ObjectiveTo investigate the relationship of diaphragmatic mobility (ΔM) evaluated by ultrasonography with quality of life and athletic ability in patients with chronic obstructive pulmonary disease (COPD) , and analyze the factors those affect the diaphragmatic mobility.MethodsA total of 48 male patients with stable COPD were recruited in the study. The body height, body weight, diaphragmatic mobility, airflow obstruction (FEV1%pred), and exercise capacity (6MWD) were measured. The quality of life was assessed using the St. George’s Respiratory Questionnaire (SGRQ).ResultsThe minimum value of ΔM was 1.89 cm and the maximal value was 8.11 cm in the COPD patients. There were significant correlationship between ΔM and the SGRQ score of the total score, symptom score, impact points, activity points and 6MWD, with correlation coefficients of –0.474, –0.416, –0.432, –0.502 and 0.536, respectively. Multivariate stepwise regression analysis showed that the factors influencing ΔM were height (β=0.407, P=0.021) and FEV1%pred (β=–0.391, P=0.035).ConclusionsDiaphragmatic mobility and quality of life are closely related in COPD patients. The height and FEV1%pred have the greatest effect on diaphragmatic activity. The smaller diaphragm mobility is relevant to the worse quality of life and the smaller activity capacity.