Profiling the Physical Performance of Young Boxers with Unsupervised Machine Learning: A Cross-Sectional Study.

Mexico City is the location with the largest number of boxers in Mexico; in fact, it is the first city in the country to open a Technological Baccalaureate in Education and Sports Promotion with a pugilism orientation. This cross-sectional study aimed to determine the physical-functional profile of applicants for admission to the baccalaureate in sports. A total of 227 young athletes (44F; 183M; 15.65 (1.79) years; 63.66 (14.98) kg; >3 years of boxing experience) participated in this study. Body mass (BM), maximal isometric handgrip (HG) strength, the height of the countermovement jump (CMJ), the velocity of straight boxing punches (PV), and the rear hand punch impact force (PIF) were measured. The young boxers were profiled using unsupervised machine learning algorithms, and the probability of superiority (ρ) was calculated as the effect size of the differences. K-Medoids clustering resulted in two sex-independent significantly different groups: Profile 1 (n = 118) and Profile 2 (n = 109). Except for BM, Profile 2 was statistically higher (p < 0.001) with a clear distinction in terms of superiority on PIF (ρ = 0.118), the PIF-to-BM ratio (ρ = 0.017), the PIF-to-HG ratio (ρ = 0.079) and the PIF-to-BM+HG ratio (ρ = 0.008). In general, strength levels explained most of the data variation; therefore, it is reasonable to recommend the implementation of tests aimed at assessing the levels of isometric and applied strength in boxing gestures. The identification of these physical-functional profiles might help to differentiate training programs during sports specialization of young boxing athletes.

Efecto del confinamiento sobre la inactividad física en poblaciones infanto-juveniles / Efeito do confinamento sobre a inatividade física em populações infantis e juvenis / Effect of confinement on physical inactivity in child and juvenile populations

RESUMEN Introducción: Un brote de enfermedad por una variedad de coronavirus que afecta a los humanos comenzó en diciembre de 2019 en Wuhan, China, donde hasta enero del 2022 ha provocado más de cinco millones y medio de muertes. A medida que la pandemia de COVID-19 continúa desarrollándose a escala mundial, las autoridades de los diferentes territorios y países han introducido varias medidas de protección, incluido el cierre de escuelas, universidades, la prohibición de viajes, eventos culturales, deportivos y de reuniones sociales. Estos procesos de reclusión y aislamiento social obligatorios fueron una realidad impuesta por el gobierno argentino como medio preventivo frente a la pandemia del SARS-CoV-2. Actualmente, existen pocos registros estadísticos donde se muestren las afectaciones ocasionadas en el estado físico de poblaciones infanto-juveniles, que hayan sido confinadas debido a las medidas preventivas tomadas frente a la pandemia del Covid-19. Objetivo: Por tal motivo, en este estudio se pretendió describir algunos de los efectos del confinamiento sobre la inactividad física en poblaciones infanto-juveniles de Comodoro Rivadavia y Rada Tilly. Materiales y métodos: Se emplearon métodos y técnicas científicas de investigación como el analítico-sintético, inductivo-deductivo, análisis de documentos y un cuestionario anónimo, contestado por 466 sujetos (femenino= 237 - masculino= 229), cuyas edades eran de 12±6 años. Resultados: Con los datos obtenidos, se concluyó (P<0,05) que esta población sufrió un incremento en el tiempo frente a las pantallas, disminuyendo el tiempo empleado para realizar actividad física, provocando modificaciones asociadas a un incremento en la cantidad de sueño, debido al confinamiento. Conclusiones: Esta situación traerá consecuencias a futuro; por ello que es necesario generar estrategias que permitan un entorno activo a través del ejercicio físico.

RESUMO Introdução: Um surto de doença de uma cepa de coronavírus afetando seres humanos começou em dezembro de 2019 em Wuhan, China, onde em janeiro de 2022 resultou em mais de cinco milhões e meio de mortes. Como a pandemia da COVID-19 continua a se desenvolver em escala global, as autoridades em diferentes territórios e países introduziram várias medidas de proteção, incluindo o fechamento de escolas, universidades, proibições de viagens, eventos culturais, encontros esportivos e sociais. Estes processos de isolamento obrigatório e isolamento social foram uma realidade imposta pelo governo argentino como medida preventiva contra a pandemia de SARS-CoV-2. Atualmente, há poucos registros estatísticos mostrando os efeitos na condição física de crianças e jovens que foram confinados devido às medidas preventivas tomadas em resposta à pandemia de Covid-19. Objetivo: Por esta razão, o objetivo deste estudo foi descrever alguns dos efeitos do confinamento sobre a inatividade física em populações infantis e jovens em Comodoro Rivadavia e Rada Tilly. Materiais e métodos: Utilizamos métodos e técnicas de pesquisa científica como analítico-sintético, indutivo-dedutivo, análise de documentos e um questionário anônimo, respondido por 466 sujeitos (feminino= 237 - masculino= 229), cuja idade era de 12±6 anos. Resultados: Com os dados obtidos, concluiu-se (P<0,05) que esta população sofreu um aumento no tempo diante das telas, diminuindo o tempo gasto em atividade física, causando modificações associadas a um aumento na quantidade de sono, devido ao confinamento. Conclusões: Esta situação terá conseqüências no futuro; portanto, é necessário gerar estratégias que permitam um ambiente ativo através do exercício físico.

ABSTRACT Introduction: An outbreak of disease due to a variety of coronavirus that affects humans began in December 2019 in Wuhan, China, where as of January 2022 it has caused more than five and a half million deaths. As the COVID-19 pandemic continues to unfold on a global scale, authorities in different territories and countries have introduced various protective measures, including the closure of schools, universities, travel bans, cultural, sporting and meeting, as well as social events. These compulsory social isolation and confinement processes were a reality imposed by the Argentine government as a preventive measure against the SARS-CoV-2 pandemic. Currently, there are few statistical records showing the damage caused to the physical state of child and adolescent populations, which have been confined due to the preventive measures taken against the Covid-19 pandemic. Objective: For this reason, this study aimed to describe some of the effects of confinement on physical inactivity in child and juvenile populations in Comodoro Rivadavia and Rada Tilly. Materials and methods: Scientific research methods and techniques were used, such as analytical-synthetic, inductive-deductive, document analysis and an anonymous questionnaire, answered by 466 subjects (female= 237 - male= 229), whose ages were 12± 6 years. Results: With the data obtained, it was concluded (P<0.05) that this population suffered an increase in the time spent in front of the screens, decreasing the time used to perform physical activity, causing changes associated with an increase in the amount of sleep, due to confinement. Conclusions: This situation will bring consequences in the future; therefore, it is necessary to generate strategies that allow an active environment through physical exercise.

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.

Mejora del rendimiento post-activación con banco plano o landmine en la fuerza del golpe recto / Melhoria do desempenho de pós-ativação com banco plano ou landmine na força do golpe reto / Post-activation performance enhancement with bench press or landmine on straight punch strength

RESUMEN La presente investigación centró sus esfuerzos en descubrir alternativas metodológicas que beneficien la posibilidad de aplicar altos niveles de fuerza en el golpe recto, favoreciendo con ello la probabilidad de una victoria por la vía del knock out. La hipótesis de trabajo planteó que, si se emplean ejercicios con un efecto de mejora del rendimiento postactivación, se puede incrementar la fuerza aplicada al golpe recto. Este cuasi-experimento tuvo como objetivo determinar los efectos agudos de la mejora del rendimiento postactivación en la fuerza aplicada en el golpe recto, utilizando el banco plano o el Landmine como actividad condicionante. Se trabajó con 20 boxeadores (ocho profesionales y 12 amateur), y dividió la población en dos grupos, emparejados según el peso corporal. Se evaluó la fuerza máxima de impactocon una celda de carga modelo WLCC01, luego se determinó la fuerza máxima dinámica para cada ejercicio, y a partir de estos datos, se colocó una carga a movilizar del 60 % de la fuerza máxima dinámica, ejecutando repeticiones hasta que la velocidad del movimiento disminuyó más del 10 %. Seguidamente, se volvió a evaluar la fuerza máxima de impacto. Se tomaron registros inmediatamente después, al minuto uno, dos, tres, cuatro y cinco. Los resultados expresaron un aumento del 9.3 % en el grupo de banco plano y del 12,46 % en el grupo de Landmine. Se concluyó que ambos ejercicios, al ser utilizados como actividad condicionante, generan un incremento significativo (p 0.05) de la fuerza máxima de impacto en el golpe recto.

RESUMO A presente investigação centrou os seus esforços na descoberta de alternativas metodológicas que beneficiem a possibilidade de aplicar níveis elevados de força no golpe reto, favorecendo assim a probabilidade de uma vitória por knock-out. A hipótese de trabalho propôs que, se forem utilizados exercícios com um efeito de melhoria do desempenho pós-ativação, a força aplicada ao golpe reto pode ser aumentada. Esta quase-experimentação visava determinar os efeitos agudos do melhoramento do desempenho pós-ativação sobre a força aplicada ao golpe reto, utilizando como atividade condicionadora a bancada plana ou Landmine. Trabalhámos com 20 pugilistas (oito profissionais e 12 amadores). A força máxima de impacto foi avaliada com uma célula de carga modelo WLCC01, depois a força dinâmica máxima foi determinada para cada exercício, e a partir destes dados, foi colocada uma carga para mobilizar 60 % da força dinâmica máxima, executando repetições até a velocidade do movimento diminuir mais de 10 %. Depois, a força máxima de impacto foi reavaliada. Os registos foram tirados imediatamente após, aos um, dois, três, quatro e cinco minutos. Os resultados mostraram um aumento de 9,3 % no grupo dos bancos planos e de 12,46 % no grupo das minas terrestres. Concluiu-se que ambos os exercícios, quando utilizados como atividade condicionante, geram um aumento significativo (p 0,05) da força máxima de impacto no soco reto.

ABSTRACT The present research focused its efforts on discovering methodological alternatives that benefit the possibility of applying high levels of strength in the straight punch, thus favoring the probability of a victory by knockout. The working hypothesis proposed that, if exercises with a post-activation performance enhancement effect are used, the strength applied to the straight punch can be increased. This quasi-experiment aimed to determine the acute effects of post activation performance enhancement on the strength applied to the straight punch, using the bench press or the Landmine as the conditioning activity. It was worked with 20 boxers (eight professional and 12 amateur), and the population was divided into two groups, matched according to body weight. The maximum impact strength was evaluated with a load cell model WLCC01, then the maximum dynamic strength was determined for each exercise, and from this data, a load was placed to mobilize 60 % of the maximum dynamic strength, performing repetitions until the speed of the movement decreased by more than 10 %. Then, the maximum impact strength was re-evaluated. Records were taken immediately after, at one, two, three, four and five minutes. The results showed an increase of 9.3 % in the bench press group and 12.46 % in the Landmine group. It was concluded that both exercises, when used as conditioning activity, generate a significant increase (p 0.05) of the maximum impact strength in the straight punch.

Effect of the COVID-19 quarantine on body mass among combat sports athletes / Efecto de la cuarentena de la COVID-19 sobre el peso corporal de los practicantes de deportes de combate

INTRODUCTION: to combat the COVID-19 pandemic governments have adopted measures such as quarantine and social distancing. OBJECTIVE: the main objective of the present study was to analyze the impact of COVID-19 quarantine on body mass in combat sports athletes. METHODS: we conducted a cross-sectional, prospective, multi-center study that evaluated 234 men (mean age and standard deviation, 29 ± 10 years) residing in Argentina (n = 38); Bolivia (n = 1); Brazil (n = 105); Chile (n = 30); El Salvador (n = 1); Spain (n = 22); Mexico (n = 22) and Peru (n = 15). Of these, 12 practiced Brazilian jiu-jitsu (BJJ), 54 boxing, 67 judo, 13 karate, 52 kick boxing & muay thai (KB & MT), 9 mixed martial arts (MMA), and 27 taekwondo (TKD). An online survey was created using Google Forms. It was implemented between April 4th and April 17th, 2020. Athletes were consulted about their body mass before starting the quarantine and after 20 ± 5 days of quarantine. RESULTS: athletes in all combat sports were heavier during quarantine as compared to pre-quarantine (p < 0.001, d = 0.12). CONCLUSIONS: combat sports athletes experienced an increase in body mass during the COVID-19 quarantine

INTRODUCCIÓN: para combatir la pandemia de COVID-19, los gobiernos han adoptado medidas como la cuarentena y el distanciamiento social. OBJETIVO: el principal objetivo del presente estudio fue analizar el impacto de la cuarentena por COVID-19 sobre la masa corporal en atletas de deportes de combate. MÉTODOS: realizamos un estudio transversal, prospectivo y multicéntrico que evaluó a 234 hombres (media de edad y desviación estándar, 29 ± 10 años) que residen en Argentina (n = 38); Bolivia (n = 1); Brasil (n = 105); Chile (n = 30); El Salvador (n = 1); España (n = 22); México (n = 22) y Perú (n = 15). De estos, 12 practicaban jiu-jitsu brasileño (BJJ), 54 boxeo, 67 judo, 13 karate, 52 kick boxing y muay thai (KB y MT), 9 artes marciales mixtas (MMA) y 27 taekwondo (TKD). Se creó una encuesta en línea usando Google Forms. Se implementó entre el 4 y el 17 de abril de 2020. Se preguntó a los deportistas sobre su masa corporal antes de comenzar la cuarentena y después de 20 ± 5 días de cuarentena. RESULTADOS: los atletas de todos los deportes de combate resultaron más pesados durante la cuarentena que durante la precuarentena (p < 0,001, d = 0,12). CONCLUSIONES: los atletas de deportes de combate presentaron una mayor masa corporal durante la cuarentena a causa de la COVID-19

Effect of the COVID-19 quarantine on body mass among combat sports athletes.

INTRODUCTION: Introduction: to combat the COVID-19 pandemic governments have adopted measures such as quarantine and social distancing. Objective: the main objective of the present study was to analyze the impact of COVID-19 quarantine on body mass in combat sports athletes. Methods: we conducted a cross-sectional, prospective, multi-center study that evaluated 234 men (mean age and standard deviation, 29 ± 10 years) residing in Argentina (n = 38); Bolivia (n = 1); Brazil (n = 105); Chile (n = 30); El Salvador (n = 1); Spain (n = 22); Mexico (n = 22) and Peru (n = 15). Of these, 12 practiced Brazilian jiu-jitsu (BJJ), 54 boxing, 67 judo, 13 karate, 52 kick boxing & muay thai (KB & MT), 9 mixed martial arts (MMA), and 27 taekwondo (TKD). An online survey was created using Google Forms. It was implemented between April 4th and April 17th, 2020. Athletes were consulted about their body mass before starting the quarantine and after 20 ± 5 days of quarantine. Results: athletes in all combat sports were heavier during quarantine as compared to pre-quarantine (p < 0.001, d = 0.12). Conclusions: combat sports athletes experienced an increase in body mass during the COVID-19 quarantine.

INTRODUCCIÓN: Introducción: para combatir la pandemia de COVID-19, los gobiernos han adoptado medidas como la cuarentena y el distanciamiento social. Objetivo: el principal objetivo del presente estudio fue analizar el impacto de la cuarentena por COVID-19 sobre la masa corporal en atletas de deportes de combate. Métodos: realizamos un estudio transversal, prospectivo y multicéntrico que evaluó a 234 hombres (media de edad y desviación estándar, 29 ± 10 años) que residen en Argentina (n = 38); Bolivia (n = 1); Brasil (n = 105); Chile (n = 30); El Salvador (n = 1); España (n = 22); México (n = 22) y Perú (n = 15). De estos, 12 practicaban jiu-jitsu brasileño (BJJ), 54 boxeo, 67 judo, 13 karate, 52 kick boxing y muay thai (KB y MT), 9 artes marciales mixtas (MMA) y 27 taekwondo (TKD). Se creó una encuesta en línea usando Google Forms. Se implementó entre el 4 y el 17 de abril de 2020. Se preguntó a los deportistas sobre su masa corporal antes de comenzar la cuarentena y después de 20 ± 5 días de cuarentena. Resultados: los atletas de todos los deportes de combate resultaron más pesados durante la cuarentena que durante la precuarentena (p < 0,001, d = 0,12). Conclusiones: los atletas de deportes de combate presentaron una mayor masa corporal durante la cuarentena a causa de la COVID-19.