Relative contributions of infraspinatus and deltoid during external rotation in healthy shoulders

Bitter, Natalie L.; Clisby, Elizabeth F.; Jones, Mark; Magarey, Mary E.; Jaberzadeh, Shapour; Sandow, Michael J.

doi:10.1016/j.jse.2006.11.007

Cited by 85 publications

(112 citation statements)

References 24 publications

(27 reference statements)

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“…Thus, we selected 40% of MVIC, which was previously identified as optimal for shoulder external-rotator muscle exercise; participants who performed the same exercise with either 10% or 70% of MVIC could not achieve the necessary activation of the infraspinatus and instead activated the deltoid. 24,26 Consequently, we measured the amount of SA, LT, infraspinatus (IS), and posterior deltoid (PD), activity during external rotation (ER) of the shoulder during isometric contractions. Furthermore, previous investigators found no difference in the amount of SA and LT electromyographic (EMG) activity between the lawn-mower and robbery exercises.…”

Section: Methodsmentioning

confidence: 99%

“…Electrodes for the SA, LT, and PD muscles were placed according to a previous report, 2 whereas the electrode for the IS muscle was placed according to another study. 24 The electrodes were placed as follows: SA, below the axilla at the level of the inferior angle of the scapula; LT, at an oblique angle 5 cm down from the scapular spine and just outside the medial border of the scapula; PD, at an oblique direction parallel to the muscle fibers of the deltoid muscles at the lateral border of the scapular spine. An electrode was also placed on the IS just below the scapular spine and at the middle of the IS fossa of the scapula.…”

Section: Electrode Placementmentioning

confidence: 99%

“…An electrode was also placed on the IS just below the scapular spine and at the middle of the IS fossa of the scapula. 24 The EMG electrodes were preamplified and routed through the EMG mainframe, which further amplified (31000) and band-pass filtered Hz) the signals. A metal reference electrode was placed between the LT and IS electrodes.…”

Section: Electrode Placementmentioning

confidence: 99%

“…Some muscle activation may not increase proportionally as the level of exercise intensity increases, and different compensation from other muscles often occurs during the same movement with different intensities. 24 Free-motion exercises that simultaneously extend the knee joints, hip joints, and trunk, such as the lawn-mower and robbery exercises, were analyzed for scapular muscle activity to identify the amounts of scapular retraction and depression. Exercises with multi-joint movement such as these activated the SA and LT by approximately 30% of maximum voluntary isometric contraction (MVIC) without providing information about exercise intensity.…”

mentioning

confidence: 99%

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Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions

Tsuruike

Ellenbecker²

2015

Journal of Athletic Training

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Context: Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. Objective: To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Design: Cross-sectional study. Setting: Health Science Laboratory. Patients or Other Participants: A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Main Outcome Measure(s): Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Results: Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Conclusions: Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited.

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Section: Methodsmentioning

confidence: 99%

Section: Electrode Placementmentioning

confidence: 99%

Section: Electrode Placementmentioning

confidence: 99%

mentioning

confidence: 99%

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Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions

Tsuruike

Ellenbecker²

2015

Journal of Athletic Training

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“…DRT and unloaded side-lying shoulder external rotation) are often prescribed for patients with shoulder disorders with the aim of improving alignment and coordination. 1,6 A complement to manual therapy interventions includes restoring normal shoulder muscle recruitment and restoring control of the rotator cuff muscles. 4,7 It has been suggested that exercises should facilitate recruitment of rotator cuff muscles (e.g.…”

Section: Introductionmentioning

confidence: 99%

Shoulder muscle activity during the modified dynamic relocation test and side-lying shoulder external rotation: a cross-sectional study on asymptomatic individuals

Ribeiro

Shemmell

Falling

et al. 2016

Journal of Manual & Manipulative Therapy

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Objectives: (1) to compare activity levels between monitored muscles during the dynamic relocation test (DRT); (2) to assess changes in muscle activation variability over 10 trials; (3) to assess within-muscle difference activity levels between the DRT and the unloaded side-lying shoulder external rotation exercise. Methods: This is a cross-sectional, laboratory-based, repeated measures study. Thirty asymptomatic individuals performed the DRT and unloaded side-lying external rotation. The order of exercises was randomized. Superficial electromyography was used for recording the supraspinatus, infraspinatus, middle deltoid, posterior deltoid, pectoralis major, and latissimus dorsi muscles. The main outcome measures were mean muscle activity, expressed as % of maximal isometric voluntary contraction. Results: We found significant between-muscles differences in activity (F t = 14.11, p < 0.001) during the DRT. Post hoc analysis suggested between-trial variability did not change over the 10 trials, (F = 18.2, p < 0.001). Within-muscle comparisons between the DRT and side-lying shoulder external rotation suggested significant differences between these exercises (F = 32.37, p < 0.001). Conclusions: considering the monitored muscles, supraspinatus, infraspinatus, pectoralis major, and latissimus dorsi are the main muscles contracting during the DRT. Of all monitored muscles, supraspinatus muscle was the only one presenting higher activity levels during the DRT when compared to the unloaded side-lying shoulder external rotation.

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Preworkshop Knowledge of Musculoskeletal Anatomy of Rheumatology Fellows and Rheumatologists of Seven North, Central, and South American Countries

Navarro‐Zarza¹,

Hernández‐Díaz

Saavedra

et al. 2014

Arthritis Care & Research

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Relative contributions of infraspinatus and deltoid during external rotation in healthy shoulders

Cited by 85 publications

References 24 publications

Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions

Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions

Shoulder muscle activity during the modified dynamic relocation test and side-lying shoulder external rotation: a cross-sectional study on asymptomatic individuals

Preworkshop Knowledge of Musculoskeletal Anatomy of Rheumatology Fellows and Rheumatologists of Seven North, Central, and South American Countries

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