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.

Validation of a novel equation to predict lower-limb muscle mass in young soccer players: a brief communication / Validación de una nueva ecuación para predecir la masa muscular de los miembros inferiores en jugadores jóvenes de fútbol: una comunicación breve

Lower-limbs appendicular muscle mass is a key body composition trait related to health and performance. Considering the relevance of lower-limbs appendicular muscle mass in soccer players, the assessment and monitoring of this variable with a low-cost tool would be of great value in order to improve performance through training and nutritional interventions. This study aimed to develop a multiple regression model in order to validate, through dual-energy X-ray absorptiometry, a novel equation to predict lower-limbs appendicular muscle mass in young soccer players using anthropometric variables. Forty-two soccer players of the Chilean National Team (age, 17.1±1.3 years; body mass, 70.0±6.8 kg; height, 175.0±6.6 cm) underwent anthropometrically and body composition assessments. Forward stepwise linear regression was used to develop the equation to estimate the lower-limb appendicular muscle mass. The estimated results were compared with measurements by dual-energy X-ray absorptiometry. The best predictor model to estimate lower-limbs appendicular muscle mass was (kg): (-21.268 + (0.087*height) - (0.853*middle thigh circumference) - (0.329*middle thigh skinfold) + (1.136*corrected middle thigh circumference) + (0.306*calf circumference)) (R2= 0.83). The lower-limbs appendicular muscle mass estimated by the equation and measured by DXA were similar (14.71±1.72 kg vs 14.76±1.89 kg, respectively), and have a good concordance according to Bland-Altman method (mean difference: 0.049 kg; 95 % IC: -1.481 to 1.578 kg) and Lin's concordance correlation coefficient (0.91; 95 % CI: 0.85 - 0.96) methods. In conclusion, the predictive equation is a valid, easy to calculate, and a low-cost tool to predict lower-limbs appendicular muscle mass in young soccer players.

La masa muscular de los miembros inferiores es un factor antropométrico clave relacionado a la salud y el rendimiento deportivo. Considerando la relevancia de este factor en jugadores de fútbol, la medición y monitoreo de esta variable a través de herramientas prácticas de bajo costo puede ser de gran utilidad para lograr objetivos relacionados a mejorar el rendimiento a través del entrenamiento e intervenciones nutricionales. El objetivo de este estudio fue desarrollar un modelo de regresión lineal con el objetivo de validar una nueva ecuación predictiva de la masa muscular de miembros inferiores en jugadores jóvenes de fútbol. Cuarenta y dos jugadores jóvenes de fútbol pertenecientes a la Selección Nacional Chilena (17,1±1,3 años; 70,0±6,8 kg; 175,0±6,6 cm) fueron sometidos a evaluaciones antropométricas y de composición corporal. La regresión lineal de pasos hacia adelante fue utilizada para desarrollar la ecuación para estimar la masa muscular de miembros inferiores. Los resultados estimados fueron comparados con medición de absorciometría de rayos X de doble energía (DEXA). El mejor modelo predictor de masa muscular de miembros inferiores (kg) fue: (-21,268 + (0,087*talla) - (0,853*circunferencia de muslo medio) - (0,329*pliegue de muslo medio) + (1,136*circunferencia de muslo medio corregida) + (0,306*circunferencia de pantorrilla)) (R2= 0,83). La masa muscular estimada por la ecuación y la medida por DEXA fue similar (14,71±1,72 kg vs 14,76±1,89 kg, respectivamente), y tuvo una buena concordancia acorde al método Bland-Altman (diferencia promedio: 0,049 kg; 95 % IC: -1,481 to 1,578 kg) y el coeficiente de correlación de concordancia de Lin (0,91; 95 % CI: 0,85 - 0,96). En conclusión, la ecuación predictiva desarrollada en este estudio es una herramienta válida, fácil de calcular y de bajo costo que permite estimar la masa muscular de miembros inferiores en futbolistas jóvenes.

Investigating the clinical effect of kinesio tape on muscle performance in healthy young soccer players - a prospective cohort study

OBJECTIVE: Kinesio tape (KT) is a visible adhesive restorative tape that has typically been utilized for injury prevention, recovery, and even performance improvement, but limited studies have assessed the effect of KT on muscle performance. The purpose of this study was to investigate the clinical impact of KT on muscle performance in healthy young soccer players. METHODS: Between 25 March and 21 April 2017, sixteen healthy soccer players with a mean age of 20±2.17 were enrolled in this prospective cohort study. All participants were selected from the college football team of Prince Sattam Bin Abdulaziz University. The muscle performance of the players was evaluated with an isokinetic dynamometer for the following three conditions: without tape, immediately after applying KT, and 8 hrs post-KT application while the tape remained on the same site. RESULTS: The differences in peak torque and total work among the three conditions were nonsignificant (p>0.05). Additionally, applying KT to the thigh muscles did not decrease or increase the performance of non injured healthy soccer players (p>0.05). CONCLUSION: KT does not lead to beneficial outcomes of muscle performance in healthy young soccer players.

Training program influences the relation between functional and neuromuscular performance indicators during the season in young soccer players / Programa de treinamento influencia a relação entre os indicadores de desempenho funcional e neuromusculares durante a temporada em jovens futebolistas / Un programa de formación influye en la relación entre los indicadores de rendimiento funcionales y neuromusculares durante la temporada en futbolistas jóvenes

Abstract The aim of this study was to investigate the influence of a training program on the relation between performance indicators of different physical capacities intra and inter functional and neuromuscular systems at different times of the season. Subjects were 16 young soccer players with an average age of 16.5 ± 0.4 years. The study was carried out for 17 weeks, including three assessment moments (T1: 1st, T2: 10th and T3: 17th week). High correlation was found between indicators of neuromuscular predominance (30 meters sprint test (30 m) and Maximum Sprint (MaxSprint) (RAST) in T1) (r = 0.93, p ≤ 0.001), functional (Sprints Average (MidSprint) and Minimal Sprint (MinSprint) (RAST) in T1, T2 and T3; MinSprint and Fatigue Index (FI) (RAST) in T3) (r = 0.95, 0.85, 0.91; -0.86, p ≤ 0.001, respectively) and between functional and neuromuscular indicators (30 m and MidSprint in T1; 30 m and MinSprint in T1; MaxSprint and MidSprint in T1 and T2 and MaxSprint and MinSprint in T1) (r = 0.95, 0.93, 0.96, 0.84, 0.87, p ≤ 0.001, respectively). The training contents had influence on the correlation of performance indicators at different times of the season.

Resumo O objetivo do presente estudo foi verificar a influência de um programa de treinamento na relação entre indicadores de desempenho de diferentes capacidades físicas intra e inter sistema funcional e neuromuscular em diferentes momentos da temporada. Participaram do estudo 16 jovens futebolistas com idade média de 16,5 ± 0,4 anos. O estudo decorreu por 17 semanas, incluindo três momentos de avaliação (T1:1ª; T2:10ª e T3:17ª semana). Foram encontradas alta correlação entre indicadores de predominância neuromuscular (Sprints em 30m (30m) e Sprint Máximo (MaxSprint) (RAST) em T1) (r = 0,93; P ≤ 0,001), funcional (Média de Sprints (MidSprint) e Sprint Mínimo (MinSprint) (RAST) em T1, T2 e T3; MinSprint e Índice de Fadiga (FI) (RAST) em T3) (r = 0,95; 0,85; 0,91; -0,86; P ≤ 0,001, respectivamente) e entre funcional e neuromuscular (30 m e MidSprint em T1; 30 m e MinSprint em T1; MaxSprint e MidSprint em T1 e T2 e MaxSprint e MinSprint em T1) (r = 0,95; 0,93; 0,96; 0,84; 0,87; P ≤ 0,001, respectivamente). Os conteúdos de treinamento exerceram influência na correlação dos indicadores de rendimento nos diferentes momentos da temporada.

Resumen El objetivo de este estudio fue investigar la influencia de un programa de formación en la relación entre los indicadores de desempeño de las diferentes capacidades físicas intra y intersistemas funcionales y neuromusculares, y en diferentes momentos de la temporada. En el estudio participaron 16 jugadores de fútbol jóvenes con una media de edad de 16,5 ± 0,4 años. El estudio duró 17 semanas, incluyendo tres momentos de evaluación (T1: 1.a; T2: 10.a y T3: 17.a semana). Se encontró una alta correlación entre los indicadores de prevalencia neuromuscular [sprints en 30 m (30 m) y sprint máximo (MaxSprint; RAST) en T1 (r = 0,93; P ≤ 0,001)], funcional [sprint medio (MidSprint) y sprint mínimo (MinSprint; RAST) en T1, T2 e T3; MinSprint e índice de fatiga (FI; RAST) en T3 (r = 0,95; 0,85; 0,91; -0,86; P ≤ 0,001, respectivamente)] y entre funcional y neuromuscular [30 m y MidSprint en T1; 30 m y MinSprint en T1; MaxSprint y MidSprint en T1 y T2, y MaxSprint y MinSprint en T1 (r = 0,95; 0,93; 0,96; 0,84; 0,87; P ≤ 0,001, respectivamente)]. Los contenidos de la formación han influido en la correlación de los indicadores de rendimiento en diferentes momentos de la temporada.

Comparison of Physical Activity Level, Physical Activity Pattern and Energy Expenditure in Male and Female Elementary School Soccer Players using Accelerometer and Physical Activity Diary / 대한지역사회영양학회지

OBJECTIVES: The purpose of this study was to compare the physical activity level (PAL), the physical activity pattern and the energy expenditure in male and female elementary school soccer players using the accelerometer and the physical activity diary. METHODS: Twenty-five (male 11, female 14) elementary school soccer players (9–12 years) participated in this study. During their daily activities, they wore an accelerometer for seven days (five weekdays and two weekend days) and completed the physical activity diary for three days (two weekdays and one weekend day). PAL was calculated by using the physical activity diary and three equations (Pate Preschool, Freedson Children, and Freedson) were used to calculate the intensity of physical activity and energy expenditure from the counts of accelerometer. RESULTS: The average of physical activity by day of the week, CPM (Counts Per Minute) and METs (Metabolic Equivalents) were significantly higher in males (723.3 ± 149.2 CPM, 2.07 ± 0.18 METs) compared to females (505.6 ± 119.9 CPM, 1.79 ± 0.20 METs), but there was no significant difference in PAEE (Physical Activity Energy Expenditure) between the two groups (males: 15.5 ± 9.1 kcal/day, females: 11.5 ± 6.0 kcal/day). During weekdays, physical activity intensity was significantly higher in males compared to females at lunch time and training time than at other times. In both genders, the PAL was higher during weekdays (males 1.98, females 1.89) compared to weekend (males 1.62, females 1.61) (p<0.05). CONCLUSIONS: Our study observations suggest the necessity to develop an accelerometer equation for accurately evaluating the physical activity of elementary school athletes.

Aerobic and anaerobic training sessions promote antioxidant changes in young male soccer players / Efeito sobre o estresse oxidativo promovido por sessões de treinamento aeróbico comparativamente a sessões anaeróbicas em jogadores juvenis brasileiros de futebol

OBJECTIVE: The aim of this study was to investigate the effect of aerobic vs. anaerobic intense training sessions on biomarkers of oxidative stress. METHODS: The included sample comprised 18 junior male soccer players (18-21 years) during the intermediate season. Blood samples were obtained before (baseline) and after aerobic or anaerobic training sessions and the following substances were assayed: (i) the biomarkers of cellular damage Thiobarbituric Acid-Reactive Substances and Oxidized Glutathione; (ii) the non-enzymatic antioxidants Reduced Glutathione and Total-Glutathione, (iii) the antioxidant enzymes Superoxide Dismutase, Catalase, Glutathione Reductase, Glutathione Peroxidase and Glutathione S-Transferase. RESULTS: (a) the contents of Thiobarbituric Acid-Reactive Substances and Oxidized Glutathione showed no significant differences before vs. after aerobic or anaerobic training sessions. (b) After aerobic training sessions, the activity of Superoxide Dismutase, Glutathione Reductase, and the contents of Reduced Glutathione and Total Glutathione were decreased; the activity of Glutathione S-transferase and Glutathione Peroxidase were increased while Catalase activity remained unaltered. (c) After anaerobic training sessions, Catalase activity decreased; Glutathione-Peroxidase increased; Superoxide Dismutase, Glutathione Reductase, and Reduced, Oxidized and Total Glutathione showed no significant differences. CONCLUSION: These results provide evidence of a more pronounced systemic oxidative stress after the aerobic as compared to the anaerobic training session in young soccer players.

OBJETIVO: Investigar o efeito no estresse oxidativo promovido por sessão de treinamento aeróbico comparativamente à sessão anaeróbica em jogadores de futebol juvenis. MÉTODOS: Amostras de sangue de 18 jogadores de futebol juvenis (idade entre 18-21 anos) foram utilizadas. Estas amostras foram obtidas imediatamente antes e após um conjunto de sessão de treinamentoaeróbico comparativamente ao de sessão anaeróbica e biomarcadores de dano celular como conteúdos de Substâncias Reativas a Ácido Tiobarbitúrico (TBARS) no plasma, os conteúdos de defesas antioxidantes nãoenzimáticas como a Glutationa Reduzida, Glutationa Oxidada, e Glutationa Total, bem como as atividades de enzimas antioxidantes como Superóxido Dismutase, Catalase, Glutationa Redutase, Glutationa Peroxidase e Glutationa S-Transferase foram avaliadas. RESULTADOS: Os conteúdos de TBARS e Glutationa Oxidada não apresentaram diferenças significativas na comparação entre ambas as sessões. Entretanto, após a sessão de treinamento aeróbico, as atividades da Superóxido Dismutase e Glutationa Redutase, bem como os conteúdos de Glutationa Reduzida e Glutationa Total mostraram diminuições significativas, enquanto que as atividades da Glutationa S-Transferase e Glutationa Peroxidase foram aumentadas e as da Catalase não mostraram diferenças. Por outro lado, após a sessão de treinamento anaeróbico, a atividade da Catalase reduziu-se, a da Glutationa Peroxidase foi significativamente aumentada, enquanto que as da Superóxido Dismutase e Glutationa Reductase, assim como os conteúdos de Glutationa Reduzida, Glutationa Oxidada e Glutationa Total não se alteraram significativamente. CONCLUSÃO: Os resultados evidenciam um estresse oxidativo sistêmico mais acentuado após a sessão de treinamento aeróbico comparativamente à sessão anaeróbica em jogadores de futebol juvenis.

The Correlation between Knee Flexion Lower Range of Motion and Osgood-Schlatter's Syndrome among Adolescent Soccer Players.

Aims: To evaluate the association between knee flexion range of motion (ROM) and Osgood-Schlatter syndrome among adolescent soccer players. Study Design: Observational case-control study. Methodology: A study group of 20 male soccer players, mean age 13.4 years (13.4±0.7) diagnosed with Osgood-Schlatter syndrome and a control group of 21 healthy soccer players, mean age 13.5 years (13.5±0.9) were enrolled. The knee flexion ROM was bilaterally measured in a prone position by the Ely's test and using a digital inclinometer for angle measurement. Results: No significant difference between groups was found as to age, height, weight and dominant leg. Body mass index (BMI) was significantly higher (t = 2.249; P = .03) in the study group (18.97±1.61 kg/m2) compared to the controls (17.79±1.71 kg/m2). A statistically significant (t = -2.701; P =.01) difference was found in knee flexion ROM between the symptomatic leg in the study group and the dominant leg in the controls, with a lower ROM in the study group (132.52±12.40) and (141.40±8.35) in the controls. In a logistic regression analysis, BMI and knee flexion ROM both showed a significant association with the presence of symptoms (BMI: P = .014; ROM: P = .013). Conclusions: Proper training including stretching regime to the quadriceps muscles, with focus on the rectus femoris muscle, during the growth phase of adolescent soccer players should be considered in order to reduce OSS symptoms or even trying to prevent them.

Relação entre impulsividade e comportamento tático de jogadores de futebol Sub-11 / Relation between impulsivity and tactical behavior of Under-11 youth soccer players / Relación entre impulsividad y comportamiento táctico de jugadores de fútbol Sub-11

O presente estudo tem por objetivo verificar de que forma a impulsividade se relaciona com os comportamentos táticos de jogadores de futebol da categoria Sub- -11. A amostra foi composta por 30 jogadores de futebol da categoria Sub-11. O instrumento utilizado para avaliar os comportamentos táticos foi o FUT-SAT, e, para avaliação da impulsividade, adotou-se a versão brasileira do Iowa Gambling Task (IGT-Br). Utili­zaram-se o teste de Shapiro-Wilk para verificar a distribuição dos dados e o teste de correlação de Pearson a fim de examinar a correlação entre as variáveis (p < 0,05). Verificou-se uma correlação negativa entre a impulsividade e a realização do princípio tático ofensivo de mobilidade. Dessa forma, jogadores menos impulsivos têm maiores chances de realizar comportamentos associados a esse princípio de maneira efetiva. Conclui-se que a impulsividade se relaciona com o comportamento tático de jogadores de futebol da categoria Sub-11, especificamente no princípio da mobilidade.

The aim of this study is to examine how impulsivity relates to the tactical behavior of under-11 youth soccer players. The sample comprised 30 Under-11 youth soccer players. FUT-SAT was used to assess the tactical behavior and the Iowa Gambling Task Brazilian version (IGT-Br) was used to evaluate impulsivity. Shapiro-Wilk test was performed to verify data distribution and Pearson correlation was used to verify the correlation between the variables (p < 0.05). Negative correlation between impulsivity and the performance of the offensive tactical principle of depth mobility was verified. Therefore, less impulsive players are more likely to engage in behaviors associated with this principle. It was concluded that the impulsivity relate to the tactical behavior of Under-11 youth soccer players, specifically with the principle of depth mobility.

El objetivo del estudio es comprobar cómo la impulsividad se relaciona con el comportamiento táctico de jugadores de fútbol Sub-11. La muestra consistió en 30 jugadores de fútbol Sub-11. El instrumento utilizado para evaluar los comportamientos tácticos fue el FUT-SAT y para evaluación de la impulsividad se utilizó el Iowa Gambling Task versión brasileña (IGT-Br). Se utilizó el teste Shapiro-Wilk para verificar la distribución de los datos y el teste de correlación de Pearson para comprobar la correlación entre las variables (p < 0,05). Se verificó una correlación negativa entre la impulsividad y la realización del principio táctico ofensivo de mobilidad. Así los jugadores menos impulsivos son más propensos a involucrarse en comportamientos asociados con este principio de manera efectiva. Se concluyó que la impulsividad se relación com el comportamiento táctico de jugadores de fútbol Sub-11, específicamente el principio de la mobilidad.

Analysis of Landing Error Scoring System during Drop Vertical Jump on Anterior Cruciate Ligament Injury Risk Factors in Female Ballet Dancers and Female Soccer Players / 대한스포츠의학회지

The incidence of anterior cruciate ligament (ACL) injuries among female ballet dancers is much lower than among female soccer players, there is currently little research examining the landing error scoring system (LESS) of female ballet dancers and female soccer players. The purpose of this study was to investigate the LESS during drop vertical jump on ACL injury risk factors in female ballet dancers and female soccer players. Thirteen professional female ballet dancers and elite female soccer players participated in the study. Independent sample t-test was used to compare the LESS score between the groups with Bonferroni collection. The elite female soccer player group showed significantly higher stance width-wide, foot position-toe out, symmetric initial foot contact, overall impression and total LESS score than those of the professional ballet dancers.

Biochemical parameters of zinc and markers of oxidative stress in soccer players / Parâmetros Bioquímicos do Zinco e Marcadores do Estresse Oxidativo em Jogadores deFutebol

The high intensity physical exercise induces to excessive formation of oxygen reactive species as well as changes in the metabolism of antioxidant nutrients. The zinc, particularly, which is a cofactor of enzymes of antioxidant defense system, seems to have alterations in its metabolic behavior in athletes. This study evaluated the effect of physical exercise on biochemical parameters of zinc and oxidative stress biomarkers of soccer players. A transectional, analytical and experimental study was performed with 20 players from the youth team (basis category sub20) in the first division of the brazilian championship with age between 17 and 19 years, male gender. The analysis of zinc intake, plasmatic and erythrocyte zinc, the activity of superoxide dismutase enzyme, and the plasma malondialdehyde were carried out before and after the match. Players showed zinc intake superior to recommendation. The mean plasmatic zinc was 77.6 ± 9.9 μg/dl pre-match and 68.9 ± 8.2 μg/dl post-match (p<0.05). The mean of erythrocyte zinc did not show significant difference after exercise (p>0.05). The mean plasmatic malondialdehyde was 1.1 ± 0.3 nmol/ml, and 5.5 ± 1.4 nmol/ml pre and post–exercise, respectively (p<0.05). The activity of superoxide dismutase enzyme did not change after 48 hours of the soccer match (p>0.05). High performance athlets like soccer players, show a reduction in zinc concentration and an increase in the plasmatic malondialdehyde. Further investigations using other biomarkers of oxidative stress and/or of inflammation may better clarify the alterations in the metabolic behavior of antioxidant nutrients in soccer players.

O exercício físico de alta intensidade favorece a formação excessiva de espécies reativas de oxigênio assim como distúrbios no metabolismo de nutrientes antioxidantes. O zinco, em particular, que é cofator de enzimas do sistema de defesa antioxidante, parece sofrer alterações no seu comportamento metabólico em atletas. Este estudo avaliou o efeito do exercício físico sobre parâmetros bioquímicos do zinco e marcadores do estresse oxidativo em jogadores de futebol. Estudo transversal, analítico e experimental realizado com 20 jogadores de futebol do time de juniores (categoria de base sub-20) da primeira divisão do campeonato brasileiro com idade entre 17 e 19 anos, do gênero masculino. Foram realizadas análises da ingestão de zinco, zinco plasmático e eritrocitário, atividade da enzima superóxido dismutase e malondialdeído plasmático antes e após a partida. Os jogadores de futebol mostraram ingestão de zinco superior à recomendação. Os valores médios de zinco plasmático foram de 77,6 ± 9,9 μg/dL no período pré-partida e de 68,9 ± 8,2 μg/dL no pós-partida (p<0,05). A média de zinco eritrocitário não mostrou diferença significativa após o exercício (p>0,05). A média do malondialdeído plasmático nos jogadores de futebol foi 1,1 ± 0,3 nmoL/mL e 5,5 ± 1,4 nmoL/mL no pré e pós-exercício, respectivamente (p<0,05). A atividade da enzima superóxido dismutase não alterou após 48 horas da partida de futebol (p>0,05). Atletas de alto rendimento, como jogadores de futebol, apresentam aumento de malondialdeído no plasma e redução nas concentrações de zinco no plasma. Novas investigações utilizando outros biomarcadores do estresse oxidativo e/ou da inflamação podem melhor esclarecer as alterações no comportamento metabólico de nutrientes antioxidantes em jogadores de futebol.

Correlações entre parâmetros aeróbios e desempenho em esforços intermitentes de alta intensidade / Relationship between aerobic parameters and intermittent high-intensity effort performance

O objetivo do presente estudo foi investigar as possíveis correlações entre parâmetros provenientes de um esforço intermitente de alta intensidade (RAST) e variáveis relacionadas ao metabolismo aeróbio (limiar anaeróbio; LAN, consumo máximo de oxigênio;VO2MAX e intensidade correspondente ao VO2MAX;iVO2MAX). Oito jogadores de futebol (16±1 anos) participaram do estudo. Os atletas foram submetidos a um teste progressivo para a determinação dos índices aeróbios e a seis esforços máximos de 35m separados por 10s de recuperação (RAST). As variáveis do RAST não foram correlacionadas ao VO2MAX e ao LAN. Entretanto, as potência média absoluta e relativa ao peso corporal, apresentaram correlações significativas com a iVO2MAX (r=0,79 e r= 0,85, respectivamente). O índice de fadiga e a potência pico relativa também foram significativamente correlacionados com a iVO2MAX (r=-0,57 e r=0,73, respectivamente). Pode-se concluir que em esforços como o RAST, com breves períodos de recuperação, a única variável aeróbia correlacionada ao desempenho foi a iVO2MAX.

The purpose of the study was to examine the relationships between intermittent high-intensity efforts (RAST) parameters and variables related to aerobic metabolism (anaerobic threshold; LAN, maximal oxygen uptake; VO2MAX and velocity correspondent to VO2MAX;iVO2MAX). Eight under-17 (U17) soccer players (16±1 years) participated in the study. The participants were submitted to a graded exercise test and six maximal sprints of 35m with 10 seconds of passive recovery between each effort (RAST). The RAST parameters were not significant correlated with VO-2MAX and LAN. However absolute and relative mean power were significantly correlated with iVO2MAX (r=0.79 e r= 0.85, respectively). Furthermore, the fatigue index and the relative peak power were significantly correlated with the iVO2MAX (r=-0,57 e r=0,73, respectively). In conclusion, the only aerobic variable correlated with performance in consecutive efforts with brief recovery periods, such as RAST, is iVO2MAX.

Comparação da potência anaeróbia mensurada pelo teste de RAST em diferentes condições de calçado e superfícies / Comparison of the anaerobic power measured by the RAST test at different footwear and surfaces conditions

INTRODUÇÃO: O Running Anaerobic Sprint Test (RAST) tem sido considerado um teste válido para avaliação anaeróbia. Entretanto, como a superfície e o calçado podem afetar alguns parâmetros mensurados durante o exercício, isso pode modificar os parâmetros do RAST. OBJETIVO: Comparar as variáveis do RAST mensuradas utilizando chuteiras na grama (RAST CG) e tênis na pista (RAST TP). MÉTODOS: Oito jogadores de futebol (da categoria sub-17) participaram do estudo. Os participantes realizaram dois RAST (intervalo > 24 h). O RAST consistiu em seis corridas máximas de 35m com 10s de intervalo passivo entre cada corrida. O tempo de cada esforço foi registrado para determinação da potência pico (PP), potência média (PM) e índice de fadiga (IF). Após o sexto esforço, amostras sanguíneas foram coletadas para determinação da lactacidemia ([Lac]). RESULTADOS: Durante o RAST TP, a PP (763,1 ± 87,2 W) e PM (621,6 ± 68,1 W) foram significativamente superiores às PP e PM mensuradas em RAST CG (PP = 667,3 ± 67,0 W e PM = 555,9 ± 74,7 W), enquanto que as [Lac] observadas em RAST TP (7,3 ± 1,8 mmol.L-1) foram significativamente inferiores às mensuradas em RAST CG (9,9 ± 3,2 mmol.L-1). No entanto, o IF não foi significativamente diferente (RAST TP = 32,5 ± 8,3%; RAST CG = 34,1 ± 6,6%). Significativas correlações foram observadas entre as PM (r = 0,90) e as [Lac] (r = 0,72). CONCLUSÃO: Podemos concluir que as variáveis do RAST são influenciadas pela superfície e calçado utilizados, com valores superiores observados em RAST TP.

INTRODUCTION: Running Anaerobic Sprint Test (RAST) has been considered a valid test for anaerobic evaluation. However, since the floor surfaces and footwear can affect some outcomes measured during exercise, this also can modify the RAST outcomes. OBJECTIVE: Was to compare the RAST outcomes measured using soccer cleats on grass (RAST SCG) and using shoes on the track (RAST ST). METHODS: Eight young male soccer players (under-17 category; 16±1 years) participated in the study. The subjects performed two RAST on different days (recovery > 24h). The RAST test consisted of six 35-meter maximal running performance with a 10-second recovery between each run. Running time during each effort was recorded to determine peak power (PP), mean power (MP) and fatigue index (FI); and blood samples were collected after each test to determine lactatemia ([Lac]). RESULTS: PP (763.1 ± 87.2 W) and MP (621.6 ± 68.1 W) were higher in RAST ST than RAST SCG (PP = 667.3 ± 67.0 W e PM = 555.9 ± 74.7 W), while [Lac] measured during RAST ST (7.3 ± 1.8 mmol.L-1) was lower than the one measured in RAST SCG (9.9 ± 3.2 mmol.L-1). However, the FI did not statistically differ (RAST ST = 32.5 ± 8.3%; RAST SCG = 34.1 ± 6.6%). Significant correlations were observed between MP values (r = 0.90) and [Lac] values (r = 0.72). CONCLUSION: We can conclude that the RAST variables are affected by floor surface and footwear, with higher values being observed during RAST ST condition.

Elaboração de tabelas de percentis através de parâmetros antropométricos, de desempenho, bioquímicos, hematológicos, hormonais e psicológicos em futebolistas profissionais / Preparation of percentile tables through anthropometric, performance, biochemical, hematological, hormonal and psychological parameters in professional soccer players

INTRODUÇÃO: A carência de valores de referência de parâmetros antropométricos, de desempenho, bioquímicos, hematológicos, hormonais e psicológicos é uma limitação importante nas investigações envolvendo futebolistas profissionais. OBJETIVO: Elaborar tabelas de percentis para servirem como referencial de comparação para estudos posteriores. MÉTODOS: Foram utilizados 82 jogadores profissionais de futebol que foram avaliados aproximadamente 30 dias após o início da principal competição disputada pelas equipes. No primeiro dia de avaliação foram coletadas amostras de sangue (25mL) em jejum para determinação dos parâmetros hematológicos (eritrócitos, hemoglobina, hematócrito, volume corpuscular médio - VCM, hemoglobina corpuscular média - HCM, concentração de hemoglobina corpuscular média - CHCM, leucócitos, neutrófilos, eosinófilos, linfócitos, monócitos e plaquetas) e das concentrações de adrenalina, cortisol, creatina quinase, creatinina, noradrenalina, testosterona e ureia. Posteriormente, os atletas foram submetidos à avaliação antropométrica e psicológica. Em seguida, a avaliação da eficiência do sistema anaeróbio lático foi realizada em pista oficial de atletismo. No segundo dia foram realizadas as avaliações para determinação da eficiência do sistema anaeróbio alático e aeróbio. RESULTADOS: A distribuição de percentis (P0, P15, P30, P50, P70, P85 e P100) foi utilizada para apresentação dos resultados. CONCLUSÃO: A elaboração de tabelas de percentis pode ser utilizada como referencial de comparação para investigações posteriores.

INTRODUCTION: The lack of reference values of anthropometric, performance, biochemical, hematological, hormonal and psychological parameters is an important limitation in the investigations with soccer players. OBJECTIVE: To elaborate percentile tables to be used as comparison reference for further studies. METHODS: 82 professional soccer players were evaluated approximately 30 days after the beginning of the main competition played by their teams. On the first day of evaluation, fast blood samples were collected for measurement of hematological parameters (i.e. erythrocytes, hemoglobin, hematocrit, mean corpuscular volume - MCV, mean corpuscular hemoglobin - MCH, mean corpuscular hemoglobin concentration - MCHC, leukocytes, eosinophils, lymphocytes, monocytes and platelets) and of concentrations of adrenaline, cortisol, creatine kinase, creatinine, norepinephrine, testosterone and urea. Subsequently, the soccer players had their anthropometric characteristics and psychological parameters assessed. In addition, the evaluation of the lactic anaerobic system efficiency was performed on a 400-m track. On the second day, both the alactic anaerobic and aerobic system efficiency was measured. RESULTS: The percentile distribution (P0, P15, P30, P50, P70, P85 e P100) was used to present the results. CONCLUSION: The elaboration of the percentile tables can be used as comparison reference for further studies.

Developmental Characteristics of Body Composition and Lower-Leg Multi-Joint Power Outputs and Sprint Ability in Junior and Youth Soccer Players / 体力科学

The purpose of this study was to investigate the cross-sectional development characteristics of body composition, lower-leg multi-joint power output and sprint running in non-elite junior and youth soccer players. The leg extension power, counter-movement vertical jump(CMJ), and 30m-sprint time for eighty male soccer players aged 13.8-18.1 yrs were measured. Junior and youth soccer players were compared with sedentary normal identical aged boys. Statistical analysis was used by one-way ANOVA and multiple comparisons of variance were performed on the basis of the Tukey-Kramer HSD test. Statistical significance was accepted at level of p < 0.05. Relative increases from 14 yrs to 18 yrs players were significantly (p < 0.05) indicated; body height (7.7%), leg extension power (87.8%), CMJ (35.3%), 30m-sprint (8.7%). 10m-sprint time was negatively correlated with both leg extension power (r = -0.52) and CMJ (r = -0.60). Comparison of relative values of increase from 14 to 18 yrs in junior and youth soccer players to those in sedentary normal boys were as follows; 2.3 (body height), 2.5 (leg extension power), 3.0 (CMJ), 2.1 (sprint ability). It might be suggested that consistent regular soccer training from junior and youth aged might prompt developmental gains not only largely for lower-leg multi-joint power but also not a little for sprint ability.

RELATIVE GROWTH AND DEVELOPMENT ON THIGH MUSCLE THICKNESSES AND BALL KICKING PERFORMANCES IN MALE JUNIOR SOCCER PLAYERS / 体力科学

The purpose of this study was to investigate the relative growth of thigh muscle thickness and development of ball kicking performance in junior male soccer players.The study participants included 235 Japanese male soccer players aged between 10 and 18 years. Subjects were classified into 10 groups on the basis of their body height every 5 cm. The thickness of the anterior and posterior thigh muscles (MTA and MTP, respectively) were measured using B-mode ultrasonography. The ball distance (BD) and ball velocity (BV) were measured using a tape measure and a speed gun, respectively. By using a custom-made speed meter, we measured the maximal swing velocity of the lower limb (SV) while the players were kicking the ball. These parameters, along with the height, were plotted on a logarithmic graph to obtain the allometric equation y = bx^a.There was a sharp bend in the graph showing the relationships between MTA, MTP, BV, SV, and body height. The growth indexes "a" of MTA and MTP were increased at 157.3 cm and 159.9 cm, respectively. The development indexes "a" of BV and SV were increased at 144.3 cm and 146.1 cm, respectively. However, there were 2 sharp bends in the graph showing the relationships between BD and body height. The development index "a" of BD showed the highest value from 150.5 to 171.2 cm.These results suggested that the developmental spurt in ball kicking performance was faster than the growth spurt in muscle thickness of the thigh.

Estudo comparativo por ressonância magnética de púbis entre atletas e sedentários assintomáticos / Comparative study between the pubis of asymptomatic athletes and non-athletes with MRI

OBJETIVO: Comparar os achados na ressonância magnética do púbis de atletas profissionais de futebol, sem histórico ou clínica de pubalgia, com sedentários também assintomáticos, determinando a prevalência de alterações compatíveis com sobrecarga púbica. MÉTODOS: Dezenove atletas profissionais de futebol, sem queixas álgicas na região púbica, e 17 sedentários, também assintomáticos, foram submetidos à ressonância magnética do púbis. Os resultados dos exames foram analisados quanto à presença de alterações degenerativas, edema medular ósseo e tendinopatia, comparando ambos os grupos estudados. RESULTADOS: Foi encontrada alta prevalência de edema ósseo e tendinopatia, bem como alterações degenerativas da sínfise púbica no grupo de atletas, encontrando-se valores maiores de odds ratio e risco relativo, com significância estatística na população estudada. CONCLUSÃO: Atletas profissionais de futebol apresentam maior risco de desenvolver alterações na região púbica, evidenciadas na ressonância magnética, se comparados a indivíduos sedentários. Estes achados não são obrigatoriamente causa de pubalgia, estando provavelmente relacionados a esforço intenso.

OBJECTIVE: To compare the magnetic resonance imaging findings of the pubis of professional soccer players, without history of or clinical groin pain, and non-athletes, also without symptoms, determining the prevalence of changes compatible with pubic overload. METHODS: Nineteen professional soccer players without complaints of groin pain and seventeen non-athletes, also asymptomatic, underwent pubic magnetic resonance images. Exam findings were analyzed for the presence of degenerative changes, medullar edema and tendinopathy, comparing both groups. RESULTS: High prevalence of bone edema, tendinopathy and degenerative findings in the pubic symphysis was seen in athletes, with statistically significant higher odds ratios and relative risk for the population studied. CONCLUSION: Professional soccer players are at a higher risk for developing changes in the pubic region, evidenced in magnetic resonance images, when compared to non-athletes. Those findings are not necessarily related to groin pain, and are probably related to intense stress.

Peptide glutamine supplementation for tolerance of intermittent exercise in soccer players

OBJECTIVE: To investigate whether supplementation of carbohydrate together with peptide glutamine would increase exercise tolerance in soccer players. METHODS: Nine male soccer players (mean age: 18.4 ± 1.1 years; body mass: 69.2 ± 4.6 kg; height: 175.5 ± 7.3 cm; and maximum oxygen consumption of 57.7 ± 4.8 ml.kg-1.min-1) were evaluated. All of them underwent a cardiopulmonary exercise test and followed a protocol that simulated the movements of a soccer game in order to evaluate their tolerance to intermittent exercise. By means of a draw, either carbohydrate with peptide glutamine (CARBOGLUT: 50g of maltodextrin + 3.5g of peptide glutamine in 250 ml of water) or carbohydrate alone (CARBO: 50g of maltodextrin in 250 ml of water) was administered in order to investigate the enhancement of the soccer players' performances. The solution was given thirty minutes before beginning the test, which was performed twice with a one-week interval between tests. RESULTS: A great improvement in the time and distance covered was observed when the athletes consumed the CARBOGLUT mixture. Total distance covered was 12750 ± 4037m when using CARBO, and 15571 ± 4184m when using CARBOGLUT (p<0.01); total duration of tolerance was 73 ± 23 min when using CARBO and 88 ± 24 min when using CARBOGLUT (p<0.01). CONCLUSION: The CARBOGLUT mixture was more efficient in increasing the distance covered and the length of time for which intermittent exercise was tolerated. CARBOGLUT also reduced feelings of fatigue in the players compared with the use of the CARBO mixture alone.

The Comparative Study on Food Consumption Patterns, Dietary Behavior, and Nutrition Knowledge of Korean Professional Soccer Players and Non-athletic Males / 대한지역사회영양학회지

This study was performed to compare food consumption patterns, dietary behavior, and nutrition knowledge between Korean professional soccer players and the non-athletic males. Data were collected from 53 soccer players working for Korean professional soccer clubs and 44 non-athletic males, using self-administered questionnaires. There were significant differences in food consumption frequency between two groups. Meats and eggs, fishes and shellfishes, sea weeds were consumed more frequently by the soccer players. The frequency scores of foods rich in iron, calcium, and protein were also higher in the soccer players compared with the non-athletes. Meanwhile, the consumption of alcohol was more frequent in the non-athletes. As for the cooking method, the soccer players showed higher preference for steaming/parboiling and consumed raw vegetables and fruits more frequently than the non-athletic males (p < 0.05). The average scores of soccer players on nutrition knowledge for basic nutrition and athletic nutrition were lower than the respective values of the non-athletic males. However, the soccer players showed better eating behaviors and dietary habits compared with non-athletic males (p < 0.001). They had well-balanced, regular diet and good habits for chronic disease prevention. No significant relationship could be observed with respect to nutrition knowledge and nutritional behavior. Moreover, the experience of getting nutrition information did not affect either nutrition knowledge score or nutritional habits score, except that for habits of chronic disease prevention in non-athletes. Therefore, it is suggested that more effective and practical nutrition education program be needed for promoting healthy eating habits and improving nutritional status in young males.

El trabajo de fuerza en el desarrollo de la potencia en futbolistas de las divisiones menores de un equipo profesional de fútbol / Strength work in the development of power in soccer players from the minor divisions of a professional soccer team

OBJETIVO: determinar en futbolistas si el entrenamiento de fuerza en un porcentaje alto (85por ciento) de una repetición máxima (1-RM), buscando el aumento en lafuerza máxima (FM), es más eficaz para mejorar la potencia muscular inmediata que un entrenamiento similar pero al 75por ciento de 1-RM. METODOLOGÍA: sesenta futbolistas de las divisiones inferiores del DIM divididos aleatoriamente en 2 grupos de 30 jugadores cada uno y se diseñaron los siguientes trabajos de fuerza: el grupo experimental realizó un entrenamiento bilateral e individual de fuerza para los extensores y flexores de la rodilla, consistente en 3 series de 5 repeticiones al 85por ciento de 1-RM, con 5 minutos de descanso entre una y otra serie, 2 veces por semana durante 12 semanas. El grupo control hizo un entrenamiento de fuerza para los mismos músculos, consistente en 3 series de 8 repeticiones al 75por ciento de 1-RM, con 5 minutos de descanso entre una y otra serie, 2 veces por semana durante 12 semanas. Al comienzo del estudio y a las 6 y 12 semanas se hicieron mediciones de fuerza máxima (1-RM) de los extensores y flexores de las rodillas y de la potencia muscular inmediata - velocidad en 20 metros, Squat Jump (SJ) y Countermovement Jump (CMJ). RESULTADOS: aunque los 60 jugadores completaron el entrenamiento de fuerza, sólo se analizaron los datos de 29 del grupo experimental y 27 del grupo control; de los 4 restantes, 2 salieron del equipo y 2 sufrieron lesiones no relacionadas con el entrenamiento. No hubo diferencias significativas entre los dos grupos, en ninguna de las variables ni en ninguna de las 3 mediciones. En la mayoría de las variables - fuerza de los extensores de la rodilla derecha, fuerza de los extensores de la rodilla izquierda, fuerza de los flexores de la rodilla derecha, fuerza de los flexores de la rodilla izquierda, Squat Jump y Countermovement Jump - hubo incrementos estadísticamente significativos (p < 0.05) en cada grupo tanto a las 6 semanas como entrelas 6...

Reproducibility of maximum aerobic power (VO2max) among soccer players using a modified heck protocol

OBJECTIVE: To determine the degree of reproducibility of maximum oxygen consumption (VO2max) among soccer players, using a modified Heck protocol. METHODS: 2 evaluations with an interval of 15 days between them were performed on 11 male soccer players. All the players were at a high performance level; they were training for an average of 10 hours per week, totaling 5 times a week. When they were evaluated, they were in the middle of the competitive season, playing 1 match per week. The soccer players were evaluated on an ergometric treadmill with velocity increments of 1.2 km.h-1 every 2 minutes and a fixed inclination of 3 percent during the test. VO2max was measured directly using a breath-by-breath metabolic gas analyzer. RESULTS: The maximum running speed and VO2max attained in the 2 tests were, respectively: (15.6 ± 1.1 vs. 15.7 ± 1.2 km.h-1; [P = .78]) and (54.5 ± 3.9 vs. 55.2 ± 4.4 ml.kg-1.min-1; [P = .88]). There was high and significant correlation of VO2max between the 2 tests with a 15-day interval between them [r = 0.97; P < .001]. CONCLUSION: The modified Heck protocol was reproducible, and the 15-day interval between the ergospirometric testing was insufficient to significantly modify the soccer players' VO2max values.

OBJETIVO: Determinar o grau de reprodutibilidade do consumo máximo de oxigênio (VO2max) em jogadores de futebol utilizando o protocolo de Heck modificado. MÉTODOS: Foram avaliados por duas vezes, com intervalo de 15 dias entre os testes, 11 futebolistas masculinos. Todos eram de alto nível, treinavam em média 10 horas por semana subdivididos em treinamentos físicos, técnicos, táticos e jogos competitivos, totalizando cinco vezes por semana e na fase em que foram avaliados se encontravam em pleno período competitivo realizando um jogo por semana. Os futebolistas foram avaliados em esteira ergométrica (1,2 km.h-1) a cada dois minutos e inclinação fixa durante o teste em 3 por cento. O VO2max foi medido diretamente utilizando analisador metabólico de análise de gases expirados respiração-a-respiração. RESULTADOS: A velocidade máxima de corrida e o VO2max atingido nos dois testes foram respectivamente: (15,6 ± 1,1 vs. 15,7 ± 1,2 km.h-1; [p = 0,78]) e (54,5 ± 3,9 vs. 55,2 ± 4,4 ml.kg-1.min-1; [P = 0,88]). Houve correlação significante e alta do VO2max entre os dois testes após 15 dias de intervalo [r = 0,97; P< 0,001]. CONCLUSÃO: O protocolo de Heck modificado foi reprodutível e o intervalo de quinze dias entre os testes ergoespirométricos não foi suficiente para modificar significativamente o VO2max dos jogadores de futebol.