Can the body mass index influence the skin temperature of adolescents assessed by infrared thermography?

Infrared thermography (IRT) is a technology that has been used as an auxiliary tool in the diagnostic process of several diseases and in sports monitoring to prevent injuries. However, the evaluation of a thermogram can be influenced by several factors that need to be understood and controlled to avoid a misinterpretation of the thermogram and, consequently, an inappropriate clinical action. Among the possible factors that can affect IRT are anthropometric factors, especially those related to body composition. Based on these, our objective was to verify the influence of Body Mass Index (BMI) on skin temperature (Tsk) in male adolescents. One hundred male adolescents (age: 16.83 ±â€¯1.08 years; body mass: 66.51 ±â€¯13.35 kg; height: 1.75 ±â€¯7.04 m and BMI: 21.57 ±â€¯4.06 kg/m2) were evaluated and divided into three groups, based on the World Health Organization (WHO) proposed classification ranges: underweight (n = 33), normal weight (n = 34) and overweight/obesity (n = 34). Thermograms were obtained using the FLIR T420 thermal imager after a period of acclimatization of the subjects in a controlled environment (temperature: 21.3 ±â€¯0.7 °C and humidity: 55.3 ±â€¯2.2%); they were evaluated using the ThermoHuman® software, integrating the original regions of interest (ROI) into seven larger ROIs. The results showed that underweight individuals had higher Tsk values than normal weight and overweight/obese individuals for all evaluated ROIs, and overweight/obese individuals had lower Tsk values than normal weight individuals for most evaluated ROIs, except for arms region. BMI showed a correlation of -0.68 and -0.64 for the anterior and posterior regions of the trunk, respectively. Thermal normality tables were proposed for various ROIs according to BMI classification. Our study demonstrated that BMI can affect the Tsk values assessed by IRT and needs to be considered to interpret the thermograms.

Physically active men with high brown adipose tissue activity showed increased energy expenditure after caffeine supplementation.

This study measured the effect of caffeine on brown adipose tissue (BAT) activity and the energy expenditure (EE) of subjects with high (HBAT) or low (LBAT) activation. We performed a quasi-experimental double-blind protocol in which 24 physically active healthy men were measured (age: 24.1 ± 6.0 yrs; BM: 75.3 ± 14.4 kg; HT: 171.8 ± 5.9 cm; BMI: 25.5 ± 4.9 kg/m2). Infrared thermography (IRT) protocol was used to separate the participants into the groups according to the BAT activation: high (HBAT; n = 11) and low (LBAT; n = 13). All participants ingested a single supplement caffeine capsule (CAF) of 375 mg (~5 mg/kg BM) or placebo (PLA). Our experimental protocol measured two groups (HBAT and LBAT) under two conditions (CAF and PLA), with intake 30-min before the data collection. BAT activity lasted 60-min (0, 10, 20, 30, 40, 50, 60 min) and was estimated by IRT in subclavicular (Δ SCV) and external (Δ EXT) regions of interest (ROI) and EE by indirect calorimetry. The main results indicated that HBAT at 40-min showed an increased EE versus the other groups and conditions (p = 0.009). There was a significant difference for BAT activation at the 30 (p = 0.019), 40 (p = 0.009), 50 (p = 0.007) and 60 min (p = 0.012) between HBAT-CAF vs. LBAT-CAF. There was also a significant difference at the 20 (p = 0.024), 30 (p = 0.036), 50 (p = 0.05) and 60 min (p = 0.011) between HBAT-CAF vs. HBAT-PLA. In conclusion CAF intake (≈5 mg) increases the thermogenic activity of BAT in healthy young men and increases EE in HBAT subjects.

Resistance Training Modulates the Humoral Inflammatory (but Not the DNA Methylation) Profile of Diabetic Older Adults Using Metformin.

BACKGROUND AND AIM: Inflammatory and methylation imbalances occur in patients with type 2 diabetes mellitus (T2DM). The aim of the present study was to analyze the effect of acute resistance exercise on the inflammatory profile and on DNA methylation of elderly patients with T2DM using metformin. METHODS: For this purpose, we enrolled 22 male and female older adults (68.2 ± 5.3 years), of whom 13 had controlled T2DM (D) under metformin use and 9 were nondiabetics (ND). All subjects underwent a neuromuscular circuit (8 exercises in 40 min, with each exercise performed in 3 sets of 40 s each and a 20-s interval between repetitions). RESULTS: The main results indicated a significant difference between groups for baseline interleukin (IL)-10, with a higher concentration in the D group compared to the ND group (p = 0.019). An increase in IL-6 concentration after intervention was observed in group D (p = 0.035). No effect was observed in total DNA methylation within or between groups. CONCLUSIONS: The resistance training protocol applied in this study modulates the IL-10 and IL-6 concentrations in elderly people with T2DM and under metformin use, possibly as a result of physiological adaptations, with no effect on nondiabetic elderly. No effects on absolute levels of DNA methylation were observed.

Daily rhythm of skin temperature of women evaluated by infrared thermal imaging.

It is well known that skin temperature varies due to circadian rhythm. Although there is information available for men, little is known about women's circadian rhythm in the analysis of skin temperature (Tsk) using infrared thermography. The objective of this study is to identify Tsk variations on different body regions in women through infrared thermography during the day. The sample consisted of 20 female (mean age of 20.5 ± 1.3 years, body weight of 62.2 ± 9.2kg and height of 165.0 ± 4.7cm). Oneway ANOVA for repeated measures, and Cosinor analysis was used to determine the MESOR, amplitude and acrophase of Tsk. The regions of the forearm, upper arm and anterior and posterior legs in the lower limbs, as well as the chest and scapulae in the upper limbs showed higher variability throughout the day. In general, distal regions had lower values compared with the central regions, and the pectoral region had the lowest standard deviation values. Tsk of the analyzed regions at different times show significant differences between periods of the day in young active women, showing the minimum absolute values for both Tsk in the early morning. These results highlight the need to consider the time of day when analyzing women's skin temperature. Future studies should report the time of day when the images were collected, as well as consider the circadian rhythm when making comparisons.

Waist circumference to height ratio predicts inflammatory risk in children.

BACKGROUND: The increase in obesity, especially the increase of visceral fat, has been directly associated with health risk. Additionally, a waist-to-height ratio (WHtR) (0.5) has been proposed as an indicator of early health risk. AIMS: To test the association between anthropometric measurements and inflammatory mRNA expression and to evaluate the effectiveness of WHtR to predict inflammatory risk in children. SUBJECTS AND METHODS: Anthropometric measurements and fasting blood samples were collected in 94 Brazilian children (46 boys) aged 9-11 years. Children were identified as being at inflammatory risk based on cytokine mRNA expression levels at and above the 75th percentile. Inflammatory cytokine mRNA expression levels were determined through buff-coat using real-time polymerase chain reaction. RESULTS: Body mass index (BMI), waist circumference (WC) and WHtR showed moderate-to-strong association with inflammatory cytokine mRNA gene expression. WHtR = 0.51 was the most accurate cut-off point in distinguishing children at inflammatory risk. Compared with children with WHtR <0.51, children with a WHtR ≥0.51 presented an odds ratio of 2.643 (95% CI = 1.749-3.994) for both diagnosed IL-6 and MCP-1 above the 75th percentile and 2.796 (95% CI = 1.802-4.338) for TNF-α above the 75th percentile. WHtR = 0.50 presented the same values of sensitivity and odds ratio and ∼7% lower specificity compared to WHtR = 0.51. CONCLUSION: Anthropometric measurements have shown a moderate-to-strong association with the mRNA expression of inflammatory genes and a WHtR of 0.5 could serve as a cut-off point, suggesting increased risk of inflammatory responses.

Habitual dietary intake and mediators of the inflammaging process in Brazilian older women.

AIM: This study aimed to assess whether the habitual intake of macronutrients by older women associates with circulating levels of important inflammaging mediators by means of a cross-sectional design with 229 Brazilian elderly women. METHODS: Laboratory tests determined serum IL1α, IL1ß, IL6, IL8, IL10, IL12 and TNFα by specific immunoassays. Food records of three alternate days were decomposed into usual intake of carbohydrates, proteins and lipids (and fractions), as well as total energy value (TEV) per patient. Moreover, the study has identified and controlled results for metabolic conditions known to influence the inflammatory profile: hypercholesterolemia, hypertension and diabetes. RESULTS AND DISCUSSION: Pearson's correlation test revealed that log10IL8 expressed a positive association with levels of saturated fatty acid (FA) (r = 0.173; p = 0.009) and total cholesterol intake (r = 0.223; p = 0.001). Similar analysis of the other mediators revealed no association with dietary intake. CONCLUSION: Higher intakes of total cholesterol and saturated FA seem to correlate with increased serum IL8 levels, being a possible mechanism by which this pro-atherogenic intake pattern may increase the risk of age-related chronic diseases with important inflammatory contribution.

Validity of inner canthus temperature recorded by infrared thermography as a non-invasive surrogate measure for core temperature at rest, during exercise and recovery.

Research into obtaining a fast, valid, reliable and non-invasive measure of core temperature is of interest in many disciplinary fields. Occupational and sports medicine research has attempted to determine a non-invasive proxy for core temperature particularly when access to participants is limited and thermal safety is of a concern due to protective encapsulating clothing, hot ambient environments and/or high endogenous heat production during athletic competition. This investigation aimed to determine the validity of inner canthus of the eye temperature (TEC) as an alternate non-invasive measure of intestinal core temperature (TC) during rest, exercise and post-exercise conditions. Twelve physically active males rested for 30min prior to exercise, performed 60min of aerobic exercise at 60% V̇O2max and passively recovered a further 60min post-exercise. TEC and TC were measured at 5min intervals during each condition. Mean differences between TEC and TC were 0.61°C during pre-exercise, -1.78°C during exercise and -1.00°C during post-exercise. The reliability between the methods was low in the pre-exercise (ICC=0.49 [-0.09 to 0.82]), exercise (ICC=-0.14 [-0.65 to 0.44]) and post-exercise (ICC=-0.25 [-0.70 to 0.35]) conditions. In conclusion, poor agreement was observed between the TEC values measured through IRT and TC measured through a gastrointestinal telemetry pill. Therefore, TEC is not a valid substitute measurement to gastrointestinal telemetry pill in sports and exercise science settings.

Serum Immune Mediators Independently Associate with Atherosclerosis in the Left (But Not Right) Carotid Territory of Older Individuals.

BACKGROUND AND AIM: Disturbance in the carotid arteries strongly predicts cerebrovascular events and correlates with a systemic inflammatory milieu. We investigated the relationship of a profile of 10 circulating inflammatory mediators with measures of carotid intima-media thickness (cIMT) in elderly subjects, taking traditional risk factors into account. METHODS: Clinical inspection for present and past chronic conditions and events, as well as biochemical and anthropometric measurements, was performed for patients in ambulatory setting. Scores of cIMT were obtained bilaterally in the distal common carotid artery wall. Serum concentrations of cytokines were assessed by bead-based, multiplexed flow cytometry immunoassays. RESULTS: Correlation analysis between log-transformed cytokines levels implicated the mediators interleukin-1ß (IL1ß), IL6, IL8, IL10, and tumor necrosis factor-α (TNFα) (P ≤ .005) with scores of the left cIMT. Stepwise multivariate regression showed that TNFα, IL1ß, and IL6 levels accounted for most of the variance in the cIMT scores. Comparison of cytokine levels across increasing tertiles of the left cIMT reproduced the positive association with TNFα and IL1ß levels. CONCLUSION: Five out of ten immune mediators independently correlated with cIMT of older subjects in a territory-sensitive manner. This possible contribution of immune mediators to an atherosclerotic process probably relates to the inflammaging process.

The physiology of judo-specific training modalities.

Understanding the physiological response to the most common judo training modalities may help to improve the prescription and monitoring of training programs. This review is based on search results using the following terms: "judo," "judo and training," "judo and physiology," "judo and specific exercises," and "judo and combat practice." Uchi-komi (repetitive technical training) is a specific judo exercise that can be used to improve aerobic and anaerobic fitness. Effort to pause ratio, total session duration, number and duration of individual sets, and the type of technique can be manipulated to emphasize specific components of metabolism. "Nage-komi" (repetitive throwing training) can also be used to improve aerobic and anaerobic fitness, depending on the format of the training session. "Randori" (combat or fight practice; sparring) is the training modality most closely related to actual judo matches. Despite the similarities, the physiological demands of randori practice are not as high as observed during real competitive matches. Heart rate has not shown to be an accurate measure of training intensity during any of the previously mentioned judo training modalities. High-volume, high-intensity training programs often lead judo athletes to experience overtraining-related symptoms, with immunosuppression being one of the most common. In conclusion, judo training and judo-specific exercise should be manipulated to maximize training response and competitive performance.

Effects of peppermint oil inhalation on vertical jump performance in elite young professional soccer players: A double-blinded randomized crossover study.

Aims: To evaluate peppermint essential oil (PEO) inhalation's effect on young soccer athletes' motor performance. Methods: A randomized crossover design was used to test the effect of the PEO. Eleven U-17 soccer players were evaluated into two conditions (PEO and Placebo - PLA). The players were tested in squat jump and countermovement jump and inhaled PEO or PLA and 10 min later performed the physical tests again. A mixed ANOVA was performed to test the hypotheses. Results: Main effects were found for the time in jumping height in the CMJ (p = 0.037). No main and interaction effects were found in the SJ variables. Conclusion: From the results, decrease CMJ performance acutely, both conditions presented decrease in JH, but based in effect size, PLA decrease is higher (more sample size for corroborate this) possibly due to improvements in the eccentric yielding sub-phase, where mentioned phase could be reflecting neural changes (required experimental verification). The PEO could be the interest in trainers for use before of match or in the half-time for minimize the decreased of physical performance by the rest.

Effect of Whole-, Upper-, and Lower-Body High-Intensity Rowing Exercise on Skin Temperature Measured by Thermography.

Purpose: Despite the growing works analyzing exercise-induced thermoregulatory adjustments through thermography, the skin temperature (Tsk) response of the same muscle groups underwent to different exercise demands has not been investigated. This study analyzed the behavior of Tsk of the same muscle groups when exercised with different demands in rowing. Methods: Eighteen men underwent three performance tests on a rowing ergometer: whole-body 2,000 m test (RTWB), upper-body (RTUB), and lower-body (RTLB) tests. In each condition, thermograms were recorded before (pre), immediately after test (post), and at 10 (REC10), 20 (REC20), and 30 (REC30) minutes post-exercise recovery. Tsk was measured at the pectoral (control body region), upper back, quadriceps, brachial biceps, and forearm. Results: Pectoral-Tsk reduced comparably in response to all testing conditions (p < .05). Upper back-Tsk decreased post (p < .001) and returned to baseline in the RTUB (REC10, p = 1.0) and RTWB (REC30, p = .128), while remained reduced in the RTLB (p < .001). Quadriceps-Tsk reduced post (p < .05) and returned to baseline in the RTWB and RTLB at REC10 (p = 1.0), remaining reduced in the RTUB during recovery (p < .05). Regarding the upper limbs, Tsk increased more markedly in the RTUB versus RTWB during the recovery period (p < .05); in the RTLB, biceps-Tsk remained below baseline over time (p < .05), whereas the forearm-Tsk was restored at REC10 (p = 1.0). Conclusion: Manipulating the muscle groups involved in rowing alters the Tsk response within equal ROI. Exercise-induced Tsk changes can reflect local hemodynamic and thermoregulatory adjustments.

Corrigendum: Effects of weight divisions in time-motion of female high-level Brazilian Jiu-jitsu combat behaviors.

[This corrects the article DOI: 10.3389/fpsyg.2023.1048642.].

Behavior of female judo weight divisions on approach and grip phases in different judo rules: The top 20 athletes from the 2016 and 2020 Olympic cycles.

In judo combat, the approach and gripping phases play a crucial role in determining victory, and it is believed that they can be influenced by the current rules. The objective of this study was to compare the technical-tactical actions executed by female judokas in the approach and gripping subphases during international competitions held in the 2016 and 2020 Olympic cycles, which featured different rules. We analyzed 1332 combat videos from the top 20 female judo athletes in the world rankings. These videos were equally distributed across weight divisions in the 2016 and 2020 Olympic cycles (48 kg = 132; 52 kg = 72; 57 kg = 109; 63 kg = 96; 70 kg = 69; 78 kg = 106; >78 kg = 82; total = 666 combats per cycle). The athletes in the 2020 cycle spent more time executing approach actions without contact with the judogi (formless: 2020 = 26.9; 2016 = 21.3 s; p < 0.001) and less time attempting grips (2020 = 24.6; 2016 = 31.2 s; p < 0.001) than the 2016 athletes. Additionally, the 2020 athletes spent less time on one-handed grips (left collar: 2020 = 7.1; 2016 = 7.9 s; p = 0.017; right sleeve: 2020 = 4.6; 2016 = 5.6 s; p = 0.018; left sleeve: 2020 = 4.7; 2016 = 5.2 s; p = 0.031) compared to the 2016 athletes. In both Olympic cycles, athletes devoted the most time to traditional grips (left collar right sleeve: 2016 = 12.3 ± 19.9; 2020 = 12.2 ± 17.5; right collar left sleeve: 2016 = 11.5 ± 20.6; 2020 = 12.3 ± 19.9 s). Differences in the approach subphases between Olympic cycles had varying impacts on different weight divisions (formless = 52 kg, 57 kg, 78 kg; right anteroposterior = 52 kg, 57 kg, 70 kg; grip attempts = 57 kg, 63 kg, 70 kg, 78 kg, >78 kg; p < 0.05), as did changes in grip types (right collar; left collar; left sleeve = 70 kg; right sleeve = >78 kg; right dorsal = 63 kg; left dorsal = 63 kg, 78 kg; right collar left sleeve = 48 kg, 52 kg; right dorsal left sleeve = 78 kg; right dorsal left collar = 48 kg, 70 kg; right dorsal left dorsal = 48 kg, 63 kg; p < 0.05). There were notable technical-tactical shifts in the behavior of female athletes between the Olympic cycles with different rules, and these findings should be taken into account for specialized training in female judo.

Effects of weight divisions in time-motion of female high-level Brazilian Jiu-jitsu combat behaviors.

Coaches and psychologists can use time-motion analysis to elaborate specific interventions for female BJJ athletes, increasing specific training context and reducing unnecessary psychological and physical demands and injuries. Therefore, the present study aimed to analyze high-level BJJ female athletes in the 2020 Pan-American Games by comparing the weight categories on the time-motion analysis. The time-motion analysis (i.e., approach, gripping, attack, defensive actions, transition, mounting, guard, side control, and submissions) of 422 high-level female BJJ combats was divided and compared by weight category as follows: Rooster (n = 8), Light Feather (n = 18), Feather (n = 122), Light (n = 84), Middle (n = 74), Medium Heavy (n = 44), Heavy (n = 36), Super Heavy (n = 36), using p ≤ 0.05. The main results indicated that the Super heavyweight category [3.1 (5.8;119.9) s] had a shorter gripping time than other weight categories, p ≤ 0.05. In contrast, roosters [7.2 (3.5;64.6) s] had longer gripping, transition [14.0 (4.8;29.6) s], and attack time [76.2 (27.7, 93.2)] than the light feather, middlers, and heavier weight categories, p ≤ 0.05. These findings should be considered for the psychological interventions and training prescription.

Enhancing performance: unveiling the physiological impact of submaximal and supramaximal tests on mixed martial arts athletes in the -61 kg and -66 kg weight divisions.

This study delves into the intricate details of Mixed Martial Arts (MMA) by examining key variables such as maximal oxygen uptake (VO2 peak), aerobic energy (EAER), anaerobic energy (EAN), and accumulated O2 deficit (DOA). By investigating associations and comparing athletes in the -61 kg bantamweight and -66 kg featherweight weight divisions, we aim to shed light on their physiological characteristics. The sample consisted of 20 male volunteers separated into two paired groups: ten athletes in the category up to 61 kg (age: 27.7 ± 5.9 years old, height: 170.9 ± 3.4 cm, body mass: 72.8 ± 1.4 kg, fat percentage: 9.5% ± 3.0%, professional experience: 7.5 ± 7.1 years) and ten athletes up to 66 kg (age: 27.6 ± 2.9 years old, height: 176.0 ± 5.5 cm, body mass: 77.0 ± 1.5 kg, fat percentage: 7.85% ± 0.3%, professional experience: 5.5 ± 1.5 years). Remarkably, our findings revealed striking similarities between the two weight divisions. Furthermore, we discovered a negative correlation between VO2 peak and the number of MMA fights, indicating a potential impact of professional experience on aerobic capacity (r = -0.65, p < 0.01). Additionally, the number of fights exhibited negative correlations with anaerobic energy (r = -0.53, p < 0.05) and total energy cost (r = -0.54, p < 0.05). These results provide valuable insights for designing training programs in the context of MMA. While training both weight divisions together can be beneficial, it is equally crucial to incorporate specific weight-class-focused training to address each division's unique physical demands and requirements.

Methods of body mass reduction by combat sport athletes.

The aim of this study was to investigate the methods adopted to reduce body mass (BM) in competitive athletes from the grappling (judo, jujitsu) and striking (karate and tae kwon do) combat sports in the state of Minas Gerais, Brazil. An exploratory methodology was employed through descriptive research, using a standardized questionnaire with objective questions self-administered to 580 athletes (25.0 ± 3.7 yr, 74.5 ± 9.7 kg, and 16.4% ± 5.1% body fat). Regardless of the sport, 60% of the athletes reported using a method of rapid weight loss (RWL) through increased energy expenditure. Strikers tend to begin reducing BM during adolescence. Furthermore, 50% of the sample used saunas and plastic clothing, and only 26.1% received advice from a nutritionist. The authors conclude that a high percentage of athletes uses RWL methods. In addition, a high percentage of athletes uses unapproved or prohibited methods such as diuretics, saunas, and plastic clothing. The age at which combat sport athletes reduce BM for the first time is also worrying, especially among strikers.

Concussion vs. resignation by submission: Technical-tactical behavior analysis considering injury in mixed martial arts.

This research study verified the technical-tactical actions during the mixed martial arts (MMA) fights to generate serious enough injury to stop the MMA round, determining technical-tactical potential risk factors for injury in official MMA combats, according to Concussion or Resignation per Submission. A total of 990 rounds with concussions and 627 resignations per submission were considered with severe injury (i.e., a fight ended by a doctor or referee). All injuries were diagnosed and managed by attending ringside physicians during the MMA fights and rounds and had a continuous technical-tactical behavior analysis, p ≤ 0.05. The leading cause of concussion was due to head trauma (~90%), with higher dependence on head strikes scored actions. Comparisons between Concussion and Resignation per Submission combats demonstrated differences between distance head strikes actions [13(6,25) vs. 9(4,18) frequencies], clinch head strikes actions [1(0;4) vs. 1(0;3) frequencies], ground head strikes actions [1(0;8) vs. 2(0;10) frequencies] and takedowns actions [0(0;1) vs. 1(0;2) frequencies]. This information may provide significant evidence regarding the doctor stoppage in concussion combats and when it could be called by officials supervising MMA.

Combat Time in International Male Judo Competitions: A Systematic Review and Meta-Analysis.

This study aimed to synthesize literature data on male judo combat time in international competitions between 2010 and 2019. The search was carried out from May 8th to June 11th, 2021, in electronic databases using the following keywords: ("technical-tactical" OR "time motion" OR "combat time") AND ("judo" OR "combat sports" OR "martial arts"). After the selection process, 8 articles were included in the systematic review and 7 in the meta-analysis. These studies analyzed 2,562 international male judo combats over the years 2010-2019. We observed that the average male judo combat time changed (2010 = 202.8; 2011-2012 = 304.8; 2016 = 237.4; 2018-2019 = 189.8 s) after each rule change (2010, 2013, 2017, and 2018). There was a significant difference between combats that ended up to the regular time and those that needed overtime (Golden Score: 2013 = 3% vs. 2018-2019 = 21%; p = 0.03). There were differences between 60 kg (p ≤ 0.019) and + 100 kg (p ≤ 0.04) categories and the others in 2011-2012. However, no significant difference was found between the combat time by weight division after the 2017 rule changes, although there are still differences in relation to the end of the combats (p < 0.001). There were significant changes in the male judo combat time with each rule change (2010, 2013, 2017, and 2018), and the data from the included studies point to a trend of homogeneity in the combat time spent between the weight divisions over the years, and an increase in the occurrence of Golden Score. More studies need to be carried out to identify the new temporal behaviors of athletes.

Rapid Weight Loss of Up to Five Percent of the Body Mass in Less Than 7 Days Does Not Affect Physical Performance in Official Olympic Combat Athletes With Weight Classes: A Systematic Review With Meta-Analysis.

Given the relevance of the effects that weight loss can generate on the physical performance in athletes, this study performed a systematic review with meta-analysis of the published literature on rapid weight loss (RWL) and examined its impact on the physical performance in Official Olympic combat sports athletes. The "Preferred Reporting Items for Systematic Reviews and Meta-Analysis" (PRISMA) guidelines were followed to ensure an ethical and complete reporting of the findings. PubMed, SPORT Discus, and EBSCO were the electronic databases explored for article retrieval and selection. The following string was applied: "RWL" OR "weight loss" OR "weight reduction" AND "judo" OR "wrestling" or "taekwondo" or "boxing" AND "performance." Based on the quality analysis, conducted according to the "Tool for the assessment of study quality and reporting in exercise training studies" (TESTEX), ten articles achieved a score >6 points. The meta-analysis showed a significant difference in pre- vs. post-weight loss (p = 0.003) and no effects in pre- vs. post-power and strength performance analysis (p > 0.05 for both results). Based on our systematic review and meta-analysis of the literature, RWL up to ≤5% of the body mass in less than 7 days does not influence performance outcomes in Official Olympic combat athletes with weight classes, considering the strength and power measures.

The Effect of Neurofeedback on the Reaction Time and Cognitive Performance of Athletes: A Systematic Review and Meta-Analysis.

Our study evaluated the effect of training with neurofeedback (NFB) in improving athletes' reaction time and decision-making. A computerized search in PubMed, PsycINFO, Scielo, Web of Science, EMBASE, Scopus, BVS, and Cochrane databases was performed to identify studies published from 2011 to June 2021. The protocol was registered in PROSPERO. The quality of studies that was peer-reviewed and included was assessed using the Review Manager tool, Cochrane Risk of Bias, and design and reporting quality according to the CRED-nf checklist. Standard mean differences and 95% confidence intervals (CIs) were calculated and combined using a random-effects model. A total of 07 randomized controlled trials (RCTs) (173 athletes) met the inclusion criteria. Significant effects of NFB in the experimental group in relation to reaction time were found, indicating an improvement in sports performance [standardized mean difference (SMD) = -1.08; 95% CI = (-1.90, -0.25), p = 0.0009] and cognitive performance vs. decision-making with moderate effect [SMD = 1.12; 95% CI = (-0.40, 1.85), p = 0.0001]. However, the control group had a very small effect on cognitive performance [SMD = 0.19; 95% CI = (-0.20, 0.59), p = 0.086]. NFB could improve athletes' reaction time and decision-making, effectively increasing their performance in the sports field. Future studies should focus on standardized protocols for NFB training. Systematic Review Registration: http://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42021258387.