RT Journal Article
SR Electronic
T1 Comparison of incremental and constant load tests of inspiratory muscle endurance in COPD
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 479
OP 486
DO 10.1183/09031936.00095406
VO 30
IS 3
A1 K. Hill
A1 S. C. Jenkins
A1 D. L. Philippe
A1 K. L. Shepherd
A1 D. R. Hillman
A1 P. R. Eastwood
YR 2007
UL http://erj.ersjournals.com/content/30/3/479.abstract
AB The aim of the present study was to determine the relative value of incremental and constant load tests in detecting changes in inspiratory muscle endurance following high-intensity inspiratory muscle training (H-IMT) in chronic obstructive pulmonary disease. In total, 16 subjects (11 males; forced expiratory volume in one second (FEV1) 37.4±12.5%) underwent H-IMT. In addition, 17 subjects (11 males; FEV1 36.5±11.5%) underwent sham inspiratory muscle training (S-IMT). Training took place three times a week for 8 weeks. Baseline and post-training measurements were obtained of maximum threshold pressure sustained during an incremental load test (Pth,max) and time breathing against a constant load (tlim). Breathing pattern was unconstrained. H-IMT increased Pth,max and tlim relative to baseline and to any change seen following S-IMT. The effect size for Pth,max was greater than for tlim. Post-training tests were accompanied by changes in breathing pattern, including decreased duty cycle, which may have served to decrease inspiratory work and thereby contribute to the increase in Pth,max and tlim in both groups. When assessing inspiratory muscle function in chronic obstructive pulmonary disease via tests in which the pattern of breathing is unconstrained, the current authors recommend incremental load tests be used in preference to constant load tests. However, to attribute changes in these tests to improvements in inspiratory muscle endurance, breathing pattern should be controlled.