Effects Of Systemic Hypoxia-Hyperoxia Preconditioning On Acute Heavy Resistance Exercise-Induced Muscle Damage In Athletes

PURPOSE: Local ischemic preconditioning was shown to improve exercise performance in previous studies, but it also causes pain. The aim of the present study is to investigate the effects of systemic hypoxia-hyperoxia preconditioning on muscle damage caused by a bout of acute heavy resistance exercise (RE). METHODS: In this double-blind, randomized-controlled crossover study design, 11 voluntary male athletes (20-24 years old) were recruited as participants. Subjects were randomly divided into normoxia and hypoxia-hyperoxia groups. For a duration of 50 min, the hypoxia-hyperoxia group was alternately supplied with 10% or 100% oxygen in 5 min intervals. The normoxia group was supplied with 20.9% oxygen for 50 min during the same period. 30 min after preconditioning, all subjects performed a bout of acute heavy RE. After a 14-day washout time, subjects swapped groups. RESULTS: The results showed that the high intensity RE decreased peak torque and increased muscle pain in both groups. Circulating creatine kinase (CK), myoglobin and interleukin 6 (IL-6) also increased immediately after RE in normoxia subjects. CK, myoglobin and testosterone/cortisol ratio (T/C ratio) of hypoxia-hyperoxia group were lower than those of normoxia group 24 and 48 h after RE. However, IL-6 of hypoxia-hyperoxia group was higher than that of normoxia group 24 and 48 h after RE. No differences were found in thiobarbituric acid reacting substance (TBARS) levels or peak torque levels between normoxia and hypoxia-hyperoxia groups. CONCLUSIONS: Systemic hypoxia-hyperoxia preconditioning could reduce muscle damage induced by high intensity RE. These effects may be due to increased anti-inflammatory cytokine secretion.