Glenohumeral internal rotation deficit on pitching biomechanics and muscle activity

2021 ◽  
Author(s):  
Yi-Hsuan Weng ◽  
Tsun-Shun Huang ◽  
Cheng-Ya Huang ◽  
Hsing-Yu Chen ◽  
Yung-Shen Tsai ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Muscular Activity ◽  
Average Difference ◽  
Triceps Brachii ◽  
Acceleration Phase ◽  
Serratus Anterior ◽  
Scapular Kinematics ◽  
Glenohumeral Internal Rotation Deficit ◽  
Posterior Tilt ◽  
Arm Elevation

To characterize the scapular pitching biomechanics in symptomatic GIRD pitchers (SG) compared to asymptomatic GIRD (ASG) and healthy pitchers. The scapular kinematics and associated muscle activities during pitching were recorded in 33 high school pitchers. Compared to healthy, GIRD pitchers had less scapular posterior tilt in each pitching event (average difference, AD = 14.4°, p < 0.01) and ASG demonstrated less scapular upward rotation at ball release (AD = 12.8°, p < 0.01) and greater muscle activity in the triceps brachii in the early-cocking phase (AD = 9.9%, p = 0.015) and in the serratus anterior in the late-cocking phase (AD = 30.8%, p < 0.01). Additionally, SG had less muscular activity on triceps brachii in the acceleration phase and serratus anterior in the cocking phase (AD = 37.8%, p = 0.016; AD = 15.5%, p < 0.01, respectively) compared to ASG. GIRD pitchers exhibited less scapular posterior tilt during pitching, which may cause impingement. Since tightness of the anterior shoulder is a common cause of inadequacy of posterior tilt during arm elevation, stretching exercise of the anterior shoulder is recommended. Given the inadequate recruitment during pitching in the GIRD pitchers, symptoms may develop following potential impingement.

Serratus Anterior Fatigue Reduces Scapular Posterior Tilt and External Rotation During Arm Elevation

2021 ◽  
pp. 1-7
Author(s):  
Nathan Harrison ◽  
W. Zach Garrett ◽  
Mark K. Timmons
Keyword(s):  
Internal Rotation ◽  
Repeated Measures ◽  
External Rotation ◽  
Elevation Angle ◽  
Serratus Anterior ◽  
Scapular Kinematics ◽  
Fatigue Protocol ◽  
Posterior Tilt ◽  
Arm Elevation ◽  
Arm Motion

Context: Fatigue of the scapular stabilizing muscles resulting from repeated arm motion has been reported to alter scapular kinematics, which could result in shoulder pathology, especially impingement. Objective: This study aimed to examine the effects of fatigue of the serratus anterior muscle on scapular kinematics, specifically, decrease scapular posterior tilt and upward scapular rotation during arm elevation. Design: Repeated measures. Setting: Laboratory. Participants: Thirty participants were included in the investigation. Interventions: Scapular kinematics and shoulder strength were measured before and immediately following a serratus anterior fatigue protocol. Main Outcome: Scapular 3-dimensional position during arm elevation. Results: No difference in upward rotation of the scapula between prefatigue and postfatigue conditions (ascending: P = .188; descending: P = .798). Scapular posterior tilt decreased during arm elevation following the fatigue protocol between 60° and 90° and 90° and 120° of arm elevation during the ascent (P = .004) and the descent (P = .013). Fatigue by arm elevation angle interaction was found for clavicular elevation during the ascent (P = .050) between 90° and 120° of arm elevation. Scapular internal rotation increased during the ascent (P = .027). There was no difference in clavicular protraction between the prefatigue and postfatigue conditions (ascending: P ≤ .001; descending: P ≤ .001). Conclusion: Fatigue of the serratus anterior decreases posterior scapular tilt and greater clavicular elevation and scapular internal rotation at higher arm elevation angles. These findings are consistent with the scapular kinematic patterns associated with shoulder pain. Improving serratus anterior endurance might delay the changes in scapular kinematics associated with repeated arm motion and shoulder injury mechanisms.

scholarly journals Single-Session Video and Electromyography Feedback in Overhead Athletes With Scapular Dyskinesis and Impingement Syndrome

2020 ◽  
Vol 55 (3) ◽  
pp. 265-273
Author(s):  
Wan-Yu Du ◽  
Tsun-Shun Huang ◽  
Yuan-Chun Chiu ◽  
Szu-Jieh Mao ◽  
Li-Wei Hung ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Training Group ◽  
Video Feedback ◽  
Emg Biofeedback ◽  
Scapular Dyskinesis ◽  
Serratus Anterior ◽  
Overhead Athletes ◽  
Feedback Training ◽  
Scapular Kinematics ◽  
Lower Trapezius

Context Subacromial impingement syndrome (SIS) is associated with scapular dyskinesis, or imbalanced scapular muscle activity. Evidence has shown that feedback can improve scapular control in patients with SIS. However, it is unknown whether real-time video feedback or electromyography (EMG) biofeedback is optimal for improving scapular kinematics and muscle activity during a functional task. Objective To compare the effects of video and EMG feedback sessions on absolute muscle activity (upper trapezius [UT], lower trapezius [LT], serratus anterior), muscle balance ratios (UT/LT, UT/serratus anterior), and scapular kinematics (anterior-posterior tilt, external-internal rotation, upward rotation) in SIS participants during arm elevation and lowering. Design Randomized controlled clinical trial. Setting Research laboratory. Patients or Other Participants Overhead athletes who were diagnosed with SIS and who also exhibited scapular dyskinesis (N = 41). Main Outcome Measure(s) Three-dimensional kinematics and EMG were recorded before and after feedback training. Results Lower trapezius muscle activity increased (4.2%–18%, P &lt; .011) and UT/LT decreased (0.56–1.17, P &lt; .013) in the EMG biofeedback training group as compared with those in the video feedback training group. Scapular upward rotation during arm elevation was higher in the video group than in the EMG group after feedback training (2.3°, P = .024). Conclusions The EMG biofeedback improved muscle control and video feedback improved the correction of scapular upward rotation in patients with SIS. Trial Registration Number ClinicalTrials.gov: NCT03252444.

Analysis of Scapular Kinematics and Muscle Activity by Use of Fine-Wire Electrodes During Shoulder Exercises

2020 ◽  
Vol 48 (5) ◽  
pp. 1213-1219
Author(s):  
Kelly Berckmans ◽  
Birgit Castelein ◽  
Dorien Borms ◽  
Tanneke Palmans ◽  
Thierry Parlevliet ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Moderate Activity ◽  
Limited Information ◽  
Serratus Anterior ◽  
Postoperative Rehabilitation ◽  
Scapular Kinematics ◽  
Fine Wire ◽  
Rehabilitation Exercises

Background: During nonoperative or postoperative rehabilitation after sports injuries, exercise selection is often based on minimal load on the injured/repaired glenohumeral structures, while optimally activating scapulothoracic muscles. Previous research explored scapular muscle activity during rehabilitation exercises using surface electromyography (EMG). However, limited information exists about the deeper lying muscle activity, measured with fine-wire electrodes, even more in combination with 3-dimensional scapular kinematics. Purpose: To report scapular kinematics synchronously with surface and fine-wire EMG during specific shoulder exercises for early rehabilitation. Study Design: Descriptive laboratory study. Methods: A total of 23 healthy male patients were recruited. Three-dimensional scapular kinematics were measured combined with EMG recording of 8 muscles during 4 commonly used shoulder exercises (inferior glide, low row, lawnmower, and robbery). Upper (UT), middle (MT), and lower (LT) trapezius and serratus anterior muscle activities were measured with bipolar surface electrodes. Intramuscular electrodes were placed in the levator scapulae (LS), rhomboid major (RM), pectoralis minor (Pm), and infraspinatus (IS) muscles. All data were normalized as a percentage of maximal voluntary isometric contraction (%MVIC). A linear mixed model with Bonferroni correction was applied for statistical analysis. Results: Scapular kinematics revealed an anterior tilt position during the inferior glide, low row, and robbery ( P < .05). An upward rotation position between 20° and 30° was reached in all exercises except low row. Inferior glide (31°) and low row (42°) represented a significantly increased internal rotation position compared with lawnmower and robbery. Lawnmower and robbery showed significantly ( P < .05) more MT (lawnmower, 36% MVIC; robbery, 39% MVIC) and RM (lawnmower, 59% MVIC; robbery, 66% MVIC) activation compared with inferior glide and low row. Lawnmower and robbery showed significantly ( P < .05) less Pm activation (9.5%-12% MVIC). LS was significantly more active during robbery (58% MVIC) compared with inferior glide and low row (27%-36% MVIC) ( P < .05). IS showed moderate activity (24%-37% MVIC) for all exercises, except low row (13% MVIC). Conclusion/Clinical Relevance: This study provides new insights about scapular positions and activation of the deeper layer muscles during 4 commonly used shoulder rehabilitation exercises. The lawnmower showed a favorable position of the scapula with less Pm activity in contrast to the low row. The inferior glide, lawnmower, and robbery should not be implemented in early phases of shoulder rehabilitation because of their moderate muscle activity.

Shoulder Muscular Activity During Isometric Three-Point Kneeling Exercise on Stable and Unstable Surfaces

2011 ◽  
Vol 27 (3) ◽  
pp. 192-196 ◽  
Author(s):  
Rodrigo Cappato de Araújo ◽  
Rodrigo de Andrade ◽  
Helga Tatiana Tucci ◽  
Jaqueline Martins ◽  
Anamaria Siriani de Oliveira
Keyword(s):  
Biceps Brachii ◽  
Isometric Force ◽  
Muscular Activity ◽  
Activity Levels ◽  
Force Output ◽  
Triceps Brachii ◽  
Serratus Anterior ◽  
Upper Trapezius ◽  
Stable Surface ◽  
Swiss Ball

The purpose of this study was to determine if performing isometric 3-point kneeling exercises on a Swiss ball influenced the isometric force output and EMG activities of the shoulder muscles when compared with performing the same exercises on a stable base of support. Twenty healthy adults performed the isometric 3-point kneeling exercises with the hand placed either on a stable surface or on a Swiss ball. Surface EMG was recorded from the posterior deltoid, pectoralis major, biceps brachii, triceps brachii, upper trapezius, and serratus anterior muscles using surface differential electrodes. All EMG data were reported as percentages of the average root mean square (RMS) values obtained in maximum voluntary contractions for each muscle studied. The highest load value was obtained during exercise on a stable surface. A significant increase was observed in the activation of glenohumeral muscles during exercises on a Swiss ball. However, there were no differences in EMG activities of the scapulothoracic muscles. These results suggest that exercises performed on unstable surfaces may provide muscular activity levels similar to those performed on stable surfaces, without the need to apply greater external loads to the musculoskeletal system. Therefore, exercises on unstable surfaces may be useful during the process of tissue regeneration.

Electrical activity and relative length changes of dog limb muscles as a function of speed and gait

1981 ◽  
Vol 94 (1) ◽  
pp. 15-42 ◽  
Author(s):  
G. E. Goslow ◽  
H. J. Seeherman ◽  
C. R. Taylor ◽  
M. N. McCutchin ◽  
N. C. Heglund
Keyword(s):  
Electrical Activity ◽  
Stance Phase ◽  
Biceps Brachii ◽  
Vastus Lateralis ◽  
Activity Patterns ◽  
Relative Length ◽  
Muscular Activity ◽  
Triceps Brachii ◽  
Limb Muscles ◽  
Length Changes

Electrical activity and length changes of 11 muscles of the fore- and hind- limbs of dogs walking, running, and galloping on a treadmill, were measured as a function of forward speed and gait. Our purpose was to find out whether the activity patterns of the major limb muscles were consistent with the two mechanisms proposed for storage and recovery of energy within a stride: a ‘pendulum-like’ mechanism during a walk, and a ‘spring-like’ mechanism during a run. In the stance phase of the walking dog, we found that the supraspinatus, long head of the triceps brachii, biceps brachii, vastus lateralis, and gastrocnemius underwent only minor length changes during a relatively long portion of their activity, Thus, a major part of their activity during the walk seems consistent with a role in stabilization of the joints as the dog ‘pole-vaulted’ over its limbs (and thereby conserved energy). In the stance phase of trotting and/or galloping dogs, we found that the supraspinatus, lateral head of the triceps, vastus lateralis, and gastrocnemius were active while being stretched prior to shortening (as would be required for elastic storage of energy), and that this type of activity increased with increasing speed. We also found muscular activity in the select limb flexors that was consistent with storage of kinetic energy at the end of the swing phase and recovery during the propulsive stroke. This activity pattern was apparent in the latissimus dorsi during a walk and trot, and in the biceps femoris during a trot and gallop. We conclude that, during locomotion, a significant fraction of the electrical activity of a number of limbs muscles occurs while they undergo little or no length change or are being stretched prior to shortening and that these types of activities occur in a manner that would enable the operation of pendulum-like and spring-like mechanisms for conserving energy within a stride. Therefore these forms of muscular activity, in addition to the more familiar activity associated with muscle shortening, should be considered to be important during locomotion.

scholarly journals Shoulder Injuries in Cricketers

2015 ◽  
Vol 49 (4) ◽  
pp. 194-196
Author(s):  
Sharad Prabhakar ◽  
Radhakant Pandey
Keyword(s):  
Rotator Cuff ◽  
Shoulder Injuries ◽  
Shoulder Injury ◽  
Internal Impingement ◽  
Scapular Kinematics ◽  
Glenohumeral Internal Rotation Deficit ◽  
Repetitive Nature ◽  
Tissue Changes ◽  
Soft Tissue Changes ◽  
Very High

ABSTRACT Shoulder injuries are very common in cricketers. Throwing athletes in cricket (both bowlers and fielders) are prone to shoulder injuries secondary to the large amount of forces generated, the resultant very high velocities and the repetitive nature of the throwing action. The shoulder joint has to balance mobility vs stability. Athletes exhibit adaptive changes that develop from the repetitive microtrauma following overhead throwing. The article discusses in detail how altered scapular kinematics, rotator cuff dysfunction with altered muscle strength patterns, internal impingement combined with anatomical adaptive bony and soft tissue changes causing a glenohumeral internal rotation deficit, predispose the cricketer to shoulder injury. How to cite this article Prabhakar S, Pandey R. Shoulder Injuries in Cricketers. J Postgrad Med Edu Res 2015;49(4): 194-196.

scholarly journals The Effects of Bench Press Variations in Competitive Athletes on Muscle Activity and Performance

2017 ◽  
Vol 57 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Atle Hole Saeterbakken ◽  
Dag-André Mo ◽  
Suzanne Scott ◽  
Vidar Andersen
Keyword(s):  
Muscle Activity ◽  
Latissimus Dorsi ◽  
Bench Press ◽  
Biceps Brachii ◽  
High Load ◽  
Emg Activity ◽  
International Level ◽  
Triceps Brachii ◽  
Competitive Athletes ◽  
And Performance

AbstractThe aim of the study was to compare the EMG activity performing 6RM competition style bench press (flat bench-wide grip) with 1) medium and narrow grip widths on a flat bench and 1) inclined and declined bench positions with a wide grip. Twelve bench press athletes competing at national and international level participated in the study. EMG activity was measured in the pectoralis major, anterior and posterior deltoid, biceps brachii, triceps brachii and latissimus dorsi. Non-significant differences in activation were observed between the three bench positions with the exception of 58.5-62.6% lower triceps brachii activation, but 48.3-68.7% greater biceps brachii activation in the inclined bench compared with the flat and declined bench position. Comparing the three grip widths, non-significant differences in activations were observed, with the exception of 25.9-30.5% lower EMG activity in the biceps brachii using a narrow grip, compared to the medium and wide grip conditions. The 6-RM loads were 5.8-11.1% greater using a medium and wide grip compared to narrow grip width and 18.5-21.5% lower in the inclined bench position compared with flat and declined. Comparing the EMG activity during the competition bench press style with either the inclined and declined bench position (wide grip) or using a narrow and medium grip (flat bench), only resulted in different EMG activity in the biceps- and triceps brachii. The 6RM loads varied with each bench press variation and we recommend the use of a wide grip on a flat bench during high load hypertrophy training to bench press athletes.

Scapular Kinematics and Subacromial-Impingement Syndrome: A Meta-Analysis

2012 ◽  
Vol 21 (4) ◽  
pp. 354-370 ◽  
Author(s):  
Mark K. Timmons ◽  
Chuck A. Thigpen ◽  
Amee L. Seitz ◽  
Andrew R. Karduna ◽  
Brent L. Arnold ◽  
...  
Keyword(s):  
General Population ◽  
Evidence Synthesis ◽  
Impingement Syndrome ◽  
Subacromial Impingement Syndrome ◽  
Lead Author ◽  
Future Research ◽  
Scapular Kinematics ◽  
Arm Elevation ◽  
The Impact ◽  
Scapular Plane

Context:The literature does not present a consistent pattern of altered scapular kinematics in patients with shoulder-impingement syndrome (SIS).Objectives:To perform meta-analyses of published comparative studies to determine the consistent differences in scapular kinematics between subjects with SIS and controls. In addition, the purpose was to analyze factors of the data-collection methods to explain the inconsistencies in reported kinematics. The results of this study will help guide future research and enable our understanding of the relationship between scapular kinematics and SIS.Evidence Acquisition:A search identified 65 studies; 9 papers met inclusion criteria. Sample sizes, means, and SDs of 5 scapular-kinematic variables were extracted or obtained from each paper’s lead author. Standard difference in the mean between SIS and controls was calculated. Moderator variables were plane of arm elevation, level of arm elevation (ARM) and population (POP).Evidence Synthesis:Overall, the SIS group had less scapular upward rotation (UR) and external rotation (ER) and greater clavicular elevation (ELE) and retraction (RET) but no differences in scapular posterior tilt (PT). In the frontal plane, SIS subjects showed greater PT and ER, and in the scapular plane, less UR and ER and greater ELE and RET. There was also greater ELE and RET in the sagittal plane. There was less UR at the low ARM and greater ELE and RET at the high ARM with SIS. Athletes and overhead workers showed less UR, while athletes showed greater PT and workers showed less PT and ER. The general population with SIS had greater ELE and RET only.Conclusions:Subjects with SIS demonstrated altered scapular kinematics, and these differences are influenced by the plane, ARM, and POP. Athletes and overhead workers have a different pattern of scapular kinematics than the general population. The scapular plane is most likely to demonstrate altered kinematics. These factors should be considered when designing futures studies to assess the impact of altered kinematics in patients with SIS.

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