However, the presence
of hyperinflation and paradoxical abdominal movement
were indeed related to relief of dyspnea in the
forward leaning position .
Forward leaning is associated
with a significant reduction in EMG activity of the
scalenes and sternomastoid muscles, an increase in transdiaphragmatic
pressure and a significant improvement in thoracoabdominal movements.
From these open studies, it was concluded that the subjective
improvement of dyspnea in patients with COPD
was the result of the more favorable position of the diaphragm
on its length-tension curve.
In addition, forward leaning with arm support allows accessory muscles (Pectoralis
minor and major) to significantly contribute to rib
cage elevation.
In summary, the forward leaning position has been
shown to improve diaphragmatic function and, hence,
improve chest wall movement and decrease accessory
muscle recruitment and dyspnea.
In addition, accessory muscles contribute to inspiration by allowing arm or head
support in this position