Current concepts in the rehabilitation of the overhead throwing athlete

Evaluation of isokinetic force production and associated muscle activity in the scapular rotators during a protraction-retraction movement in overhead athletes with impingement symptoms

OBJECTIVES

To determine if the muscle force and electromyographic activity in the scapular rotators of overhead athletes with impingement symptoms showed differences between the injured and non-injured sides.

METHODS

Isokinetic peak force was evaluated during protraction and retraction of the shoulder girdle, with simultaneous recording of electromyographic activity of the three trapezius muscles and the serratus anterior muscle, in 19 overhead athletes with impingement symptoms.

RESULTS

Paired t tests showed significantly lower peak force during isokinetic protraction at high velocity (p<0.05), a significantly lower protraction/retraction ratio (p<0.01), and significantly lower electromyographic activity in the lower trapezius muscle during isokinetic retraction on the injured side than on the non-injured side (p<0.05).

CONCLUSION

These results confirm that patients with impingement symptoms show abnormal muscle performance at the scapulothoracic joint.

Stretching and Injury Prevention

It is generally accepted that increasing the flexibility of a muscle-tendon unit promotes better performances and decreases the number of injuries. Stretching exercises are regularly included in warm-up and cooling-down exercises; however, contradictory findings have been reported in the literature. Several authors have suggested that stretching has a beneficial effect on injury prevention. In contrast, clinical evidence suggesting that stretching before exercise does not prevent injuries has also been reported. Apparently, no scientifically based prescription for stretching exercises exists and no conclusive statements can be made about the relationship of stretching and athletic injuries. Stretching recommendations are clouded by misconceptions and conflicting research reports. We believe that part of these contradictions can be explained by considering the type of sports activity in which an individual is participating. Sports involving bouncing and jumping activities with a high intensity of stretch-shortening cycles (SSCs) [e.g. soccer and football] require a muscle-tendon unit that is compliant enough to store and release the high amount of elastic energy that benefits performance in such sports. If the participants of these sports have an insufficient compliant muscle-tendon unit, the demands in energy absorption and release may rapidly exceed the capacity of the muscle-tendon unit. This may lead to an increased risk for injury of this structure. Consequently, the rationale for injury prevention in these sports is to increase the compliance of the muscle-tendon unit. Recent studies have shown that stretching programmes can significantly influence the viscosity of the tendon and make it significantly more compliant, and when a sport demands SSCs of high intensity, stretching may be important for injury prevention. This conjecture is in agreement with the available scientific clinical evidence from these types of sports activities. In contrast, when the type of sports activity contains low-intensity, or limited SSCs (e.g. jogging, cycling and swimming) there is no need for a very compliant muscle-tendon unit since most of its power generation is a consequence of active (contractile) muscle work that needs to be directly transferred (by the tendon) to the articular system to generate motion. Therefore, stretching (and thus making the tendon more compliant) may not be advantageous. This conjecture is supported by the literature, where strong evidence exists that stretching has no beneficial effect on injury prevention in these sports. If this point of view is used when examining research findings concerning stretching and injuries, the reasons for the contrasting findings in the literature are in many instances resolved.

Arthroscopic management of the thrower's shoulder: internal impingement

Our understanding of internal impingement in the overhand athlete is an evolving body of knowledge. More recent improved understanding of the pathophysiology of events that leads to the spectrum of injury has caused us to refine our techniques of treatment. Improved surgical techniques and instrumentation have made refinement of our approach to treatment possible. Only time will tell whether the perceived understanding of these disorders, resulting in alteration of our treatment methods, is making our treatment outcomes more successful.

Thermal-assisted capsular shrinkage of the glenohumeral joint in overhead athletes: a 15- to 47-month follow-up

STUDY DESIGN

Descriptive postoperative follow-up research.

OBJECTIVES

The purpose of this investigation was to describe the return-to-competition rate and functional outcome of overhead athletes following arthroscopic thermal-assisted capsular shrinkage (TACS).

BACKGROUND

Traditional open procedures to correct instability in overhead athletes, such as capsulolabral repairs and capsular shifts, have produced less-than-favorable results, which have led to the development of TACS. Currently there are no long-term follow-up studies documenting the efficacy of this procedure in groups greater than 31 subjects or for a time period greater than 27 months.

METHODS AND MEASURES

Two hundred thirty-one consecutive overhead athletes who due to symptoms of hyperlaxity had previously undergone a TACS procedure from 1997 to 1999 were selected for inclusion in the study. During a 1-month period, 130 of these athletes (mean age +/- SD, 24 +/- 6 years; 113 male, 17 female) were contacted by phone for follow-up at a mean of 29.3 months postoperatively (range, 15.4-46.6 months). Of the 130, 105 participated in baseball (80 pitchers), 14 in softball, 4 in football (quarterbacks), 4 in tennis, and 3 in swimming. Fifty-four (42%) subjects were professional, 49 (38%) collegiate, 16 (12%) high school, and 11 (8%) recreational athletes. One hundred twenty-three of the 130 (95%) underwent 1 or more concomitant procedure(s) at the time of TACS. Most commonly performed were labral debridements (69%), rotator cuff debridements (65%), and superior labral repairs (35%). Subjects who returned to competition were retrospectively evaluated using a modified Athletic Shoulder Outcome Rating Scale to subjectively assess pain, strength and endurance, stability, intensity, and performance. Overall results were based on a 90-point scale with scores of 80 to 90 representing excellent, 60 to 79 good, 40 to 59 fair, and less than 40 poor results.

RESULTS

One hundred thirteen out of 130 subjects (87%) returned to competition. Mean (+/-SD) time from surgery to return to competition was 8.4 +/- 4.6 months. Mean outcome score for all subjects was 79/90; 75 (66%) subjects had excellent, 24 (21%) good, 11 (10%) fair, and 3 (3%) poor result. The mean outcome score for males was 80/90 and for females was 70/90.

CONCLUSIONS

The majority of overhead athletes (87%) successfully returned to competition following a TACS procedure with good-to-excellent long-term outcomes (88%). Based on the results of this study, TACS of the glenohumeral joint is a viable option for overhead athletes with pathological instability.

Scapular muscle recruitment patterns: trapezius muscle latency with and without impingement symptoms

BACKGROUND

Altered muscle activity in the scapular muscles is commonly believed to be a factor contributing to shoulder impingement syndrome. However, one important measure of the muscular coordination in the scapular muscles, the timing of the temporal recruitment pattern, is undetermined.

PURPOSE

To evaluate the timing of trapezius muscle activity in response to an unexpected arm movement in athletes with impingement and in normal control subjects.

STUDY DESIGN

Prospective cohort study.

METHODS

Muscle latency times were measured in all three parts of the trapezius muscle and in the middle deltoid muscle of 39 "overhand athletes" with shoulder impingement and compared with that of 30 overhand athletes with no impingement during a sudden downward falling movement of the arm.

RESULTS

There were significant differences in the relative muscle latency times between the impingement and the control group subjects. Those with impingement showed a delay in muscle activation of the middle and lower trapezius muscle.

CONCLUSION

The results of this study indicate that overhand athletes with impingement symptoms show abnormal muscle recruitment timing in the trapezius muscle. The findings support the theory that impingement of the shoulder may be related to delayed onset of contraction in the middle and lower parts of the trapezius muscle.

Isokinetic eccentric-to-concentric strength ratios of the shoulder rotator muscles in throwers and nonthrowers

BACKGROUND

One of the possible mechanisms leading to shoulder injury may be a strength imbalance between those muscles that accelerate the upper limb and those responsible for deceleration. Many studies have examined shoulder balance through a concentric strength ratio of external and internal shoulder rotator muscles.

HYPOTHESIS

A functional external eccentric-to-internal concentric ratio may be a better identifier of muscular imbalance in dominant and nondominant shoulders of throwers and nonthrowers.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eccentric external and concentric internal peak torques were measured bilaterally in 59 men (16 throwers and 43 nonthrowers) at 300 deg/sec. Subjects were tested in the supine position with the shoulder abducted to 90 degrees and the elbow flexed to 90 degrees.

RESULTS

Throwers exhibited significantly lower ratios than nonthrowers in their dominant limb; there was no difference between groups for the nondominant limb.

CONCLUSIONS

The lower ratio in the throwers' dominant limb was attributed to significantly greater concentric internal rotation torques without concomitant eccentric external torque gains.

CLINICAL RELEVANCE

Rehabilitation and injury prevention regimens that include functional exercises to improve eccentric external rotation strength may bring more balance to the dominant shoulder of throwing athletes.

Musculoskeletal fitness: the keystone in overall well-being and injury prevention

Musculoskeletal fitness is an important and inadequately appreciated component of overall health and well-being. Wellness as it applies to strength and conditioning has numerous benefits. It allows maintenance of functional independence for longer periods in older adults. It impacts the metabolic capabilities of children and adults affecting the ability to maintain an ideal body weight. It has been shown to influence the prevalence and possibly the prevention of many musculoskeletal disorders such as muscle sprains, low back pain, osteoarthritis, osteoporosis, shoulder instability, and knee stability and pain. The current author summarizes the most recent recommendations for achievement and maintenance of musculoskeletal fitness for children and adults.

Rehabilitation following thermal-assisted capsular shrinkage of the glenohumeral joint: current concepts

Glenohumeral joint instability is a common pathology observed in the orthopedic and sports medicine settings. Overhead athletes often exhibit a certain degree of acquired laxity that can lead to various pathologies. Unfavorable results often observed with traditional open procedures to correct instability in the overhead athlete have led to the development of arthroscopic thermal-assisted capsular shrinkage (TACS). TACS is not commonly used as an isolated procedure in overhead athletes; various procedures are often performed concomitantly. The overall outcome greatly depends on a postoperative rehabilitation program that must be assessed and adjusted frequently based on several factors. Knowledge of the basic science of TACS as well as emphasis on dynamic stabilization, proprioception, and neuromuscular control are vital to the rehabilitation program for overhead athletes. The purpose of this paper is to discuss the basic science and clinical application of thermal-assisted capsular shrinkage of the glenohumeral joint as well as the postoperative rehabilitation for the overhead athlete and the patient with congenital laxity and related multidirectional instability.

Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers

The throwing shoulder in pitchers frequently exhibits a paradox of glenohumeral joint motion, in which excessive external rotation is present at the expense of decreased internal rotation. The object of this study was to determine the role of humeral head retroversion in relation to increased glenohumeral external rotation. Glenohumeral joint range of motion and laxity along with humeral head and glenoid version of the dominant versus nondominant shoulders were studied in 25 professional pitchers and 25 nonthrowing subjects. Each subject underwent a computed tomography scan to determine bilateral humeral head and glenoid version. The throwing group demonstrated a significant increase in the dominant shoulder versus the nondominant shoulder in humeral head retroversion, glenoid retroversion, external rotation at 90 degrees, and external rotation in the scapular plane. Internal rotation was decreased in the dominant shoulder. Total range of motion, anterior glenohumeral laxity, and posterior glenohumeral laxity were found to be equal bilaterally. The nonthrowing group demonstrated no significant difference in humeral head retroversion, glenoid retroversion, external rotation at 90 degrees or external rotation in the scapular plane between shoulders, and no difference in internal rotation at 90 degrees, total motion, or laxity. A comparison of the dominant shoulders of the two groups indicated that both external rotation at 90 degrees and humeral head retroversion were significantly greater in the throwing group.