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  kg; and height 179.5 [4.3] cm) and 8 women (age 22.4  y; weight 58.6  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  s, 1106  s, 1098  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.
John Molphy, John W. Dickinson, Neil J. Chester, Mike Loosemore and Gregory Whyte
Michele Merlini, Greg Whyte, Sam Marcora, Mike Loosemore, Neil Chester and John Dickinson
Purpose: To investigate the impact of twice-daily inhalation of 100 µg of salmeterol (SAL) or 12 µg of formoterol (FOR) in addition to a strength- and power-training program over a 5-wk period on a 30-m sprint, strength, power, mood, stress, and skinfold thickness. Methods: In a randomized, single-blind study, 23 male and 15 female nonasthmatic, recreationally active individuals were recruited (mean [SD] age 26.3 [5.4] y, weight 76.2 [11.5] kg, height 176.9 [8.5] cm). Participants completed 3 standardized whole-body strength- and power-training sessions per week for 5 wk during which they were assigned to an SAL, FOR, or placebo group. Participants used their inhaler twice per day as instructed and completed assessments of sprint, strength, and power at baseline and 1 wk after cessation of the training program. The assessments included a 30-m sprint, vertical jump, 1-repetition-maximum (1RM) bench press, 1RM leg press, peak torque flexion and extension, anthropometric evaluation, and Rest-Q questionnaires. Results: After 5 wk of strength and power training, 30-m sprint time reduced in the FOR (0.29 [0.11] s, P = .049) and SAL (0.35 [0.05] s, P = .040) groups compared with placebo (+0.01 [0.11] s). No significant change was found in other assessments of strength, mood, or skinfold thickness. Conclusions: When strength and power training are combined with the inhalation of FOR or SAL over a 5-wk period, moderately trained individuals experience an improvement in 30-m sprint performance.