Abdominal muscle activity during breathing with and without inspiratory and expiratory loads in healthy subjects

• Published in: Journal of electromyography and kinesiology Vol. 30; pp. 143 - 150
• Main Authors: Mesquita Montes, António, Baptista, João, Crasto, Carlos, de Melo, Cristina Argel, Santos, Rita, Vilas-Boas, João Paulo
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2016
• Subjects: Abdominal Muscles - physiology; Abdominal Oblique Muscles - physiology; Adolescent; Anthropometry - methods; Core abdominal; Electromyography - methods; Exhalation - physiology; Female; Healthy Volunteers; Humans; Inhalation - physiology; Male; Physical Medicine and Rehabilitation; Postural control; Posture - physiology; Pressure; Rectus Abdominis - physiology; Respiration; Respiratory loads; Surface electromyographic activity; Young Adult; Surface electromyographic activity; Core abdominal; Respiration; Respiratory loads; Postural control
• ISSN: 1050-6411; 1873-5711
• DOI: 10.1016/j.jelekin.2016.07.002

Central Nervous System modulates the motor activities of all trunk muscles to concurrently regulate the intra-abdominal and intra-thoracic pressures. The study aims to evaluate the effect of inspiratory and expiratory loads on abdominal muscle activity during breathing in healthy subjects. Twenty-three higher education students (21.09±1.56years; 8males) breathed at a same rhythm (inspiration: two seconds; expiration: four seconds) without load and with 10% of the maximal inspiratory or expiratory pressures, in standing. Surface electromyography was performed to assess the activation intensity of rectus abdominis, external oblique and transversus abdominis/internal oblique muscles, during inspiration and expiration. During inspiration, transversus abdominis/internal oblique activation intensity was significantly lower with inspiratory load when compared to without load (p=0.009) and expiratory load (p=0.002). During expiration, the activation intensity of all abdominal muscles was significantly higher with expiratory load when compared to without load (p<0.05). The activation intensity of external oblique (p=0.036) and transversus abdominis/internal oblique (p=0.022) was significantly higher with inspiratory load when compared to without load. Transversus abdominis/internal oblique activation intensity was significantly higher with expiratory load when compared to inspiratory load (p<0.001). Transversus abdominis/internal oblique seems to be the most relevant muscle to modulate the intra-abdominal pressure for the breathing mechanics.