane of the scapula (Fig. 18). Jobe and col-
translation. Another essential goal is to restore flexibility leagues40, 43, 46 referred to this as “hyperangulation” of the
to the posterior rotator cuff muscles of the glenohumeral arm. This type of fault leads to excessive strain on the
joint. We strongly suggest caution against aggressive anterior capsule and to internal impingement of the pos-
stretching of the anterior and inferior glenohumeral struc- terior rotator cuff.40 – 42 Correction of throwing pathome-
tures as this may result in increased anterior translation. chanics is critical to returning the athlete to asymptom-
Additionally, the program emphasizes muscle strengthen- atic and effective throwing.
Vol. 30, No. 1, 2002 Rehabilitation of the Overhead Throwing Athlete 147

EMG activity of 44% ⫾ 32% maximum voluntary isomet-

ric contraction during the deceleration phase of throwing.
In our opinion, bicipital tendinitis that is present in the
overhead thrower usually represents a secondary condi-
tion. The primary disorder may be instability, a SLAP
(superior labral, anterior and posterior) lesion, or some
similar malady. The rehabilitation of this condition fo-
cuses on improving dynamic stabilization of the glenohu-
meral joint through muscle training drills. Knatt et al.50
studied the synergistic action of the capsule and shoulder
muscles in a feline model and described a glenohumeral
joint capsule-biceps reflex. The authors reported that
stimulation of the anterior capsule caused a reflexive bi-
ceps muscle contraction. They demonstrated that the bi-
ceps brachii muscle was the first muscle to reflexively
respond to stimulation of the capsule, occurring in 2.7
Figure 18. Hyperangulation during the overhead throwing
msec. Therefore, it is the belief of one of the authors
motion. During the late cocking phase of the overhead throw,
(KEW) that the biceps brachii muscle is activated to a
as the thrower’s humerus excessively abducts horizontally,
greater extent when the thrower exhibits hyperlaxity or
posterosuperior impingement of the shoulder joint may oc-
inflammation of the capsule.
cur. To prevent this, the thrower must stay in the plane of the
Glousman et al.33 reported that throwers with instabil-
scapula. A, normal angular relationship; B, hyperangulation.
ity exhibited a higher level of rotator cuff EMG activity
(Reprinted with permission from Davidson PA, Elattrache
compared with throwers without instability. Further-
NS, Jobe CM, et al: Rotator cuff and posterior-superior gle-
more, Gowan et al.34 noted higher EMG activity in ama-
noid injury associated with increased glenohumeral motion:
teur throwers compared with skilled throwers. Nonopera-
A new site of impingement. J Shoulder Elbow Surg 4: 384 –
tive rehabilitation for this condition usually consists of a
390, 1995.)
reduction in throwing activities and reestablishment of
dynamic stability and modalities such as ice, ultrasound,
Overuse Syndrome Tendinitis iontophorosis, and electrical stimulation to reduce bicipi-
tal inflammation.
Occasionally, throwers will describe the symptoms and
exhibit the signs of overuse tendinitis of the shoulder Posterior Rotator Cuff Musculature Tendinitis
musculature. The tendinitis signs and symptoms can be of
the rotator cuff or of the long head of the biceps brachii The successful treatment of posterior rotator cuff muscu-
muscles, or both. These signs frequently occur early in the lature tendinitis, or tensile rotator cuff musculature fail-
season, when the athlete’s arm is not in the best condition. ure, depends on its differential diagnosis from internal
They can also occur at the end of the competitive season impingement. Frequently, the athlete complains of pain in
when the athlete begins to fatigue. Additionally, we see the same location for both lesions. However, subjectively
these signs develop when the athlete does not perform the the athlete notes posterior shoulder pain during the de-
in-season strengthening program while throwing. Mere celeration phase of throwing. Conversely, athletes who
participation in throwing activities does not ensure the exhibit internal impingement complain of pain during the
maintenance of proper shoulder muscle strength and flex- late cocking and early acceleration phases. During the
ibility. Specific muscles (external rotator muscles, scapu- deceleration phase of the overhead pitch, the distraction
lar muscles) often become weak and painful because of the forces at the glenohumeral joint approach one to one and
stresses involved with throwing. a half times body weight.29 These are excessive forces that
The rehabilitation program for overuse rotator cuff must be dissipated and opposed by the posterior rotator
muscle tendinitis should concentrate on treating the cuff muscles. Pitchers occasionally exhibit this condition.
cause(s) of the tendinitis and not merely the symptoms. Once the athlete is examined, the most common findings
The athlete is often instructed to discontinue throwing for are significant posterior rotator cuff muscle weakness,
a short period (2 to 4 weeks) to reduce inflammation and weakness of the lower trapezius muscle and scapular re-
restore strength and flexibility. Other times, the athlete is tractor muscles, and tightness of the posterior rotator cuff
instructed to reduce the number of throws during compe- muscles.
tition or practice. Thus, a strict pitch count is enforced. The rehabilitation program focuses on several key ar-
The rehabilitation program will be successful if the cause eas. First, throwing activities are discontinued until the
is identified, throwing activities are modified, and proper athlete exhibits proper muscle strength ratios between
strength and flexibility are restored. the external and internal rotator muscles. This ratio
Often, the thrower will complain of bicipital pain, occa- should be at least 64% (optimal goal, 66% to 75%).94 Sec-
sionally referred to as “groove pain.” The biceps brachii ond, the athlete is placed on an aggressive strengthening
muscle appears to be moderately active during the over- program for the posterior rotator cuff muscles and the
head throwing motion. DiGiovine et al.26 reported peak retractor and depressor muscles of the scapula. Exercises
148 Wilk et al. American Journal of Sports Medicine

that we emphasize are sidelying external rotation, prone humeral joint capsule. Furthermore, the clinician should
rowing into external rotation, prone horizontal abduction be cautious with closed kinetic chain exercises that result
with external rotation, scapular retraction, and prone hor- in excessively high joint compressive loads that could re-
izontal abduction. Fleisig et al.30 have shown that teres sult in further compromise of the glenoid labrum.
minor muscle EMG activity can be enhanced with the use
of a towel roll placed between the humerus and the side of
the body. Once strength levels have improved, the exercise
Subacromial Impingement
program should emphasize eccentric muscle training. In
particular, the external rotator muscles and the lower Primary subacromial impingement in the young profes-
trapezius muscle are the focus of the eccentric program sional baseball player is unusual, but it may occur.46
(Fig. 8). DiGiovine et al.26 determined that the EMG ac- Subacromial impingement complaints in this group of ath-
tivity of the teres minor muscle is 84% and that of the letes usually represent primary hyperlaxity leading to
lower trapezius muscle is 78% of a maximum voluntary secondary impingement.46 Neer and Walsh68 and Bigliani
isometric contraction during the deceleration phase of the et al.9 reported that abnormal acromial architecture may
throw. These two muscles are the most active during this lead to rotator cuff muscle disease. In cases of abnormal
phase and, thus, must be the focus of the strengthening acromial architecture, the athlete may require surgical
program.
treatment. Hawkins and Kennedy36 and Penny and
In addition, flexibility and stretching exercises for the
Welsh74 stated that the coracoacromial ligament can be a
posterior rotator cuff muscles are performed throughout
primary source of abnormality in the athlete.
the rehabilitation program. We also use heat and ultra-
The nonoperative treatment for subacromial impinge-
sound before stretching to enhance tissue extensibility
ment should focus on a five-step program. First, abstain
while increasing circulation to the area. Once flexibility
and muscle strength are improved and the athlete’s from irritating activities such as throwing or other over-
pain and inflammation have abated, an interval throw- head motions for 7 to 10 days, until inflammation is di-
ing program can be initiated. The interval throwing minished. Second, normalize glenohumeral motion and
program should be progressed slowly so that the capsular mobility. Harryman et al.35 reported that poste-
stresses of throwing are gradually increased. The ath- rior capsular tightness results in anterosuperior migra-
lete is instructed to be sure to follow through properly tion of the humeral head, thus leading to subacromial
and not to terminate the deceleration phase abruptly, impingement. We have noted that patients with inferior
which may lead to increased stresses on the posterior capsular tightness frequently complain of subacromial
rotator cuff muscles. pain. Thus, the rehabilitation program must focus on re-
storing normal capsular and soft tissue mobility posteri-
SLAP Lesions orly and inferiorly. The third step is to enhance dynamic
stability of the glenohumeral and scapulothoracic joint.
The nonoperative treatment of SLAP lesions depends on Jobe et al.46 noted subacromial impingement may be sec-
the type of lesion present. Using the classification system ondary to hyperelasticity of the capsular ligaments. Thus,
developed by Snyder et al.,76 type I SLAP lesions appear the rehabilitation program must focus on rotator cuff mus-
as fraying of the labrum and often respond favorably to a cle strength to adequately compress and stabilize the hu-
nonoperative treatment regimen. Throwers who exhibit meral head within the glenoid fossa. Furthermore, scap-
this type of lesion are treated with a program similar to ular strengthening should also be an area of focus. During
the posterosuperior glenoid impingement protocol (previ- arm elevation, the scapula upwardly rotates, retracts, and
ously discussed). Conversely, players with a type II or type posteriorly tilts. Lukasiewicz et al.58 reported that pa-
IV SLAP lesion are probably best served by undergoing tients with impingement exhibit less posterior tilting than
surgical intervention. If rehabilitation is indicated before
do subjects without impingement. We have clinically
surgery, the program should emphasize restoration of
noted this phenomenon for some time. Thus, the rehabil-
range of motion through stretching exercises within the
itation program should include pectoralis minor muscle
patient’s tolerance. Avoidance of overhead motions with
stretching and inferior trapezius muscle strengthening to
excessive internal/external rotation is enforced because of
ensure posterior scapular tilting. This is especially true
possible joint snapping and pain.
A strengthening program should be performed in an with the recreational baseball player who performs a sed-
attempt to prevent muscle atrophy. The strengthening entary job. The fourth step is to emphasize the retractor
exercises should be performed with the arm below shoul- muscles of the scapula and to correct any forward-head
der level to prevent further damage to the glenoid labrum. posture. Solem-Bertoft et al.,77 using MRI, have demon-
Strengthening exercises such as external/internal rotation strated that excessive scapular protraction reduces ante-
with the arm at the side or scapular plane, scapular rior tilt of the scapula and diminishes the acromial-hu-
strengthening, and deltoid muscle exercises to 90° of ab- meral space, whereas scapular retraction increases the
duction can be safely performed. Exercises such as shoul- subacromial space. Thus, we employ scapular retraction-
der press, bench press, and latissimus dorsi muscle pull- strengthening exercises. The last step is a gradual return
downs (behind the neck) are avoided because of increased to throwing activities once pain has significantly
stress applied to the superior labrum and anterior gleno- diminished.
Vol. 30, No. 1, 2002 Rehabilitation of the Overhead Throwing Athlete 149

Bennett’s Lesion most objective analysis is a high-speed video biomechani-

cal evaluation. This can be done at a biomechanics labo-
The successful nonoperative treatment of throwing ath- ratory using specialized high-speed video cameras and
letes with ossification of the posterior capsule (Bennett’s computer analysis of the data.
lesion) is often difficult. It has been our clinical experience When evaluating an athlete’s throwing mechanics, we
that the thrower with symptomatic thrower’s exostosis commonly look at several different aspects of the move-
can be conservatively managed for some time; however, ment. The clinician can use a video recorder to film the
long-term success is limited and often surgical debride- thrower and analyze the biomechanics during slow-motion
ment of the ossification may become necessary. Nonopera- playback to pinpoint improper mechanics. Filming should
tive treatment includes abstaining from throwing until be performed from multiple views to accurately assess the
pain subsides, restoring posterior capsule and muscle flex- athlete, including lateral (facing the athlete), posterior,
ibility, improving posterior rotator cuff musculature and and anterior views. We normally analyze several aspects
scapular strength, and a gradual return to throwing of the throwing motion in sequential order to detect subtle
activities. pathomechanical deviations through the phases of
throwing.
Primary Instability Biomechanical analysis of the throwing motion begins
with the lateral view; there are several critical moments to
Most skillful throwers exhibit significant hyperelasticity observe from this view. During the wind-up phase, the
of their anterior glenohumeral joint capsule, which allows pitcher should be in a balanced position when the lead leg
excessive external rotation and proper throwing mechan- reaches the highest point. Forward movement should not
ics. Because of the repetitive microtraumatic forces of begin until the lead leg is fully raised. Rushing the deliv-
throwing, the hyperelasticity may progress to primary ery by falling toward home plate during the wind-up
instability and associated lesions and complaints. This is a phase may decrease the amount of energy generated by
very common occurrence in the overhead thrower. The the lower body and result in a loss of velocity. As the
nonoperative treatment for this condition has been thor- athlete begins the early cocking phase, the path of motion
oughly discussed in the rehabilitation program in this as the thrower removes the ball from the glove should be
article. The key aspects are reduction of throwing activity smooth, with the elbow flexed and the fingers on top of the
to allow diminished inflammation, normalization of mo- ball. As the lead leg comes in contact with the ground, the
tion, restoration of proper strength of glenohumeral and knee should be slightly flexed and the elbow should be
scapular muscles, enhancement of proprioception, and a level with the shoulder. A right-handed pitcher will show
gradual return to throwing. In the majority of cases, this the ball to the shortstop and a left-handed pitcher will
treatment will be effective. show the ball to the second baseman. The stride should be
long enough to allow sufficient rotation and force genera-
Acute Traumatic Instability tion from the hips and trunk, approximately equal to the
height of the thrower. At maximal external rotation dur-
An acute traumatic dislocation to a throwing athlete’s ing the late cocking phase, the arm should be abducted
dominant shoulder can be devastating. The injury may approximately 90° to 100°. Fleisig28 reported that throw-
include a Bankart lesion, rotator cuff muscle tear, labral ing with reduced external rotation at the time of foot
tear, or even injury to the brachial plexus muscle. The contact causes an increase in strain on the shoulder dur-
treatment for a dislocation in the thrower is surgical cor- ing acceleration and ball release. Furthermore, the
rection. Before surgery, the athlete’s shoulder should be thrower should begin straightening the elbow before
placed in a sling for comfort. In addition, gentle range of shoulder internal rotation during the acceleration phase.
motion exercises should be performed to gradually restore At this time, the lead leg extends, or straightens, to sta-
motion before surgery. A mild strengthening program for bilize the body and provide a fulcrum for body rotation.
the glenohumeral and scapular muscles should also be During the deceleration and follow-through phases, the
performed with the goal of preventing muscle atrophy and throwing shoulder should internally rotate and horizon-
weakness and loss of dynamic stabilization. tally adduct across the body. The upper extremity should
cross the front of the body and end outside the lead leg.
Improper Mechanics Abbreviating the follow-through and ending with the
hand toward the target may increase the stresses applied
Throwing with improper or faulty mechanics can lead to to the shoulder.
shoulder pain or injury, or both, because of the abnormal Observing the thrower from a posterior view allows the
stresses that are applied across various tissues. To deter- clinician to observe two instants during the throwing mo-
mine whether the thrower exhibits improper throwing tion. As the thrower removes the ball from the glove dur-
mechanics, the clinician should carefully observe the ath- ing early cocking, the arm path should move smoothly in
lete throw. Obvious flaws can be seen occasionally. The a down, back, and upward motion as the thrower strides
clinician may often require assistance from an experi- toward the target. A thrower whose arm moves behind the
enced and knowledgeable baseball coach. The skilled eye body may cause excessive anterior capsular straining and
of an experienced coach can frequently determine subtle possible internal impingement. Also of interest from the
abnormalities in the throwing mechanics. Perhaps the posterior view is the hand position during late cocking. As
150 Wilk et al. American Journal of Sports Medicine

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