The effect of EEG neurofeedback on lowering the stress reaction level depending on various stressors on the biochemical, muscular and psychomotor sphere: A preliminary randomized study.

BACKGROUND: The human body is exposed to stressors on a daily basis. Short-term exposure to a particular stressor can cause the release of inflammatory markers - including c-reactive protein (CRP). EEG neurofeedback is a noninvasive form of therapy that aims to improve brain function. Neurofeedback is a type of feedback based on brain activity. METHODS: The research process was performed by a group of 80 men who were divided into 2 research groups and 2 control groups. In the first research group and the first control group, the stressor of high temperature was applied, while in the second research group and the second control group, the stressor was physical exertion to refusal. Meanwhile, blood samples were taken to visualize inflammatory markers. These were taken before and after the stressor, as well as before and after the application of EEG neurofeedback. RESULTS: In research group after EEG neurofeedback intervention, the level of CRP significantly dropped in the measurement after stressor implementation. Analysis of the SMK test revealed a significant influence of both factors (time F = 13.525, P = .035; state F = 10.658, P = .047) and their interaction (F = 16.709, P = .026). Same statically significant decrease was observed in the level of rect. abdom. EMG was after physical work after neurofeedback. In all tests, a decrease in the EMG amplitude of upper trap. was observed after physical work before neurofeedback with its further increase after neurofeedback. After neurofeedback training, the results of the 3 tested parameters of the sensorimotor coordination test performed after the second heat stressor improved statistically insignificantly compared to the values obtained before. CONCLUSION: This article shows the effect of EGG neurofeedback on reducing the negative effects of stress exposure in humans. The study showed that the level and a pattern of EEG neurofeedback influence and significance is different depending on the applied stressor. Furthermore, the level of EEG neurofeedback influence and significance in decreasing the stressor effect is different depending on the examined sphere.

Effect of Supplementation with Black Chokeberry (Aronia melanocarpa) Extract on Inflammatory Status and Selected Markers of Iron Metabolism in Young Football Players: A Randomized Double-Blind Trial.

The use of herbal medicinal products and supplements in amateur and professional sports has increased in the last decades. This is because most of these products and supplements contain bioactive compounds with a variety of biological properties that exert a physiological effect on the human body. The aim of this study was to analyze the effect of dietary supplementation with lyophilized black chokeberry extract on the levels of pro-inflammatory cytokines, hepcidin, and selected markers of iron metabolism in a group of young football players. This double-blind study included 22 male football players (mean = 19.96 ± 0.56), divided into two groups: supplemented and placebo. Before and after a 90-day period of training combined with supplementation (6 g of lyophilized black chokeberry extract), participants performed maximal multistage 20-m shuttle run tests at the beginning and at the end of the supplementation period, with blood sampled for analysis at different times before and after exercise. The levels of IL-6, IL-10, ferritin, myoglobin, hepcidin, 8-OHdG, albumin, and TAC were analyzed. The analysis of variance revealed a significant effect of 90-day supplementation with the lyophilized extract on changes in the IL-6 and IL-10 levels, and TAC induced by maximal aerobic effort. In conclusion, supplementation with lyophilized black chokeberry extract improves the performance and antioxidant status of serum in humans and induces protective changes in inflammatory markers.

Effects of 8-Week Online, Supervised High-Intensity Interval Training on the Parameters Related to the Anaerobic Threshold, Body Weight, and Body Composition during Pregnancy: A Randomized Controlled Trial.

We aimed to assess the effects of an 8-week, online high-intensity interval training (HIIT) program on the parameters related to the anaerobic threshold (AT), body weight, and body composition in pregnant women. A total of 69 Caucasian women with an uncomplicated singleton pregnancy (age: 31 ± 4 years; gestational age: 22 ± 5 weeks; mean ± standard deviation) were randomly allocated to either an 8-week HIIT program (HIIT group) or to a comparative 8-week educational program (EDU group). Our most important finding was that even with the 8-week progression of pregnancy and physiological weight gain, the HIIT group maintained the same level of parameters related to AT: volume of oxygen at the AT (VO2/AT), percentage of maximal oxygen uptake at the AT (%VO2max/AT), and heart rate at the AT (HR/AT). In contrast, in the EDU group we observed a substantial deterioration of parameters related to the AT. The HIIT intervention substantially reduced the fat mass percentage (median: 30 to 28%; p < 0.01) and improved the total fat-free mass percentage (median: 70% to 72%; p < 0.01). In the EDU group, the body composition did not change significantly. An online, supervised HIIT program may be used to prevent the pregnancy-related risk of excessive weight gain and reduction in exercise capacity without yielding adverse obstetric or neonatal outcomes.

Impact of hydration with beverages containing free sugars or xylitol on metabolic and acute kidney injury markers after physical exercise.

The proper fluid and carbohydrates intake is essential before and during physical exercise, and for this reason most athletes drink beverages containing a high amount of free sugars. Sweetened soft drinks are also commonly consumed by those not doing any sport, and this habit seems to be both unhealthy and also the cause of metabolic problems. Recently, several sweeteners have been proposed to replace sugars in popular beverages. To examine the impact of free sugars and the popular sweetener xylitol on metabolic profile and the markers of kidney function and injury after exercise the present study was conducted with semi-professional football players. All participants were healthy, with a mean age of 21.91 years. Their sports skills were on the level of the 4th-5th division of the league. The subjects took part in four football training sessions. During each session they drank a 7% solution of sugar (sucrose, fructose, glucose) or xylitol. The tolerability of these beverages and well-being during exercise was monitored. Before and after each training session, blood and urine were collected. The markers of kidney function and injury, uric acid, electrolytes, complete blood count, CRP, serum albumin, serum glucose and the lipid profile were analyzed. The main finding of this study was that the xylitol beverage is the least tolerated during exercise and 38.89% of participants experienced diarrhea after training and xylitol intake. Xylitol also led to unfavorable metabolic changes and a large increase in uric acid and creatinine levels. A mean increase of 1.8 mg/dl in the uric acid level was observed after xylitol intake. Increases in acute kidney injury markers were observed after all experiments, but changes in urine albumin and cystatin C were highest after xylitol. The other three beverages (containing "free sugars" - glucose, fructose and sucrose) had a similar impact on the variables studied, although the glucose solution seems to have some advantages over other beverages. The conclusion is that sweeteners are not a good alternative to sugars, especially during exercise. Pure water without sweeteners should be drunk by those who need to limit their calorie consumption. Clinical Trial Registration: ClinicalTrials.gov, (NCT04310514).

The Influence of COVID-19 Pandemic Lockdown on the Physical Performance of Professional Soccer Players: An Example of German and Polish Leagues.

The purpose of this study was to investigate whether the in-season pandemic lockdown influenced physical match performance in professional soccer players who participated in the competition of German Bundesliga and Polish Ekstraklasa. The data from 306 games for German Bundesliga and 296 games for Polish Ekstraklasa were divided into before- and after-lockdown periods. The physical performance of German Bundesliga teams after the 63-day COVID-19 lockdown did not differ significantly from that in the first part of the season. In contrast, Polish Ekstraklasa teams, after the 81-day lockdown, displayed significantly shorter total distances (p < 0.001), shorter high-intensity running distances (p = 0.03), and fewer high-intensity actions (p = 0.02). Moreover, when the effective playing time was considered, teams covered significantly less relative total distance (p < 0.001) and relative high-intensity running distance (p = 0.02). The results of the current study suggest that physical performance during the matches of the German Bundesliga was not influenced by the COVID-19 lockdown, contrary to those of the Polish Ekstraklasa. This difference could have been caused by different break lengths and different restrictions implemented in these countries during the pandemic lockdown.

Relationships between Training Loads and Selected Blood Parameters in Professional Soccer Players during a 12-Day Sports Camp.

The main purpose of this study is to assess the relations between training loads and selected blood parameters in professional soccer players during a preseason sports camp. Fifteen professional soccer players (age: 24.3 ± 5.25 year; height: 182.6 ± 6.75 cm; weight: 76.4 ± 6.72 kg) participated in the 12-day training camp. All the training sessions and friendly games were accurately analyzed with a GPS system. Blood samples were taken from the players and analyzed before the camp (PRE), in the middle (MID), and one day after the camp (POST). Mean total distance covered by the players during the camp was 85,205 ± 2685 m, high-intensity running 12,454 ± 1873 m, and sprinting 639 ± 219 m. The highest aspartate transaminase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), and C-reactive protein (CRP) values were observed after six days of the camp. The application of intensive training during a 12-day sports camp can be associated with chronic muscle pain with high activity of some blood enzymes (CK, AST) and a high concentration of myoglobin (Mb). During training camps longer than 10 days, it would be necessary to apply, every second or third day, one day of rest, and the training load should not exceed two units every day.

Correlations between body composition, aerobic capacity, speed and distance covered among professional soccer players during official matches.

BACKGROUND: The importance of sprinting and high-speed running activities during a soccer match is indisputable. The main purpose of this study was to investigate the relations between the players' speed, aerobic capacity, body composition and distance covered in different speed zones during official soccer matches and to compare the match performance variables according to playing position. METHODS: Twenty-three professional soccer players (age: 27.9±4.58 y, body mass: 78.8±7.35 kg, height: 181.7±6.53 cm) participated in this study. During 13 weeks of the competitive season, players participated in 16 official matches and completed body composition analyses, sprint tests, multistage shuttle run tests (MST), and incremental running tests (IRTs). RESULTS: Significant negative correlations were found between sprint distance and percent of fat mass (FM; r=-0.57, P<0.0001), MST (r=0.45, P<0.001), maximal speed (r=0.44, P<0.001). High-speed running (HSR) distance covered by the players during the matches was significantly correlated with FM (r=-0.38, P<0.001) and MST distance (r=0.30, P<0.01). CONCLUSIONS: These data indicate that professional soccer players with lower fat content and higher levels of aerobic capacity are able to cover longer distances in sprinting and HSR during official matches.

Motion analysis of elite Polish soccer goalkeepers throughout a season.

The study aims were to determine the distance covered by goalkeepers during matches in the context of game duration and result, to identify the area of their most frequent activity, and to assess goalkeepers' involvement in games finished with a win, draw, or loss. The investigation was based on two innovative tools: the goalkeeper's activity index (GAI) and an analysis of 5-min periods. A video tracking system was used to monitor 17 goalkeepers from Polish National League teams during 15 matches. The GAI was applied to assess their involvement in the game. Elite goalkeepers covered 72.7%, 25.8%, and 2.5% of the distance during the game by walking/jogging, running, and sprinting, respectively. The distances covered in lost, won, and drawn matches turned out similar (mean ± SD: 4800 ± 906 m, 4696 ± 1033 m, and 4660 ± 754 m, respectively). There were no significant differences between the distances covered in the first and second halves. The area of most frequent activity was the middle sector of the penalty area between the goal and penalty area lines. ANOVA results showed that in drawn matches, goalkeepers' activity significantly differed in mean values of the GAI in comparison with that in won and lost games (p = 0.034, p = 0.039, respectively). It was noted that goalkeepers tended to intervene more often in games where their team was winning rather than in those with a losing result. Their direct involvement in defending the goal was the lowest in drawn games.

Physical responses of professional soccer players during 4 vs. 4 small-sided games with mini-goals according to rule changes.

The aim of this study was to investigate the influence of the number of ball touches authorised per game (one touch [T1], two touches [T2], and free touches [FT]) on the players' physical responses throughout the bouts in 4 vs 4 soccer small-sided games (SSGs) with mini-goals (without a goalkeeper). Fourteen professional Polish players (age 23.2±2.7 years, height 177.9±6.1 cm, weight: 73.2±6.9 kg, body fat 12.6±2%, playing experience: 14±5 years) completed nine series of 4 vs 4 SSGs. Each trial included three series of SSGs with a game duration of 4 minutes on an equal sized pitch (30x24 m; 720 m2; individual occupied area per player=90 m2). Differences in physical responses and time-motion characteristics of players were measured with the Global Positioning System (GPS) and assessed using a repeated measures ANOVA to compare the three game conditions and the magnitude-based inference to evaluate the pairwise comparison effects. The results showed that only the variables distance covered at low speed, time walking, time at low speed, and accelerations of >4 m/s² were statistically significantly different among game conditions. The pairwise comparisons only identified significant effects for distance covered at low speed (between FT and T2), for time walking (between FT and T1), for time at moderate and low speed (between FT and T2), and for accelerations of >4 m/s² (between FT and T1). The players' performances are affected by the ball touch constraint during SSGs with mini-goals. The results provide useful information for training and task design that replicate specific physical demands (i.e., accelerations of >4 m/s², time walking or running at a lower speed).