Background Exercise-induced bronchospasm (EIB) that is a transient airway obstruction occurring after strenuous exertion can occur in non-asthmatic athletes as well. However acute effects of different warm-up modalities on EIB in athletes without asthma remain uncertain.

Objective The aim of this study was to determine the efficacy of different warm-up modalities on improving EIB in non-asthmatic athletes.

Design Randomized crossover controlled trial. Each participant performed four experimental trials on nonconsecutive days, consisting of exercise challenge test for 6 min (at velocity of 90%HR_max) following either continuous warm-up (CW), high-intensity interval warm-up (HW), modified warm-up (MW) or no warm-up (NW). Pulmonary functions were measured prior to each experimental trial, and repeated before and at 1, 5, 10, 15, 20 min after exercise challenge.

Setting Research laboratory in a university setting.

Participants Eleven competitive collegiate athletes.

Interventions CW consisted of 15-min run at a velocity corresponding to 60%VO_2max, HW involved 8 repetitions of 30-sec run (45-sec rest between bouts of running) at an intensity equivalent to 90–100%VO_2max, and MW was composed with combination of HW (6 repetitions) and CW (5-min).

Main Outcome Measurements The main spirometric parameters of airway obstruction included forced expiratory volume in 1 second (FEV_1.0), forced vital capacity (FVC), and their ratio (FEV_1.0/FVC), forced mid-expiratory flow (FEF_25–75) and peak expiratory flow (PEF).

Results The mean maximum percent fall in pre- to post-exercise FEV_1.0 for all subjects during the EIB screening test was −17.7±6.5%. The mean maximum percent decrease in post-exercise FEV_1.0 significantly decreased to −4.0±5.5% and −5.2±3.5% following CW and MW, respectively (all p<0.01). All of three warm-up modalities significantly attenuated the mean percentage fall in FEV_1.0 at 5, 10 and 15 min compared to control (all p<0.05).

Conclusions These data indicate that all of three warm-up modalities have a protective effect against developing EIB in non-asthmatic athletes.