Serratus Anterior Muscle Activity Research Articles

Comparison of Serratus Anterior and Abdominal Muscle Activity During Push-up Plus Exercise With Hip Adduction and the Abdominal Drawing-in Maneuver

Comparison of Serratus Anterior and Abdominal Muscle Activity During Push-up Plus Exercise With Hip Adduction and the Abdominal Drawing-in Maneuver

Comparison of upper and lower trapezius electromyographic activity during Y-raise exercise with and without isometric adduction in healthy volunteers

BACKGROUND: Lower trapezius (LT) plays an important role in maintaining the stability of the scapula. Sufficient activation of LT can reduce the risk of rotator cuff tear and shoulder impingement syndrome. The Y-raise exercise has been recommended for effective LT activation. However, the upper trapezius (UT) can be co-activated during universal Y-raise exercise. OBJECTIVE: This study aimed to compare the activity of the UT, LT, and serratus anterior (SA) during Y-raise exercise with and without isometric adduction (IAD) using Thera-Band. METHODS: 21 healthy males voluntarily participated in the study. The participants were asked to perform Y-raise exercise with and without IAD using Thera-Band. Surface electromyography was used to measure the muscle activity of UT, LT, and SA during Y-raise exercise with and without IAD. Paired t-test was used to analyze the significance of the muscle activity of UT, LT, and SA as well as the activity ratio of LT/UT and LT/SA. The significance level was set at α= 0.05. RESULTS: Compared with Y-raise exercise without IAD, the muscle activity of UT and SA decreased (p= 0.001 and p= 0.003, respectively), whereas that of LT increased (p= 0.038) during Y-raise exercise with IAD. Additionally, the activity ratio of LT/UT and LT/SA was greater during Y-raise exercise with IAD (p= 0.001 and p= 0.001, respectively). CONCLUSION: Y-raise exercise with IAD using Thera-Band is recommended as an efficient exercise to selectively activate the LT and increase the activity ratio of LT/UT and LT/SA.

Voluntary Contraction of the Abdominal Muscles During Shoulder Exercises Increases Scapular Muscle Activation: A Critically Appraised Topic.

The fascial relationship between scapular muscles and abdominal muscles has been documented from previous studies. However, it is not yet clear whether voluntary abdominal contraction has a beneficial effect on scapular muscle activity during shoulder exercises. Do scapulothoracic muscle activation levels increase if shoulder exercises are performed with voluntary abdominal activation? Summary of Key Finding: After the literature review, 4 cross-sectional studies met the inclusion criteria and were included in this critically appraised topic. There is moderate evidence to support dynamic shoulder exercises with voluntary abdominal contraction can increase trapezius and serratus anterior muscle activation level in asymptomatic shoulders. Strength and Recommendation: Findings from 4 cross-sectional trials indicate that there is moderate evidence supporting that dynamic shoulder exercises performed with voluntary abdominal contraction can increase scapular muscle activity.

The influence of shoulder position during multi-joint exercises in the relative scapular muscles activity in symptomatic and asymptomatic conditions.

Scapular muscles changes, as increased upper trapezius activity and decreased middle and lower trapezius and serratus anterior muscle activity, have been demonstrated in shoulder pain specific or non-specific conditions. Shoulder external rotation exercises have been recommended to improve scapular activity in shoulder pain. To evaluate the relative scapular muscles activity during multi-joint exercises combining shoulder external rotation, trunk rotation and scapular squeeze. Forty-one participants with and without shoulder pain were assessed in a cross-sectional study. They performed isometric multi-joint exercises at 0∘ and 90∘ of shoulder abduction with and without support. The relative activity of upper, middle, and lower trapezius and serratus anterior (upper/middle and lower portions) was measured through electromyography. The scapular muscular balance was assessed by the ratio between relative activity of the upper trapezius and the other muscles. Both groups presented similar results. The exercise at 90∘ abduction led to increased relative muscle activity against maximal voluntary contraction in both groups for upper trapezius (with support: 4% MVIC, p= 0.001 or 15% MVIC, p< 0.0001; and without support: 11% MVIC, p< 0.0001 or 13%, p< 0.0001, for asymptomatic and symptomatic group, respectively) and lower trapezius (with support: 66% MVIC, p< 0.0001 or 62% MVIC, p< 0.0001, for asymptomatic and symptomatic group.

The effect of EMG biofeedback training on muscle activation in an impingement population

Subacromial impingement syndrome (SAIS) is one of the most diagnosed causes of pain in the upper extremity. The purpose of this study was to investigate muscle activity between asymptomatic and SAIS shoulders on the same subject while understanding the effectiveness of EMG biofeedback training (EBFB) on bilateral overhead movements. Ten participants (7 male), that tested positive for 2/3 SAIS clinical tests, volunteered for the study. Bilateral muscle activity was measured via electrodes on the upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), and lumbar paraspinals (LP). Participants performed bilateral scapular plane overhead movements before and after EBFB. EBFB consisted of 10 bilateral repetitions of I, W, T, and Y exercises focused on reducing UT and increasing LT and SA activity. Prior to EBFB, no significant difference in muscle activity was present between sides. A significant main effect of time indicated that after EBFB both sides exhibited reduced UT activity at 60° (p=0.003) and 90° (p=0.036), LT activity was increased at all measured humeral angles (p<0.0005), and SA muscle activity was increased at 110° (p=0.001). EBFB in conjunction with scapular based exercise effectively alters muscle activity of asymptomatic and symptomatic scapular musculature.

Comparison of the Effects of Isometric Horizontal Abduction on Shoulder Muscle Activity During Wall Push-Up Plus and Wall Slide in Individuals With Scapular Winging.

Wall push-up plus (WPP) and wall slide (WS) are commonly prescribed in early rehabilitation to increase serratus anterior (SA) muscle activity. For individuals with scapular winging (SW), synergistic muscles such as upper trapezius (UT) and pectoralis major (PM) may compensate for weak SA during scapular movement. However, no studies have applied isometric horizontal abduction (IHA) during WS in individuals with SW nor have compared it with WPP with IHA. This study compared the effects of IHA on shoulder muscle activity during WPP and WS exercises in individuals with SW. Cross-sectional study; 2-way repeated-measures analysis of variance was used to assess the statistical significance of observed differences in SA, UT, PM, lower trapezius (LT), and infraspinatus (IS) muscle activities. Research laboratory. We recruited 30 individuals with SW comprising 20 men and 10 women. The individuals performed WPP and WS exercises with and without IHA using Thera-Band. Surface electromyography was used to measure muscle activity of the SA, UT, PM, LT, and IS during the isometric phase of WPP and WS. Maximal voluntary isometric contractions were recorded to normalize electromyographic data. There was no significant interaction between IHA application and exercise type for any of the shoulder muscles. IHA application increased SA (P = .008), UT (P = .001), LT (P = .009), and IS (P = .000) activities and decreased PM (P = .001) activity compared with those without IHA. WS exercises elicited higher PM (P = .017) and LT (P = .011) activities than WPP. WPP and WS with IHA may be effective in increasing the muscle activities of shoulder stabilizers and preventing overactivation of PM activity. WPP may be recommended for individuals with overactivated PM, whereas WS may be used to increase LT activity.

Comparison of the EMG Activity of Shoulder Muscles according to Arm Position during Prone Arm Lift Exercise

Background Full-can exercise was associated with a significantly higher scapulohumeral rhythm than empty-can exercise. These findings suggest that the movements of the scapula and glenohumeral joint are affected by the position of the arm. Purpose We investigated the effect of arm position on the muscle activity of scapular upward rotators during prone arm lift exercise. Study design Cross-sectional study Methods Thirty-two healthy subjects were participated in this study. The muscle activity of the serratus anterior (SA), upper trapezius (UT), lower trapezius (LT), and infraspinatus (IS) were measured using a surface electromyography device. All subjects were asked to perform prone arm lift exercise according to the three arm positions: palm down (PD), neutral (NT), and palm up (PU). One-way repeated analysis of variance was conducted. Results The EMG activities of the UT, LT, and SA were significantly different among three conditions (PU vs. NT vs. PD; <italic>p</italic>&lt;0.05). The muscle activities of the UT and LT were significantly higher in the PD than in the PU (<italic>p</italic>&lt;0.017). The muscle activity of SA was significantly higher in the PU than in the PD (<italic>p</italic>&lt;0.017). However, the activity of the IS muscle was not significantly different among the three conditions (<italic>p</italic>&gt;0.05). Conclusions Prone arm lift exercise for SA strengthening is recommended to be performed in a PU position.

The Effect of Modified Push-up Exercise Using Electromyography Biofeedback on Selection of Scapular Stabilizing Muscles

Background: The serratus anterior (SA) muscle is an important scapular stabilizer and has a profound role in retaining the scapulohumeral rhythm. Therefore, modified push-up plus (MPUP) has been advised to strengthen this muscle as a closed chain workout. However, few previous studies have reported the possibility of a reparative motion from pectoralis major (PM) that could replace and amend SA's function during push-up plus. Objectives: The current study examined MPUP's effect using biofeedback EMG on some of the selected scapular stabilizers. Methods: Sixteen healthy young subjects voluntarily participated in this study. Each subject performed push-ups, from the quadruped position, under two conditions (i.e., with or without visual and auditory biofeedback). Surface EMG measured pectoralis major, serratus anterior, and upper trapezius activity. A paired t-test was used to determine any statistically significant difference between the two conditions. Additionally, the effect size was calculated to quantify the magnitude of EMG biofeedback in each muscle. Results: MPUP training using biofeedback significantly increased SA muscle activity and decreased PM muscle activity, but there was no significant change in UT activity. Conclusions: Excessive PM activity was repressed because of biofeedback, and the workout was done with the enhancement of SA muscular activity. Thus, including biofeedback while doing MPUPs helps limit PM's supplementary action and enhance SA muscle activity.

Using biofeedback to optimize scapular muscle activation ratios during a seated resisted scaption exercise

Impairments in muscle activation have been linked to increased risk of developing shoulder pathologies such as subacromial impingement syndrome (SIS) and associated rotator cuff injuries. Individuals with SIS have demonstrated increased upper trapezius (UT) muscle activation and reduced serratus anterior (SA) and lower trapezius (LT) muscle activation, which can be collectively represented as ratios (UT/SA and UT/LT). Targeted exercise is an important component of shoulder rehabilitation programs to re-establish optimal muscle activation and ratios. Electromyography (EMG) biofeedback during exercise has been shown to reduce UT activation and favorably alter scapular muscle activation ratios, however, a literature gap exists regarding the efficacy of other types of biofeedback. Therefore, we compared the effects of three types of biofeedback (visual EMG, auditory, verbal cues) on UT/SA and UT/LT ratios during a seated resisted scaption exercise in fifteen subjects without shoulder pain. Baseline muscle activation was recorded and compared to real-time muscle activation during each randomized biofeedback trial. All biofeedback types showed improvements in the UT/SA and UT/LT ratios, with visual EMG demonstrating a significant change in UT/LT ratio (p < 0.05). These results suggest that biofeedback could be utilized as a component of rehabilitation programs to prevent or treat shoulder pain.

Supine scapular punch: An exercise for early phases of shoulder rehabilitation?

BackgroundSerratus anterior strengthening generally appears in shoulder rehabilitation protocols. This study's aim was to measure electromyographic activity of the serratus anterior, upper trapezius, and infraspinatus muscles during the Supine Scapular Punch exercise in healthy volunteers and those with unilateral shoulder pain. MethodsFifty-four participants were included and grouped as without (n = 34, age = 25.8 years) or with unilateral shoulder pain (n = 20, age = 26.3 years, visual analogue scale = 4.15 cm). Electromyographic activity of the serratus anterior, upper trapezius, and infraspinatus muscles was assessed during Supine Scapular Punch (four phases: P1 = press up concentric, P2 = Supine Scapular Punch concentric, P3 = Supine Scapular Punch eccentric, P4 = press up eccentric) performed under two conditions, with and without additional load. FindingsOverall muscle activity during P1 and P4 was negligible (< 10% maximal voluntary isometric contractions). During P2 and P3, no statistically significant differences in serratus anterior and upper trapezius muscle activity were found between groups, with moderate to high serratus anterior activity (28.94% to 44.3%) and very low upper trapezius activity (< 6%). Upper trapezius/serratus anterior activity ratios ranged from 0.09 to 0.18. Overall infraspinatus muscle activity was always very low (< 10%). InterpretationThe Supine Scapular Punch induces moderate to high serratus anterior muscle activity with very low upper trapezius and infraspinatus activation. Based on these results, the Supine Scapular Punch is a safe exercise that can be used in the early phases of shoulder rehabilitation.

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

Background The muscle activation of the serratus anterior (SA) is important for the performance of glenohumeral joint during functional activities. However, little research in comparison of SA muscle activation during self-resisted scapular protraction exercises in forward flexion of shoulder has been reported. Purpose The purpose of this study was to compare muscle activity of SA during three different scapular protraction exercises according to various conditions [Forward flexion with protraction (FFP), FFP with self-resistance (FFPS), FFPS with hand-exerciser (FFPSH)] in healthy individuals in sitting position. Study design Comparative, repeated measures design Methods Twenty subjects were participated. The muscle activity of SA, upper trapezius (UT) and pectoralis major (PM) were measured by using a surface electromyography device. Each subject was asked to perform three different scapular protraction exercises (FFP vs. FFPS vs. FFPSH) in random order. One-way repeated measures analysis of the variance and a Bonferroni post hoc test were used. The level of statistical significance was set at α=0.01. Results The muscle activity of SA and the SA/UT ratio were significantly different among three conditions (FFP vs. FFPS vs. FFPSH) (<italic>p</italic>&lt;0.01). The muscle activity of SA and the SA/UT ratio during FFPSH were significantly greater compared to those with FFP and FFPS (<italic>p</italic>&lt;0.01). However, the SA/PM ratio was not significantly different among three conditions (<italic>p</italic>&gt;0.05). Conclusions FFPSH exercise for facilitation of SA muscle can be recommended.

Evidence for increased neuromuscular drive following spinal manipulation in individuals with subacromial pain syndrome

BackgroundThoracic spinal manipulation can improve pain and function in individuals with shoulder pain; however, the mechanisms underlying these benefits remain unclear. Here, we evaluated the effects of thoracic spinal manipulation on muscle activity, as alteration in muscle activity is a key impairment for those with shoulder pain. We also evaluated the relationship between changes in muscle activity and clinical outcomes, to characterize the meaningful context of a change in neuromuscular drive. MethodsParticipants with shoulder pain related to subacromial pain syndrome (n = 28) received thoracic manipulation of low amplitude high velocity thrusts to the lower, middle and upper thoracic spine. Electromyographic muscle activity (trapezius-upper, middle, lower; serratus anterior; deltoid; infraspinatus) and shoulder pain (11-point scale) was collected pre and post-manipulation during arm elevation, and normalized to a reference contraction. Clinical benefits were assessed using the Pennsylvania Shoulder Score (Penn) at baseline and 2–3 days post-intervention. FindingsA significant increase in muscle activity was observed during arm ascent (p = 0.002). Using backward stepwise regression analysis, a specific increase in the serratus anterior muscle activity during arm elevation explained improved Penn scores following post-manipulation (p < 0.05). InterpretationThoracic spinal manipulation immediately increases neuromuscular drive. In addition, increased serratus anterior muscle activity, a key muscle for scapular motion, is associated with short-term improvements in shoulder clinical outcomes.

The effect of short-term strength intervention on muscle activity of shoulder girdle during simulated crawl in elite swimmers

Background: Specific strength intervention can influence muscle activity during swimming performance and can increase pain. Objective: The aim of this study was to assess the effect of strength intervention on muscle activity and pain during simulated crawl in elite swimmers. Methods: Fifteen elite Czech swimmers (4 females, 11 males) within the age of 22.8 &plusmn; 3.4 years participated in this study. At the baseline, muscle activity and pain evaluation was performed. For the shoulder joint pain assessment, the visual numeric scale (VNS) and the Swimmer's Functional Pain Scale (SFPS) questionnaires were used. Participants underwent surface electromyography (SEMG) examination of 8 evaluated muscles (trunk and upper arm) during simulated a 100 metres crawl race on swimming ergometer (VASA SwimErg, Essex Junction, Vermont, USA). After a 30 minutes long strength intervention, 100 metres crawl SEMG, VNS and SFPS were evaluated again. The smallest important change in muscle activation was set to 10%. Results: The effect of strength intervention on muscle activity was not significant in all muscles, however effect size evaluation showed small effect of intervention in biceps brachii (p = .311, d = 0.33), upper part of trapezius (p = .033, d = 0.46) and serratus anterior (p = .103, d = 0.22) and medium effect in lower part of trapezius (p = .053, d = 0.62). Magnitude-based decision analysis showed a highly increased muscle activity in biceps brachii. Also in serratus anterior muscle activity increased as well. Difference in shoulder joint pain before and after intervention of the dominant upper limb according to the SFPS questionnaire and VNS was not statistically significant. Conclusion: A 30 minutes long strength intervention had a significant effect on the muscle activity of the upper part of m. trapezius. There was no significant effect of the intervention on pain.

Does the Activity in Scapular Muscles During Plyometric Exercises Change When the Kinetic Chain Is Challenged?-An EMG Study.

Werin, MB, Maenhout, AG, Icket, J, Jacxsens, N, Kempkes, E, and Cools, AM. Does the activity in scapular muscles during plyometric exercises change when the kinetic chain is challenged?-An EMG study. J Strength Cond Res 36(7): 1793-1800, 2022-Plyometric exercises for the shoulder are used in rehabilitation and in workout regime when the sport demands high speed power training. The aim of this clinical laboratory electromyography (EMG) study was to determine whether scapular muscle performance differs during plyometric shoulder exercises when changing the demand on the kinetic chain. Thirty healthy overhead athletes, with a mean age of 22.7 years (±2.2), performed 6 exercises, with both a low and a high demand on the kinetic chain, in prone, side and standing in positions. The EMG activity of the upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) on the tested side and bilateral of gluteus maximus (GM) and abdominal oblique externus (OE) was registered with wireless surface EMG. Intermuscular muscle ratios UT/SA, UT/MT, and UT/LT were also calculated. The level of significance set for the study was alpha = 0.05. The muscle ratio UT/SA was significantly lower (p < 0.05) when high demand on the kinetic chain compared with low. SA muscle activity showed significantly (<0.001) higher values in the prone position with high demand on the kinetic chain compared with low. All 3 trapezius muscle parts had significantly higher values (p < 0.001) in the prone compared with side and standing positions. The GM and OE showed significantly higher (p ≤ 0.01) activity in positions more demanding for the kinetic chain. When composing a strengthening or a rehabilitation program for athletes, the knowledge of how scapular and trunk muscles interact can be used to amplify the strengthening effect.

Analysis of Scapular Muscle EMG Activity During Elastic Resistance Oscillation Exercises From the Perspective of Different Arm Positions.

Little is known about the optimal exercise intensity and the effects of arm position on elastic resistance exercise. The purpose of this study was to investigate scapular muscle activity in different arm positions utilized during standing elastic resistance exercise. Lower trapezius (LT), serratus anterior (SA), and infraspinatus (IS) muscle activity will vary across arm positions above shoulder level. Also, oscillation resistance exercise will result in increased muscle activity compared with isometric contraction. Controlled laboratory study. Level 4. A total of 19 uninjured male collegiate baseball players volunteered to participate in this study. The electromyography (EMG) activity of the LT, upper trapezius (UT), middle deltoid (MD), SA, and IS muscles was determined using surface EMG in 3 arm positions: diagonal pattern 1 (D1), 120° of shoulder abduction (120), and 90° shoulder abduction with external rotation and elbow flexion (90/90) during both isometric contraction and oscillation resistance exercise. No difference in EMG activity of the LT muscle was found between the 120 and 90/90 position. However, the 120 position increased UT and MD muscle activity significantly more than those of the 90/90 position. The D1 arm position significantly increased SA muscle activity more than the 120 and 90/90 positions while the LT muscle activity was nearly silent. The standing 90/90 position effectively generated both LT and IS muscle EMG activity while minimizing both UT and MD muscle activity. The use of oscillation movements under elastic loading can create high muscle activation in the LT muscle without an adverse effect of the humeral head position and scapular rotation.

Effects of Active Vibration Exercise Using a Flexi-Bar on the Activity of Scapular Stabilizing Muscles: A Randomized Controlled Trial

Background: It has been argued that changes in muscle activity in the upper trapezius and serratus anterior may or may not cause shoulder joint pain and dysfunction. Objective: To investigate the effects of active vibration exercise on muscle activity regarding scapular stabilization using a flexi-bar. Design: A randomized controlled trial. Methods: A total of 24 subjects were randomly assigned to a flexi-bar group with active vibration and general stick group with non-active vibration. Both groups performed the same four action programs for 6 weeks, three times a week for 30 minutes at a time. The upper trapezius muscle, middle trapezius muscle, lower trapezius muscle and serratus anterior muscle of the dominant side was measured by electromyography before and after the 6 weeks of exercise. The independent t-test and paired t-test were used to analyze data. Results: There was a significant difference between groups in upper trapezius muscle and serratus anterior muscle activity after exercise (P<.05). Also, there was a significant difference in upper trapezius muscle and serratus anterior muscle activity before and after exercise in the flexi-bar group (P<.05). Conclusion: This study demonstrates that active vibration exercise using a flexi-Bar contribute to reduce the activity of the upper trapezius muscle and promote the activity of the serratus anterior muscle.

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

Comparative Analysis of the Serratus Anterior Muscle Activity When Right and Left Knee Lift during Quadruped Position on Push Up Plus

Purpose: This study examined the effects of the right or left knee lift during push up plus in the quadruped position on the serratus an terior (SA) muscle activity. Methods: Twenty-one subjects (male 11, female 10) performed the quadruped position on push up plus. The muscle activities of the lower trapezius (LT), SA, and upper trapezius (UT) were measured by surface electromyography. Repeated measurements of one-way ANOVA were performed for statistical analysis of the data, and the criterion for statistical significance was set to p<0.05 and compara tive analysis of the UT and SA ratio using a Paired t-test. Results: The right SA increased the muscle activity of the right knee lift during quadruped position push up plus (p<0.05). In particular, the right SA muscle activity was higher than the left. In addition, comparative analysis of the UT and SA ratio to the right knee lift during quadruped position push up plus was performed (p<0.05). The right was found to be a significant statistic compared to the left, but the left SA increased the muscle activity of the left knee lift during quadruped position push up plus (p<0.05). The left SA muscle activity was higher than right. In addition, comparative analysis of UT and SA ratio to the left knee lift during quadruped position push up plus was performed (p<0.05). The left was found to be a significance statistic than the right. In addition, the interaction effect between the groups showed significant differences (p<0.05). Conclusion: Knee lift during push up plus is recommended for the selective activation of a research exercise protocol of one side of the serratus anterior.

EFFECTS OF LOWER EXTREMITY AND TRUNK KINETIC CHAIN RECRUITMENT ON SERRATUS ANTERIOR MUSCLE ACTIVATION DURING FORWARD PUNCH PLUS EXERCISE ON STABLE AND UNSTABLE SURFACES

The stabilizing action of the serratus anterior (SA) muscle is vital in maintaining normal scapulothoracic rhythm. This warrants investigation of exercises to discern which are best to activate the SA muscle. Recruitment of the muscles in the trunk and lower extremity kinetic chain during exercises has demonstrated increased SA activation due to the myofascial connections between various segments of the body. Variation of surfaces during an exercise has also been shown to alter the muscle recruitment patterns. The primary purpose was to determine the effects of trunk and lower extremity kinetic chain muscle recruitment on the SA muscle activity while on an unstable surface. The secondary purpose was to determine if the SA muscle activity would change when the surface stability during the exercises was reduced. Descriptive, within-subject repeated measures. Surface electromyographic activity of the SA, latissimus dorsi (LD), external oblique (EO) on the dominant, and femoral adductor (FA) muscles on the non-dominant side and gluteus maximus bilaterally was analyzed during forward punch plus (FPP) and two of its' variations: FPP with closed chain serape (CS), FPP with open chain serape (OS) on stable and unstable surface in twenty-one healthy males. A two-way repeated measure ANOVA was used to determine the difference in the muscle activation between exercises, surfaces, and interaction between these two variables. A separate one-way repeated measures ANOVA with Sidak post hoc test was used for comparisons between stable and unstable surfaces. (p≤0.05). Muscle activity was statistically significantly higher for the CS and the OS exercises compared to the FPP for all the muscles except for the LD within the same surface. There was no significant difference in muscle activity for any of the muscles when compared between stable and unstable surfaces. Incorporating the trunk and lower extremity kinetic chain during the FPP exercise increased the SA activation on both stable and unstable surfaces. However, the type of surface did not influence the activation of any muscle across exercises. The results of this study further strengthen the benefit of the kinetic chain exercises but also caution that adding an unstable surface to an exercise does not always imply higher muscle activation. 2b.

Comparative study of the differences in shoulder muscle activation according to arm rotation angle

BackgroundScapular muscle exercise is important for patients with shoulder disorders. Distal variance leads to changes in shoulder muscle activation. Here, we aimed to determine whether scapular muscle activation is affected by different arm rotation angles. MethodsOverall, 30 healthy men participated in this study. The subjects were asked to keep their arms at 120 degrees of shoulder flexion while holding a 1.0-kg dumbbell in palms down (pronation) and palms up (supination) positions. Electromyography was used to measure anterior, middle, posterior deltoid, serratus anterior, upper, and lower trapezius muscle activation during the task. The muscle activations of each shoulder were compared between the pronation and supination positions. ResultsAnterior deltoid and serratus anterior activations were significantly higher in supination than in pronation (p < .05). Alternatively, posterior deltoid and lower trapezius muscles were significantly more activated in pronation than in supination (p < .05). ConclusionScapular muscle activation changed with arm rotation angle. Arm rotation angle should be assessed to estimate scapular muscle activation during exercise and motion analysis in clinical practice.