scholarly journals Muscle Activation of Serratus Anterior during Self-Resisted Scapular Protraction with Forward Flexion on Unstable Surface in Sitting Position

2021 ◽  
Vol 5 (2) ◽  
pp. 41-46
Author(s):  
Tae-Jin Jang ◽  
In-Cheol Jeon
2017 ◽  
Vol 26 (4) ◽  
pp. 281-286 ◽  
Author(s):  
Rafaela J.B. Torres ◽  
André L.T. Pirauá ◽  
Vinícius Y.S. Nascimento ◽  
Priscila S. dos Santos ◽  
Natália B. Beltrão ◽  
...  

The aim of this study was to evaluate the acute effect of the use of stable and unstable surfaces on electromyography (EMG) activity and coactivation of the scapular and upper-limb muscles during the push-up plus (with full protraction of the scapula). Muscle activation of anterior deltoid (AD), posterior deltoid (PD), pectoralis major, biceps brachii (BB), triceps brachii (TB), upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) levels and coactivation index were determined by surface EMG in 20 young men during push-up plus performed on a stable and unstable condition (2 unstable devices applied to hands and feet). The paired t test and Cohen d were used for statistical analysis. The results showed that during the execution of the push-up plus on the unstable surface an increased EMG activity of the scapular stabilizing muscles (SA, MT, and LT) was observed, while AD and PD muscles showed a decrease. During exercise execution on the unstable surface there was a higher index of coactivation of the scapular muscles (SA–MT and UT–LT pairs). No significant differences were observed in TB–BB and AD–PD pairs. These results suggest that the push-up-plus exercise associated with unstable surfaces produced greater EMG activity levels and coactivation index of the scapular stabilizing muscle. On the other hand, the use of an unstable surface does not promote the same effect for the shoulder muscles.


2021 ◽  
pp. 175857322110193
Author(s):  
Katie L Kowalski ◽  
Denise M Connelly ◽  
Jennifer M Jakobi ◽  
Jackie Sadi

Background Push-ups (PU) are a common closed chain exercise used to enhance shoulder girdle stability, with variations that alter the difficulty or target specific muscles. To appropriately select and prescribe PU exercises, an understanding of muscle activity during variations of the PU is needed. The purpose of this scoping review was to identify common PU variations and describe their muscle activation levels. Methods Databases searched included PubMed, CINAHL, Scopus, and SPORTDiscus for articles published between January 2000 and November 2019. Results Three hundred three articles were screened for eligibility with 30 articles included in the analysis. Six PU types and five muscles met the criteria for analysis. Weighted mean electromyography (EMG) amplitude was calculated for each muscle across PU types and for each PU type as a measure of global muscle activity. Triceps and pectoralis major had the highest EMG amplitude during unstable, suspension, incline with hands on a ball and the standard PU. Serratus anterior had the highest EMG amplitude during PU plus and incline PU. The greatest global EMG amplitude occurred during unstable surface PU. Discussion These results provide clinicians with a framework for prescribing PU to target specific muscles and scale exercise difficulty to facilitate rehabilitation outcomes.


2015 ◽  
Vol 20 (2) ◽  
pp. 5-13
Author(s):  
Taylor Meier ◽  
Brice Snyder ◽  
Jennifer W. Cuchna ◽  
Johanna M. Hoch

Clinical Question:In a healthy adult population, which push-up position produces the greatest mean serratus anterior (SA) activation, expressed as a percentage of maximum voluntary isometric contraction (MVIC)?Clinical Bottom Line:In a healthy population, there is moderate evidence to support the use of the standard push-up on an unstable surface, elbow push-ups on stable and unstable surfaces, wall push-ups on an unstable surface, the full weight-bearing position using the Cuff Link system, and all three hand positions (shoulder width, wide base, and narrow base) with and without the use of the Perfect Pushup™ handgrips for the purpose of SA strengthening. These exercises produced a mean SA activation of at least 50% of the MVIC in the four cross-sectional studies that were reviewed for this critically appraised topic.


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 ◽  
...  

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.


2021 ◽  
pp. 036354652110250
Author(s):  
Kelly R. Berckmans ◽  
Birgit Castelein ◽  
Dorien Borms ◽  
Thierry Parlevliet ◽  
Ann Cools

Background: Scapular muscle activity during shoulder exercises has been explored with surface electromyography (EMG). However, knowledge about the activity of deeper-layer scapular muscles is still limited. Purpose: To investigate EMG activation of the deeper-layer scapular stabilizers (levator scapulae [LS], rhomboid major [RM], pectoralis minor [Pm] muscles) together with superficial muscle activity (upper [UT], middle [MT], and lower trapezius [LT] and serratus anterior [SA]) during 4 exercises often used for training scapular function. Based on the amplitude EMG of the deeper-layer muscles, scapular muscle activation ratios for the 4 exercises were calculated, hereby providing knowledge of the optimal muscle balance. Study Design: Descriptive laboratory study. Methods: A total of 26 healthy participants performed 4 shoulder exercises (side-lying external rotation [ER], side-lying forward flexion, prone horizontal abduction with ER, and prone extension) while simultaneously measuring scapular muscle activity. Intramuscular electrodes were used for the deeper layer, in contrast to surface electrodes for the superficial muscles. All data were normalized to percentage of maximal voluntary isometric contraction (%MVIC), and the activation ratios (the muscle activity of the deeper layer relative to the other muscles) were calculated. A 1-way analysis of variance with Bonferroni correction was applied for statistical analysis. Results: Moderate activity was found in all exercises for the LS and RM (25%-45% MVIC). The Pm resulted in low activity during both side-lying exercises (13%-18% MVIC). Ratios involving LS or RM showed values >1 for all exercises (1.28-12.41) except for LS/MT, LS/LT, and LS/RM (0.85-0.98) during side-lying ER, and LS/MT, RM/MT and RM/LS (0.85-0.99) during side-lying forward flexion. Likewise, values <1 were found when MT (0.85) and LS (0.99) were involved with RM in the numerator during side-lying forward flexion. Ratios with Pm in the numerator showed values <1, apart from the ratios with UT and SA in the denominator. Conclusion: The study provides extended knowledge about the deeper-layer scapular muscle activity and related ratios during the 4 shoulder exercises mentioned here. Putting theory into practice, based on our results, we advise both side-lying exercises to be performed to strengthen LT and MT, even in case of hyperactivity of the Pm. However, the 4 exercises should be given carefully to patients with hyperactivity in the LS and/or RM. Clinical Relevance: The findings of this study may assist clinical decision making in exercise selection for restoring scapular function.


2013 ◽  
Vol 48 (1) ◽  
pp. 12-24 ◽  
Author(s):  
Ashley K. Cole ◽  
Melanie L. McGrath ◽  
Shana E. Harrington ◽  
Darin A. Padua ◽  
Terri J. Rucinski ◽  
...  

Context: Overhead athletes commonly have poor posture. Commercial braces are used to improve posture and function, but few researchers have examined the effects of shoulder or scapular bracing on posture and scapular muscle activity. Objective: To examine whether a scapular stabilization brace acutely alters posture and scapular muscle activity in healthy overhead athletes with forward-head, rounded-shoulder posture (FHRSP). Design: Randomized controlled clinical trial. Setting: Applied biomechanics laboratory. Patients or Other Participants: Thirty-eight healthy overhead athletes with FHRSP. Intervention(s): Participants were assigned randomly to 2 groups: compression shirt with no strap tension (S) and compression shirt with the straps fully tensioned (S + T). Posture was measured using lateral-view photography with retroreflective markers. Electromyography (EMG) of the upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) in the dominant upper extremity was measured during 4 exercises (scapular punches, W's, Y's, T's) and 2 glenohumeral motions (forward flexion, shoulder extension). Posture and exercise EMG measurements were taken with and without the brace applied. Main Outcome Measure(s): Head and shoulder angles were measured from lateral-view digital photographs. Normalized surface EMG was used to assess mean muscle activation of the UT, MT, LT, and SA. Results: Application of the brace decreased forward shoulder angle in the S + T condition. Brace application also caused a small increase in LT EMG during forward flexion and Y's and a small decrease in UT and MT EMG during shoulder extension. Brace application in the S + T group decreased UT EMG during W's, whereas UT EMG increased during W's in the S group. Conclusions: Application of the scapular brace improved shoulder posture and scapular muscle activity, but EMG changes were highly variable. Use of a scapular brace might improve shoulder posture and muscle activity in overhead athletes with poor posture.


2020 ◽  
Author(s):  
Leanda J McKenna ◽  
Luke Bonnett ◽  
Kelly Panzich ◽  
Jacinta Lim ◽  
Snorre K Hansen ◽  
...  

Abstract Background Serratus anterior (SA) muscle activation may be decreased with subacromial pain syndrome. Determining whether real-time ultrasound (RTUS) can improve SA muscle activation may improve physical therapist interventions for subacromial pain syndrome. Objective The objective of this study was to determine whether the addition of RTUS visual feedback increased the activation of SA in adults with painful shoulders in comparison to manual facilitation alone. Design This was an assessor-masked, 2-period, randomized crossover trial. Setting The setting was a university medical imaging laboratory. Participants Adults with mild to moderate unilateral subacromial pain received both interventions in random order with at least a 1-week washout between interventions. Fourteen participants were randomized to receive manual facilitation with RTUS first, and 13 were randomized to receive manual facilitation only first. Intervention The intervention was 15 repetitions of a supine “serratus punch” facilitated by manual facilitation with RTUS visual feedback or manual facilitation alone. Measurements Levels of SA activation were measured with surface electromyography normalized to a maximal voluntary isometric contraction. Results A total of 25 participants completed the full trial of both interventions. Data from 25 participant periods for RTUS with manual facilitation and data from 26 participant periods for manual facilitation only were analyzed. The predicted marginal mean difference between interventions was 55.5% (95% CI = 13.9% to 97.1%) (P = .009), favoring the addition of RTUS feedback. No adverse effects occurred. Limitations The results are applicable only to mild to moderate levels of shoulder pain, and it is unknown whether the addition of RTUS visual feedback reduces pain or disability. Conclusion Manual facilitation with RTUS visual feedback increased SA activation in adults with painful shoulders compared with manual facilitation alone. Impact Determining if real-time ultrasound (RTUS) can improve SA muscle activation may help clinicians improve physical therapist interventions for subacromial pain syndrome.


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