Previous studies have shown that thixotropy conditioning of inspiratory muscles consisting of maximal inspiratory effort performed at an inflated lung volume is followed by an increase in end-expiratory position of the rib cage in normal human subjects. When performed at a deflated lung volume, conditioning is followed by a reduction in end-expiratory position. The present study was performed to determine whether changes in end-expiratory chest wall and lung volumes occur after thixotropy conditioning. We first examined the acute effects of conditioning on chest wall volume during subsequent 5-breath cycles using respiratory inductive plethysmography (n=8). End-expiratory chest wall volume increased after conditioning at an inflated lung volume (P<0.05), which was attained mainly by rib cage movements. Conditioning at a deflated lung volume was followed by reductions in end-expiratory chest wall volume, which was explained by rib cage and abdominal volume changes (P<0.05). End-expiratory esophageal pressure decreased and increased after conditioning at inflated and deflated lung volumes, respectively (n=3). These changes in end-expiratory volumes and esophageal pressure were greatest for the first breath after conditioning. We also found that an increase in spirometrically determined inspiratory capacity (n=13) was maintained for 3 min after conditioning at a deflated lung volume, and a decrease for 1 min after conditioning at a inflated lung volume. Helium-dilution end-expiratory lung volume increased and decreased after conditioning at inflated and deflated lung volumes, respectively (both P<0.05, n=11). These results suggest that thixotropy conditioning changes end-expiratory volume of the chest wall and lung in normal human subjects.