Case-Based Understanding of the Role of the Scapula in Common Shoulder Pathologies.

Scapular dyskinesis is an extremely common component of shoulder pathology, especially in the overhead athlete; despite its prevalence, proper diagnosis and management of scapular disorders remains an enigma for many clinicians. An understanding of the contribution of the scapula to pathomechanics and clinical symptoms is necessary to optimize both surgical and nonsurgical treatment of shoulder disorders. Without correction of scapular dysfunction, even effective management of the pathoanatomy is unlikely to produce optimal results. It is important to examine the role of the scapula in common shoulder pathologies and elucidate a case-based treatment strategy for both surgical and nonsurgical shoulder disorders.

More Elevated Fastballs Associated With Placement on the Injured List due to Shoulder Injury.

Purpose: To evaluate whether impending shoulder injury was associated with changes in pitch location or velocity immediately preceding injury. Methods: Pitchers placed on the injured list (IL) due to a shoulder injury between 2015 and 2020 were identified in the Major League Baseball transactions database. Four-seam fastball velocity and frequency of pitch location for each pitch type was collected for each player in the season before placement on the IL and within 1 month of placement on the IL with a minimum of 55 pitches thrown of 1 type. Pitch locations were collected as identified by Baseball Savant's Game-Day Zones. Game-Day Zones were consolidated into high (above the strike zone midpoint) versus low, arm side (closer to the pitcher's arm side of the plate) versus opposite side, and within the strike zone versus out of zone. Repeated measures analysis of variance determined differences in four-seam velocity and the location distribution of 4-seam fastballs, change-ups, and breaking balls among each group. Results: In total, 267 pitchers were placed on the IL for a shoulder injury with the majority diagnosed with inflammation (89/267) followed by strain or sprain (69/267). Four-seam fastball locations significantly increased above the mid-point of the zone (45.9% vs 42.4%, P = .008) and out of the strike zone (48.5% vs 46.5%, P = .011) within a month before IL placement. There was no significant change in 4-seam fastball velocity immediately before IL placement. Conclusions: Pitchers threw more elevated 4-seam fastballs and out-of-zone 4-seam fastballs in the month before IL placement for shoulder injury. These findings suggest that a loss of 4-seam fastball command decreases with impending shoulder injury. Level of Evidence: IV, prognostic case series.

Increasing Ball Velocity in the Overhead Athlete: A Meta-analysis of Randomized Controlled Trials.

Overhead athletes routinely search for ways to improve sport performance, and one component of performance is ball velocity. The purpose of this meta-analysis was to investigate the effect of different strengthening interventions on ball and serve velocity. A comprehensive literature search with pre-set inclusion and exclusion criteria from 1970 to 2014 was conducted. Eligible studies were randomized control trials including the mean and SDs of both pretest and posttest ball velocities in both the experimental and the control groups. The outcome of interest was ball/serve velocity in baseball, tennis, or softball athletes. Level 2 evidence or higher was investigated to determine the effect different training interventions had on velocity. Pretest and posttest data were extracted to calculate Hedges's g effect sizes with 95% confidence intervals (CIs). Methodological qualities of the final 13 articles within the analysis were assessed using the Physiotherapy Evidence Database scale. The majority of the articles included in this analysis had an effect on velocity with the strongest effect sizes found in periodized training (Hedges's g = 3.445; 95% CI = 1.976-4.914). Six studies had CI that crossed zero, indicating that those specific interventions should be interpreted with caution. Consistent and high-quality evidence exists that specific resistance training interventions have an effect on velocity. These findings suggest that interventions consisting of isokinetic training, multimodal training, and periodization training are clinically beneficial at increasing velocity in the overhead athlete over different windows of time.

ISAKOS upper extremity committee consensus statement on the need for diversification of the Rockwood classification for acromioclavicular joint injuries.

Optimal treatment for the unstable acromioclavicular (AC) joint remains a highly debated topic in the field of orthopaedic medicine. In particular, no consensus exists regarding treatment of grade III injuries, which are classified according to the Rockwood classification by disruption of both the coracoclavicular and AC ligaments. The ISAKOS Upper Extremity Committee has provided a more specific classification of shoulder pathologies to enhance the knowledge on and clinical approach to these injuries. We suggest the addition of grade IIIA and grade IIIB injuries to a modified Rockwood classification. Grade IIIA injuries would be defined by a stable AC joint without overriding of the clavicle on the cross-body adduction view and without significant scapular dysfunction. The unstable grade IIIB injury would be further defined by therapy-resistant scapular dysfunction and an overriding clavicle on the cross-body adduction view.

Muscle activation in coupled scapulohumeral motions in the high performance tennis serve.

OBJECTIVE: To evaluate muscle activation patterns in selected scapulohumeral muscles in the tennis serve. These patterns of muscle activation have not been evaluated in other studies of the tennis serve. Fine wire and surface EMG was used to calculate onset and offset timing of muscle activation. DESIGN: Controlled laboratory study. SETTING: Biomechanical laboratory. SUBJECTS: 16 tennis players (age 18-40) with rated skills (National Tennis Rating Program (NTRP) rating 4.5-6.5; club tournament level or higher) were subjects. MAIN OUTCOMES MEASURE: Dependent variables of muscle activation onset and offset as well as sequencing of the stabilising muscles of the scapula (upper trapezius, lower trapezius, serratus anterior; the muscles that position the arm) anterior deltoid and posterior deltoid; and the muscles of the rotator cuff muscles (supraspinatus, infraspinatus, teres minor) during the tennis serve motion. RESULTS: Patterns of muscle activation were observed during the tennis serve motion. The serratus anterior (-287 ms before ball impact) and upper trapezius (-234 ms) were active in the early cocking phase, while the lower trapezius (-120 ms) was activated in the late cocking phase just before the acceleration phase. The anterior deltoid (-250 ms) was activated in early cocking, while the posterior deltoid (-157 ms) was activated later. The teres minor (-214 ms) was activated early in the cocking phase. The supraspinatus (-103 ms) was activated in late cocking. The infraspinatus (+47 ms after ball impact) was activated in follow-through. All muscles except infraspinatus were activated in duration of more than 50% of the service motion. CONCLUSIONS: This study demonstrates that there are patterns of activation of muscles around the scapulohumeral articulation in the normal accomplished tennis serve. Rehabilitation and conditioning programs for tennis players should be structured to restore and optimise the activation sequences (scapular stabilisers before rotator cuff), task specific functions (serratus anterior as a retractor of the scapula, lower trapezius as a scapular stabiliser in the elevated rotating arm) and duration of activation of these muscles.