| A total of twenty-nine subjects, 15 healthy subjects and 14 subjects with chronic obstructive pulmonary disease (COPD) were recruited to compare endurance performance on the two types of incremental threshold loading (ITL) tests. In the continuous ITL (C-ITL) test, inspiratory loads continuously increased every two minutes. The discontinuous ITL (DC-ITL) was identical with the C-ITL test except that subjects had a one minute rest period between each stage. Endurance performance was significantly greater in the DC-ITL test for the healthy subjects, but for the subjects with COPD, endurance performance was similar in both tests. In terms of breathing difficulty associated with the ITL, there were no differences between the C-ITL and DC-ITL tests. However, the majority of the healthy subjects preferred the DC-ITL test to the C-ITL test due to the rest periods incorporated in the DC-ITL test. The higher level of performance in the healthy subjects may be influenced by the rest periods during which the subjects are relieved from discomforts accompanied with the ITL test. |
