Effect of Body Position on Respiratory Muscle Activity in Subjects with Upper Costal or Costo-diaphragmatic Breathing Type

Abstract

Effect of body position on electromyographic (EMG) activity has been studied in the cranio-cervical-mandibular muscles, but its effect on the activity of respiratory muscles in subjects with different breathing types has not yet been elucidated. This study included two groups of twenty male subjects each, one with upper costal and the other with costo-diaphragmatic breathing type. EMG activity was recorded using bipolar surface electrode technique. Electrodes were placed on the sternocleidomastoid (SCM), diaphragm (DIA), and external intercostal (EIC) and Latissimus dorsi (LAT) muscles. EMG activity was recorded in standing and lateral decubitus positions, during the following tasks: (1) Normal quiet breathing; (2) speaking the word "Mississippi"; (3) forced deep breathing. EMG activity of DIA and EIC muscles was higher in the standing than in the lateral decubitus position during all tasks in both breathing groups (p<0.05), excepting DIA activity during task 2 in the costo-diaphragmatic group. EMG activity of LAT muscle was higher in the standing than in the lateral decubitus position during task 3 in both breathing groups (p<0.05). EMG activity of DIA activity was higher in subjects with upper costal than in subjects with costo-diaphragmatic breathing type in the standing position during all tasks and also in the lateral decubitus position during tasks 1 and 2 (p<0.05). EMG activity of ECM, EIC and LAT muscles was not significantly different between both breathing types in the studied body positions. The higher EMG activity observed in the standing than in the lateral decubitus positions in both breathing groups, suggests differences in the respiratory effort depending on the body position. The higher EMG activity observed in DIA muscle of subjects with upper costal than costo-diaphragmatic breathing types, suggests differences in the respiratory effort depending on the breathing type.

Respiratory EMG Activity between Subjects with Costo-diaphragmatic, Upper Costal or Mixed Breathing Type

“…EMG activity of EIC, SCM and LAT muscles recorded in the present study did no show a consistent significant difference among breathing types studied. This is in agreement with the finding observed in previous works between participants with upper costal and costo-diaphragmatic breathing in the standing and right decubitus positions [17][18][19][20][21].…”

“…The absence of SCM activity differences among the breathing types studied could be explained by the predominant effect of vestibular and/or visual afferents than other influences on its pool of motoneurons, due to its role as a postural rather than respiratory muscle [19].…”

“…One calibrated examiner (R.C.) determined the breathing type according to previous works [17][18][19][20][21]. Briefly, the examiner gently placed the right hand on the upper chest and the left hand on the upper back.…”

“…Impedance was decreased by careful skin abrasion with alcohol. Electrodes were placed as follows [17][18][19][20][21]26]: on the DIA muscle, 1 cm below the xiphoid process; on the EIC muscle, between the 6th and 7th ribs on the imaginary vertical line that passes through the nipple; on the SCM muscle (middle portion), in the anterior border; and on the LAT muscle, in the projection of the 12th rib or lumbar vertebra L1 following the thoraco-lumbar fascia edge. The electrodes were located on the right side (except in the DIA muscle), because each participant was arbitrarily asked to lie on his left side.…”

“…Breathing type has been defined depending on the expansion of the abdomino-thoracic region during inspiration at rest, and three types have been described [15,16]: 1) costo-diaphragmatic breathing; 2) upper costal breathing; 3) mixed breathing. diaphragmatic breathing type was compared in the standing position [17][18][19] and in the right lateral decubitus position [19,20]. Higher EMG activity of DIA muscle was observed in subjects with upper costal than costo-diaphragmatic breathing type in both body positions.…”