Effect of Selective Muscle Training Using Visual Emg Biofeedback on Infraspinatus and Posterior Deltoid

Abstract We investigated the effects of visual electromyography (EMG) biofeedback during side-lying shoulder external rotation exercise on the EMG amplitude for the posterior deltoid, infraspinatus, and infraspinatus/posterior deltoid EMG activity ratio. Thirty-one asymptomatic subjects were included. Subjects performed side-lying shoulder external rotation exercise with and without visual EMG biofeedback. Surface EMG was used to collect data from the posterior deltoid and infraspinatus muscles. The visual EMG biofeedback applied the pre-established threshold to prevent excessive posterior deltoid muscle contraction. A paired t-test was used to determine the significance of the measurements between without vs. with visual EMG biofeedback. Posterior deltoid activity significantly decreased while infraspinatus activity and the infraspinatus/posterior activity ratio significantly increased during side-lying shoulder external rotation exercise with visual EMG biofeedback. This suggests that using visual EMG biofeedback during shoulder external rotation exercise is a clinically effective training method for reducing posterior deltoid activity and increasing infraspinatus activity.

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Use of a Shoulder Rest for Playing the Violin Revisited: An Analysis of the Effect of Shoulder Rest Height on Muscle Activity, Violin Fixation Force, and Player Comfort

Medical Problems of Performing Artists ◽

10.21091/mppa.2019.1009 ◽

2019 ◽

Vol 34 (1) ◽

pp. 39-46 ◽

Cited By ~ 1

Author(s):

Laura M Kok ◽

Jim Schrijvers ◽

Marta Fiocco ◽

Barend van Royen ◽

Jaap Harlaar

Keyword(s):

Muscle Activity ◽

Anterior Part ◽

Activity Patterns ◽

Deltoid Muscle ◽

Surface Emg ◽

Emg Activity ◽

Linear Regression Models ◽

Upper Trapezius ◽

Shoulder Muscles ◽

Rest Condition

AIMS: For violinists, the shoulder rest is an ergonomic adaptation to reduce musculoskeletal load. In this study, we aimed to evaluate how the height of the shoulder rest affects the violin fixation force and electromyographic (EMG) activity of the superficial neck and shoulder muscles. METHODS: In professional violinists, four different shoulder rest heights during five playing conditions were evaluated. Outcome variables included the jaw-shoulder violin fixation force and bilateral surface EMG of the upper trapezius (mTP), sternocleidomastoid (mSCM), and left anterior part of the left deltoid muscle (mDTA). Playing comfort was subjectively rated on a visual analogue scale (VAS). Linear regression models were estimated to investigate the influence of the shoulder rest height on muscle activity and violin fixation force as well as the muscle activity of the five evaluated muscles on violin fixation force. RESULTS: 20 professional violinists (4 males, 16 females, mean age 29.4 yrs) participated in this study. The shoulder rest condition had a significant effect on playing comfort (p<0.001), with higher shoulder rest conditions associated with decreased subjective playing comfort. The mean violin fixation force for each shoulder rest condition ranged between 2.92 and 3.39 N; higher shoulder rests were related to a higher violin fixation force (p<0.001). CONCLUSION: In this study, violin fixation force and muscle activity of the left mDTA increased while playing with an increasing height of the shoulder rest. As the shoulder rest influences muscle activity patterns and violin fixation force, adjustment of the shoulder rest and positioning of the violin need to be carefully optimized.

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Shoulder-Muscle Electromyography During Shoulder External-Rotation Exercises With and Without Slight Abduction

Journal of Sport Rehabilitation ◽

10.1123/jsr.2013-0116 ◽

2015 ◽

Vol 24 (2) ◽

pp. 109-115 ◽

Cited By ~ 6

Author(s):

Kazuto Sakita ◽

Matthew K. Seeley ◽

Joseph William Myrer ◽

J. Ty Hopkins

Keyword(s):

Outcome Measures ◽

External Rotation ◽

Surface Emg ◽

Pectoralis Major ◽

Shoulder Abduction ◽

High Activation ◽

Maximal Voluntary Isometric Contraction ◽

Major Activity ◽

Shoulder Muscle ◽

Shoulder External Rotation

Context:Standing and side-lying external-rotation exercises produce high activation of the deltoid and infraspinatus. Slight shoulder abduction during these exercises may decrease deltoid activity and increase infraspinatus activity.Objective:To determine if the addition of a towel under the arm during standing and side-lying external rotation affects infraspinatus, middle and posterior deltoid, and pectoralis major activation characteristics compared with a no-towel condition.Design:Controlled laboratory study.Participants:20 male volunteers (age 26 ± 3 y, height 1.80 ± 0.07 m, mass 77 ± 10 kg) who were right-hand dominant and had bilaterally healthy shoulders with no current cervical pathology and no skin infection or shoulder lesion.Interventions:External-rotation exercises without a towel roll (0° shoulder abduction) and with a towel roll (30° shoulder abduction) were performed in a standing and side-lying.Main Outcome Measures:Maximal voluntary isometric contraction for the infraspinatus, middle and posterior deltoid, and pectoralis major and external rotation in standing and side-lying with and without a towel roll were performed. Normalized average and peak surface EMG amplitude were compared between the towel conditions during standing and side-lying external rotation.Results:Both infraspinatus and pectoralis major activity had no significant differences between the towel conditions in standing and side-lying (P > .05). In standing and side-lying, posterior-deltoid activity was significantly greater with a towel roll (P < .05). Middle-deltoid activity had no significant differences between the towel conditions in standing (P > .05). However, in side-lying, middle-deltoid activity was significantly lower with a towel roll (P < .05).Conclusion:Middle-deltoid activity decreased with a towel roll during side-lying exercises. More data are needed to determine if a towel roll could be used to potentially reduce superior glide during external-rotation exercises.

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The Relationship Between Surface Electromyographic Activity and Torque Production of the Infraspinatus Muscle in Shoulder Rehabilitation Exercises

Journal of Applied Biomechanics ◽

10.1123/jab.2019-0257 ◽

2020 ◽

Vol 36 (3) ◽

pp. 141-147

Author(s):

Bill Stodart ◽

Maria Cup ◽

Curtis Kindel

Keyword(s):

Inverse Relationship ◽

External Rotation ◽

Surface Emg ◽

Joint Torque ◽

Emg Activity ◽

Electromyographic Activity ◽

Maximum Voluntary Isometric Contraction ◽

Relative Value ◽

Torque Values ◽

The Relationship

In current rehabilitation practice, exercise selection is commonly based on the amount of muscle recruitment demonstrated by electromyographic (EMG) analysis. A preponderance of evidence supports the concept that EMG of a muscle and torque output are positively correlated. This study was designed to investigate the relationship between surface EMG activity of the infraspinatus and torque production during exercises involving shoulder external rotation (ER). A total of 30 participants (average age = 24.6 y) performed maximum voluntary isometric contraction of ER at 5 points within the range of motion of 3 shoulder exercise positions with concomitant surface EMG recording. As a maximal internally rotated position was approached, maximum ER torque and minimum or near-minimum EMG recruitment were demonstrated. Conversely, at maximally externally rotated positions, EMG activity was greatest and torque values were lowest. An inverse relationship between joint torque output and EMG activity was established in each of the 3 exercises. The inverse relationship between EMG activity and torque output during Shoulder ER suggests that there may be additional factors warranting consideration during exercise selection. Further research may be needed to determine the relative value of electrical activity versus torque output to optimize the selection of rehabilitative exercises.

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Estimation of Rotator Cuff Activity Using a Surface EMG during Shoulder External Rotation

2006 IEEE International Conference on Robotics and Biomimetics ◽

10.1109/robio.2006.340189 ◽

2006 ◽

Cited By ~ 3

Author(s):

Takeshi Ando ◽

Misato Nihei ◽

Masakatsu G. Fujie

Keyword(s):

Rotator Cuff ◽

External Rotation ◽

Surface Emg ◽

Shoulder External Rotation

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Appropriate Resistance Intensity and Effective Exercise for Activation of Infraspinatus

International Journal of Sports Medicine ◽

10.1055/a-0960-9676 ◽

2019 ◽

Vol 40 (09) ◽

pp. 569-575

Author(s):

Il-Young Yu ◽

Se-Il Oh ◽

Won-Jeong Jung ◽

Jaeseop Oh

Keyword(s):

Muscle Activity ◽

Surface Electromyography ◽

High Intensity ◽

Activity Ratio ◽

External Rotation ◽

Deltoid Muscle ◽

Selective Activation ◽

Low Intensity ◽

Medium Intensity ◽

Healthy Males

AbstractWe investigated the muscle activities of the infraspinatus and posterior deltoid, as well as the ratio of the infraspinatus to posterior deltoid muscle activities, in response to 3 resistance intensities during prone external rotation (PER) and sitting external rotation (SITER) exercises. Fifteen healthy males participated; the subjects performed two exercises randomly at three resistance intensity levels: 1) low intensity (10–20%); 2) medium intensity (45–55%); 3) high intensity (60–70%). Surface electromyography was used to measure the activities of the infraspinatus and posterior deltoid muscles. The activities of the infraspinatus and posterior deltoid increased significantly as the resistance intensity increased during both PER and SITER exercises (p<0.001). The infraspinatus-to-posterior deltoid activity ratio increased as the resistance intensity decreased. Whereas the muscle activity ratio was highest under low and medium intensity during PER and SITER, respectively, and the muscle activity ratio was significantly increased at medium intensity compared with high intensity during both PER (p=0.023) and SITER (p=0.001). Our results suggest that low to medium intensity is the appropriate resistance intensity for selective activation of the infraspinatus. In addition, our results suggest that PER and SITER are effective for strengthening the infraspinatus.

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Is surface EMG biofeedback an effective training method for persons with neck and shoulder complaints after whiplash-associated disorders concerning activities of daily living and pain — a randomized controlled trial

Clinical Rehabilitation ◽

10.1177/0269215510362325 ◽

2010 ◽

Vol 24 (8) ◽

pp. 715-726 ◽

Cited By ~ 17

Author(s):

Cecilia Ehrenborg ◽

Birgitha Archenholtz

Keyword(s):

Randomized Controlled Trial ◽

Daily Living ◽

Controlled Trial ◽

Surface Emg ◽

Emg Biofeedback ◽

Training Method ◽

Randomized Controlled ◽

Effective Training ◽

Whiplash Associated Disorders ◽

Neck And Shoulder Complaints

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Selective Activation of the Infraspinatus Muscle

Journal of Athletic Training ◽

10.4085/1062-6050-48.2.18 ◽

2013 ◽

Vol 48 (3) ◽

pp. 346-352 ◽

Cited By ~ 16

Author(s):

Sung-Min Ha ◽

Oh-Yun Kwon ◽

Heon-Seock Cynn ◽

Won-Hwee Lee ◽

Su-Jung Kim ◽

...

Keyword(s):

Muscle Activity ◽

Repeated Measures ◽

External Rotation ◽

Trapezius Muscle ◽

Deltoid Muscle ◽

Limited Information ◽

Cross Sectional ◽

Bonferroni Adjustment ◽

Infraspinatus Muscle ◽

Shoulder External Rotation

Context: To improve selective infraspinatus muscle strength and endurance, researchers have recommended selective shoulder external-rotation exercise during rehabilitation or athletic conditioning programs. Although selective strengthening of the infraspinatus muscle is recommended for therapy and training, limited information is available to help clinicians design a selective strengthening program. Objective: To determine the most effective of 4 shoulder external-rotation exercises for selectively stimulating infraspinatus muscle activity while minimizing the use of the middle trapezius and posterior deltoid muscles. Design: Cross-sectional study. Setting: University research laboratory. Patients or Other Participants: A total of 30 healthy participants (24 men, 6 women; age = 22.6 ± 1.7 years, height = 176.2 ± 4.5 cm, mass = 65.6 ± 7.4 kg) from a university population. Intervention(s): The participants were instructed to perform 4 exercises: (1) prone horizontal abduction with external rotation (PER), (2) side-lying wiper exercise (SWE), (3) side-lying external rotation (SER), and (4) standing external-rotation exercise (STER). Main Outcome Measure(s): Surface electromyography signals were recorded from the infraspinatus, middle trapezius, and posterior deltoid muscles. Differences among the exercise positions were tested using a 1-way repeated-measures analysis of variance with Bonferroni adjustment. Results: The infraspinatus muscle activity was greater in the SWE (55.98% ± 18.79%) than in the PER (46.14% ± 15.65%), SER (43.38% ± 22.26%), and STER (26.11% ± 15.00%) (F3,87 = 19.97, P < .001). Furthermore, the SWE elicited the least amount of activity in the middle trapezius muscle (F3,87 = 20.15, P < .001). Posterior deltoid muscle activity was similar in the SWE and SER but less than that measured in the PER and STER (F3,87 = 25.10, P < .001). Conclusions: The SWE was superior to the PER, SER, and STER in maximizing infraspinatus activity with the least amount of middle trapezius and posterior deltoid activity. These findings may help clinicians design effective exercise programs.

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Effect of Shoulder External Rotation on EMG Activity of the Scapular Upward Rotators during Arm Elevation

Journal of the Korean Society of Physical Medicine ◽

10.13066/kspm.2015.10.4.113 ◽

2015 ◽

Vol 10 (4) ◽

pp. 113-122

Author(s):

Do-Young Jung ◽

Jong-Hyuck Weon

Keyword(s):

External Rotation ◽

Emg Activity ◽

Arm Elevation ◽

Shoulder External Rotation

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Nerve graft versus nerve transfer for neonatal brachial plexus: shoulder outcomes

Journal of Neurosurgery Pediatrics ◽

10.3171/2020.6.peds2027 ◽

2021 ◽

Vol 27 (1) ◽

pp. 87-92

Author(s):

Brandon W. Smith ◽

Kate W. C. Chang ◽

Sravanthi Koduri ◽

Lynda J. S. Yang

Keyword(s):

Brachial Plexus ◽

Clinical Data ◽

External Rotation ◽

Nerve Transfer ◽

Shoulder Function ◽

Nerve Transfers ◽

Shoulder Flexion ◽

Significant Difference ◽

Transfer Strategies ◽

Shoulder External Rotation

OBJECTIVEThe decision-making in neonatal brachial plexus palsy (NBPP) treatment continues to have many areas in need of clarification. Graft repair was the gold standard until the introduction of nerve transfer strategies. Currently, there is conflicting evidence regarding outcomes in patients with nerve grafts versus nerve transfers in relation to shoulder function. The objective of this study was to further define the outcomes for reconstruction strategies in NBPP with a specific focus on the shoulder.METHODSA cohort of patients with NBPP and surgical repairs from a single center were reviewed. Demographic and standard clinical data, including imaging and electrodiagnostics, were gathered from a clinical database. Clinical data from physical therapy evaluations, including active and passive range of motion, were examined. Statistical analysis was performed on the available data.RESULTSForty-five patients met the inclusion criteria for this study, 19 with graft repair and 26 with nerve transfers. There were no significant differences in demographics between the two groups. Understandably, there were no patients in the nerve grafting group with preganglionic lesions, resulting in a difference in lesion type between the cohorts. There were no differences in preoperative shoulder function between the cohorts. Both groups reached statistically significant improvements in shoulder flexion and shoulder abduction. The nerve transfer group experienced a significant improvement in shoulder external rotation, from −78° to −28° (p = 0.0001), whereas a significant difference was not reached in the graft group. When compared between groups, there appeared to be a trend favoring nerve transfer in shoulder external rotation, with the graft patients improving by 17° and the transfer patients improving by 49° (p = 0.07).CONCLUSIONSIn NBPP, patients with shoulder weakness experience statistically significant improvements in shoulder flexion and abduction after graft repair or nerve transfer, and patients with nerve transfers additionally experience significant improvement in external rotation. With regard to shoulder external rotation, there appear to be some data supporting the use of nerve transfers.

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