Two weeks of detraining reduces cardiopulmonary function and muscular fitness in endurance athletes

We investigated the effects of 2 weeks of detraining on cardiopulmonary function and muscular fitness in 15 endurance-trained male athletes (age: 19–26 years; height: 176.1 ± 7.5 cm; body mass: 68.3 ± 7.6 kg). VO₂max, exercise time to exhaustion (ET), maximal stroke volume (SVmax), maximal heart rate (HRmax), isokinetic muscle strength, and muscle endurance were measured before and after 2 weeks of detraining. We determined that short-term detraining resulted in a significant decrease (p < 0.05) in VO₂max, ET, SVmax and isokinetic knee extensor strength but not in isokinetic knee flexor strength or muscle endurance. HRmax and body mass increased significantly (p < 0.05), whereas body fat percentage remained stable after detraining. Furthermore, significant correlations were identified between VO₂max and SVmax (p < 0.01, r = 0.6) and between VO₂max and knee extensor strength (p < 0.01, r = 0.6). The results suggest that 2 weeks of detraining reduces cardiopulmonary functions, possibly as a result of the attenuation of hemodynamic and neuromuscular adaptations. Moreover, we observed that short periods of detraining appeared to increase lean mass and maintain muscle endurance in endurance runners. Highlights Two weeks of detraining reduces VO2max, SVmax and muscle strength but maintains muscle endurance in male runners. Short periods of detraining may enhance anabolic hormonal milieu and increase lean mass. Detraining reduced cardiopulmonary function is associated with attenuation of hemodynamic and muscle adaptations.