ORIGINAL PAPER A Controlled Trial of the Effects of Leg Training on Breathing Pattern and Dynamic Hyperinflation in Severe COPD Luis Puente-Maestu ® Yolanda Martinez Abad ® Fernando Pedraza ® Gemma Sa ´nchez ® William W. Stringer Accepted: 26 October 2005 Ó Springer Science+Business Media, Inc. 2006 Abstract The effects of training on dynamic hyperinfla- tion in stable chronic obstructive pulmonary disease (COPD) were investigated by using a controlled study of 28 subjects with FEV 1 = 42.5 (8.3 SD)%pred and 20 matched controls [FEV 1 = 44.9 (10.4)%pred]. Training consisted of spending 45 min/day, 4 days/week on a cycle- ergometer for six weeks. Maximal inspiratory and expira- tory pressures (MIP and MEP), lung volumes, and two constant-work-rate (CWR) exercise tests (low- and high-intensity) were performed. Significant (p < 0.0l) improvements in the training group were observed in MIP [+8 (12) cmH 2 O], MEP [+18 (20) cmH 2 O], and endurance to high-intensity CWR [+7(5) min], and there were sig- nificant decreases in respiratory rate and end-expiratory lung volume (EELV) during both exercise tests. At 5 min, EELV decreased 0.1(0.08) L and 0.31(0.13) L and at end of exercise, EELV decreased by 0.09(0.07) L and 0.15(0.11) L respectively, for the moderate- and high-intensity tests. Dyspnea also decreased significantly at both exercise intensities. No changes were observed in the control group. Increased endurance showed independent significant (p < 0.05) correlation with changes in EELV, leg fatigue, and MEP. EELV changes showed a significant negative cor- relation with resting inspiratory capacity. We conclude that exercise training has beneficial effects on respiratory pat- tern and dynamic hyperinflation that may partially explain the reduction in dyspnea and the improvement in exercise tolerance. Keywords Rehabilitation ® Breathing pattern ® COPD ® Dynamic hyperinflation ® Respiratory musclesc Introduction Rehabilitation for subjects with chronic obstructive pul- monary disease (COPD) is a well established and widely accepted method of enhancing standard therapy in order to alleviate symptoms and optimize function. Exercise pro- grams involving the muscles of ambulation are a part of virtually every program of pulmonary rehabilitation. A large body of literature supports their effectiveness [3, 33]. It is well recognized that the benefits of rehabilitative exercise programs for the lower limbs are multifactorial, consisting of structural and biochemical changes in exer- cising muscles that improve their capacity to tolerate work, a more efficient and coordinated use of the muscles in- volved, and psychological benefits, among which are the loss of fear and the ‘‘desensitization to dyspnea’’ [14]. In previous studies of leg training in COPD it has been found that high-intensity training, either on treadmill [28] or on a cycle-ergometer [4, 30, 35], induced a deeper and slower respiratory pattern during exercise. These changes were apparent only after high-intensity training and not with training of less intensity [28], and they faded out long term when other physiologic effects of training diminished [31]. Therefore, these changes in respiratory pattern suggest a L. Puente-Maestu ® Y. Martinez Abad ® F. Pedraza ® G. Sa ´nchez Hospital General Universitario Gregorio Maran ˜o ´n, Servicio de Neumologia, Madrid, Spain W. W. Stringer Los Angeles BioMedical Research Institute at Harbor-UCLA Medical Center, 1000 West Carson Street, Bin 400, Torrance, CA 90509, USA L. Puente-Maestu (&) Hospital General Universitario Gregorio Maran ˜o ´n, Servicio de Neumologia, c/ Doctor Ezquerdo 46, 28007 Madrid, Spain E-mail: lpuente@separ.es or lpuente.hgugm@madrid.salud.org Lung (2006) 184:159–167 DOI 10.1007/s00408-005-2576-x 123