Scapula Muscle Activations During Overhead Throwing Holds

2016 ◽  
Vol 21 (3) ◽  
pp. 42-46 ◽  
Author(s):  
Gretchen Oliver ◽  
Lisa Henning ◽  
Hillary Plummer
Keyword(s):  
Surface Electromyography ◽  
Serratus Anterior ◽  
Upper Trapezius ◽  
Overhead Throwing ◽  
Muscle Activations ◽  
Lower Trapezius

The purpose of this study was to examine activations of selected scapular stabilizing musculature while performing an overhead throw with a hold (not releasing the ball) in two different throwing positions—standing with a crow hop and kneeling on the ipsilateral knee. Surface electromyography was used to examine activations of throwing side lower trapezius (LT), middle trapezius (MT), serratus anterior (SA), and upper trapezius (UT). Muscle activations were recorded while performing the overhead throw with holds while in two throwing positions. MANOVA results revealed no significant differences between the two throwing conditions and muscle activations of LT, MT, SA, and UT: F(8,124) = .804, p = .600; Wilks’s Λ = .904, partial η2 = .049. Although no significant differences were observed in the scapular stabilizers between the two conditions, moderate (21–50% MVIC) to high (> 50% MVIC) activations of each muscle were present, indicating that nonrelease throws may be beneficial for scapular stabilization in throwers.

scholarly journals Shoulder External Rotation Fatigue and Scapular Muscle Activation and Kinematics in Overhead Athletes

2011 ◽  
Vol 46 (4) ◽  
pp. 349-357 ◽  
Author(s):  
Mithun Joshi ◽  
Charles A. Thigpen ◽  
Kevin Bunn ◽  
Spero G. Karas ◽  
Darin A. Padua
Keyword(s):  
Muscle Fatigue ◽  
Muscle Activation ◽  
External Rotation ◽  
Shoulder Injuries ◽  
Serratus Anterior ◽  
Overhead Athletes ◽  
Scapular Kinematics ◽  
Fatigue Protocol ◽  
Upper Trapezius ◽  
Lower Trapezius

Context: Glenohumeral external rotation (GH ER) muscle fatigue might contribute to shoulder injuries in overhead athletes. Few researchers have examined the effect of such fatigue on scapular kinematics and muscle activation during a functional movement pattern. Objective: To examine the effects of GH ER muscle fatigue on upper trapezius, lower trapezius, serratus anterior, and infraspinatus muscle activation and to examine scapular kinematics during a diagonal movement task in overhead athletes. Setting: Human performance research laboratory. Design: Descriptive laboratory study. Patients or Other Participants: Our study included 25 overhead athletes (15 men, 10 women; age = 20 ± 2 years, height = 180 ± 11 cm, mass = 80 ± 11 kg) without a history of shoulder pain on the dominant side. Intervention(s): We tested the healthy, dominant shoulder through a diagonal movement task before and after a fatiguing exercise involving low-resistance, high-repetition, prone GH ER from 0° to 75° with the shoulder in 90° of abduction. Main Outcome Measure(s): Surface electromyography was used to measure muscle activity for the upper trapezius, lower trapezius, serratus anterior, and infraspinatus. An electromyographic motion analysis system was used to assess 3-dimensional scapular kinematics. Repeated-measures analyses of variance (phase × condition) were used to test for differences. Results: We found a decrease in ascending-phase and descending-phase lower trapezius activity (F1,25 = 5.098, P = .03) and an increase in descending-phase infraspinatus activity (F1,25 = 5.534, P = .03) after the fatigue protocol. We also found an increase in scapular upward rotation (F1,24 = 3.7, P = .04) postfatigue. Conclusions: The GH ER muscle fatigue protocol used in this study caused decreased lower trapezius and increased infraspinatus activation concurrent with increased scapular upward rotation range of motion during the functional task. This highlights the interdependence of scapular and glenohumeral force couples. Fatigue-induced alterations in the lower trapezius might predispose the infraspinatus to injury through chronically increased activation.

scholarly journals Lower trapezius and serratus anterior activation: which exercise to use for scapular neuromuscular reeducation?

2013 ◽  
Vol 11 (4) ◽  
pp. 660-667
Author(s):  
Rodrigo Py Gonçalves Barreto ◽  
Caroline Cabral Robinson ◽  
Clarice Sperotto dos Santos Rocha ◽  
Fernando Carlos Mothes ◽  
Fábio Matsumoto ◽  
...  
Keyword(s):  
Functional Recovery ◽  
Surface Electromyography ◽  
Maximal Voluntary Contraction ◽  
Healthy Subjects ◽  
Voluntary Contraction ◽  
Serratus Anterior ◽  
Low Levels ◽  
Lower Trapezius ◽  
The Military ◽  
Muscular Activation

Introduction: Low levels of activation of the serratus anterior (SA) and lower trapezius (LT) muscles are associated with kinematics dysfunctions of the scapular belt, for which the focus of functional recovery is neuromuscular reeducation. Hence, the proposed exercises should keep muscular activation at levels between 20% and 40% of the maximal voluntary contraction. Objectives: To compare the activation of SA and LT muscles in different exercises by using surface electromyography. Methods: Five exercises (modified crucifix, scaption, modified military press, pull over and low row) were executed by ten healthy subjects. Results: The highest SA activation was found during scaption, and the adequate activation occurred in the modified military press. The highest LT activation was found during scaption and low row exercises. Conclusions: The exercises that kept the recommended range of activation for neuromuscular reeducation were the military press, for the SA muscle, and the low row and scaption, for the LT muscle.

scholarly journals Volitional Preemptive Abdominal Contraction and Upper Extremity Muscle Latencies During D1 Flexion and Scaption Shoulder Exercises

2018 ◽  
Vol 53 (12) ◽  
pp. 1181-1189 ◽  
Author(s):  
Ramonica Scott ◽  
Hyung Suk Yang ◽  
C. Roger James ◽  
Steven F. Sawyer ◽  
Phillip S. Sizer
Keyword(s):  
Serratus Anterior ◽  
Movement Initiation ◽  
Open Chain ◽  
Cross Sectional ◽  
Upper Trapezius ◽  
Shoulder Muscle ◽  
Onset Timing ◽  
Asymptomatic Volunteers ◽  
Anterior Deltoid ◽  
Lower Trapezius

Context The abdominal-bracing maneuver, a volitional preemptive abdominal contraction (VPAC) strategy, is commonly used during resisted shoulder exercises. How VPAC affects shoulder-muscle function during resisted shoulder exercise is unknown. Objective To identify the effects of VPAC on selected parascapular and glenohumeral muscles during specific shoulder exercises with or without resistance. Design Cross-sectional study. Setting Clinical biomechanics research laboratory. Patients or Other Participants Twenty-two asymptomatic volunteers between 18 and 40 years of age. Intervention(s) Participants performed arm elevation in scaption and D1 shoulder-flexion (D1F) patterns with and without resistance and VPAC. Main Outcome Measure(s) Electromyography was used to test the muscle-contraction amplitudes and onset timing of the anterior deltoid, posterior deltoid, upper trapezius, lower trapezius, and serratus anterior. Muscle-response amplitudes were quantified using root mean square electromyography. Shoulder-muscle relative-onset timing was quantified in reference to kinematic elbow-movement initiation. Results The VPAC increased serratus anterior amplitude during D1F (P < .001) and scaption (P < .001) and upper trapezius amplitude (P < .001) in scaption. All muscle amplitudes increased with resistance. The VPAC decreased muscle-onset latencies for the anterior deltoid (P < .001), posterior deltoid (P = .008), upper trapezius (P = .001), lower trapezius (P = .006), and serratus anterior (P = .001) during D1F. In addition, the VPAC decreased muscle-onset latencies for the anterior deltoid (P < .001), posterior deltoid (P = .007), upper trapezius (P < .001), lower trapezius (P < .001), and serratus anterior (P < .001) during scaption. Conclusions The VPAC affected only the parascapular muscles that had the greatest scapular-stabilizing roles during the specific open chain movement we tested. It decreased latencies in all muscles. These neuromuscular changes may enhance the stability of the shoulder during D1F and scaption exercises.

Comparison of scapular upward rotator muscle activities and activity ratios during three scapular upward rotator strengthening exercises

2021 ◽  
pp. 1-8
Author(s):  
Jun-Hee Kim ◽  
Oh-Yun Kwon ◽  
Ui-Jae Hwang ◽  
Sung-Hoon Jung ◽  
Sun-Hee Ahn ◽  
...  
Keyword(s):  
Young Adult ◽  
Moderate Intensity ◽  
Serratus Anterior ◽  
Healthy Young Adult ◽  
Adult Men ◽  
Muscle Imbalance ◽  
Upper Trapezius ◽  
Strengthening Exercises ◽  
Activity Ratios ◽  
Lower Trapezius

BACKGROUND: The focus of exercises for restoring the imbalance between scapular upward rotator muscles – upper trapezius (UT), serratus anterior (SA), and lower trapezius (LT) – commonly aims to increase SA and LT activities while not increasing UT activity. OBJECTIVES: The purpose of this study was to compare the activity of the UT, SA, and LT muscles during scapation and protraction exercises, which are two traditional exercises, and during a newly designed scapular upward rotation (SUR) exercise. METHODS: A total of 29 healthy young adult men performed all three exercises with maximum isometric contraction. The electromyographic activities of the UT, SA, and LT were recorded. RESULTS: UT demonstrated the highest activity during scapation. SA activity was the lowest during protraction. However, no difference was found in SA activity during the performance of scapation and SUR. The SA/UT ratio was the highest during scapation. CONCLUSIONS: SUR is a new exercise that can be performed at moderate intensity for shoulder rehabilitation to restore scapular upward rotator muscle imbalance.

scholarly journals Scapular Muscle Tests in Subjects With Shoulder Pain and Functional Loss: Reliability and Construct Validity

2005 ◽  
Vol 85 (11) ◽  
pp. 1128-1138 ◽  
Author(s):  
Lori A Michener ◽  
N Douglas Boardman ◽  
Peter E Pidcoe ◽  
Angela M Frith
Keyword(s):  
Construct Validity ◽  
Shoulder Pain ◽  
Muscle Activity ◽  
Trapezius Muscle ◽  
Muscle Performance ◽  
Serratus Anterior ◽  
Functional Loss ◽  
Upper Trapezius ◽  
Lower Trapezius ◽  
Isometric Muscle

Abstract Background and Purpose. Scapular muscle performance evaluated with a handheld dynamometer (HHD) has been investigated only in people without shoulder dysfunction for test-retest reliability of data obtained with a single scapular muscle test. The purpose of this study was to assess the reliability, error, and validity of data obtained with an HHD for 4 scapular muscle tests in subjects with shoulder pain and functional loss. Subjects and Methods. Subjects (N=40) with shoulder pain and functional loss were tested bymeasuring the kilograms applied with an HHD during 3 trials for muscle tests for the lower trapezius, upper trapezius, middle trapezius, and serratus anterior muscles. Concurrently, surface electromyography (sEMG) data were collected for the 4 muscles. The same procedures were performed 24 to 72 hours after the initial testing by the same tester. Muscle tests were performed 3 times, and the results were averaged for data analysis. Results. Intraclass correlation coefficients for intratester reliability of measurements of isometricforce obtained using an HHD ranged from .89 to .96. The standard error of the measure (90% confidenceinterval [CI]) ranged from 1.3 to 2.7 kg; the minimal detectable change (90% CI) ranged from 1.8 to 3.6 kg. Construct validity assessment, done by comparing the amounts of isometric muscle activity (sEMG) for each muscle across the 4 muscle tests, revealed that the muscle activity of the upper trapezius and lower trapezius muscles washighest during their respective tests. Conversely, the isometric muscle activity of the middle trapezius and serratus anterior muscles was not highest during their respective tests. Discussion and Conclusion. In people with shoulder pain and functional loss, the intrarater reliability and error over 1 to 3 days were established using an HHD for measurement of isometric force for the assessment of scapular muscle performance. Error values can be used to make decisions regarding individual patients. Construct validity was established for the lower and upper trapezius muscle tests; therefore, these tests are advocated for use. However, construct validity was not demonstrated for the serratus anterior and middle trapezius muscle tests as performed in this study. Further investigation of these muscle tests is warranted.

Rehabilitation of Scapular Muscle Balance

2007 ◽  
Vol 35 (10) ◽  
pp. 1744-1751 ◽  
Author(s):  
Ann M. Cools ◽  
Vincent Dewitte ◽  
Frederick Lanszweert ◽  
Dries Notebaert ◽  
Arne Roets ◽  
...  
Keyword(s):  
External Rotation ◽  
Trapezius Muscle ◽  
Electromyographic Activity ◽  
Shoulder Injury ◽  
Serratus Anterior ◽  
Upper Trapezius ◽  
Strengthening Exercises ◽  
Muscle Balance ◽  
Lower Trapezius ◽  
Balance Rehabilitation

Background Strengthening exercises for the scapular muscles are used in the treatment of scapulothoracic dysfunction related to shoulder injury. In view of the intermuscular and intramuscular imbalances often established in these patients, exercises promoting lower trapezius (LT), middle trapezius (MT), and serratus anterior (SA) activation with minimal activity in the upper trapezius (UT) are recommended. Hypothesis Of 12 commonly used trapezius strengthening exercises, a selection can be performed for muscle balance rehabilitation, based on a low UT/LT, UT/MT, or UT/SA muscle ratio. Study Design Controlled laboratory study. Methods Electromyographic activity of the 3 trapezius parts and the SA was measured in 45 healthy subjects performing 12 commonly described scapular exercises, using surface electromyography. Results For each intramuscular trapezius ratio (UT/LT, UT/MT), 3 exercises were selected for restoration of muscle balance. The exercises side-lying external rotation, side-lying forward flexion, prone horizontal abduction with external rotation, and prone extension were found to be the most appropriate for intramuscular trapezius muscle balance rehabilitation. For the UT/SA ratio, none of the exercises met the criteria for optimal intermuscular balance restoration. Conclusion In cases of trapezius muscle imbalance, some exercises are preferable over others because of their low UT/LT and UT/MT ratios. Clinical Relevance In the selection of rehabilitation exercises, the clinician should have a preference for exercises with high activation of the LT and MT and low activity of the UT.

Shoulder Muscle Activation Levels During Exercises With Axial and Rotational Load on Stable and Unstable Surfaces

2017 ◽  
Vol 33 (2) ◽  
pp. 118-123 ◽  
Author(s):  
Vinícius Yan Santos Nascimento ◽  
Rafaela Joyce Barbosa Torres ◽  
Natália Barros Beltrão ◽  
Priscila Soares dos Santos ◽  
André Luiz Torres Pirauá ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Bench Press ◽  
Biceps Brachii ◽  
Emg Activity ◽  
Triceps Brachii ◽  
Serratus Anterior ◽  
Upper Trapezius ◽  
Unstable Surface ◽  
Lower Trapezius ◽  
Rotational Load

This study evaluated the effects of instability on the EMG activity of scapular stabilizing and upper limb muscles during exercises with axial and rotational load. Twenty male volunteers (20.9 ± 1.8 years, 174.1 ± 0.04 cm, 73.17 ± 8.77 kg) experienced in strength training participated in a crossover design. Muscle activation of anterior deltoid (AD), posterior deltoid (PD), pectoralis major (PM), biceps brachii (BB), triceps brachii (TB), upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) were determined on both conditions. Participants performed a single series of 10 repetitions of bench press and fly exercises on stable (bench) and unstable (proprioceptive disc) conditions at 60% of 1-RM. The Friedman test and post hoc Dunn’s indicated that the unstable condition showed greater EMG activity for AD (P = .001) and BB (P = .002) on the fly exercise, SA (P = .001) and LT (P = .048) on the bench press, and PM (P ≤ .002) on both exercises. These results show that using an unstable surface in exercises with rotational load provides superior EMG activity of the agonist muscles, while in exercise with axial load, the instability favors EMG activity of the scapular stabilizing muscles.

scholarly journals Comparison of Activity in Scapular Stabilizing Muscles during Knee Push-Up Plus and Modified Vojta’s 3-Point Support Exercises

Healthcare ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1636
Author(s):  
Hyoungwon Lim
Keyword(s):  
Muscle Activity ◽  
Surface Emg ◽  
Emg Activity ◽  
Shoulder Injury ◽  
Serratus Anterior ◽  
Point Support ◽  
Upper Trapezius ◽  
The Difference ◽  
Lower Trapezius ◽  
Push Up

Selective serratus anterior (SA) strengthening without compensatory movement of the shoulder stabilizers is essential for shoulder stability and functional movement without causing shoulder injury and dysfunction. The purpose of this study was to compare electromyographic (EMG) activity between the SA, upper trapezius (UT), lower trapezius (LT), and pectoralis major (PM) during the knee push-up plus (KPUP) and modified Vojta’s 3-point support (MV3PS) exercises. Scapular stabilizer muscle activity (UT, LT, SA, and PM) was investigated during the KPUP and MV3PS exercises in 40 healthy adults (19 males, 21 females) using surface EMG. Muscle activity of the SA was significantly higher during the MV3PS exercise than during the KPUP (p < 0.05). However, muscle activity in the PM was significantly lower during the MV3PS exercise (p < 0.05). In addition, the LT and UT showed less muscle activity during the MV3PS exercise, although the difference was not statistically significant (p > 0.05). These findings suggest that the MV3PS exercise better activates the SA than KPUP.

Intrarater Reliability of Assessing Strength of the Shoulder and Scapular Muscles

2012 ◽  
Vol 21 (1) ◽  
Author(s):  
Derya Celik ◽  
Ahmet Dirican ◽  
Gul Baltaci
Keyword(s):  
Muscle Strength ◽  
Healthy Subjects ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Mean Value ◽  
Intrarater Reliability ◽  
Serratus Anterior ◽  
Upper Trapezius ◽  
Muscle Groups ◽  
Lower Trapezius

Context: Handheld dynamometry (HHD) is considered an objective method of measuring strength, but the reliability of the procedure can be compromised by inadequate tester strength and insufficient stabilization of the dynamometer especially, for the scapular muscles. Objective: Primarily, to determine the intrarater reliability of HHD when testing shoulder and scapular muscle strength, and secondarily, to report reliability when corrected for body-mass index (BMI). Design: Technical report. Setting: University physiotherapy department. Participants: 57 adults (17 men, 40 women; mean age = 35.05 ± 13.5 y), both healthy individuals and patients with shoulder impingement. Intervention: HHD. Main Outcome Variables: Muscle strength of the upper, middle, and lower trapezius; anterior deltoid; serratus anterior; supraspinatus; and latissimus dorsi determined by HHD. Each muscle was assessed 3 times, and the mean value was calculated. The subjects were divided into 3 groups according to BMI. Group 1: BMI ≤ 20 kg/m2 (n = 22); Group 2: BMI ≤ 24.9 kg/m2 (n = 54); and Group 3: BMI ≤ 29.9 kg/m2 (n = 38). Results: Correlations were calculated for each pair of strength scores. Intraclass correlation coefficients (ICCs) ranged from .77 to .99 in healthy subjects and from .75 to .99 in patients, for all muscle groups except the upper trapezius (P < .05). Reliability values ranged from good to high in healthy subjects but were less consistent for the upper trapezius (ICC .45-.65). The relationship with BMI and muscle strength illustrates that as BMI increases, there is a decrease in reliability values of the lower trapezius (ICC = .35-.65). Conclusion: The study demonstrates that evaluating the strength of scapular and shoulder muscles using HHD presents reliable results for both patients with impingement syndrome and healthy subjects. Reliability values were compressed when testing the trapezius in subjects with higher BMI. This is likely a result of the examiner's difficulty in overcoming the patients with this maneuver.

Figure-8 Strap Application: Immediate Alteration of Pectoralis Minor Length and Scapular Alignment During Arm-Lifting Exercise in Participants With Forward Shoulder Posture

2016 ◽  
Vol 25 (3) ◽  
pp. 273-279 ◽  
Author(s):  
Chang-Hee Ko ◽  
Heon-Seock Cynn ◽  
Ji-Hyun Lee ◽  
Tae-Lim Yoon ◽  
Sil-Ah Choi
Keyword(s):  
Outcome Measures ◽  
Muscle Activity ◽  
Muscle Length ◽  
Cross Sectional Study ◽  
Serratus Anterior ◽  
Cross Sectional ◽  
Upper Trapezius ◽  
Pectoralis Minor ◽  
Forward Shoulder Posture ◽  
Lower Trapezius

Context:Scapular bracing can correct scapular kinematics and restore normal scapular-muscle activity. However, there is little evidence to support the beneficial effects of a figure-8 strap, a type of scapular bracing, on muscle length, scapular alignment, and muscle activity during arm-lifting exercise.Objective:To investigate the immediate effect of a figure-8 strap on pectoralis minor length, scapular alignment, and scapular upward-rotator-muscle activity.Design:Cross-sectional study.Setting:Research laboratory.Participants:Fifteen male participants (age 22.1 ± 1.9 y, weight 68.2 ± 5.7 kg, height 176.2 ± 3.3 cm) with forward shoulder posture (FSP) were examined for pectoralis minor length and scapular alignment with and without the application of a figure-8 strap.Main Outcome Measures:Pectoralis minor length was measured using the Pectoralis Minor Index (PMI), scapular alignment was measured with FSP, and upper trapezius, lower trapezius, and serratus anterior muscle activity were measured using surface electromyography while participants performed an arm-lifting exercise. Data collected with and without applying a figure-8 strap were compared using a paired t-test.Results:Applying a figure-8 strap significantly decreased the PMI (P = .005) and scapular anterior tilting (P = .000). There were no differences in the muscle activity of the upper trapezius (P = .784), lower trapezius (P = .241), and serratus anterior muscles (P = .639).Conclusions:A figure-8 strap resulted in positive changes in pectoralis minor length and scapular alignment. The results support its use as a treatment aid in managing pectoralis minor length and scapular alignment during arm-lifting exercises.

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