Published in:
01-12-2014 | Original Article
High-dose inhaled terbutaline increases muscle strength and enhances maximal sprint performance in trained men
Published in: European Journal of Applied Physiology | Issue 12/2014
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Purpose
The purpose of the present study was to investigate the effect of high-dose inhaled terbutaline on muscle strength, maximal sprinting, and time-trial performance in trained men.
Methods
Nine non-asthmatic males with a \(\dot{V}O_{2max}\) of 58.9 ± 3.1 ml min−1 kg−1 (mean ± SEM) participated in a double-blinded randomized crossover study. After administration of inhaled terbutaline (30 × 0.5 mg) or placebo, subjects’ maximal voluntary isometric contraction (MVC) of m.quadriceps was measured. After MVC, subjects performed a 30-s Wingate test. Sixty minutes following the Wingate test, subjects exercised for 10 min at 80 % of \(\dot{V}O_{2max}\) and completed a 100-kcal time trial. Aerobic contribution was determined during the Wingate test by indirect calorimetry. Furthermore, plasma terbutaline, lactate, glucose, and K+ were measured.
Results
Inhalation of 15 mg terbutaline resulted in systemic concentrations of terbutaline of 23.6 ± 1.1 ng ml−1 30 min after administration, and elevated plasma lactate (P = 0.001) and glucose (P = 0.007). MVC was higher for terbutaline than placebo (738 ± 64 vs. 681 ± 68 N) (P = 0.007). In addition, Wingate peak power and mean power were 2.2 ± 0.8 (P = 0.019) and 3.3 ± 1.0 % (P = 0.009) higher for terbutaline than placebo. Net accumulation of plasma lactate was higher (P = 0.003) for terbutaline than placebo during the Wingate test, whereas \(\dot{V}O_{2}\) above baseline was unchanged by terbutaline (P = 0.882). Time-trial performance was not different between treatments (P = 0.236).
Conclusion
High-dose inhaled terbutaline elicits a systemic response that enhances muscle strength and sprint performance. High-dose terbutaline should therefore continue to be restricted in competitive sport.