Muscle fatigue (fatigue) is considered a limiter of sports performance. Its origin is multifactorial, but it has been accepted that fatigue involves ATP depletion, muscle damage and increased production of reactive oxygen species (ROS), resulting in a state of oxidative stress. In general, fatigue negatively affects the production of force, and in the case of cycling, pedal force, power output and cadence are disturbed. Repeated sessions of heavy physical exertion lead to a state of cumulative fatigue, in which the ability to develop effort is reduced, and for the quadriceps muscles, recovery after fatigue can take up to 3 days.
In addition to the acute (one-time) effects of fatigue on performance, consistent exercise sessions in a state of fatigue can lead to poor performance during training and competitions. Conditions of cumulative fatigue can also increase the risk of injury and promote negative psychobiological adaptations. However, there are many situations in which athletes have no choice but to maintain performance in case of fatigue. Therefore, strategies to minimize the impact of fatigue on performance during repeated exercise sessions are of interest to both coaches and athletes. A realistic strategy to achieve this goal is to promote faster recovery after exercise.
Green tea to fight fatigue
In this regard, supplements with natural products attracted the interest of athletes of different levels of competition. Whereas in fatigue and its impact on
performance during repeated exercise sessions, significant participation has oxidative stress and muscle damage, there is great interest in supplements with antioxidants such as green tea extract (GTE) from Camellia sinensis. GTE is rich in polyphenols, including epigallocatechin gallate, epicatechin, epigallocatechin, and epicatechin gallate, which lead to high antioxidant (antioxidant) activity. Previous studies have shown that GTE supplementation can reduce oxidative stress and help improve maximum oxygen uptake during cycling until exhaustion. In addition, GTE can reduce muscle pain resulting from eccentric exercise and reduce markers of muscle damage after eccentric training, intense aerobic exercises, and strength exercises. In this case, no similar effect was found when a single dose of GTE was taken before intense muscle endurance tests.
Study of the effects of green tea extract on muscle damage
The effects listed for GTE supplements taken regularly on muscle damage and oxidative stress suggest that GTE could be an effective strategy for maintaining performance during repeated periods of exercise resulting in cumulative fatigue. To solve this question, a study was conducted (triple blind versus placebo, a control experiment) described herein, whose main purpose was to determine whether the addition of green tea extract (GTE) from Camellia sinensis reduced muscle damage and oxidative stress in subjects trained athletes consistent victims of exercise sessions, leading to кумулятивному to fatigue, whether it contributes to the preservation of neuromuscular function.
Sixteen trained amateur male athletes were randomly assigned to a completed GTE Group (500 mg of extract / day-one capsule per day, before breakfast with a glass of water) or placebo consumed for 15 days. The effects of supplementation were tested in repeated submaximal cycling trials on a bicycle ergometer at 60% of maximum output power, performed after the cumulative fatigue protocol of the hip extensor muscles. Cumulative fatigue is defined here as the condition tested after the end of the Knee extension Training until complete exhaustion for two consecutive days before the submaximal cyclic test.
Green tea extract reduces muscle damage
Muscle damage and oxidative stress showed lower amounts in response to fatigue after adding GTE. The placebo group showed altered neuromuscular activity and higher muscle damage (creatine kinase level – CK plasma) and oxidative stress (lipid peroxidation by – products-TBARS) compared to the GTE group in cumulative fatigue cycling trials.
Cardiovascular responses evaluated on the basis of heart rate showed that the GTE group had a lower heart load (HR) than the placebo group.
Green tea supports neuromuscular interaction
Neuromuscular activation of vastus lateralis left (LVL) of participants in the placebo group showed a significant deterioration in the state of fatigue. Fatigue had an impact on the extent of neuromuscular activity assessed from Mean square values demonstrating a decrease in neuromuscular activation at the end of fatigue training in the placebo group, but not in the GTE group.
Thus, the addition of GTE showed a positive effect on neuromuscular function in response to the state of cumulative fatigue. He suggests that the addition of GTE could serve as a strategy to improve and maintain performance under conditions of cumulative fatigue.
Finding
“Green tea extract supplementation before a cumulative fatigue event minimizes muscle damage and oxidative stress in trained athletes. Green tea extract also has a positive effect on neuromuscular parameters associated with muscle activation and muscle fatigue. Therefore, supplements can be considered the right strategy in the context of a competitive endurance sport, where the goal is to prevent a decrease in performance,” summed up the researchers.
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