The specific aims of the study are:~difference of respiratory muscle performance between three groups~the correlation between respiratory symptom and pulmonary functional test~difference of functional respiratory performance (peak cough flow of voluntary cough) between three groups~muscle activation of abdominal muscle and diaphragm during performing voluntary force~performance of diaphragm under different breathing load
The study will recruit subject of healthy adult, COPD-like patient and patient with COPD to investigate the difference of respiratory performance. We will measure the body composition, respiratory muscle force, pulmonary function and performance of voluntary cough. The muscle thickness of abdominal muscle and diaphragm, assessment of diaphragm during different breathing pattern and the muscle activation during voluntary cough will also being determined. We hypothesized that there will be a significantly different between three group on the performance of voluntary cough, and the correlation between each variable will be further investigated.