Analysis of co-contraction of the trunk muscles in the side bridge stabilization exercise w ith different unstable surfaces / Análise da cocontração dos músculos do tronco no exercício de estabilização prancha lateral com diferentes superfícies instáveis

The muscle co-contraction is a phenomenon characterized by the simultaneous contraction of two or more muscles around a joint. The objective of this study was to compare the antagonist co-contraction of the local and global trunk muscles during side bridge exercise, in four situations: (a) stable; (b) instability in the upper limbs with bosu; (c) instability in the upper limbs with disc and (d) double instability. The sample consisted of 20 male volunteers and data collection was performed with simple differential surface electrodes. The electromyographic activity was collected from the Rectus Abdominis (RA), Internal Oblique Abdominis (IO), Multifidus (MF) and Erector Spinae (ES). Were utilized specific routines developed in the Matlab program (Mathworks Natick, USA) to calculate the percentage of antagonist co-contraction between local (IO/MF) and global muscles (RA/ES). The collected data were submitted to parametric statistical analysis (repeated measures ANOVA) or non-parametric (Friedman). The results demonstrated that no significant differences were observed in the pattern of global and local co-contraction in the different side bridge exercises with and without unstable surface. It is concluded that the use of unstable surface in the side bridge stabilization exercise does not increase the level of co-contraction of the trunk flexor and extensor muscles compared to normal stability. However, future studies should use a longer time ofisometric contraction in trunk stabilization exercises to optimize the understanding of the effects of different unstable equipment on global and local levels of co-contraction of the trunk muscles

A cocontração muscular é um fenômeno caracterizado pela contração simultânea de dois ou mais músculos em torno de uma articulação. Objetivou-se comparar a cocontração antagonista da musculatura local e global do tronco durante o exercício prancha lateral, em quatro situações: (a) estável; (b) instabilidade no membro superior com bosu; (c) instabilidade no membro superior com disco e (d) instabilidade dupla. A amostra foi composta por 20 voluntários do gênero masculino e a coleta de dados foi realizada com eletrodos de superfície diferenciais simples. A atividade eletromiográfica foi coletada dos músculos Reto do Abdome (RA), Oblíquo Interno do Abdome (OI), Multifido (MU) e Eretor da Espinha (EE). Foram utilizadasrotinas específicas desenvolvidas no programa Matlab (Mathworks Natick, EUA) para calcular a porcentagem de cocontração antagonista entre os músculos locais (OI / MU) e globais (RA / ES). Os dados obtidos foram submetidos à análise estatística paramétrica (ANOVA medidas repetidas) ou não paramétrica (Friedman). Os resultados demonstraram que não foram observadas diferenças significativas no padrão de cocontração global e local nos distintos exercícios de prancha lateral com e sem superfície instável. Conclui-se que a utilização de superfície instável no exercício de estabilização de prancha lateral não aumenta o nível de cocontração dos músculos flexores e extensores do tronco em comparação a estabilidade normal. Todavia, futuros estudosdevem utilizar um tempo maior de contração isométrica nos exercícios de estabilização do tronco para otimizar a compreensão dos efeitos dos diferentes equipamentos instáveis sobre os níveis de cocontração global e local dos músculos do tronco.

Eletromyography of abdominal muscles in different physical exercises: An update protocol for systematic review and meta-analysis.

BACKGROUND: The abdominal muscles are extremely important because they are directly involved in the functions of support, containment of viscera, and help in the process of expiration, defecation, urination, vomiting, and also at the time of childbirth. Many exercises and equipment are used to strengthen the abdominal muscles, and the workouts are proposed for a variety of purposes, such as preventing and rehabilitating low back pain, improving sports performance, achieving aesthetic standards, among others. Exercises that potentiate the electromyographic activity promote a greater recruitment of muscle fibers and are more effective to improve or maintain of the force. The electromyographic activity analysis allows us to reflect on the quality of the exercises proposed, consequently, to choose and order the exercises properly in a training session. METHODS: Our systematic review protocol will developed following the reporting items for the systematic review. To identify relevant studies, we sought articles on the following bases: MEDLINE, PubMed, Europubmed, SciELO, Physiotherapy Evidences Data Base (PEDro), Cochrane, and Google Scholar. The methodological quality of the studies included in the review will evaluated using a checklist and quality assessment. For intervention studies, risk of bias will estimated using the Cochrane Collaboration tool. RESULTS: The results of this study will show the electromyographic activation of the abdomen in the different types of exercises. CONCLUSION: Ethics approval was not required for this study because it was based on published studies. The results and findings of this study will be submitted and published in a scientific peer-reviewed journal. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42018086172.