Reliability and Reproducibility of Chest Wall Expansion Measurement in Young Healthy Adults.

OBJECTIVE: The purposes of this study were to (1) evaluate the reliability and reproducibility of chest expansion (CE) measurement on 2 different levels and (2) observe relationships between upper and lower CE measurements and lung function.

METHODS: Fifty-three healthy subjects aged between 18 and 39 years were recruited. Chest expansion measurements were taken with a cloth tape measure at 2 levels of the rib cage (upper and lower). Reproducibility of the measurement was measured for 2 physiotherapists and on 2 different days. Lung function (ie, forced expiratory volume in 1 second [FEV1], forced vital capacity (FVC), vital capacity and, inspiratory capacity) was measured for all subjects by a spirometer (MEC Pocket-spiro USB100, Medical Electronic Construction, Brussels, Belgium).

RESULTS: Upper CE was less than lower CE (5.4 cm and 6.4 cm, respectively; P < .001). Intrarater and interrater reliability were good for upper and lower CE. Reproducibility between physiotherapists was verified for both CE measurements. Reproducibility between days was only verified for upper CE. Sex influenced lower CE. Upper and lower CE values were correlated (r = 0.747; P < .01). Lower and upper CE were significantly and positively correlated with all lung function parameters and inspiratory muscle strength (moderately and weakly, respectively) except to inspiratory capacity for upper CE (P = .051) and for FEV1/FVC for both CE measurements.

CONCLUSION: Upper and lower CE measurements showed good intra- and interrater reliability and reproducibility in healthy subjects. Although both measurements were correlated with lung functions (ie, FEV1, FVC, and vital capacity), the findings of this study showed that upper CE measurements may be more useful in clinical practice to evaluate chest mobility and to give indirect information on lung volume function and inspiratory muscle strength.