The effect of restrictive chest wall loading on pulmonary function and maximal exercise performance

Abstract

The purpose of this study was to develop a constant pressure chest wall restrictive device which simulates the restriction seen in some forms of restrictive pulmonary disease as well as in occupational situations (i.e., bulletproof vests, firefighter's gear). Once the device was developed, five males and five females participated in the establishment of the test-retest reliability of the device; after which ten males and eight females volunteered to participate in examining the effects of the chest wall restrictive device on resting pulmonary function and maximal exercise performance. First, ten subjects wore the restrictive device while performing pulmonary function tests at four added external loads (0, 20, 40, and 60 mmHg) on three separate occasions. A two-way repeated measures multivariate analysis of variance (MANOVA) revealed significant decreases in forced expiratory vital capacity (FVC) and forced expiratory volume in one second (FEV1>0) while the ratio of FEV1>0 to FVC (FEV1 0%) was maintained. No significant differences were found across time. Second, eighteen subjects wore the restrictive device while performing both resting pulmonary tests and maximal bicycle ergometry tests at the same four added external restrictive loads. Resting pulmonary function measurements included FVC, FEV., 0, FEV1 0%, and maximal voluntary ventilation (MW) . Measured variables at maximal exercise included maximal oxygen consumption, maximal minute ventilation, tidal volume at maximal exercise, breathing frequency at maximal exercise, and time-to-maximal exercise. One way repeated measures MANOVA revealed significant decreases in FVC, FEV, 0, and M W with increasing restrictive loads. All maximal exercise values decreased significantly with increasing restrictive loads except breathing frequency, which showed no changes among the four loads. These results indicate that this chest wall restrictive device allows for mobility during exercise, but also provides a quantifiable added inspiratory load in the breathing cycle that results in pulmonary function decrements and decreases in maximal exercise capacity similar to those seen in some restrictive pulmonary disease and occupational situations.