Is the physical fitness of schoolchildren dependent on their physical activity levels and nutritional status? The experience from Serbia.

Introduction: Introduction: based on the presumed relationship between physical activity and physical fitness, it seems reasonable to expect that being active would result in sufficient fitness levels. However, the relationship between physical activity and fitness is not so plausible and needs deeper exploration. Objectives: we conducted a study aimed at exploring: a) the potential variation in physical activity level by gender and school grade; and b) the effect of physical activity level, gender, and nutritional status on physical fitness test results. Methods: a total of 2795 males and 2614 females participated in the study (11-14 years). Their physical fitness was assessed by measuring anthropometric status, muscular fitness, endurance, flexibility, agility, and cardiorespiratory fitness, while their physical activity was assessed using the Physical Activity Questionnaire (PAQ-A). Results: a higher percentage of boys were highly active, while a higher percentage of girls were scarcely active (χ2 [2, n = 5017] = 151.4, p < 0.01). Decline in physical activity with age was higher in girls than in boys (χ2 [6, n = 5409] = 90.4, p < 0.01). MANOVA revealed a significant effect of gender (V = 0.009, F [6, 3669] = 5.29, p < 0.01), nutritional status (V = 0.193, F [12, 7340] = 65.16, p < 0.01) and physical activity levels (V = 0.043, F [12, 7340] = 13.60, p < 0.01) on tests outcomes. Conclusions: our study has shown that activity level in Serbian schoolchildren declines with age and is affected by nutritional status. Nutritional status represents a significant factor confounding physical fitness scores, regardless of activity levels.

Introducción: Introducción: basado en la presumible relación entre la actividad física y la condición física, parece razonable esperar que ser activo físicamente resulte en niveles suficientes de condición física. Sin embargo, la relación entre la actividad física y la forma física no es tan plausible y necesita una exploración más profunda. Objetivos: realizamos un estudio con el objetivo de explorar: a) la variación potencial en el nivel de actividad física en función del género y el grado escolar; y b) el efecto del nivel de actividad física, el género y el estado nutricional en el resultado de las pruebas de condición física. Métodos: un total de 2795 hombres y 2614 mujeres participaron en el estudio (11-14 años). Su condición física se evaluó midiendo el estado antropométrico, la aptitud muscular, la resistencia, la flexibilidad, la agilidad y la aptitud cardiorrespiratoria, mientras que la actividad física se evaluó mediante el Cuestionario de Actividad Física (PAQ-A). Resultados: un mayor porcentaje de niños eran muy activos, mientras que un mayor porcentaje de niñas eran poco activas (χ2 [2, n = 5017] = 151,4, p < 0,01). La disminución de la actividad física con el incremento de la edad fue mayor en las niñas que en los niños (χ2 [6, n = 5409] = 90,4, p < 0,01). El MANOVA reveló un efecto significativo del género (V = 0.009, F [6, 3669] = 5.29, p < 0.01), el estado nutricional (V = 0.193, F [12, 7340] = 65.16, p < 0.01) y los niveles de actividad física (V = 0.043, F [12, 7340] = 13.60, p < 0.01) en los resultados de las pruebas. Conclusiones: nuestro estudio ha demostrado que el nivel de actividad física en los escolares serbios disminuye con la edad y se ve afectado por el estado nutricional. El estado nutricional representa un factor significativo que confunde las puntuaciones de condición física, independientemente de los niveles de actividad.

[Seasonal alterations in serum iron levels in elite football players].

INTRODUCTION: It is very important to monitor levels of serum iron and other factors of iron metabolism and oxygen transport system as they play a very important role in functional ability of football players. A decrease in serum iron level can be the very first sign of development of iron deficiency anaemia, which seriously influences health and functional ability of an athlete and is a common problem in competitive sports. OBJECTIVE: The aim of this study was to observe and evaluate changes in serum iron values during the competition season in relation to the training process. METHOD: During four years, serum iron level was measured in 28-34 players of one of the top football clubs in Serbia, four times a year: at the beginning and at peak-point of both half-seasons. Differences between basic and control findings, relative and absolute changes in serum iron levels and statistical significance of the findings were than calculated. RESULTS: There was a significant decrease in mean serum iron levels on each control test, compared to basic values. Mean value of control serum iron levels is significantly lower than mean of preseason values (20.64 +/- 6.58 vs. 16.38 +/- 5.51 micromol/l). CONCLUSION: A significant decrease in serum iron level among footballers during both half-seasons is most probably due to an increased loss and/or diminished absorption resulting from a high intensity training process. Because the decline in serum iron may be an early sign of iron store depletion and iron deficiency anaemia, it is very important to evaluate it regularly, along with other factors of iron metabolism and oxygen transport system.

[Immune response to hepatitis B vaccine in elite athletes].

INTRODUCTION: Hepatitis B viral infection can create serious health problems, such as acute and chronic hepatitis, cirrhosis of liver and hepatocellular carcinoma. Athletes have bigger risk of hepatitis B infection due to frequent injuries with bleeding, their style of living (promiscuity), close contact with teammates, etc. The aim of this study was to investigate the immune response to hepatitis B vaccine among elite athletes, compared to corresponding control group of male subjects front general non-athlete population, and to test out reaction in relation to age. METHOD: There were 21 elite football players and 30 control non-athlete males. After written consent, they all received three doses of hepatitis B vaccine (Euvax B, Sanofi Pasteur) during 6 months. Eight weeks later, their immune response (as anti-HBs antibody titre in serum) was assessed and statistical significance of the findings was tested. The level of immune response was also evaluated in different age clusters within test groups. RESULTS: None of the footballers was without response to the vaccine. One of the subjects from the control group did not develop it. The group of athletes was with better mean values of antibody titre (1626621 mIU/ml vs. 1568455 mIU/ml), but without statistical significance (t = 0.375: p > 0.05), and with a greater deal of subjects who developed very good immune response (titre over 2000 mIU/ml). Younger football players had better immune reaction than older (age 18-24, 1795560 mIU/ml, vs. age 25-29 years, 1597470 mIU/ml vs. age 30 and more, 1360904 mIU/ml), but without statistical importance (H = 1.593; p > 0.05). CONCLUSION: Our study has shown that elite athletes respond very well to hepatitis B vaccination and have good immune response. Vaccination against hepatitis B of elite athletes is very important, because viral infection can seriously affect their health and stop their careers.

[The significance of age and sex for the absence of immune response to hepatitis B vaccination].

INTRODUCTION: Seroepidemiological investigations after the administration of hepatitis B vaccine have shown that even 15% of vaccinated healthy persons do not generate immune response to the vaccines currently in use. OBJECTIVE: The aim of the research is to test the immunogenicity of hepatitis B vaccine in different age groups on the adult vaccinated population sample in Serbia. METHOD: The tested general population sample consisted of 154 adult subjects. Immunization was done using the recombinant fungal vaccine obtained by genetic engineering (Euvax B vaccine, manufacturer LG, distributor Sanofi Pasteur). All tested subjects in the research received 1 ml of hepatitis B vaccine administered intramuscularly into the deltoid muscle by 0, 1, 6 schedule. RESULTS: In the tested sample, 3.13% of persons aged up to 29 years, 6.25% aged 30-35 year and 19.23% of the tested persons aged 40 years and older had no immune response. The relative risk of"no response"findings was twice higher in the group aged 30-39 as compared to the population aged up to 29 years. The detected risk was six times higher for the population of 40 years and older in comparison to the population aged up to 29 years. Also, the relative risk of"no response" findings for the population of 40 years and older was more than three times higher than for the group aged 30-39. Absent immune response in relation to sex was found to be higher in male subjects. CONCLUSION: The rates of"no response"finding was the following: 3.13% in the group aged up to 29 years, 6.25% in the group aged 30-39, as well as in the group aged 40 years and older (19.23%). Immune response in relation to age groups was statistically significantly different (p<0.001), while there was a statistically significant correlation (C=0.473; p<0.001) between the age of the subjects and the immune response. In relation to sex, the "no response"finding was found to be increased in the males, but without any statistically significant difference (p>0.05).