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.

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.

Mechanical Determinants of Sprinting and Change of Direction in Elite Female Field Hockey Players.

Profile determination in field hockey is critical to determining athletes' physical strengths and weaknesses, and is key in planning, programming, and monitoring training. This study pursued two primary objectives: (i) to provide descriptive data on sprinting, deceleration, and change of direction (COD) abilities and (ii) to elucidate the mechanical variables that influence sprint and COD performance in elite female field hockey players. Using radar and time-gate technology, we assessed performance and mechanical data from 30 m sprinting, deceleration, and COD tests for 26 elite female hockey players. A machine learning approach identified mechanical variables related to sprint and COD performance. Our findings offer a framework for athlete categorization and the design of performance-enhancing training strategies at the international level. Two pivotal mechanical variables-relative maximum horizontal force (F0) and maximum velocity (Vmax)-predominantly influence the times across all tested distances. However, the force-velocity profile (FVP) and horizontal deceleration do not influence the variance in the COD test outcomes. These insights can guide the design, adjustment, and monitoring of training programs, assisting coaches in decision making to optimize performance and mitigate injury risks for female hockey players.

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.].

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.

The effects of weight categories on the time-motion analysis of female high-level judo athletes between the 2016 and 2020 Olympic cycles.

This study compared the time of female judo combat phases in international competitions between two Olympic cycles (2016; 2020) according to weight divisions (48 kg = 132; 52 kg = 72; 57 kg = 109; 63 kg = 96; 70 kg = 69; 78 kg = 106; >78 kg = 82; total = 666 combats/cycle). The behaviors of 1,332 high-level female judo combats were randomly observed over two Olympic cycles (2016 = 666; 2020 = 666) from the top 20 athletes in the world ranking by weight division. We performed time-motion analysis according to the combat phase and sequential judo actions (approach, gripping, attack, defense, groundwork, pause, and effort: pause ratio) considering the moment when the combat ended (Regular time = RT; Golden score = GS). The weight division groups were compared between Olympic cycles (2016; 2020), and p < 0.05 was defined as significant. The main results showed that 2020 athletes spent less time in the gripping (p = 0.005), attack (p < 0.001), defense (p < 0.001), groundwork (p<0.001) and pause (p = 0.002) phases than 2016 athletes. However, compared by the end-of-combat, 2020 female athletes spent less time in all combat phases for RT combats (p < 0.001), and more time in the approach phase for GS combats (p < 0.05) than in 2016. The 2016 weight divisions showed a higher diversity in the effort: pause ratio (2.5:1-3.4:1), whereas the 2020 weight divisions had values closer to each other (2.8,1-3:1). Analyzing each weight division separately and by the end-of-combat, the main results showed that (p < 0.05): 48, 63, 70, and 78 kg reduced the time in almost every phase of RT combat (except for: 63 kg = gripping and attack; 70 kg = approach and groundwork; 78 kg = approach); 48 and 57 kg increased the groundwork time in GS combats whereas 78 kg decreased; 52 kg and 78 kg increased the GS approach time. The temporal behavior of the combats changed between the Olympic cycles with different rules. These data must be considered to understand the characteristics of each group and to prescribe specialized training in female judo.

Dynamic Stretching Increases the Eccentric Rate of Force Development, but not Jump Height in Female Volleyball Players.

The present study aimed to analyze the effect of static and dynamic stretching exercises on the rate of force development (RFD) during the eccentric braking phase and jump height in a countermovement jump (CMJ) in female volleyball players. Thirty female volleyball players were randomly distributed in a static stretching (n = 10; SG), a dynamic stretching, and (n = 10; DG) a control group (n = 10; CG). A force plate and a 3D analysis system were employed to detect the eccentric braking phase during the CMJ. The RFD was analyzed in RFD (RFDi) intervals and the accumulated RFD (RFDa), and normalized to body mass. The SG experienced a likely small decrease in the RFDa (mean difference -17.4 N/s/kg) and a likely small decrease in the RFDi (mean difference -19.1 N/s/kg). Contrarily, the DG showed a likely small increase in the RFDa (mean difference 31.2 N/s/kg) and a most likely small increase in the RFDi (mean difference 34.8 N/s/kg). The effect of both static and dynamic stretching on jump height was trivial. Practitioners should consider utilizing dynamic stretching exercises instead of static stretching before a competition in female volleyball players. Further research is needed in order to find complementary strategies during the warm-up that could increase jump height.

Training at moderate altitude improves submaximal but not maximal performance-related parameters in elite rowers.

Maximal oxygen consumption (V̇O2max), physiological thresholds, and hemoglobin mass are strong predictors of endurance performance. High values of V̇O2max, maximal aerobic power (MAP), and power output at anaerobic thresholds are key variables in elite rowers. Endurance athletes often use altitude training as a strategy to improve performance. However, no clear evidence exists that training at natural altitude enhances sea-level performance in elite rowers. This study aimed to evaluate the effect of altitude training on rowing-performance parameters at sea level. The study was conducted on eleven rowers (Six females, five males) from the Chilean National Team during a 3-week moderate altitude training (∼2,900 m. a.s.l.) under the live high-train high (LHTH) model. It included a rowing ergometer maximal incremental test and blood analysis (pre and post-altitude). Gas exchange analysis was performed to measure V̇O2max, ventilatory thresholds (VTs) and rowing economy/efficiency (ECR/GE%). LHTL training improves performance-related variables at sea level (V̇Emax: 3.3% (95% CI, 1.2-5.5); hemoglobin concentration ([Hb]): 4.3% (95% CI, 1.7-6.9); hematocrit (%): 4.5% (95% CI, 0.9-8.2); RBC (red blood cells) count: 5.3% (95% CI, 2.3-8.2); power at VT2: 6.9% (95% CI, 1.7-12.1), V̇EVT2: 6.4% (95% CI, 0.4-12.4); power at VT1: 7.3% (95% CI, 1.3-13.3), V̇EVT1: 8.7% (95% CI, 1.6-15.8)) and economy/efficiency-related variables (ECRVT2: 5.3% (95% CI, -0.6 to -10.0); GE(%): 5.8% (95% CI, 0.8-10.7)). The LHTH training decreased breathing economy at MAP (-2.8% (95% CI, 0.1-5.6)), pVT2 (-9.3% (95% CI, -5.9 to -12.7)), and pVT1 (-9.3% (95% CI, -4.1 to -14.4)). Non-significant changes were found for V̇O2max and MAP. This study describes the effects of a 3-week moderate altitude (LHTH training) on performance and economy/efficiency-related variables in elite rowers, suggesting that it is an excellent option to induce positive adaptations related to endurance performance.

Effects of plyometric training on softer vs. Harder surfaces on jump-related performance in rugby sevens players.

This study aimed to compare jump-related performance after plyometric training on harder vs. softer surfaces in rugby sevens players. Fourteen players were randomly assigned to the harder surface group (H-G, n = 7) and softer surface group (S-G, n = 7). Three times per week, in the morning, the players performed plyometric training on different surfaces and strength training. Before and after the 4-week intervention period, squat jump (SJ), countermovement jump (CMJ), and CMJ with arms (CMJA) tests were performed to measure vertical jump displacement (d), rate of force development (r), and power (p). The main results indicated a significant improvement in S-G for CMJd (∆% = +8.2%; p = 0.029; ES = 0.59) and for CMJAp (∆% = +8.7%; p = 0.035; ES = 0.44). These improvements were significant compared to H-G for CMJAd (F1,12 = 8.50; p = 0.013; η p 2 = 0.41; ES = 0.83) and CMJAp (F1,12 = 7.69; p = 0.017; η p 2 = 0.39; ES = 0.79). This study reveals that performance related to the counter movement jump with arms on softer surfaces after 4-week plyometric training improved vertical jump displacement and lower body power in rugby sevens players.

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.

Effect of a Six Week In-Season Training Program on Wrestling-Specific Competitive Performance.

The effect of multi-component training on specific performance is under-researched in wrestlers. The aim of this study was to determine the effect of six weeks of multi-component training on The Special Wrestling Fitness Test (SWFT) performances of wrestlers who were preparing for an international championship, and to, additionally, determine their inter-individual adaptive variability. The wrestlers (n = 13; 7 females; all international level) underwent technical-tactical and physical fitness training for the six weeks before the championship, 12 sessions per week (i.e., 36 h per week). Before and after the intervention the athletes were assessed with the SWFT, a wrestling-specific competitive performance test that includes measurements for throws, heart rate response to the SWFT, and the SWFT index. Significant pre-post intervention improvements were noted for throws (pre = 23.5 ± 2.9; post = 24.9 ± 3.6; p = 0.022) and SWFTindex (pre = 14.9 ± 2.2; post = 14.1 ± 2.2; p = 0.013. In conclusion, six weeks of multi-component training improved wrestling-specific competitive performances in highly-trained wrestlers, although with a meaningful inter-subject variability.

Efectos en el estado de bienestar en periodo de confinamiento debido al COVID-19 en jugadores profesionales de fútbol / Effects on the wellness state in period of confinement due to COVID-19 in professional soccer players

Resumen El propósito del estudio fue conocer las alteraciones en el estado de bienestar en periodo de confinamiento debido al COVID-19 en jugadores de fútbol profesional de la primera división B de Chile. Participaron 28 jugadores profesionales de fútbol varones, edad 26 ± 6.3 años, masa corporal de 74.2 ± 5.5 kg y estatura de 177 ± 0.05 cm. Se evaluó el grado de bienestar a través de un cuestionario (McLean et al., 2010) durante periodo competitivo y periodo de confinamiento de la temporada 2020. Se muestran diferencias estadísticamente significativas (p<0.05) entre el periodo competitivo y el periodo de confinamiento, en FT (t = 2.5; p = 0.0), SO (t = 2.71; p = 0.01), ES (t = 5.07; p = 0.0), EA (t = 1.82; p = 0.08) y T (t = 4.87; p = 0.0). Se reflejaron TE pequeños en las variables EA y DM (d = 0.7; d = 0.4 respectivamente), moderados en FT y SO (d = 1.0; d = 1.2 respectivamente) y muy grandes en ES y T (d = 2.1; d = 2.0 respectivamente). Los PC y CV entre periodos para las variables de bienestar fueron para FT 11% y 11.6%, para DM 5.3% y 13.1%, para SO 9.3%; 7.5%, ES 11.6% y 5.9, para EA 3.9%; 5.2%, y finalmente para T 8.1% y 4.0% respectivamente. Es posible concluir que el estado de bienestar en jugadores profesionales de fútbol se ve alterado en el periodo de confinamiento respecto al de competición, encontrándose cambios significativos en las variables FT, SO, ES y T, que coincidieron con los cambios de moderados a muy grandes de estas mismas variables, como también los PC fueron más grandes que el CV entre periodos; por lo que podríamos considerar estos cambios como reales, y que pudiesen ser un efecto atribuible al aislamiento obligatorio.

Abstract This study aimed to find changes in the wellness state, during the confinement period due to COVID-19, in professional soccer players from the first division B of Chile. The studied sample consisted of 28 professional male soccer players aged 26 ± 6.3 years, body mass 74.2 ± 5.5 kg, and height 177 ± 0.05 cm. The degree of well-being was evaluated through a questionnaire (McLean et al., 2010) during the 2020 competitive and confinement periods. Statistically, significant differences (p <0.05) between the competitive period and the confinement period are shown in FT (t = 2.5; p = 0.0), SO (t = 2.71; p = 0.01), ES (t = 5.07; p = 0.0), EA (t = 1.82; p = 0.08), and T (t = 4.87; p = 0.0). Small TE were reflected in the variables EA and DM (d = 0.7; d = 0.4 respectively), moderate in FAT and SO (d = 1.0; d = 1.2 respectively), and very large in ES and T (d = 2.1; d = 2.0 respectively). The CP and CV between periods for the well-being variables were the following: for FAT, 11% and 11.6%, for DM, 5.3% and 13.1%; for SO, 9.3%; 7.5%, ES 11.6% and 5.9, for EA 3.9%; 5.2%, and finally for T 8.1% and 4.0% respectively. It is possible to conclude that the state of well-being in professional soccer players is altered in the period of confinement with respect to that of competition, finding significant changes in the variables FT, SO, ES, and T, which coincided with the changes from moderate to very large of these same variables, as well as the PC were larger than the CV between periods. Therefore, we could consider these changes as real, and they could be an effect attributable to the mandatory isolation.

Resumo O objetivo do estudo foi conhecer as alterações no estado de bem-estar no período de confinamento devido à COVID-19 entre jogadores profissionais de futebol da primeira divisão B do Chile. Vinte e oito jogadores profissionais de futebol masculino participaram, com idade de 26 ± 6,3 anos, massa corporal de 74,2 ± 5,5 kg e altura de 177 ± 0,05 cm. O grau de bem-estar foi avaliado por meio de um questionário (McLean et al., 2010) durante os períodos competitivos e de confinamento da temporada 2020. Forma demonstradas diferenças estatisticamente significativas (p<0,05) entre o período competitivo e o de confinamento, em FT (t = 2,5; p = 0,0), SO (t = 2,71; p = 0,01), ES (t = 5,07; p = 0,0), EA (t = 1,82; p = 0,08) e T (t = 4,87; p = 0,0). TE pequenos foram refletidos nas variáveis EA e DM (d = 0,7; d = 0,4 respectivamente), moderados em FT e SO (d = 1,0; d = 1,2 respectivamente) e muito grandes em ES e T (d = 2,1; d = 2,0 respectivamente). O PC e o CV entre períodos para as variáveis de bem-estar foram para FT 11% e 11,6%, para DM 5,3% e 13,1%, para SO 9,3%; 7,5%, ES 11,6% e 5,9, para EA 3,9%; 5,2%, e finalmente para T 8,1% e 4,0% respectivamente. É possível concluir que o estado de bem-estar dos jogadores de futebol profissional ficou alterado no período de confinamento em relação ao período de competição, encontrando alterações significativas nas variáveis FT, SO, ES e T, que coincidiram com alterações moderadas a muito grandes nestas mesmas variáveis, assim como o PC foi maior que o CV entre períodos; desta forma, poderíamos considerar estas alterações como reais, e que poderiam ser um efeito atribuível ao isolamento obrigatório.

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.

Diferencias de carga interna y externa entre futbolistas adultosy juveniles en un partido amistoso / Differences in internal and external load between adult and youth players in a friendly match

Objetivo: Determinar diferencias de carga interna y externa durante un partido no-oficial entre jugadores de Primera División Adultos y Sub-19 del mismo club empleando sistemas portátiles de posicionamiento global. Método: Durante un partido no-oficial entre una categoría Adulta y una Sub-19, se monitoreó la carga interna a través de la frecuencia cardíaca y carga externa a través del rendimiento de carrera. Se monitorearon a siete jugadores adultos (25,57 ± 5,06 años) y cinco jugadores Sub-19 (18,6 ± 0,54 años). Se realizaron comparaciones entre las categorías en el primer tiempo, segundo tiempo y partido total mediante la prueba U de Mann-Whitney y calculando los tamaños del efecto a través de porcentajes de diferencia (PD). Resultados: Se encontraron diferencias (p<0,05) de carga externa en velocidad máxima en primer tiempo y partido total, alcanzando los jugadores Sub-19 los valores más elevados (velocidad máxima primer tiempo: 32,34 vs 27,77 km/h y PD = 15,3%; partido total: 32,6 vs 28,14 km/h y PD = 14,7%). Por otro lado, solo se hallaron diferencias en carga interna en zona 3 de frecuencia cardíaca (70 a 80% de la FC máxima) en primer y segundo tiempo, donde los jugadores Sub-19 pasaron más tiempo en esta zona (zona 3 de frecuencia cardiaca primer tiempo: 6,1 vs 1,73 minutos y PD = 111,6%; segundo tiempo: 20,49 vs 5,21 minutos y PD = 118,8%). No se hallaron diferencias en las demás variables analizadas. Conclusión: A partir de los resultados obtenidos podemos concluir que no existen diferencias de carga interna y externa en jugadores adultos con jugadores sub-19, con excepción de velocidad máxima y zona 3 de frecuencia cardiaca en este equipo durante un partido no oficial. Por lo que, para efectos prácticos, los jugadores Sub-19 de este equipo, podrían encontrarse en condiciones para enfrentar las exigencias físicas que requiere la competencia de categoría adulta.(AU)

Objective: To determine differences in internal and external load during an unofficial match between First Division Adult and U-19 players of the same club using portable global positioning systems. Methods: During an unofficial match between an adult and a U-19 category, internal load through heart rate and external load through running performance were monitored. Seven adult players (25.57 ± 5.06 years) and five U-19 players (18.6 ± 0.54 years) were monitored. Comparisons were made between categories in the first half, second half and total match using the Mann-Whitney U test and calculating effect sizes through percent difference (PD). Results: Differences were found (p<0.05) of external load in maximum speed in first half and total match, with U-19 players reaching the highest values (maximum speed first half: 32.34 vs 27.77 km/h and PD = 15.3%; total match: 32.6 vs 28.14 km/h and PD = 14.7%). On the other hand, differences in internal load were only found in heart rate zone 3 (70 to 80% of maximum HR) in the first and second half, where U-19 players spent more time in this zone (heart rate zone 3 first half: 6.1 vs 1.73 minutes and PD = 111.6%; second half: 20.49 vs 5.21 minutes and PD = 118.8%). No differences were found in the other variables analyzed. Conclusion: From the results obtained we can conclude that there are no differences in internal and external load in adult players with U-19 players, except for maximum speed and heart rate zone 3 in this team during a non-official match. Therefore, for practical purposes, the U-19 players of this team could be in conditions to face the physical demands required by the adult category competition.(AU)

Changes in the Mechanical Properties of the Horizontal Force-Velocity Profile during a Repeated Sprint Test in Professional Soccer Players.

The objective was to analyze the changes in the horizontal force-velocity profile (HFVP) during the execution of repeated sprinting. Methods: Seventeen first-division Chilean soccer players completed a repeated sprint protocol consisting of eight sprints of 30 m with 25-s pauses between repetitions. The behavior of HFVP variables in each attempt was recorded from video recordings and analysis in the MySprint® application. Results: Differences (p < 0.05) were found between sprints in the following: time (T), starting from sprint 5 (F = 35.6; η2p = 0.69); theoretical maximum speed (V0), starting from sprint 4 (F = 29.3; η2p = 0.51); maximum power (PM), starting from sprint 5 (F = 17; η2p = 0.52); rate of decrease in force index produced at each step (DRF), starting from sprint 1 (F = 3.20; η2p = 0.17); and RF10, starting from sprint 1 (F = 15.5; η2p = 0.49). In comparison, F0 and RFpeak did not present any differences (p > 0.05). Conclusion: The HFVP variables more sensitive to the effects of fatigue induced by an RSA protocol are those associated with the production of force at high speeds, being V0, DRF, and Pmax, while those that contribute to the generation of force at the beginning of the sprint, F0 and RFpeak, do not present essential variations.

Vínculo entre composición corporal, sprint y salto vertical en futbolistas jóvenes de élite de Chile / Link Between Body Composition, Sprint and Vertical Jump in Young Elite Soccer Players from Chile

Resumen El objetivo de este trabajo fue conocer las relaciones entre indicadores de composición corporal y rendimiento físico en jugadores jóvenes de élite y determinar si existen diferencias entre posiciones de juego y series. La muestra fue de futbolistas seleccionados Sub-15 (n=24) y Sub-17 (n=20) varones, divididos por posición de juego. Se evaluaron indicadores composición corporal, porcentaje de masa grasa (%MG) y porcentaje de masa muscular (%MM). Se evaluaron salto desde sentadilla (SJ), salto con contramovimiento (CMJ), velocidad lineal en 10 (T10) y 30 metros (T30). Se relacionaron variables de composición corporal y rendimiento físico, y se buscaron diferencias entre posiciones de juego y entre categorías. Se hallaron grandes asociaciones significativas en la categoría Sub-15 entre %MM con SJ y CMJ, y moderadas entre %MG con T10, SJ y CMJ. En Sub-17 una asociación significativa grande entre %MM y T30, y entre %MG y T30. Se hallaron diferencias significativas en %MG en la categoría Sub-17, entre los arqueros vs defensas y delanteros. Se encontraron diferencias significativas moderadas en %MM entre categorías y diferencias muy grandes en T10 y T30, y una diferencia moderada en SJ. Es posible concluir que la composición corporal %MM y %MG se relaciona con el rendimiento físico. Además, existen diferencias en %MG entre los arqueros vs los jugadores de campo y diferencias en las variables de composición corporal y rendimiento físico entre jugadores Sub-17 y sub-15. Los resultados obtenidos pueden servir de referencia o de parámetros de comparación de jugadores jóvenes a nivel nacional en la detección de talentos.

Abstract The study aimed to know the relationships between indicators of body composition and physical performance in elite young players and determine if there are differences between playing positions and series. The sample was of selected U-15 (n=24) and U-17 (n=20) male players, divided by playing position. Body composition, fat mass percentage (%MG), and muscle mass percentage (%MM) indicators were evaluated. Also, Squat Jump (SJ), Countermovement Jump (CMJ), linear velocity in 10 (T10) and 30 meters (T30) were evaluated. Body composition and physical performance variables were related, and differences between playing positions and between categories were sought. Significant large associations were found in the U-15 category between %MM with SJ and CMJ and moderate associations between %MG with T10, SJ, and CMJ. In the U-17 category, a significant large association was found between %MM and T30 and between %MG and T30. Significant differences in %MG were found in the U-17 category between goalkeepers vs. defenders and forwards. Moderate significant differences were found in %MM between categories and very large differences in T10 and T30, and a moderate difference in SJ. Therefore, it is possible to conclude that the body composition %MM and %MG is related to physical performance. In addition, there are differences in %MG between goalkeepers vs. outfield players and differences in body composition and physical performance variables between U-17 and U-15 players. The results obtained can be used as a reference or as parameters for comparing young players at the national level in the detection of talent.

Resumo O objetivo deste trabalho foi conhecer as relações entre indicadores de composição corporal e desempenho físico em jovens jogadores de elite e verificar se existem diferenças entre posições de jogo e séries. A amostra foi composta por jogadores de futebol masculino sub-15 (n = 24) e sub-17 (n = 20) selecionados, divididos por posição de jogo. Foram avaliados indicadores de composição corporal, percentual de massa gorda (% MG) e percentual de massa muscular (% MM). Foram avaliados o salto de agachamento (SJ), salto de contra movimento (CMJ), velocidade linear a 10 (T10) e 30 metros (T30). Variáveis de composição corporal e desempenho físico foram relacionadas, e diferenças entre as posições de jogo e entre as categorias foram pesquisadas. Grandes associações significativas foram encontradas na categoria de menores de 15 anos entre% MM com SJ e CMJ, e moderadas entre% MG com T10, SJ e CMJ. Em Sub-17, uma grande associação significativa entre% MM e T30 e entre% MG e T30. Diferenças significativas foram encontradas na % MG na categoria Sub-17, entre goleiros x zagueiros e atacantes. Diferenças moderadas significativas foram encontradas em % MM entre as categorias e diferenças muito grandes em T10 e T30, e uma diferença moderada em SJ. É possível concluir que a composição corporal % MM e% MG está relacionada ao desempenho físico. Além disso, há diferenças na % MG entre goleiros e jogadores de campo e diferenças nas variáveis de composição corporal e desempenho físico entre jogadores Sub-17 e Sub-15. Os resultados obtidos podem servir de referência ou parâmetro de comparação de jovens jogadores a nível nacional para a detecção de talentos.

Effects of Olympic Combat Sports on Older Adults' Health Status: A Systematic Review.

The aim of this systematic review was to analyse the studies centered on the effects of Olympic combat sports (OCS [i.e., boxing, fencing, judo, karate, taekwondo, wrestling]) on older adults' physical-functional, physiological, and psychoemotional health status. The review comprised randomised-controlled trials with OCS interventions, including older adults (≥60 years), and measures of physical-functional, physiological, and/or psychoemotional health. The studies were searched through SCOPUS, PubMed/MEDLINE, Web of Science, PsycINFO, and EBSCO databases until 5 January 2021. The PRISMA-P and TESTEX scales were used to assess the quality of the selected studies. The protocol was registered in PROSPERO (code: CRD42020204034). Twelve OCS intervention studies were found (scored ≥ 60% for methodological quality), comprising 392 females and 343 males (mean age: 69.6 years), participating in boxing, judo, karate, and taekwondo. The qualitative analysis revealed that compared to controls, OCS training improved muscle strength, cardiorespiratory capacity, agility, balance, movement, attention, memory, mental health, anxiety, and stress tolerance. Meta-analysis was available only for the chair stand test, and an improvement was noted after OCS training compared to control. In conclusion, OCS interventions improves older adults' physical-functional, physiological, and psychoemotional health. Our systematic review confirms that OCS training has high adherence (greater than 80%) in older adults.

Effects of COVID-19 confinement measures on training loads and the level of well-being in players from Chile women's national soccer team / Efectos de las medidas de confinamiento por COVID-19 en el grado de bienestar y la carga de entrenamiento de las jugadoras de la selección nacional de fútbol de Chile

Abstract Introduction: Due to the current COVID-19 pandemic, many countries have implemented control and prevention measures, such as compulsory lockdowns, affecting all spheres of life. Since the field of professional soccer is no exception, such measures may have a negative impact on the player's well-being and their perceived training loads. Objective: To determine the impact of COVID-19 lockdown measures on the training load and the well-being of female professional soccer players in Chile. Materials and methods: Exploratory, cross-sectional, descriptive study conducted on 32 players of the Chile women's national soccer team. The perception of training load and the level of well-being were assessed by means of the rating of perceived exertion (RPE) scale and a questionnaire developed in 2010, respectively. Both the administration of the questionnaire and the permanent monitoring of the RPE records were carried out in two periods of 12 weeks: regular preparatory phase (12/12/2019-10/03/2020) and lockdown (16/03/2020-07/06/2020). Data were analyzed using descriptive statistics and the Wilcoxon test was used to determine if there were significant differences between periods. Results: Significant differences (p<0.05) and threshold effect sizes (ES)=1.2, 2.0 and 4.0 (large, very large, and extremely large, respectively) were found between both periods in all variables evaluated by the well-being questionnaire (except for sleep quality): muscle soreness and stress level (ES=1.9), perceived fatigue (ES=2.5), general well-being (ES=2.4), and mood (ES=4.2). No differences were found regarding the perception of the training load (ES=0.1) between both periods. Conclusions: The level of well-being among the participants was negatively affected by the compulsory lock-down. Therefore, coaching staffs should continue to monitor the level of the well-being of professional soccer players during the lockdown, both individually and collectively. Even though the perception of training load was not affected, it is not possible to state that a more extended period of confinement will not reduce it, resulting in a drop in performance.

Resumen Introducción. Debido a la actual pandemia por COVID-19, muchos países tomaron medidas de control y prevención como el confinamiento obligatorio, afectando todas las esferas de la vida. Ya que los futbolistas profesionales no son una excepción, este tipo de medidas puede tener un impacto negativo en su bienestar y en su percepción sobre las cargas de entrenamiento. Objetivo. Determinar los efectos de las medidas de confinamiento por COVID-19 en la carga de entrenamiento y el grado de bienestar de jugadoras de fútbol profesional de Chile. Materiales y métodos. Estudio transversal, exploratorio-descriptivo realizado en 32 jugadoras de la Selección Nacional de Fútbol de Chile. El grado de bienestar y la carga de entrenamiento se evaluaron mediante un cuestionario desarrollado en 2010 y mediante la escala de percepción subjetiva del esfuerzo (PSE) y el volumen de entrenamiento expresado en minutos, respectivamente. Ambas evaluaciones se realizaron en 2 periodos de 12 semanas : periodo preparatorio regular (12/12/2019-10/03/2020) y periodo de confinamiento (16/03/2020-07/06/2020). Los datos se analizaron mediante estadística descriptiva y la prueba de Wilcoxon se utilizó para determinar si hubo diferencias significativas entre ambos periodos. Resultados. Se encontraron diferencias significativas (p<0.05) y umbrales de tamaño del efecto (TE) iguales a 1.2, 2.0 y 4.0 (grande, muy grande y extremadamente grande, respectivamente) entre ambos periodos en todas las variables evaluadas por el cuestionario de bienestar (a excepción de calidad de sueño): dolor muscular y nivel de estrés (TE=1.9), fatiga percibida (TE=2.5), bienestar general (TE=2.4) y estado de ánimo (TE=4.2). No se observaron diferencias en la PSE (TE=0.1) entre ambos periodos. Conclusiones. El confinamiento obligatorio afectó negativamente el grado de bienestar de las participantes, por lo que es necesario que los cuerpos técnicos monitoreen constantemente, de manera individual y colectiva, el grado de bienestar de los futbolistas profesionales durante estos periodos; si bien la percepción en la carga de entrenamiento no se vio afectada, no es posible asegurar que un periodo mayor de confinamiento no la disminuya y esto resulte en una baja del rendimiento.

Caffeine improves biochemical and specific performance after judo training: a double-blind crossover study in a real judo training situation.

BACKGROUND: Nutritional ergogenic aids are foods or nutrients that can improve physical performance. Among these foods with ergogenic properties, caffeine has shown that it can increase the fat catabolism, strength, and improve the cognition and time reaction of an athlete, therefore, it is hoped that it can improve the performance of judokas. This study through a double-blind crossover (supplement X placebo) protocol, investigated the effects caffeine supplementation (single capsule containing 5 mg/kg body mass intake 60 min before the session) on biochemical, anthropometrical, physical, subjective and hemodynamic variables measured before, during and after two typical judo trainingcxs sessions (120-min: 40-min of gymnastics; 40-min of specific technics and; 40-min of judo combat). METHODS: 8 high-level athletes (21.4 ± 2.0 years; 83.6 ± 15.2 kg; 1.8 ± 0.1 m; 17.9 ± 7.0 Fat%) were evaluated before and after each training for body mass, hydration, upper and lower limb power, performance in the special judo fitness test (SJFT), free fatty acids (FFA) in plasma, uric acid, glucose, lactate, heart rate, and pain. In addition, heart rate, FFA in plasma, uric acid, glucose, lactate, rating of perceived exertion and pain were assessed during the training. RESULTS: At 120 min, supplementation resulted in a higher concentration of plasma FFA (1.5 ± 0.5 vs. 1.0 ± 0.3 mmol/L; p = 0.047) and lactate (4.9 ± 1.8 vs. 3.0 ± 1.2 mmol/L; p = 0.047), and a lower concentration of uric acid (5.4 ± 0.9 vs. 7.0 ± 1.5 mg/dL; p = 0.04). Supplementation also resulted in performance maintenance (fatigue index) in the SJFT (Δ0.3 ± 2.0 vs Δ1.7 ± 2.5, for caffeine and placebo respectively, p = 0.046). No adverse effects were observed. CONCLUSION: Based on the applied dose, intake time, and sample of this study, we can conclude that caffeine produces an ergogenic biochemical effect, and improves performance in judo athletes.

Comparisons of Motor Actions and Biomechanical Assessments of Judo Techniques Between Female Weight Categories.

This study aimed to perform motor action and biomechanical analysis of techniques in female judo athletes separated by weight categories of 638 female bouts (103 extra lightweight <48 kg, 140 half lightweight 48>52 kg, 65 lightweight 52>57 kg, 73 half middleweight 57>63 kg, 77 middleweight 63>70 kg, 80 half heavyweight 70>78 kg and 60 heavyweight >78 kg). All bouts were analyzed following the phases of approach, gripping, defensive action, attack, also biomechanical analysis of techniques and groundwork was performed (p ≤ .05). Results indicated that lightweight athletes presented lower attempts to grip, right collar grip and left collar grip frequencies than other categories. Extra lightweight judokas presented lower right back grip and left back and sleeve grip frequencies as well as lower occurrence of techniques with arm and leg lever scored than half lightweight athletes, while half lightweight athletes demonstrated higher frequency of techniques with waist lever variable scored than lightweight ones. These findings should be considered for training prescription.