EFFECTS OF BODY POSITIONS, WATER IMMERSION, AND SWIMMING TRAINING ON HUMAN LUNG MECHANICS / 体力科学

ABSTRACT

Maximum expiratory and inspiratory flow-volume curves (MEFV, MIFV) along with vital capacity (VC), expiratory reserve volume (ERV), and residual volume (RV) were determined on 7 swimmers and 7 physical education students (control group) in three positions (standing, supine and prone) both in air and during head out water immertion, in order to analyze the effects of body positions, immersion and swimming training on their lung mechanics.<BR>Total lung capacity in standing position decreased in water as a result of decrease in both VC and RV. The ERV in standing position significantly fell in water, while IRV increased. Lung volumes both in supine and prone position did not change significantly in water except an increase in ERV in supine position. The fact that lung volumes decreased more in the standing position in water than horizontal positions probably means that the thorax and abdomen in standing position is more sensitively influenced by the hydrostatic pressure compared with horizontal positions. Lung volumes of the swimmer tended to be larger than that of the control group, while the influence of immersion on lung volumes was similar for the both groups.<BR>Peak flow rate (Vp) was smaller during inspiration than during expiration. Vp decreased more eminently during inspiration in water, while it tended to decrease in water during both expiration and inspiration. When body position turned from standing to supine or prone, Vp tended to decrease, and influence of postural change on Vp was more marked during inspiration than during expiration. By contrast, V<SUB>50</SUB>, V<SUB>25</SUB> and VV were notably larger during inspiration than during expiration. These indexes tended to decrease in water during both expiration and inspiration.<BR>The difference in dynamic lung mechanics between the swimmer and the control group appeared more apparently during inspiration than during expiration, and the swimmer showed significantly higher Vp, V<SUB>50</SUB>, V<SUB>25</SUB>, and VV in inspiration than the control group probably due to the effect of their swimming training.