Submitted on March 21, 2005
Accepted on July 4, 2005
Exercise flow-volume loops in prepubescent aerobically-trained children
Cedric NOURRY1*, Fabien DERUELLE2, Claudine FABRE2, Georges BAQUET2, Frederic BART3, Jean-Marie GROSBOIS3, Serge BERTHOIN2, and Patrick MUCCI4
1 Laboratoire d'Analyse Multidisciplinaire des Pratiques Sportives, Univerte d'Artois, Lievin, France
2 Laboratoire d'Etudes de la Motricite Humaine, Universite de Lille 2, Lille, France
3 Service de pneumologie, Hopital Germon-Gauthier, Beuvry, France
4 Laboratoire d'Analyse Multidisciplinaire des Pratiques Sportives, Univerte d'Artois, Lievin, France; Laboratoire d'Etudes de la Motricite Humaine, Universite de Lille 2, Lille, France
* To whom correspondence should be addressed. E-mail: nourryce{at}wanadoo.fr.
We studied mechanical ventilatory constraints in 13 aerobically-trained (Tr) and 11 untrained (UT) prepubescent children by plotting the exercise flow-volume (FV) loops within the maximal FV loop (MFVL) measured at rest. The MFVL allowed to determine forced vital
capacity (FVC) and maximal expiratory flows. Expiratory and inspiratory reserve volumes relative to FVC (ERV/FVC and IRV/FVC respectively) were measured during a progressive exercise test until exhaustion. Breathing reserve (BR) and expiratory flow limitation (expFL),
expressed in percentage of VT and defined as the part of the tidal breath meeting the boundary of the MFVL, were measured. Higher FVC and maximal expiratory flows were found in Tr than UT (P<0.05) at rest. Our results have shown that during exercise, excepting one subject, all Tr regulated their VT within FVC similarly during exercise, by breathing at low lung
volume at the beginning of exercise followed breathing at high lung volume at strenuous exercise. In UT, ERV/FVC and IRV/FVC were regulated during exercise in many ways. The
proportion of children who presented an expFL was nearly the same in both groups (~70 % with a range of 14 % to 65 % of VT) and no significant difference was found during exercise concerning expFL. However, higher ventilation (VE), ERV/FVC and dyspnea associated with lower BR, IRV/FVC and SaO2 were reported at Ppeak in Tr than UT (P<0.05). Theses results
suggest that, because of their higher VE level, trained children presented higher ventilatory constraints than untrained. These may influence negatively the SaO2 level and dyspnea during strenuous exercise.
