Acute Effects of Breathing Resistance During Exercise in Football Players

This randomized crossover study will examine the immediate effects of breathing resistance during exercise in 35 active football players aged 18-30 years. Each participant will perform the same football-related field tests under two conditions: wearing an exercise mask that adds mechanical resistance to breathing, and without the mask. The order will be randomized, with at least 72 hours between sessions. Respiratory muscle strength will be assessed before and after exercise using maximal inspiratory and expiratory mouth pressures. Heart rate, oxygen saturation, perceived exertion, breathlessness, repeated-sprint performance, and change-of-direction performance will be compared between conditions. The mask is considered a breathing-resistance device, not a method of producing genuine altitude exposure or hypoxia.