Relationship between Indirect Measures of Aerobic and Muscle Power with Frequency Speed of Kick Test Multiple Performance in Taekwondo Athletes.

This study aimed to determine the relationship between indirect measures of aerobic power and muscular power with Frequency Speed of Kick Test performance using multiple sets (FSKTmult) in high-level taekwondo athletes. We used a known-group method to test differences in FSKTmult performance between two groups designated as lower and higher performance in both aerobic power and muscular power. In total, 42 international or national taekwondo athletes of both sexes performed the FSKTmult, Progressive Specific Taekwondo Test (PSTT), and countermovement jump (CMJ). Our results showed that average of the three CMJ was moderately correlated with FSKTmult performance (r=0.44); whereas PSTT and FSKTmult were highly correlated (r=0.83). Moreover, the groups formed by lower and higher performance of time to exhaustion in PSTT, as well as the average of CMJ were able to discriminate performance in the FSKTmult (p ≤0.05). The present study thus suggests that aerobic and muscle power are important for FSKTmult performance.

Reliability of physical performance and thermoregulatory parameters in rats subjected to incremental treadmill running.

Thermoregulatory changes may influence the rats' prolonged physical performance and are commonly evaluated during treadmill running. Therefore, we determined the reliability of performance and thermoregulatory parameters in rats subjected to incremental-speed exercises (i.e., we assessed whether the testing protocol provides measurements that are consistent and free from error). Twenty rats were subjected to two sessions of incremental exercises at 24 °C, separated by 48 h, until they were fatigued. The rats' performance and thermoregulatory responses were determined, and values concerning the reliability of these parameters [e.g., intraclass correlation coefficient (ICC) and minimal detectable change (MDC)] were calculated. Our data revealed that the core temperature (TCORE) at fatigue and heat loss threshold were the most reproducible parameters, showing good reliability (ICC between 0.75 and 0.90). Moreover, all performance parameters assessed, the change in TCORE, the rate of TCORE increase, and the TCORE increase-to-distance traveled ratio presented moderate reliability. We then investigated whether changes in performance and thermoregulation induced by a warm environment were greater than the MDC95% values determined in the first experiment. Eight rats were subjected to incremental exercises at two environmental conditions: 24 °C and 31 °C. Individual analyses showed that most rats presented thermoregulatory differences between exercises at 31 °C and 24 °C greater than the calculated MDC95% values; this was not the case for their performance. In conclusion, we provide data on the reliability of rats' performance and thermoregulatory parameters during incremental-speed running. Also, the exercise in a warm environment produced detectable thermoregulatory changes relative to the exercise under temperate conditions.

Attention deficit and hyperactivity disorder and nocturnal enuresis co-occurrence in the pediatric population: a systematic review and meta-analysis.

BACKGROUND: Attention deficit and hyperactivity/impulsivity disorder (ADHD) and enuresis are common behavioral disorders in childhood, impacting adolescence and adult life. Enuresis (NE) is an incontinence disorder frequently observed in children with ADHD. The relationship between ADHD and NE has been a matter of debate. OBJECTIVES: We aimed to verify the relationship between ADHD and enuresis and how these conditions can modify each other during development. Using PRISMA guidelines, under the PROSPERO registration number CRD42020208299, we systematically searched the literature and conducted a meta-analysis to answer the following question: how frequent is ADHD and enuresis comorbidity? Twenty-five studies were fully read, and data from seven less heterogeneous case-control studies were pooled to estimate enuresis prevalence comparing ADHD and control samples, whereas six studies were combined to evaluate ADHD frequencies in children with and without enuresis. RESULTS: We found the ADHD rates in children with enuresis are similar to the enuresis rates in the group of children with ADHD. The presence of ADHD and enuresis comorbidity does not seem to play a role in gender distribution and the presence of other comorbidities in comparison to controls. However, enuresis seems to persist for more time in children with ADHD. LIMITATIONS: The selected papers differed in study type, research question, samples, and controls utilized. CONCLUSIONS: Our systematic review with meta-analysis supports the reciprocal association between enuresis and ADHD. Further studies are necessary to build more robust evidence.

Prevalence and incidence of injuries in para athletes: a systematic review with meta-analysis and GRADE recommendations.

OBJECTIVE: To investigate prevalence, incidence and profile of musculoskeletal injuries in para athletes. DESIGN: Systematic review. DATA SOURCES: Searches were conducted in MEDLINE, EMBASE, AMED, SPORTSDiscus, CINAHL and hand searching. ELIGIBILITY CRITERIA: Studies were considered if they reported prevalence or incidence of musculoskeletal injuries in para athletes. Study selection, data extraction and analysis followed the protocol. Meta-analyses were conducted to estimate the prevalence and incidence rate among studies and subgroup analyses investigated whether methodological quality and sample size of the studies influenced on the estimated injury prevalence and incidence. The Grading of Recommendations Assessment, Development and Evaluation system determined the strength of evidence. RESULTS: Forty-two studies were included. The prevalence of musculoskeletal injuries was 40.8% (95% CI 32.5% to 49.8%). Because of imprecision, indirectness and inconsistency, the strength of evidence was very low quality. The incidence of musculoskeletal injuries was 14.3 injuries per 1000 athlete-days (95% CI 11.9 to 16.8). The strength of evidence was low quality because of imprecision and indirectness. The subgroup analyses revealed that the sample size influenced on estimated injury prevalence and methodological quality influenced on estimated incidence. Injuries were more prevalent in the shoulder, for non-ambulant para athletes, and in the lower limbs, for ambulant para athletes. SUMMARY/CONCLUSION: Para athletes show high prevalence and incidence of musculoskeletal injuries. Current very low-quality and low-quality evidence suggests that future high-quality studies with systematic data collection, larger sample size and specificities of para athletes are likely to change estimates of injury prevalence and incidence in para athletes. PROSPERO REGISTRATION NUMBER: CRD42020147982.

Transcranial Stimulation Improves Volume and Perceived Exertion but does not Change Power.

This study aimed to analyze the acute effect of anodal transcranial direct current stimulation (a-tDCS) over the primary motor cortex (M1) on the volume, perceived exertion, and neuromuscular performance measurements in trained and untrained adults. Twenty-four male adults (12 trained and 12 untrained) participated in this single-blind, randomized, and sham-controlled study. The participants performed three back squat repetitions using the 15RM load with maximal concentric velocity to assess neuromuscular performance before tDCS and 30-min after resistance exercise. Next, they were randomly assigned to a-tDCS over M1 or the sham condition. Participants performed ten sets of parallel back squat with 15RM load and repetitions sustained to momentary muscular failure. The total number of repetitions was higher (p<0.05) and perceived exertion was lower (p<0.05) after a-tDCS in both groups. Peak power, velocity, and force decreased in both groups after the RE session (p<0.05), but with a higher rate in untrained individuals (p<0.05). No significant effect was found for peak power, peak velocity, and peak force (p>0.05). This study suggests that using a-tDCS may improve the total volume of repetitions and perceived exertion in trained and untrained individuals.

Correlation between strength and skin temperature asymmetries in the lower limbs of Brazilian elite soccer players before and after a competitive season.

This study aimed to investigate the correlation between strength and skin temperature (Tsk) asymmetries in the lower limbs of elite soccer players before and after a competitive season. The sample (n = 20) was composed of elite male soccer players. Strength asymmetry and Tsk asymmetry was measured through the countermovement jump (CMJ) test and infrared thermography, respectively. Asymmetries were quantified using the symmetry angle (SA) equation. A strong correlation was found between the SA of rate of force development (RFD) and the SA of Tsk before (baseline) (r = 0.7; r2 = 0.43; p = 0.03) and after (r = 0.6; r2 = 0.42; p = 0.04) the competitive season. Moreover, after the competitive season there were significant decreases in Peak force (p < 0.018), Impulse (p < 0.04), RFD (p = 0.0001) and CMJ height (p = 0.05), and significant increases in Tsk (p < 0.03), C-reactive protein (p = 0.03), Creatine kinase (p = 0.0001) and Cortisol (p = 0.04), even after a 3-day rest interval (no training). These results suggest that the CMJ test can be combined with infrared thermography for monitoring strength asymmetry and contribute to the prevention of muscle injuries.

Motor learning and COMT Val158met polymorphism: Analyses of oculomotor behavior and corticocortical communication.

Differences in motor learning can be partially explained by differences in genotype. The catechol-O-methyltransferase (COMT) Val158Met polymorphism regulates the dopamine (DA) availability in the prefrontal cortex modulating motor learning and performance. Given the differences in tonic and phasic DA transmission, this study aimed to investigate whether the greater cognitive flexibility associated with the Val allele would favor the learning of movement parametrization, while the greater cognitive stability associated with the Met allele favors the acquisition of the movement pattern. Furthermore, we investigated if the genotypic characteristics impact visual scanning of information related to parametrization and to the movement pattern, and the level of cortical connectivity associated with motor planning and control. Performance and learning of a sequential motor task were compared among three genotypes (Val/Val, Val/Met, and Met/Met), as well as their oculomotor behavior and level of cortical coherence. The findings show that the cognitive flexibility promoted by the Val allele is associated with a better parametrization. The search for information through visual scanning was specific to each genotype. Also, a greater cortical connectivity associated with the Val allele was found. The combined study of behavioral, electrophysiological and molecular levels of analysis showed that the cognitive stability and flexibility associated with the COMT alleles, influence specific aspects of motor learning.

THE RELATIVE AGE EFFECT IN COMBAT SPORTS: AN ANALYSIS OF OLYMPIC JUDO ATHLETES, 1964-2012.

This study assessed the relative age effect (RAE) in judo athletes who participated in the Olympic Games from 1964 to 2012. The names and birthdates of the Olympic judo athletes were collected from open-access websites. Data from male (n=1,762) and female (n=665) competitors were analyzed separately. Chi-squared tests were performed to investigate REA in medalists, and by weight categories and sexes. When the analyses used semesters to divide the period when the athletes were born, a RAE was found in male heavyweight athletes and male medallists. Thus, in a selected group of judo athletes who had participated at the highest competitive level, RAEs were present in both athletes who won Olympic medals and heavyweight athletes in the male group.

Effects of knowledge of results frequency on the learning of generalized motor programs and parameters under conditions of constant practice.

The present study investigated the effects of the frequency of knowledge of results (KR) on both generalized motor programs and parameters. Two experiments were conducted that compared two frequencies of KR in terms of generalized motor programs and parameters: (1) the first experiment compared the effects of KR frequency on generalized motor programs in the 100% and 50% groups; and (2) the second experiment compared the effects of reduced KR frequency on parameters in the 100% and 50% groups. In the first experiment, results showed that the 50% group exhibited smaller relative timing errors than did the 100% group, but absolute timing errors in the transfer test were similar between these two groups. In the second experiment, both groups exhibited similar relative and absolute timing errors. These results suggested that the beneficial effects of reduced KR frequency were restricted to generalized motor programs.

Evaluating the Stroop Test With Older Adults: Construct Validity, Short Term Test-Retest Reliability, and Sensitivity to Mental Fatigue.

We conducted two studies to evaluate the construct validity, short term test-retest reliability, and sensitivity to mental fatigue of the Stroop task when used with older adults. In Study 1, 40 participants visited our lab on two separate days. On the first visit, they took five screening scales, and we measured their height and body mass. On the second visit, they completed the Stroop task twice with a 30-minute interval between assessments. In Study 2, 15 different participants took a 30-minute Flanker/Reverse Flanker task during the interval between the two administrations of the Stroop tasks and they gave subjective ratings of their mental fatigue on the Visual Analogue Scale (VAS) prior to taking either of the Stroop tasks. In Study 1, participants showed a ceiling effect on the Stroop accuracy measure, there was strong concurrent validity for the Stroop with significant score differences between the Stroop's congruent and incongruent conditions (p < .001), and there was excellent response time reliability (ICC = 0.926) on day two when participants took the Stroop twice within a 30-minute inter-test interval. However, there were significant test-retest performance differences with respect to cognitive inhibition (p < .001). In Study 2, mental fatigue from the Flanker/Reverse Flanker test resulted in a significantly worse second Stroop performance (p = .045). We concluded that the Stroop task demonstrated strong concurrent validity and response time reliability among older adults, but it showed sensitivity to mental fatigue, and repeated administrations within the short 30-minute test-retest interval revealed that the most important Stroop measure (cognitive inhibition) was unreliable. We discuss the implications of these findings.

Effects of Ischemic Preconditioning on Sport-Specific Performance in Highly Trained Taekwondo Athletes.

Ischemic preconditioning (IPC), which involves episodes of blood flow restriction followed by reperfusion, has uncertain effects on athletes. Additionally, employing sports-specific tests that are highly familiar to athletes can enhance methodological rigor in determining IPC's effects on taekwondo performance. This study aimed to investigate IPC's influence on taekwondo athletes' performance through two studies. To induce occlusion in both studies, the cuff was inflated to an individualized occlusion pressure established for each athlete's lower limb, with four cycles of occlusion lasting five minutes each, alternated with five-minute reperfusion intervals. Both traditional frequentist statistics and Bayesian analysis were employed. In the first study, eleven high-level athletes were subjected to either IPC or a placebo (SHAM) procedure on both legs, followed by performing countermovement jumps (CMJs) and a specific taekwondo endurance test. However, no significant differences were observed in taekwondo endurance performance or CMJ between the IPC and SHAM conditions. The second study involved fourteen elite athletes who underwent the same IPC or SHAM conditions, performing CMJ and three bouts of the Multiple Frequency Speed of Kick test (FSKTmult) in three blocks, each separated by approximately thirty minutes. Again, the results indicated no significant differences in FSKTmult measures or CMJ performance between the two conditions. In conclusion, IPC did not significantly affect neuromuscular (in both studies), endurance (in the first study), or anaerobic (in the second study) performance in these taekwondo athletes.

Sex differences in dimensions of impulsivity in a non-clinical sample.

Impulsivity has been more closely associated with men than with women because men are more often involved in illegal behaviors. The few studies that have investigated sex differences in impulsivity have used self-report questionnaires and have obtained contradictory results. Two computerized behavioral tests were administered to 125 healthy undergraduate students (75 women, M age 23.8 yr.; 50 men, M age 25.0 yr.). Men exhibited higher scores on motor impulsivity, but there were no significant differences between men and women on attentional and non-planning impulsivity scores. These findings are discussed in terms of the relationship between impulsivity and low- and high-order control.

Acute Effects of Fitlight Training on Cognitive-Motor Processes in Young Basketball Players.

Cognitive-motor training could be used to improve open-skill sport performances, increasing cognitive demands to stimulate executive function (EF) development. Nevertheless, a distributed training proposal for the improvement of EFs is increasingly difficult to combine with seasonal sport commitments. This study aimed to investigate whether a massed basketball training program enriched with Fitlight training can improve EFs and motor performance. Forty-nine players (age = 15.0 ± 1.5 yrs) were assigned to the control and Fitlight-trained (FITL) groups, which performed 3 weeks of massed basketball practice, including 25 min per day of shooting sessions or Fitlight training, respectively. All athletes were tested in cognitive tasks (Flanker/Reverse Flanker; Digit Span) and fitness tests (Agility T-test; Yo-Yo IR1). During the intervention, exercise/session perceived effort (eRPE/sRPE) and enjoyment were collected. RM-ANOVA showed significant EFs scores increased in both groups over time, without differences between the groups. Moreover, an increased sRPE and eRPE appeared in the FITL group (p = 0.0001; p = 0.01), with no group differences in activity enjoyment and fitness tests. Three weeks of massed basketball training improved EFs and motor performance in young players. The additional Fitlight training increased the perceived cognitive effort without decreasing enjoyment, even if it seems unable to induce additional improvements in EFs.

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.

Do executive function performance, gaze behavior, and pupil size change during incremental acute physical exercise?

Several studies have investigated the interaction between acute physical exercise and cognitive performance. However, few studies have investigated this issue during acute high-intensity exercise. In the present study, we evaluated executive functions (EFs) during incremental exercise in three different intensities [below lactate threshold (LT), at LT, and above LT], measuring EFs performance, gaze behavior, and pupil diameter. Twenty subjects were familiarized with the EFs test and participated in a graded maximal exercise test on a cycle ergometer on the first visit. On the second visit, they performed the EFs task at rest and while exercising at three different intensities using mobile eye-tracking glasses. Our results showed that the psychophysiological measures differed between the conditions. Regarding EFs performance, during exercise above LT, the subjects showed worse accuracy when compared with rest (p < .001) and below LT (p < .001). In addition, the response time (RT) at LT and above LT was shorter than in the rest condition (p < .050). Further, RT was faster (p = .002) in the above LT than in the below LT condition. In addition, the gaze behavior measures indicated that exercise, independently of the intensity, improves the number of fixations with shorter fixation durations compared to the rest condition (p < .050). Additionally, we found no significant differences in average and peak pupil diameter between conditions. In conclusion, exercise at LT improves the EFs performance while exercising above LT worsens EFs performance. However, there were no significant differences in average and peak pupil diameter between conditions.

Playing videogames or using social media applications on smartphones causes mental fatigue and impairs decision-making performance in amateur boxers.

This study aimed to analyze the effect of playing videogames and using social media applications on smartphones on decision-making and countermovement jump (CMJ) performance in amateur boxers. Twenty one boxers were enrolled in the study and were randomly assigned to all three experimental conditions [smartphone (30SMA), videogame (30VID), and control (CON)]. CMJ was measured before and 30-min after each experimental condition. The athletes ran simulated combat recorded for decision-making analysis. The boxers watched coaching videos (CON), used social media applications on smartphones (30SMA), and played video games (30VID) for 30 min just before the combat simulation. Both attack and defense decision-making performance were worse in both 30SMA and 30VID conditions compared to the CON condition (p = 0.001). Regarding CMJ, despite no condition effect (p = 0.96) been obtained, a time effect (p = 0.001) was observed; So, it was found a decrease in CMJ performance after all experimental conditions (p = 0.001), with no difference between them. Using social media applications on smartphones and playing video game impairs decision-making performance in amateur boxers, with no harms for CMJ performance.

Monitoring Training Loads in Judo Athletes: Different Time Courses of Physiological, Neuromuscular, and Perceptual Responses.

This study aims to elucidate the internal load, performance, physiological, and perceptual recovery responses during four weeks of traditional judo training. Ten cadet and junior judo athletes were evaluated daily for four weeks, in which their perception of recovery, heart rate variability, handgrip strength, and countermovement jump performance were assessed. A one-way repeated-measures ANOVA was performed to analyze the variables across the weeks. A significant time effect in internal load (F = 6.51; p = 0.001) has been observed. Handgrip test performance showed significantly higher values in the 3rd and 4th weeks (p <0.001), while countermovement jump performance was significantly higher in the 4th week (p =0.0007). The heart rate variability's coefficient of variation was lower in both the 3rd and 4th weeks (p =0.02). Regarding perceptual aspects, the Hooper Index showed a significant time effect (p =0.04), but pairwise comparison did not reveal differences between weeks. The present study indicates that neuromuscular, physiological, and perceptual responses to training load alterations present different time courses. This must be considered for the adequate monitoring of training programs.

Relative age effect in Olympic Taekwondo athletes.

Relative age effects refer to the effects of age differences among individuals who have been grouped together for a performance activity. This study aimed to investigate the relative age effect on Olympic Taekwondo athletes, in several Olympic Games, and in both sexes. The study sample consisted of 291 athletes who had competed in Atlanta, Sydney, and Beijing Olympic Games. The relative age effect was examined for the general distribution of athletes by quartile, for each of the individuals, and for male and female athletes. There were no discernable effects of relative age on Olympic Taekwondo athletes.

Development and reliability of a test for assessing executive functions during exercise.

Previous research suggests that performance on executive functions tests may be different at rest, versus when one is engaged in physical exercise. Therefore, the present study aimed to develop an integrated system that evaluates executive functions during exercise. We conducted two test-retest studies, with ten healthy male volunteers participating in each study. Participants visited the laboratory three (Study 1) or four (Study 2) times. During the first visit in both studies, questionnaires were administered, and a maximal cardiopulmonary exercise test (CPT) was performed. In Study 1, during the second and third visits, participants exercised on a cycle ergometer at a moderate intensity for 30 minutes before starting the Flanker/Reverse Flanker test while they were still cycling. In Study 2, during the second visit, participants performed three sets of the executive functions test while sitting on the bike, with a 5 min interval between each set. On visits 3 and 4, participants performed the same exercise protocol as the one described in Study 1. In summary, our results indicated that the Flanker/Reverse Flanker test that we developed and conducted in exercising individuals has similar elements to previous versions and can be considered a reliable test for executive functions assessment during exercise.

Effects of social media on smartphone use before and during velocity-based resistance exercise on cognitive interference control and physiological measures in trained adults.

The purpose is to analyze the effect of social networks on smartphones before and during velocity-based resistance exercise on the internal training load, heart rate variability (HRV), and cognitive interference control. Twelve trained adults volunteered to participate in this randomized and crossover design research study with three experimental conditions. The participants randomly performed a resistance exercise session, watching TV before (CON) the session or using social networks on a smartphone prior to (30SMA-P) and intra-session (SMA-INT). The participants underwent sets with repetitions [15RM load] up to 20% mean velocity loss. HRV indicators and cognitive interference control were measured before and 30-min after each experimental session. Internal training load was evaluated 30-min after each experimental session, which was calculated by the product between resistance exercise volume and RPE. No condition versus time interaction for HRV indicators (p > 0.05) was observed. It was not revealed a condition versus time interaction for cognitive interference control (p > 0.05). No condition effect for internal training load (p > 0.05) was observed. It was concluded that 30-min of social networks on smartphones before or intra-session resistance exercise had no effects on HRV indicators, cognitive interference control, and internal training load in trained adults.