Relative scapular-muscle ratios during maximal isokinetic shoulder-girdle strength performance in elite field hockey players

Context: The shoulder joint and girdle are highly loaded during field hockey play. To optimize performance and to better substantiate preventive programs, it is important to gain insight into shoulder-girdle muscle function and balance in this athlete population. Objective: To evaluate relative scapular muscle-activity ratios through surface electromyography during maximal isokinetic strength testing in elite male field hockey players compared with nonathletes. Design: Cross-sectional study. Setting: Institutional laboratory. Patients or Other Participants: Twenty-five elite field hockey players from the Belgian National Team and 25 age-and sex-matched nonathletes. Intervention(s): We measured bilateral activity in 4 scapular muscles (upper trapezius [UT], middle trapezius [MT], lower trapezius [LT], and serratus anterior [SA]) during an external-internal rotation and protraction-retraction isokinetic shoulder protocol. Main Outcome Measure(s): Relative scapular muscleactivity ratios, or balance ratios, of the UT : MT, UT : LT, UT: SA, SA : MT, and SA : LT. Results: We noted lower ratios bilaterally in the athlete group compared with the control group for the UT: MT, UT: LT, and SA: MT ratios during protraction, retraction, and external rotation, respectively, and unilaterally (dominant side only) for the UT: LT ratio during protraction. No consistent trend was present for established side differences in the studied balance ratios. Conclusions: Compared with nonathletes, elite field hockey players had altered intramuscular (within the trapezius) and intermuscular (between the trapezius and SA) balance ratios during maximal shoulder-girdle contractions, with relatively more MT and LT activity. This may reflect a sport-specific adaptation to optimize coordinated activity of the scapulothoracic muscles, meeting the specific demands of field hockey movements and simultaneously better protecting the shoulder against injury. Our results can assist in optimizing high-performance training and in supporting injury-prevention programs, which are key to both successful and long-lasting athletic careers

Home-based exercise therapy for treating shoulder instability in patients with hypermobile Ehlers-Danlos syndrome/hypermobility spectrum disorders : a randomized trial

Purpose To investigate the effectiveness of two home-based exercise programs for treating multidirectional shoulder instability (MDI) in patients diagnosed with Hypermobile Ehlers-Danlos syndrome (hEDS) or Hypermobility Spectrum Disorders (HSD). Methods Twenty-one hEDS/HSD patients with MDI were recruited from the Center for Medical Genetics of the Ghent University Hospital. Patients were randomly assigned to either the experimental or the control group. Both groups received a 6-month home-based exercise program. The primary outcome measure was the Western Ontario Shoulder Index (WOSI). Secondary outcomes included the Disabilities of the Arm, Shoulder and Hand (DASH), Tampa Scale for Kinesiophobia (TSK), Patient-Specific Functional Scale (PSFS), Global Rating of Change (GROC), and pain pressure thresholds. Outcomes were assessed at baseline, after 6 weeks, 12 weeks, and 24 weeks. Results Significant main effects for time were observed for all questionnaires, except for the TSK (p = 0.12). Patients improved 240 and 325 points on the WOSI after 12 (p = 0.02) and 24 weeks (p = 0.001), respectively. Additionally, patients improved 8.6 points on the DASH (p = 0.002), 4.3 points on the PSFS (p = 0.01), and 1.02 points on the GROC (p = 0.001) after 24 weeks. Conclusion No significant differences were found between group A and B. Both home-based exercise programs led to significant improvements in shoulder function

Scapulothoracic muscle activity during kinetic chain variations of a prone elevation exercise

BACKGROUND: Scapular rehabilitation exercises should target appropriate muscles. Recently, adding external rotation resistance to scapular exercises has gained interest. Moreover, clinical experts advise kinetic chain integration into shoulder rehabilitation exercises. OBJECTIVE: To investigate scapular muscle activity during kinetic chain variations of a prone elevation exercise. METHODS: Activity of the upper (UT), middle (MT), and lower (LT) trapezius and serratus anterior (SA) muscles was determined with surface electromyography (EMG) in 31 asymptomatic participants during six prone elevation exercise variations. Variation was created by adding external rotation resistance, adding trunk extension, or changing exercise position (prone on a Swiss ball with knees or feet supported, or prone on a physiotable). All data were normalized as a percentage of maximal voluntary isometric contraction (% MVIC). For each muscle, a Friedman's ANOVA was conducted to analyse statistical differences in EMG signal intensity between exercises. RESULTS: The LT was moderately (42 - 48% MVIC) and MT highly (63 - 66% MVIC) activated during all exercise variations. No significant differences between exercises for these muscles could be detected. Adding external rotation to a prone elevation exercise decreased UT activity while adding trunk extension increased UT activity. Altering exercise position had no influence on scapular muscle activity except increased UT activity when lying prone on a physiotable with trunk extension. CONCLUSION: Prone elevation exercises are appropriate for facilitating LT and MT activity. Adding external rotation inhibits UT activity while UT facilitation could be achieved when adding trunk extension

The effect of five isometric exercises on glenohumeral translations in healthy subjects and patients with the hypermobility type of the Ehlers-Danlos syndrome (hEDS) or hypermobility spectrum disorder (HSD) with multidirectional shoulder instability : an observational study

Objectives: To examine whether patients, diagnosed with the hypermobility type of the Ehlers-Danlos syndrome (hEDS) or Hypermobility Spectrum Disorder (HSD), with multidirectional shoulder instability (MDI) have increased humeral head translations compared to healthy controls and to describe the direction of the humeral translations during five exercises. Design: Observational study. Setting: Ghent University Hospital. Participants: Twenty-seven female patients (aged mean (SD) 35 (13) years) with hEDS/HSD and MDI and 20 female healthy controls (aged 34 (11) years) participated in this study. Interventions: The acromiohumeral (AHD) and humeralglenoid distance (HGD) were measured using ultrasound during five isometric exercises: shoulder external rotation, shoulder extension, shoulder flexion, elbow extension and holding a 2 kg dumbbell. Main outcome measures: Ultrasound measures of the AHD and HGD. Results: During isometric shoulder extension, elbow extension and dumbbell loading, patients had a significantly larger change in AHD compared to controls. In patients, the AHD was significantly smaller during isometric shoulder flexion, extension and elbow extension compared to the AHD measured in rest. By contrast, the AHD was significantly larger during isometric external rotation and dumbbell loading compared to the AHD measured in rest. Regarding the HGD, no significant differences between patients and controls were observed. However, significantly smaller HGD values were found in patients during isometric shoulder flexion compared to the HGD in rest. Conclusions: Isometric external rotation and holding a 2 kg dumbbell caused an inferior translation in patients with hEDS/HSD and MDI, whereas isometric shoulder flexion and shoulder/elbow extension respectively led to an anterior-superior and superior translation

Electromyographic muscle activity and three-dimensional scapular kinematics in patients with multidirectional shoulder instability : a study in the hypermobile type of the Ehlers-Danlos syndrome and the hypermobility spectrum disorders

Objective To investigate differences in electromyography (EMG), muscle activity, and scapular kinematics during elevation in the scapular plane between healthy controls, participants with multidirectional shoulder laxity (MDL), and patients with multidirectional shoulder instability (MDI) who are diagnosed with hypermobile Ehlers-Danlos syndrome (hEDS) or hypermobility spectrum disorder (HSD). Methods Twenty-seven women with hEDS/HSD and MDI, 27 female healthy control subjects, and 28 female subjects with MDL participated in this study. Scapular 3-dimensional kinematic data were obtained using 8 Oqus Qualisys cameras. Simultaneously, surface EMG was used to measure muscle activity of the upper, middle, and lower trapezius, infraspinatus, latissimus dorsi, serratus anterior, posterior deltoid, and pectoralis major during arm elevation in the scapular plane. Group differences were assessed using statistical parametric mapping. Results Regarding scapular kinematics, significantly less upward rotation was observed in hEDS/HSD patients with MDI compared to both healthy controls and MDL subjects. Significantly less posterior tilt was seen in hEDS/HSD patients compared to MDL subjects. Furthermore, significantly higher EMG activity of the infraspinatus, middle trapezius, and posterior deltoid was found in hEDS/HSD patients with MDI. Conclusion hEDS/HSD patients with MDI demonstrate altered scapular kinematics and increased EMG muscle activity compared to subjects without MDI. These findings could serve as a stepping stone for future research regarding treatment strategies in patients whose conditions belong to the hypermobility spectrum