Effects Of Recovery Using Cryotherapy On The Athlete’S Immune System After Repetitive Exhausting Aerobic Exercise

It is documented that intense periods of soccer can induce oxidative stress, the negative effects of which can compromise performance. However, few studies have explored the potential association between exercise-induced oxidative stress and training load intensity. PURPOSE: The aim of the study was to quantify oxidative stress relative to indicators of high-intensity training load in a cohort of professional soccer players throughout different phases of a competitive in-season. METHODS: Ten professional soccer players (age: 23±2yrs; body mass: 83.5±6.2kg; stature: 181.3±5.3 cm; V O2max: 57.2±6.7mL·kg·minˉ ), representatives from an English Football League One team, participated in the study. Training load was assessed at three time points throughout a competitive in-season (T1: early in-season; T2: mid-season; T3: end of in-season [1, 16 & 32 microcycle]) using global positioning system (GPS) and heart rate (HR) based methods to quantify external (HETL) and internal high-intensity training load (HITL). Urine samples were collected at each time point and analysed for malondialdehyde (MDA) as a biomarker of oxidative stress. Data normalised to creatinine. Results presented as M ± SD. RESULTS: High-intensity training load varied significantly throughout the competitive in-season and was significantly higher at T2 compared to T1 (HETL: 18.56 ± 7.30 mmin vs. 6.72 ± 2.62 mmin, an increase of 11.84 mmin, 95% CI [4.33, 19.36], p = .004; HITL: 60 ± 34 %Time spent > 80% HRmax vs. 23 ± 15 %Time spent > 80% HRmax, an increase of 37 %Time > 80% HRmax, 95% CI [13, 60], p = .004; T2 vs. T1, respectively). Urinary MDA concentrations decreased significantly throughout the competitive in-season, x (2) = 6.889; p = .032, (T1: 0.76 ± 0.90 μMmmol vs. T3: 0.18 ± 0.12 μMmmol, Z = -2.192, r = .52, p = .028). No significant correlations were observed between indicators of high-intensity training load and MDA. CONCLUSION: Chronic soccer training appears to promote an adaptive response as oxidative stress was attenuated over the competitive in-season, irrespective of the intensity of the training load. Monitoring urinary MDA may be a useful tool to provide coaches and sports scientists an insight into adaptive or maladaptive responses throughout a competitive season in soccer.