Electromyographic analysis of the serratus anterior and upper trapezius in closed kinetic chain exercises performed on different unstable support surfaces: a systematic review and meta-analysis.

Background: Multiple investigations have compared the electromyographic (EMG) activity of the scapular muscles between stable and unstable support surfaces during the execution of closed kinetic chain exercises. However, these comparative analyses have grouped different unstable surfaces (wobble board, BOSU, therapeutic ball, and suspension equipment) into a single data pool, without considering the possible differences in neuromuscular demand induced by each unstable support surface. This study aimed to analyze the individual effect of different unstable support surfaces compared to a stable support surface on scapular muscles EMG activity during the execution of closed kinetic chain exercises. Methodology: A literature search was conducted of the Pubmed Central, ScienceDirect and SPORTDiscus databases. Studies which investigated scapular muscles EMG during push-ups and compared at least two support surfaces were included. The risk of bias of included articles was assessed using a standardized quality assessment form for descriptive, observational and EMG studies, and the certainty of the evidence was measured with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. A random-effects model was used to calculate effect sizes (ES, Hedge's g). Results: Thirty studies were selected in the systematic review. Of these, twenty-three low-to-high quality studies (498 participants) were included in the meta-analysis. The main analyzes revealed, in decreasing order, greater UT EMG activity during push-ups performed on suspension equipment (ES = 2.92; p = 0.004), therapeutic ball (ES = 1.03; p < 0.001) and wobble board (ES = 0.33; p = 0.003); without effect on the BOSU ball. In addition, no effect was observed for SA on any unstable device. The certainty of the evidence ranged from low to very low due to the inclusion of descriptive studies, as well as high imprecision, inconsistency, and risk of publication bias. Conclusion: These findings could be applied in scapular muscles strengthening in healthy individuals. The use of suspension equipment achieves higher UT activation levels. Conversely, the use of any type of unstable devices to increase the activation levels of the SA in shoulder musculoskeletal dysfunctions is not recommended. These conclusions should be interpreted with caution as the available evidence showed a low to very low certainty of evidence, downgraded mostly by inconsistency and imprecision.

Instruction and feedback for conscious contraction of the abdominal muscles increases the scapular muscles activation during shoulder exercises.

PURPOSE: The study aimed to investigate the effect of the instruction for conscious contraction of the abdominal muscles on the scapulothoracic muscles activation during shoulder exercises. DESIGN: Repeated measures design in a single group, pre-post instruction. METHODS: Sixty healthy male and female subjects (mean age 23.5 ± 3 years) volunteered for this study. Two isometric and three dynamic exercises for the scapulothoracic muscles, focusing on the serratus anterior muscle were assessed before and after familiarization training, standardized verbal, and tactile feedback applied to encourage abdominal muscle contraction. Repeated measures ANOVA and Bonferroni post-hoc test were used to compare normalized EMG amplitudes. RESULTS: Instruction increased EMG amplitude only for serratus anterior muscle during isometric exercises (Inferior Glide and Isometric Low Row). Conscious contraction of the abdominal muscles resulted in significant increase (p < 0.05) in the serratus anterior, upper, middle and lower trapezius EMG amplitude, during dynamic exercises (Wall Slide, Wall Press, and Knee Push-Up). CONCLUSION: Conscious contraction of the abdominal muscle increased the activation of the serratus anterior e the three parts of the trapezius during dynamic shoulder exercises with moderate to minimal levels of EMG activation. In the other hand, abdominal muscles contraction was effective to increase the activation of the serratus anterior during isometric exercises but did not increase the trapezius activation. So, Inferior Glide and Isometric Low Row performed along with encouraged abdominal muscle contraction are compatible to initial phases of the serratus anterior strengthening with low levels of upper trapezius muscle activation.

Eccentric and isometric shoulder rotator cuff strength testing using a hand-held dynamometer: reference values for overhead athletes.

PURPOSE: In order to provide science-based guidelines for injury prevention or return to play, regular measurement of isometric and eccentric internal (IR) and external (ER) rotator strength is warranted in overhead athletes. However, up to date, no normative database exists regarding these values, when measured with a hand-held dynamometer. Therefore, the purpose of the study was to provide a normative database on isometric and eccentric rotator cuff (RC) strength values in a sample of overhead athletes, and to discuss gender, age and sports differences. METHODS: A HHD was used to measure RC strength in 201 overhead athletes between 18 and 50 years old from three different sports disciplines: tennis, volleyball and handball. Isometric as well as eccentric strength was measured in different shoulder positions. Outcome variables of interest were isometric ER and IR strength, eccentric ER strength, and intermuscular strength ratios ER/IR. RESULTS: Our results show significant side, gender and sports discipline differences in the isometric and eccentric RC strength. However, when normalized to body weight, gender differences often are absent. In general, strength differences are in favour of the dominant side, the male athletes and handball. Intermuscular ER/IR ratios showed gender, sports, and side differences. CONCLUSION: This normative database is necessary to help the clinician in the evaluation of RC strength in healthy and injured overhead athletes. In view of the preventive screening and return-to-play decisions in overhead athletes, normalization to body weight and calculating intermuscular ratios are key points in this evaluation. LEVEL OF EVIDENCE: Diagnostic study, Level III.

Consensus for physiotherapy for shoulder pain.

PURPOSE: Shoulder pain is a common disorder. Despite growing evidence of the importance of physiotherapy, in particular active exercise therapy, little data is available to guide treatment. The aim of this project was to contribute to the development of an internationally accepted assessment and treatment algorithm for patients with shoulder pain. METHODS: Nine physiotherapists with expertise in the treatment of shoulder dysfunction met in Sweden 2012 to begin the process of developing a treatment algorithm. A questionnaire was completed prior to the meeting to guide discussions. Virtual conferences were thereafter the platform to reach consensus. RESULTS: Consensus was achieved on a clinical reasoning algorithm to guide the assessment and treatment for patients presenting with local shoulder pain, without significant passive range of motion deficits and no symptoms or signs of instability. The algorithm emphasises that physiotherapy treatment decisions should be based on physical assessment findings and not structural pathology, that active exercises should be the primary treatment approach, and that regular re-assessment is performed to ensure that all clinical features contributing to the presenting shoulder pain are addressed. Consensus was also achieved on a set of guiding principles for implementing exercise therapy for shoulder pain, namely, a limited number of exercises, performed with appropriate scapulo-humeral coordination and humeral head alignment, in a graduated manner without provoking the presenting shoulder pain. CONCLUSION: The assessment and treatment algorithm presented could contribute to a more formal, extensive process aimed at achieving international agreement on an algorithm to guide physiotherapy treatment for shoulder pain.

Functional outcome and quality of life after rehabilitation for voluntary posterior shoulder dislocation: a prospective blinded cohort study.

BACKGROUND: Voluntary posterior instability of the shoulder is a rare condition in which the patient is able to cause a subluxation by voluntary muscle activation. A shoulder rehabilitation program aimed to correct abnormal muscle patterns and restore correct scapular motion may provide good results and improve the quality of life of these patients. METHODS: Fifteen subjects (six males, nine females; mean age 19 years) underwent physical examination and clinical tests [Disability of the Arm, Shoulder and Hand (DASH) score, Shoulder Pain and Disability Index (SPADI), and modified Rowe score] and compiled the patient global assessment (PGA). Articular or rotator cuff lesions were excluded by X-rays and MRI. The rehabilitation program included three phases: (1) assessment and correction of abnormal muscle patterns, (2) restoration of correct scapular motion, and (3) strengthening of scapular and posterior glenohumeral muscles. Follow-up was at 3, 6, 12, and 24 months. RESULTS: DASH and SPADI scores improved significantly at 3 (p < 0.01), 6 (p < 0.009), 12 (p < 0.001), and 24 months (p < 0.001). The Rowe score was fair at 3 months and good at 6, 12, and 24 months. Active flexion, abduction, and external rotation increased at all follow-up points (p < 0.01), whereas internal rotation remained unchanged (p > 0.05). PGA values were high. Compliance was good without serious adverse events reported during the treatment. A correlation was found between age and DASH changes (Spearman's ρ -0.56; p = 0.0455). CONCLUSIONS: Our findings stress the value of a rehabilitation program that teaches subjects with voluntary instability how to correct abnormal muscle patterns to restore scapular motion, and the importance of adopting home rehabilitation exercises as a part of the normal lifestyle.

Rehabilitation of scapular dyskinesis: from the office worker to the elite overhead athlete.

The scapula functions as a bridge between the shoulder complex and the cervical spine and plays a very important role in providing both mobility and stability of the neck/shoulder region. The association between abnormal scapular positions and motions and glenohumeral joint pathology has been well established in the literature, whereas studies investigating the relationship between neck pain and scapular dysfunction have only recently begun to emerge. Although several authors have emphasised the relevance of restoring normal scapular kinematics through exercise and manual therapy techniques, overall scapular rehabilitation guidelines decent for both patients with shoulder pain as well as patients with neck problems are lacking. The purpose of this paper is to provide a science-based clinical reasoning algorithm with practical guidelines for the rehabilitation of scapular dyskinesis in patients with chronic complaints in the upper quadrant.

Clinical assessment of the scapula: a review of the literature.

Scientific evidence supporting a role for faulty scapular positioning in patients with various shoulder disorders is cumulating. Clinicians who manage patients with shoulder pain and athletes at risk of developing shoulder pain need to have the skills to assess static and dynamic scapular positioning and dynamic control. Several methods for the assessment of scapular positioning are described in scientific literature. However, the majority uses expensive and specialised equipment (laboratory methods), making their use in clinical practice nearly impossible. On the basis of biometric and kinematic studies, guidelines for interpreting the observation of static and dynamic scapular positioning pattern in patients with shoulder pain are provided. At this point, clinicians can use reliable clinical tests for the assessment of both static and dynamic scapular positioning in patients with shoulder pain. However, this review also provides clinicians several possible pitfalls when performing clinical scapular evaluation. On the basis of its clinical relevance, its proven reliability, its relation to body length and its applicability in a clinical setting, this review recommends to assess the scapula both static (visual observation and acromial distance or Baylor/double square method for shoulder protraction) and semidynamic (visual observation and inclinometry for scapular upward rotation). In addition, when the patient demonstrates with shoulder impingement symptoms, the scapular repositioning test and scapular assistant test are recommended for relating the patients' symptoms to the position or movement of the scapula.

Biomechanical insights into the aetiology of infraspinatus syndrome.

OBJECTIVE: Infraspinatus syndrome (IS) results from injury to the suprascapular nerve. For reasons that are poorly understood, volleyball players are at greater risk of developing IS than are athletes who compete in other overhead sports. Differences between the shoulder kinematics of volleyball-related overhead skills and those skills demanded by other overhead sports might explain the pronounced prevalence of IS among volleyball athletes. DESIGN: Observational, laboratory-based, cross-sectional study. SETTING: The American Sports Medicine Institute. PARTICIPANTS: Fourteen healthy female Division 1 collegiate volleyball athletes. METHODS: Upper limb biomechanics of 14 healthy female Division 1 collegiate volleyball athletes while spiking and serving were quantified, then compared to the results from data previously obtained from female baseball pitchers and tennis players. RESULTS: Although the general movement pattern at the shoulder girdle is qualitatively similar for the upper limb skills required by a variety of overhead sports, volleyball spiking and serving result in greater shoulder abduction and horizontal adduction at the moment of ball contact/release than do baseball pitching or tennis serving. CONCLUSION: The authors suggest that the unique scapular mechanics which permit the extreme shoulder abduction and horizontal adduction that characterise volleyball spiking and serving place anatomically predisposed volleyball athletes at increased risk for developing cumulative traction-related injury to the suprascapular nerve at the level of the spinoglenoid notch.