title: Alternative strategies for exercise critical power estimation in patients with COPD.
abstract: Exercise critical power (CP) has been shown to represent the highest sustainable work rate (WR) in patients with chronic obstructive pulmonary disease (COPD). Parameter estimation, however, depends on 4 high-intensity tests performed, on different days, to the limit of tolerance (T(lim)). In order to establish a milder protocol that would be more suitable for disabled patients, we contrasted CP derived from 4, 3 and 2 tests (CP4, CP3 and CP2) in 8 males with moderate COPD. In addition, CP was calculated from 2 single-day tests performed on an inverse sequence (CP(2AB) and CP(2BA)): CP values within 5 W from CP4 were assumed as "clinically-acceptable" estimates. We found that [CP4-CP3] and [CP4-CP2] differences were within 5 W in 8 and 6 patients, respectively (95% confidence interval of the differences = -1.3 to 3.5 W and -11.5 to 6.5 W). There was a systematic decline on T(lim) when an exercise bout was performed after a previous test on the same day (P<0.05). Consequently, substantial differences were found between CP4 and any of the CP estimates obtained from single-day tests. In conclusion, clinically-acceptable estimates of CP can be obtained by using 3 or, in most circumstances, 2 constant WR tests in patients with moderate COPD--provided that they are not performed on the same day.
authors.affiliation: Respiratory Division, Department of Medicine, Federal University of Sao Paulo-Paulista School of Medicine, Rua Professor Francisco de Castro 54, Vila Clementino, CEP, 04020-050, Sao Paulo, Brazil.
authors.forename: Carla
authors.initials: C
authors.lastname: Malaguti
authors.forename: Luiz E
authors.initials: LE
authors.lastname: Nery
authors.forename: Simone
authors.initials: S
authors.lastname: Dal Corso
authors.forename: Marcelo Bicalho
authors.initials: MB
authors.lastname: De Fuccio
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Lerario
authors.forename: Sonia
authors.initials: S
authors.lastname: Cendon
authors.forename: J Alberto
authors.initials: JA
authors.lastname: Neder
mesh_terms: D000368:Aged; D001837:Body Weights and Measures; D016552:Ergometry / Q000706:statistics & numerical data*; D005069:Evaluation Studies as Topic; D015444:Exercise; D005080:Exercise Test; D006801:Humans; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012129:Respiratory Function Tests; D013995:Time