With respect to range of motion, loss of internal range of motion is known to be a risk factor for chronic shoulder pain. Therefore it is advised that side differences in internal rotation ROM should be less than 18°, and the difference in total range of motion should not be more than 5°. The assessment of the ROM into rotation of the shoulder can be measured with a goniometer or an inclinometer and in many positions of the body and the shoulder. A comprehensive reliability study [31] showed high to excellent inter- and intra-tester reliability for a variety of test positions and equipment. Based on the results of this study and in view of optimal standardisation of body and shoulder position, the authors advise the following procedure: the patient is supine with the shoulder in the frontal plane and the elbow flexed 90°. The upper arm should be horizontal, if needed (e.g. in case the patient has protracted shoulders or a thoracic kyphosis), the arm is supported by a towel to reach the horizontal position. For internal rotation the examiner palpates the spine of the scapula and the coracoid. The inclinometer is aligned with the forearm (olecranon and styloid process of the ulna), and the shoulder is moved into internal rotation (Fig. 8.2). The movement reaches its endpoint when the coracoid tends to move against the palpating thumb. For external rotation the fixating hand is gently put over the shoulder top, and the shoulder is moved into external rotation, aligning the inclinometer with the forearm.

Given the evidenced impact of posterior shoulder tightness on shoulder kinematics, increasing posterior shoulder flexibility is advisory when mobility deficits exceed the limits associated with increased injury risk. Both the cross body stretch (Fig. 8.3) and the sleeper stretch (Fig. 8.4) can be recommended to decrease posterior shoulder tightness. It was shown that a 6-week daily sleeper stretch programme (3 reps of 30 s) is able to significantly increase the acromiohumeral distance in the dominant shoulder of healthy overhead athletes with GIRD. Additional joint mobilisation performed by a physiotherapist has a small but nonsignificant advantage over a home stretching programme alone. No difference in mobility gain was seen after angular (sleeper stretch and horizontal adduction stretch) and non-angular (dorsal and caudal humeral head glides) joint mobilisation by a physiotherapist. Muscle energy techniques (hold-relax) during the sleeper stretch and the horizontal adduction stretch have proven useful to immediately increase internal rotation range of motion.

Regarding rotator cuff strength, it is generally recognised that overhead athletes often exhibit sport-specific adaptations leading to a relative decrease of the strength of the external rotators. Absolute side differences as well as muscle balance ratio between external and internal rotators have been found to be altered. In general, with respect to cut-off values distinguishing a healthy shoulder from a shoulder at risk, an isokinetic ER/IR ratio of 66 % or an isometric ER/IR ratio of 75 % (when measured in neutral position) is advised [31], with a general rotator cuff strength increase of 10 % of the dominant throwing side compared to the nondominant side. Recently, focus has shifted from isometric or concentric to eccentric muscle strength of the rotator cuff. In particular the eccentric strength of the external rotators is of interest. These muscles function as a decelerator mechanism during powerful throwing, serving or smashing.

In view of the importance of eccentric rotator cuff strength in relation to injury-free overhead throwing or serving, it is imperative that strength is assessed on a regular basis in healthy as well as injured players. With respect to the isometric strength measurements, hand-held dynamometry (HHD) has attracted more and more interest during the last years due to the more practical, less expensive and user-friendly advantages over the more advanced and expensive isokinetic devices (Fig. 8.5).

Recently, a new testing protocol was published, showing that the use of a hand-held dynamometer (HHD) measuring eccentric external rotator strength has excellent intra-tester (ICC = 0.88) and good inter-tester (ICC = 0.71) reliability, as well as concurrent validity (compared to an isokinetic device, Pearson correlation = 0.78). During the procedure, the patient is seated with gentle support of the arm by the tester; the tester brings the shoulder from 90° abduction–90° external rotation (throwing position) to 90° abduction–0° external rotation, loading the external rotators eccentrically (Fig. 8.4). A large normative database on 200 overhead athletes (volleyball, tennis and handball) was recently set up and shows an average normalised eccentric external rotator strength (N/kg) of approximately 2, with significant side differences in favour of the dominant sides and significant higher values for handball and tennis compared to volleyball.

Numerous exercises have been described to strengthen the rotator cuff muscles, including concentric, isometric, eccentric and plyometric exercises. In view of the eccentric component of the function of the external rotators, the sport-specific exercises for overhead athlete players should focus on three areas:

Evidence supporting cut-off values for prevention of injury or return to play after injury with respect to scapular function is scarce. A number of studies used visual observation as a criterion, whereas others provide objective data on healthy athletes as a reference base for return to play. In general, visual observation is performed either by using the yes/no method (scapular dyskinesis or not), a method proven to be reliable and valid, on the condition that the examiner/therapist is educated in a standardised manner, or by categorising the scapular dysfunction into different types, based on the specific position of the scapula. However, the latter method was shown to have acceptable intra-rater, but low inter-rater reliability. A statement saying that scapular behaviour should be symmetrical in overhead athletes is not supported by research data, on the contrary. In volleyball, as well as in handball players, asymmetry was found in resting scapular posture. Therefore clinicians should be aware that some degree of scapular asymmetry may be normal in some athletes. It should not be considered automatically as a pathological sign but rather an adaptation to sports practice and extensive use of the upper limb.

Several studies measured scapular upward inclination in healthy overhead athletes. These data may be used as a reference base and cut-off values for correct scapular positioning in several elevation angles. In general, a large variety is found in scapular upward inclination in the mid range of motion (probably due to a large variation between individuals); however, in full elevation, most studies suggest that upward inclination should be at least 45–55°.

For the scapular muscles, proper inter- and intramuscular balance should be assessed. Isokinetic ratio protraction/retraction is shown to be 100 % in a healthy population, with slight changes in overhead athletes, in case of throwing athletes in favour of the protractors. In bilateral sports (swimming, rowing, gymnastics), there should be no side differences in scapular muscle strength, and in one-handed overhead sports, an increase of scapular muscle strength of 10 % is advised on the dominant side. In particular, the lower trapezius and serratus anterior should receive special attention, since these muscles are shown to be susceptible to weakness in injured athletes.

Once deficits and imbalances in scapular behaviour are assessed, an intervention programme to restore flexibility and muscle performance needs to be installed. Recently, a science-based clinical reasoning algorithm was published guiding the clinician into the different steps and progression. The main goals are (a) to restore flexibility of the surrounding soft tissue of the scapula, in particular the pectoralis minor, levator scapulae, rhomboid and posterior shoulder structures, and (b) to increase scapular muscle performance around the scapula, focusing on either muscle control and inter- and intramuscular coordination or muscle strength and balance. Exercises to restore scapular muscle balance have been shown to increase isokinetic protraction and retraction strength, increase external rotator strength of the shoulder and alter EMG activity of the scapular muscles in favour of efficient muscle recruitment during a loaded elevation task. In general focus should be put on training the lower and middle portions of the trapezius (Fig. 8.9) and training the scapular muscles in higher elevation angles, relevant to the specific sport (Fig. 8.10).

The risk factor with the strongest correlation to elbow injury is the amount of pitching. Based on the research of Olsen et al., there they concluded that averaging more than 80 pitches per game almost quadrupled the chance of surgery (OR 3.83) and pitching competitively more than 8 months per year increased the odds of surgery by fivefold (OR 5.05). A pitcher who regularly pitched with his arm fatigued was 36 times as likely to have an injury which required surgery (OR 36.18). Little League and high school pitchers who also pitched for travel teams or showcases had increased risk of elbow injuries. Studies show that it is not uncommon for youth pitchers to play 70 games or more per year, often playing more than 8 consecutive months [23]. The rise in overuse elbow injuries in young pitchers corresponds with the extended competitive baseball of recent times.

Maximum values of internal rotation torque of the shoulder and varus torque of the elbow are produced near the time of maximum external rotation to decelerate shoulder external rotation, prevent elbow valgus opening and initiate shoulder internal rotation. Tension in the UCL absorbs about half the varus torque in this position. Pitchers at the youth level have greater inconsistency in their biomechanics from pitch to pitch [12]. Improper pitching mechanics can lead to increased elbow varus torque and consequently increased risk of elbow injury.

Changes in other parts influence the elbow biomechanics during the throwing motion: trunk range of motion, late arm rotation, excessive shoulder external rotation, passive total shoulder rotation, excessive elbow flexion and improper shoulder abduction and trunk tilt [9, 10, 13, 16]. The study of Huang and colleagues demonstrated that youth baseball players with a history of elbow pain threw with a more extended elbow at maximum shoulder external rotation and greater lateral trunk tilt at ball release [11]. But there is not known if the pitchers with an injury history demonstrated the error prior to the time of injury or if the error developed after the injury. Improving elbow and body biomechanics can increase a pitcher’s chance of staying healthy [24].