Prolonged Intermittent Running Induces Inspiratory-Muscle Fatigue in Female Runners

Inspiratory-muscle fatigue (IMF) may occur after long-duration or continuous short-duration exercise and may limit exercise performance. Daily athletics training is often intermittent, but it is unclear if intermittent running induces IMF. We investigated IMF after a maximal anaerobic running test (MART) and maximal intermittent graded exercise test. Nine female middle-distance (400 or 800 m) runners performed MART and maximal intermittent graded exercise tests. Maximal inspiratory pressure (MIP) was measured before and after each test using a portable autospirometer. There was no significant difference in mean MIPs before (105 ± 24 cm H2O) and after (104 ± 28 cm H2O) the MART (P = 0.95, effect size [ES] as partial η 2 = 0.01). Mean MIP after the maximal intermittent graded exercise test (97 ± 26 cm H2O) was lower than before exercise (105 ± 27 cm H2O) (P = 0.01, η 2 = 0.83). Mean IMF was higher for the maximal intermittent graded exercise test (8.5 ± 4.2 cm H2O) than for the MART (0.8 ± 4.1 cm H2O) (P = 0.01, ES as Cohen’s d = 1.88). IMF occurs after relatively long-duration intermittent running exercise. Coaches may consider recommending inspiratory-muscle training or warm-up to reduce IMF resulting from relatively long-duration intermittent running exercise.