Journal Title (Medline/Pubmed accepted abbreviation): Br J Nutr
Page numbers: 1492-1499
Summary of Background and Research Design
Background:Strenuous intermittent exercise increases the production of reactive oxygen species (ROS), which may lead to oxidative stress if the balance between antioxidant defenses is disturbed. Excessive exercise-induced oxidative stress is believed to be a factor leading to fatigue, therefore an efficient recovery would promote optimal competitive performance, and may help elite players to cope with high training and game loads. Active recovery has been proposed as a method to accelerate recovery time of neuromuscular and blood markers of physical stress and allow a quicker restoration of the redox balance and inflammatory reaction.
Hypothesis/purpose of study: To compare the oxidative stress reaction and the response of endogenous and dietary antioxidants following 2 repeated female soccer games separated by 72 hours of either passive or active recovery.
Subjects:Sixteen female players of elite soccer (height 167 ± 5 cm, weight 64 ± 2 kg, age 22 ± 3 yr, maximal oxygen consumption [VO2max] 54 ± 3 mL/kg/min) participated.
Experimental design:Randomized, single-blinded
Treatments and protocol: Two 90-minute games were played during a period of 4 days. The players performed a standardized 20-minute soccer-specific warm-up on the field before both games. The active recovery group (n = 8) trained for 1 hour at 22 hours and 46 hours after the first game. The training consisted of 30 minutes of submaximal cycling (60% of peak heart rate) and 30 minutes of low-intensity resistance training (< 50% of 1-repetition maximum). The passive group (n = 8) was instructed to rest. Blood was sampled before the games (23 hours); within 15 to 20 minutes of the games (0 hours); at 21, 45 and 69 hours after the first game; and within 15 to 20 minutes of the second game (74 hours). Food intake was standardized to replicate the players' normal diet as much as possible and did not include food items with high antioxidant potential. All players were allowed to perform their habitual daily activities with the exception of participating in any kind of exercise during the study period.
Summary of Research Findings
- No differences were observed between the active and passive recovery groups for endogenous or dietary antioxidants or for oxidative stress markers.
- There was a significant time effect on the response of both endogenous and dietary antioxidants as well as on oxidative stress markers.
- Dietary antioxidants showed either a rapid and persistent increase (α-tocopherol, total tocopherols, ascorbic acid [AA]), a decrease (polyphenols), or a delayed increase (carotenoids) after the first game
- The oxidative stress marker oxidized glutathione (GSSG) increased by the same extent after both games.
- The lipid peroxidation marker diacron-reactive oxygen metabolite remained unchanged.
- The acute responses of the dietary antioxidants tocopherols, AAs, and polyphenols differed between the 2 games.
- The acute increase in tocopherols and AA and decrease in polyphenols observed after the first game did not occur after the second game.
- Polyphenols returned to baseline at 69 hours, and were not affected by the second game.
Interpretation of findings/Key practice applications:
Although there were similar acute oxidative stress and endogenous antioxidant responses among female players in 2 repeated elite soccer games, the dietary antioxidant responses differed. The dietary antioxidant response, but not the endogenous antioxidant response, was persistent. In general, there was a similar acute response pattern of endogenous antioxidants following both the games, suggesting that the endogenous antioxidants in the early line of defense against ROS are maintained during 2 repeated soccer games. The acute increase in the tocopherols and AA and decrease in polyphenols after the first game indicate a role of dietary antioxidants in the early line of defense against increased ROS production, as well. These findings do not support the beneficial role of active recovery training in the antioxidant response in elite female soccer players. It would have been interesting to see if antioxidant supplementation might have altered the responses in either group, but this question was not the focus of this study.