Helga Tatiana Tucci

Electromyographic Amplitude Ratio of Serratus Anterior and Upper Trapezius Muscles During Modified Push-ups and Bench Press Exercises

Imbalance and weakness of the serratus anterior and upper trapezius force couple have been described in patients with shoulder dysfunction. There is interest in identifying exercises that selectively activate these muscles and including it in rehabilitation protocols. This study aims to verify the UT/SA electromyographic (EMG) amplitude ratio, performed in different upper limb exercises and on two bases of support. Twelve healthy men were tested (average age = 22.8 ± 3.1 years), and surface EMG was recorded from the upper trapezius and serratus anterior using single differential surface electrodes. Volunteers performed isometric contractions over a stable base of support and on a Swiss ball during the wall push-up (WP), bench press (BP), and push-up (PU) exercises. All SEMG data are reported as a percentage of root mean square or integral of linear envelope from the maximal value obtained in one of three maximal voluntary contractions for each muscle studied. A linear mixed-effect model was performed to compare UT/SA ratio values. The WP, BP, and PU exercises showed UT/SA ratio mean ± SD values of 0.69 ± 0.72, 0.14 ± 0.12, and 0.39 ± 0.37 for stable surfaces, respectively, whereas for unstable surfaces, the values were 0.73 ± 0.67, 0.43 ± 0.39, and 0.32 ± 0.30. The results demonstrate that UT/SA ratio was influenced by the exercises and by the upper limb base of support. The practical application is to show that BP on a stable surface is the exercise preferred over WP and PU on either surfaces for serratus anterior muscle training in patients with imbalance between the UT/SA force couple or serratus anterior weakness.

Reliability of electromyographic amplitude values of the upper limb muscles during closed kinetic chain exercises with stable and unstable surfaces.

The purpose of the present study was to evaluate the intra and interday reliability of surface electromyographic amplitude values of the scapular girdle muscles and upper limbs during 3 isometric closed kinetic chain exercises, involving upper limbs with the fixed distal segment extremity on stable base of support and on a Swiss ball (relatively unstable). Twenty healthy adults performed the exercises push-up, bench-press and wall-press with different effort levels (80% and 100% maximal load). Subjects performed three maximal voluntary contractions (MVC) in muscular testing position of each muscle to obtain a reference value for root mean square (RMS) normalization. Individuals were instructed to randomly perform three isometric contraction series, in which each exercise lasted 6 s with a 2-min resting-period between series and exercises. Intra and interday reliabilities were calculated through the intraclass correlation coefficient (ICC 2.1), standard error of the measurement (SEM). Results indicated an excellent intraday reliability of electromyographic amplitude values (ICC > or = 0.75). The interday reliability of normalized RMS values ranged between good and excellent (ICC 0.52-0.98). Finally, it is suggested that the reliability of normalized electromyographic amplitude values of the analyzed muscles present better values during exercises on a stable surface. However, load levels used during the exercises do not seem to have any influence on variability levels, possibly because the loads were quite similar.

Activation of selected shoulder muscles during unilateral wall and bench press tasks under submaximal isometric effort.

STUDY DESIGN Controlled laboratory study. OBJECTIVE To assess the activation of 7 shoulder muscles under 2 closed kinetic chain (CKC) tasks for the upper extremity using submaximal isometric effort, thus providing relative quantification of muscular isometric effort for these muscles across the CKC exercises, which may be applied to rehabilitation protocols for individuals with shoulder weakness. BACKGROUND CKC exercises favor joint congruence, reduce shear load, and promote joint dynamic stability. Additionally, knowledge about glenohumeral and periscapular muscle activity elicited during CKC exercises may help clinicians to design protocols for shoulder rehabilitation. METHODS Using surface electromyography, activation level was measured across 7 shoulder muscles in 20 healthy males, during the performance of a submaximal isometric wall press and bench press. Signals were normalized to the maximal voluntary isometric contraction, and, using paired t tests, data were analyzed between the exercises for each muscle. RESULTS Compared to the wall press, the bench press elicited higher activity for most muscles, except for the upper trapezius. Levels of activity were usually low but were above 20% maximal voluntary isometric contraction for the serratus anterior on both tasks, and for the long head triceps brachii on the bench press. CONCLUSIONS Both the bench press and wall press, as performed in this study, led to relatively low EMG activation levels for the muscles measured and may be considered for use in the early phases of rehabilitation.

Avaliação eletromiográfica de músculos da cintura escapular e braço durante a realização de exercícios com extremidade fixa e carga axial

The objective of this study was to compare the electromyography activity of scapular and arm muscles in the wall-press 90°, wall-press 45°, bench-press and push-up exercises, accomplished with the distal extremity of the segment on a stable surface and in maximum isometric effort. Twenty male sedentary (23±7 years), and without trauma history or diseases in the upper extremity volunteers participated in this research. The electric activity of the long head of the muscle biceps brachii, the anterior portion of the deltoid muscle, the clavicular portion of the pectoralis major and the serratus anterior muscle was registered by electromyography surface. The ANOVA and Tukey post hoc were used to determine differences between the RMS values of each muscle and in each exercise, normalized by the maximal voluntary isometric contractions. The results of the present study demonstrated that the biceps brachii muscle presented the smallest electromyographic activity in comparison to the other muscles in all exercises, while the anterior portion of the deltoid and the serratus anterior muscles presented larger electromyography activity in relation to the other muscles in the bench-press and push-up exercises. These findings demonstrate that there was not similarity in the electromyography activity of the evaluated muscles during the exercises; however, there was a muscular coactivation, since the exercises activated all muscles, even if at different levels. The studied exercises are not recommended for activation of the biceps brachii muscle; however, the bench-press and push-up exercises are recommended to activate the anterior portion of deltoid and serratus anterior muscles. Moreover, the wall-press 90° and the wall-press 45° are recommended for activation of the upper trapezius muscle.

Influência da posição do braço na relação EMG-força em músculos do braço

A relacao entre a amplitude do sinal eletromiografico e a forca muscular (EMG-forca) tem sido tomada como medida indireta da forca muscular. Este estudo, em 18 voluntarias saudaveis e destras, visou avaliar a influencia da posicao do braco na relacao EMG-forca em musculos do braco em tres tarefas - flexao do braco (FB), abducao do braco (AB) e neutra do braco (NB) - enquanto se tomavam ambas as medidas: uma celula de carga foi acoplada ao conversor do eletromiografo para registrar simultaneamente forca e sinal eletromiografico. Foram analisados os sinais dos musculos biceps braquial, braquiorradial e triceps braquial, e estimada a forca de flexao e de extensao do braco nas diferentes tarefas. A relacao entre esses conjuntos de valores foi analisada estatisticamente, verificando se havia correlacao entre forca e sinal eletromiografico. Os resultados mostraram nao haver tal correlacao nas tarefas avaliadas. A posicao do braco nao influenciou a relacao EMG-forca dos musculos avaliados, com excecao do triceps braquial, cuja atividade eletromiografica foi maior durante a tarefa NB. Conclui-se que, em isometria, as tarefas podem ser empregadas para ativar o biceps braquial e o braquiorradial; a tarefa NB e a mais indicada para ativar o triceps braquial.

Biomechanical Analysis of Closed Kinetic Chain Upper Extremity Stability Test.

CONTEXT The closed kinetic chain upper-extremity stability (CKCUES) test is a functional test for the upper extremity performed in the push-up position, where individuals support their body weight on 1 hand placed on the ground and swing the opposite hand until touching the hand on the ground, then switch hands and repeat the process as fast as possible for 15 s. OBJECTIVE To study scapular kinematic and kinetic measures during the CKCUES test for 3 different distances between hands. DESIGN Experimental. SETTING Laboratory. PARTICIPANTS 30 healthy individuals (15 male, 15 female). MAIN OUTCOME MEASURES Participants performed 3 repetitions of the test at 3 distance conditions: original (36 in), interacromial, and 150% interacromial distance between hands. Participants completed a questionnaire on pain intensity and perceived exertion before and after the procedures. Scapular internal/external rotation, upward/downward rotation, and posterior/anterior tilting kinematics and kinetic data on maximum force and time to maximum force were measured bilaterally in all participants. Percentage of body weight on upper extremities was calculated. Data analyses were based on the total numbers of hand touches performed for each distance condition, and scapular kinematics and kinetic values were averaged over the 3 trials. Scapular kinematics, maximum force, and time to maximum force were compared for the 3 distance conditions within each gender. Significance level was set at α = .05. RESULTS Scapular internal rotation, posterior tilting, and upward rotation were significantly greater in the dominant side for both genders. Scapular upward rotation was significantly greater in original distance than interacromial distance in swing phase. Time to maximum force in women was significantly greater in the dominant side. CONCLUSION CKCUES test kinematic and kinetic measures were not different among 3 conditions based on distance between hands. However, the test might not be suitable for initial or mild-level rehabilitation due to its challenging requirements.

Can clinical observation differentiate individuals with and without scapular dyskinesis

Background: Altered scapular rotation and position have been named scapular dyskinesis. Visual dynamic assessment could be applied to classify this alteration based on the clinical observation of the winging of the inferior medial scapular border (Type I) or of the prominence of the entire medial border (Type II), or by the excessive superior translation of the scapula (Type III). Objective: The aim of this study was to determine if there were differences in scapular rotations (Type I and II) and position (Type III) between a group of subjects with scapular dyskinesis, diagnosed by the clinical observation of an expert physical therapist, using a group of healthy individuals (Type IV). Method: Twenty-six asymptomatic subjects volunteered for this study. After a fatigue protocol for the periscapular muscles, the dynamic scapular dyskinesis tests were conducted to visually classify each scapula into one of the four categories (Type IV dyskinesis-free). The kinematic variables studied were the differences between the maximum rotational dysfunctions and the minimum value that represented both normal function and a small dysfunctional movement. Results: Only scapular anterior tilt was significantly greater in the type I dyskinesis group (clinical observation of the posterior projection of the inferior angle of the scapula) when compared to the scapular dyskinesis-free group (p=0.037 scapular and p=0.001 sagittal plane). Conclusions: Clinical observation was considered appropriate only in the diagnoses of dyskinesis type I. Considering the lower prevalence and sample sizes for types II and III, further studies are necessary to validate the clinical observation as a tool to diagnose scapular dyskinesis.