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The Effects of Inhaled Terbutaline on 3-km Running Time-Trial Performance

Molphy, J, Dickinson, JW, Chester, NJ, Loosemore, M and Whyte, G (2019) The Effects of Inhaled Terbutaline on 3-km Running Time-Trial Performance. International Journal of Sports Physiology and Performance, 14 (6). pp. 822-828. ISSN 1555-0265

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Abstract

Terbutaline is a prohibited drug except for athletes with a therapeutic use exemption certificate; terbutaline’s effects on endurance performance are relatively unknown. Purpose: To investigate the effects of 2 therapeutic (2 and 4 mg) inhaled doses of terbutaline on 3-km running time-trial performance. Methods: A total of 8 men (age 24.3 [2.4] y; weight 77.6 [8] kg; and height 179.5 [4.3] cm) and 8 women (age 22.4 [3] y; weight 58.6 [6] kg; and height 163 [9.2] cm) free from respiratory disease and illness provided written informed consent. Participants completed 3-km running time trials on a nonmotorized treadmill on 3 separate occasions following placebo and 2- and 4-mg inhaled terbutaline in a single-blind, repeated-measures design. Urine samples (15 min postexercise) were analyzed for terbutaline concentration. Data were analyzed using 1-way repeated-measures analysis of variance, and significance was set at P < .05 for all analyses. Results: No differences were observed for completion times (1103 [201] s, 1106 [195] s, 1098 [165] s; P = .913) for the placebo or 2- and 4-mg inhaled trials, respectively. Lactate values were higher (P = .02) after 4 mg terbutaline (10.7 [2.3] mmol·L−1) vs placebo (8.9 [1.8] mmol·L−1). Values of forced expiratory volume in the first second of expiration (FEV1) were greater after inhalation of 2 mg (5.08 [0.2]; P = .01) and 4 mg terbutaline (5.07 [0.2]; P = .02) compared with placebo (4.83 [0.5] L) postinhalation. Urinary terbutaline concentrations were mean 306 (288) ng·mL−1 and 435 (410) ng·mL−1 (P = .2) and peak 956 ng·mL−1 and 1244 ng·mL−1 after 2 and 4 mg inhaled terbutaline, respectively. No differences were observed between the male and female participants. Conclusions: Therapeutic dosing of terbutaline does not lead to an improvement in 3-km running performance despite significantly increased FEV1. The findings suggest that athletes using inhaled terbutaline at high therapeutic doses to treat asthma will not gain an ergogenic advantage during 3-km running performance.

Item Type: Article
Additional Information: Accepted author manuscript version reprinted, by permission, from International Journal of Sports Physiology and Performance, 2019, 14 (6): pp-pp 822-828, https://doi.org/10.1123/ijspp.2018-0633. © Human Kinetics, Inc.
Uncontrolled Keywords: 1106 Human Movement and Sports Sciences, 1701 Psychology, 1116 Medical Physiology
Subjects: R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions: Sports & Exercise Sciences
Publisher: Human Kinetics
Related URLs:
Date Deposited: 07 Oct 2019 10:28
Last Modified: 07 Oct 2019 10:30
DOI or Identification number: 10.1123/ijspp.2018-0633
URI: http://researchonline.ljmu.ac.uk/id/eprint/11405

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