Electromyographic Pattern of Respiratory Muscles in Young People during Incremental Exercise

Abstract

Open Access Research ArticleVentilation occurs through the coordinated contraction of specific muscle groups, which in inspiration produces enough energy to distend the pulmonary structures [3,5]. In the healthy individual the ventilatory requirements during exercise, are easily achieved because the breathing muscles are anatomically suited for increasing ventilatory requirements and neural regulation of respiration is ideal [6].It should be emphasized that the accessory respiratory muscles are progressively recruited with the increased ventilatory demand. Thus, sharing the load required to bear hyperpnea, shallow and rapid breathing that occurs during exercise [6,7].Among the respiratory muscles recruited during exercise, the external intercostal sternum sternums are considered important because of their important postural and respiratory role in stabilizing and maintaining the shape and integrity of the rib cage when the ribs elevate and expand the chest during inspiration. The sternocleidomastoid is also considered by some authors the most important accessory muscle of inspiration along with the upper trapezius whose ventilatory role is to assist in the inspiration on effort helping to raise the rib cage [8].Understanding the physiological changes of the respiratory muscles before physical effort is a largely explored subject in exercise physiology. The proper functioning of these muscles results in an improvement of the performance of elite athletes, besides its great importance for chronic lung diseases, Parkinson's, and cardiovascular disorders whose clinical changes result in weakness of these muscles [9]. AbstractDuring exercise, the muscles involved inbreathing is progressively recruited due to increased demand in respiratory effort. Surface electromyography (sEMG) is a technique that allows evaluation of these muscles providing information on the recruitment of motor units. The aim of this study was describe the electrical activity of the upper trapezius, sternocleidomastoid and intercostal sternum muscles in active and sedentary young subjects during incremental exercise test. Cross-sectional research design, including 20 young adults of both genders, aged 18to 36 years participated of study. The EMG signal amplitudes were analyzed in the time domain from muscular activity of the upper trapezius, sternocleidomastoid and intercostal sternum muscles, in relation to the variation of the load imposed on the incremental exercise. A mixed linear adjustments model was used to study the effects of the load, groups (active and sedentary) and the interaction (load x group) .The results there was no significant difference between-groups and interaction effects (group x load). Significant increase in the EMG signal amplitude was however found during the increase of the load for the three muscles studied. There was an increase in the amplitude of the electromyographic signal of accessories respiratory muscles in relation to the load increase during incremental exercise test.