Preferred Name


Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Date of Graduation

Spring 2019

Document Type


Degree Name

Master of Science (MS)


Department of Kinesiology


Stephanie P Kurti


Expiratory flow limitation (EFL) has been reported in pre-pubescent adolescents and elite, adult endurance athletes; however, the occurrence of EFL in elite adolescent endurance athletes has not been determined. Purpose: To determine incidence and severity of EFL in elite youth male cyclists of adolescent age. We hypothesized that elite, endurance trained youth will experience a higher prevalence and severity of EFL and dyspnea compared to an untrained control group. Pulmonary function will be similar pre- to post-exercise with bronchodilation occurring in both groups. Methods: 12 elite endurance- trained (ET) youth male cyclists (16.3 ± 1.0 years; 176.5 ± 6.2 cm; 64.2 ± 5.9 kg) and 12 recreationally active males (CON) (17.6 ± 2.2 years; 177.9 ± 7.1 cm; 74.8 ± 11.2 kg) completed an incremental test to exhaustion to determine peak oxygen consumption (VO2peak) on a cycle ergometer. Heart rate and ventilation (VE) were assessed throughout the exercise test. Dyspnea and ratings of perceived exertion (RPE) were assessed at the end of each stage. Subjects performed maximal flow volume loops (forced vital capacity (FVC), forced expiratory volume in 1-second (FEV1), FEV1/FVC, forced expiratory flow between 25-75% of FVC (FEF25-75%) and peak expiratory flow (PEF)) pre- and post- exercise. The occurrence and severity of EFL was quantified as the percentage of the expiratory tidal volume that overlapped with the maximum flow volume loop. Results: VO2peak in the ET group was 69.4±7.0 mL/kg/min and 45.7±3.9 ml/kg/min in the CON group. Peak power (390 ± 57 W vs. 273 ± 45 W) and peak VE (158 ± 18 L/min) were higher in ET vs. CON (124.7 ± 15.3). The ET group experienced significant EFL at VO2peak (p < 0.001), with 11/12 subjects exhibiting flow limitation. In the CON group, 5/12 subjects exhibited EFL. There was a significant change in pulmonary function from pre- to post-exercise in FEV1 in both groups, with greater post-exercise bronchodilation in the CON group. There was no change in FVC, FEV1/FVC, FEF25-75% of FVC or PEF. The ET cyclists also had higher dyspnea ratings and RPE at peak exercise (8.5 ± 1.2, p < 0.01; 18.5 ± 1.2) than CON (6.3 ± 2.6, 17.2 ± 1.6). Conclusions: Elite youth male cyclists have a higher occurrence of and severity of EFL at maximal exercise than recreationally active counterparts, which may limit exercise tolerance. Considering subjects are of pubertal age, or nearing the end of puberty, the participants may outgrow their flow limitation.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.