Effects Of Different FIO₂ On Exercise Performance And Exercise Load In Repeated-sprint Training In Hypoxia

Objective:This study intends to observe the effects of defferent fraction of inspiration O₂?FIO₂?on exercise performance and exercise load in repeated-sprint training in hypoxia for team-sport athletes,and explore the effective training effect between different hypoxic levels and exercise performance and exercise load.Methods:this study took 10 male sub-elite athletes of high-intensity interval sports?football?as the experimental subjects.Age:20.5±1.9,Height:177.4±4.5 cm,Weight:70.4±8.6 kg,Body fat percentage:11.4±2.8%.The subjects were all members of the football team of Hong Kong Baptist university.The FIO₂=20.8±0.2%,17.3±0.1%,15.6±0.2%and 13.8±0.1%,respectively.Four repeated sprint training tests were conducted in the hypoxia chamber which was equivalent to the normal altitude,the simulated altitude of 1500m,the simulated altitude of 2500m and the simulated altitude of 3500m.Each experiment was conducted one week apart to avoid potential training effects.Record indicators include:Fraction of inspiration O₂?FIO₂?,Temperature?Temp°C?,Humidity?RH?,concentration of carbon dioxide?CO₂?,Pulse Oxygen Saturation?SpO₂?,Heart rate?HR?.The tests include Peak velocity,Mean velocity,Percent sprint velocity decrement score,Training impulse,Session RPE and Blood Lactate.Results:1.In the experimental results of this study,with the increase of simulated altitude,the influence of hypoxic environment on experimental subjects gradually increases.When FIO₂:13.8±0.1%?simulated altitude is 3500m?,it is difficult to maintain the performance,and hypoxic training has the most significant effect?P<0.05?.In this study,Peak velocity,Average velocity and Percent sprint velocity decrement score in the three indexes representing sports performance,Peak velocity and Average velocity all reflect this conclusion.2.Among the three indexes,Training impulse,Session RPE and Blood Lactate,which represent the exercise load,did not show the expected sensutivity and need futther discussion.Conclusion:with the increase of simulated altitude,the influence of hypoxia on the experimental subjects of team sports gradually increases.When FIO₂:13.8±0.1%?simulated altitude is 3500m?,Repeated-sprint training in hypoxia has the most significant effect.