scholarly journals A Comparison of Teres Minor and Infraspinatus Muscle Activation in the Prone Position

2021 ◽  
Author(s):  
Masaaki Tsuruike ◽  
Todd S. Ellenbecker
Keyword(s):  
Prone Position ◽  
Muscle Activation ◽  
Infraspinatus Muscle ◽  
Teres Minor

Chronic Adaptations of the Posterior Rotator Cuff in Professional Pitchers

2021 ◽  
pp. 036354652098868
Author(s):  
Stephen J. Thomas ◽  
Justin Cobb ◽  
Scott Sheridan ◽  
Joseph Rauch ◽  
Ryan W. Paul
Keyword(s):  
Soft Tissue ◽  
Rotator Cuff ◽  
Internal Rotation ◽  
External Rotation ◽  
Negative Relationship ◽  
Muscle Thickness ◽  
Pennation Angle ◽  
Muscle Architecture ◽  
Infraspinatus Muscle ◽  
Teres Minor

Background: Because of the large forces and high frequency of throwing, the upper extremity experiences repetitive stresses that lead to acute and chronic adaptations. While the importance of pennation angle and muscle thickness as predictors of muscle force production has been shown in other populations and other joints, there has been little research done that examines these variables in the shoulders of baseball players. Purpose: (1) To examine the chronic effect pitching has on the rotator cuff muscle architecture (pennation angle and muscle thickness) in healthy professional baseball pitchers, and (2) to examine the correlation between muscle architecture and clinical measures of strength and range of motion (ROM). Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty-eight healthy professional pitchers were recruited during the 2019 spring training. Internal rotation (IR) and external rotation (ER) strength were measured with a handheld dynamometer and IR and ER ROM were measured with an inclinometer. A diagnostic ultrasound machine was utilized to capture images of humeral retroversion, as well as the pennation angle and muscle thickness of the infraspinatus and teres minor muscles. ImageJ software was used to quantify the pennation angle and muscle thickness. Results: There were no significant differences between the dominant and nondominant arms for ER or IR strength. Also, no pennation angle and muscle thickness differences were found between the dominant and nondominant arms. A weak positive relationship between infraspinatus muscle thickness (superficial and total) and ER strength ( P = .016, R = 0.287 and P = .009, R = 0.316) and a moderate negative relationship between soft tissue glenohumeral internal rotation deficit (GIRD) and the bilateral difference of the teres minor deep pennation angle ( R = −0.477, P = .008) were observed. No other significant relationships were noted. Conclusion: Our results are contrary to current literature as we expected to see a stronger dominant arm, with a larger pennation angle and greater muscle thickness. Interestingly, we found that ER strength was positively related to only the thickness of the infraspinatus muscle, and that soft tissue GIRD was positively related to only the side-to-side adaptation of the pennation angle within the deep portion of the teres minor. This suggests that when posterior shoulder tightness occurs, specifically the architecture of the teres minor muscle is involved. However, the organization to which these players belonged has a very extensive training protocol throughout the year that emphasizes bilateral training during a large majority of the exercises. Therefore, the results may not be generalizable to all professional players.

scholarly journals Construct Validity of Muscle Force Tests of the Rotator Cuff Muscles: An Electromyographic Investigation

2010 ◽  
Vol 90 (4) ◽  
pp. 572-580 ◽  
Author(s):  
Rebecca L. Brookham ◽  
Linda McLean ◽  
Clark R. Dickerson
Keyword(s):  
Rotator Cuff ◽  
Muscle Activation ◽  
Muscle Force ◽  
Test Group ◽  
Clinical Test ◽  
Shoulder Muscles ◽  
Frequent Use ◽  
Medial Rotation ◽  
Generating Capacity ◽  
Teres Minor

Background Manual muscle tests (MMTs) are used in clinical settings to evaluate the function and strength (force-generating capacity) of a specific muscle in a position at which the muscle is believed to be most isolated from other synergists and antagonists. Despite frequent use of MMTs, few electromyographic evaluations exist to confirm the ability of MMTs to isolate rotator cuff muscles. Objective This study examined rotator cuff isolation during 29 shoulder muscle force tests (9 clinical and 20 generic tests). Design An experimental design was used in this study. Participants and Measurements Electromyographic data were recorded from 4 rotator cuff muscles and 10 additional shoulder muscles of 12 male participants. Maximal isolation ratios (mean specific rotator cuff muscle activation to mean activation of the other 13 recorded muscles) defined which of these tests most isolated the rotator cuff muscles. Results Three rotator cuff muscles were maximally isolated (obtained highest isolation ratios) within their respective clinical test groups (lateral rotator test group for the infraspinatus and teres minor muscles and abduction test group for the supraspinatus muscle). The subscapularis muscle was maximally isolated equally as effectively within the generic ulnar force and clinical medial rotation groups. Similarly, the supraspinatus and teres minor muscles were isolated equally as effectively in some generic test groups as they were in their respective clinical test groups. Limitations Postural artifact in the wire electrodes caused exclusion of some channels from calculations. The grouping of muscle force tests based on test criteria (clinical or generic tests and muscle action) may have influenced which groups most isolated the muscle of interest. Conclusions The results confirmed the appropriateness of 9 commonly used clinical tests for isolating rotator cuff muscles, but suggested that several other muscle force tests were equally appropriate for isolating these muscles.

Rotator-Cuff Muscle-Recruitment Strategies During Shoulder Rehabilitation Exercises

2011 ◽  
Vol 20 (4) ◽  
pp. 471-486 ◽  
Author(s):  
Kathleen A. Swanik ◽  
Kellie Huxel Bliven ◽  
Charles Buz Swanik
Keyword(s):  
Rotator Cuff ◽  
Muscle Activation ◽  
Glenohumeral Joint ◽  
Neuromuscular Control ◽  
Muscle Recruitment ◽  
Individual Muscle ◽  
Muscle Activation Patterns ◽  
Outcomes Measures ◽  
Rehabilitation Exercises ◽  
Teres Minor

Context:There are contradictory data on optimal muscle-activation strategies for restoring shoulder stability. Further investigation of neuromuscular-control strategies for glenohumeral-joint stability will guide clinicians in decisions regarding appropriate rehabilitation exercises.Objectives:To determine whether subscapularis, infraspinatus, and teres minor (anteroposterior force couple) muscle activation differ between 4 shoulder exercises and describe coactivation ratios and individual muscle-recruitment characteristics of rotator-cuff muscles throughout each shoulder exercise.Design:Crossover.Setting:Laboratory.Participants:healthy, physically active men, age 20.55 ± 2.0 y.Interventions:4 rehabilitation exercises: pitchback, PNF D2 pattern with tubing, push-up plus, and slide board.Main Outcomes Measures:Mean coactivation level, coactivation-ratio patterns, and level (area) of muscle-activation patterns of the subscapularis, infraspinatus, and teres minor throughout each exercise.Results:Coactivation levels varied throughout each exercise. Subscapularis activity was consistently higher than that of the infraspinatus and teres minor combined at the start of each exercise and in end ranges of motion. Individual muscle-recruitment levels in the subscapularis were also different between exercises.Conclusion:Results provide descriptive data for determining normative coactivation-ratio values for muscle recruitment for the functional exercises studied. Differences in subscapularis activation suggest a reliance to resist anteriorly directed forces.

scholarly journals Electromyography of the Shoulder Musculature during Passive Rehabilitation Exercises

2020 ◽  
Vol 4 ◽  
pp. 247154922096004
Author(s):  
Janelle A Cross ◽  
John deVries ◽  
Mason Mocarski ◽  
Nicholas C Ketchum ◽  
Eileen Compty ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Rotator Cuff Repair ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Emg Activity ◽  
Maximum Voluntary Isometric Contraction ◽  
Subscapularis Muscle ◽  
Shoulder Muscles ◽  
Cuff Repair ◽  
Teres Minor

Background Medical professionals remain conflicted about the best rehabilitation protocol a patient should perform after rotator cuff repair surgery. Exercises deemed passive may be activating the shoulder muscles to a moderate level, thus putting the surgical repair construct at risk for re-injury. The purpose of this study was to measure the activation of the rotator cuff and surrounding musculature during exercises used in physical therapy following rotator cuff repair surgery using electromyography (EMG). Methods Muscle activation was recorded in fourteen participants performing sixteen exercises. Four fine wire electrodes (supraspinatus, infraspinatus, subscapularis, teres minor) and six surface electrodes (upper and middle division of the trapezius, anterior, medial and posterior head of the deltoid, biceps brachii) were utilized. EMG activity values for each muscle were normalized to the maximum voluntary isometric contraction and activation levels were assessed. Results Twelve of the sixteen exercises tested were moderately active in the subscapularis muscle. The results show the subscapularis muscle was activated in all three planes of motion. Discussion Most exercises were found to have low activation levels for the supraspinatus, infraspinatus and teres minor muscles. While the exercises examined in this study appear to be safe for the more commonly repaired supraspinatus, caution should be used when administering exercises to individuals with repairs involving the subscapularis.

Metoda prone position jako sposób na poprawienie oksygenacji u pacjentów oparzonych z zespołem ostrej niewydolności oddechowej

2016 ◽  
Vol 4 (1) ◽  
pp. 1-5
Author(s):  
Andrzej Krajewski ◽  
Elżbieta Młyńska-Krajewska ◽  
Marta Markowska
Keyword(s):  
Prone Position
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