Objective：This study investigated the relationship between posture and voluntary cough strength in healthy people.

Methods：The participants were 50 normal adults. We measured cough peak flow (CPF), chest circumferences at maximal inspiratory level and maximal expiratory level, blood pressure, and pulse rate in the supine position, prone position, and prone position with a pillow under the abdomen. The difference between chest circumferences at maximal inspiratory and maximal expiratory levels was calculated and defined as the thoracic expansion difference.

Results：CPF and chest circumferences at maximal inspiratory level and maximal expiratory level were significantly higher in the prone position with a pillow under the abdomen than in the supine position. There were no differences in thoracic expansion difference and blood pressure among all the positions. Pulse rate was significantly lower in the supine position compared with the other positions.

Conclusion：We concluded that voluntary cough strength would increase in the prone position with a pillow under the abdomen.