Effets des β2-mimétiques inhalés, à doses thérapeutiques et juxtathérapeutiques, sur la force et la fatigabilité du quadriceps

Synthesis of facts. - Increasing incidence of exercise-induced bronchoconstriction is observed in endurance athletes. This study refers to the potentially undue benefits of treatment used for this condition by β2-agonists. High doses of these medications (p. o., 4 mg per pill) provide beneficial effects on muscle metabolism and performance. With inhaled β2-agonists (100 μg per puff) no beneficial effects have been reported. Non-cooperative tests of muscle function (magnetic stimulation of the femoral nerve) offer new possibilities to investigate potential effects of these treatments on muscular fatigue after exercise. We plan to investigate changes in quadriceps force in response to stimulation after exercise (i.e. exercise induced quadriceps fatigue) after the inhalation of a placebo, or 200 or 800 μg of β2-agonist. Maximal strength of the quadriceps, and percentage of central activation of the muscle may provide additional information on neuromuscular excitability induced by the drug.