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1.
Behav Med ; : 1-10, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32275194

RESUMO

Few studies have examined variations in obesity by geographic location in youth and its relation with fitness levels. The present study investigated the association between geographic status (islands versus mainland), excess of body weight and fitness levels among 335.810 schoolchildren (male: 51.3%, 6-18 y, during the school year 2014-2015). Students' anthropometric parameters and fitness levels - accessed via the Euro-fit test - were measured by trained physical education teachers and evaluated according to published norms. Prevalence of overweight (23.0 Vs 21.8%) and obese (10.1 Vs 8.0%) was significantly higher for students living in the islands contrary to their mainland counterparts. A significant difference was also observed for centrally obese children (33.5 Vs 28.2%). Except for speed test .408), in all other four fitness tests, the students from the islands presented significantly lower performance (≤25th percentile of published age- and sex-specific normative values) versus their mainland counterparts. Boys and girls living in the islands had 48% and 37% increased odds of low physical fitness (as a total), respectively, compared to their mainland counterparts. Likewise, children living in islands presented increased odds of being overweight or obese by 19% and 15% in boys and girls, respectively, as compared to those living in the mainland. Increased general and abdominal adiposity have a direct negative impact on students' performance in Physical Fitness tests. Our data highlight the problem of excessive body weight that children living in rural areas, face.

2.
Nutrients ; 12(4)2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32260197

RESUMO

Research on hyponatremia during mountain marathons is scarce. The present study aimed to investigate the prevalence of exercise-associated hyponatremia during a 44-km trail running race that reached an altitude of 2780 m (Olympus Marathon). Sixty-two runners (five women) who completed the race participated in the study (age: 34.4 ± 8.6 years; height: 1.77 ± 0.06 m; and weight: 75.3 ± 10.0 kg). Anthropometric characteristics, blood, and urine samples were collected pre- and post-race. Food and fluid intake were recorded at each checkpoint. Due to race regulations, the runners could not carry any additional food and fluids besides the ones provided at specific checkpoints. Five runners (8%) exhibited asymptomatic hyponatremia (serum sodium <135 mmol∙L-1). Serum sodium in the hyponatremic runners decreased from 138.4 ± 0.9 (pre) to 131.4 ± 5.0 mmol∙L-1 (post), p < 0.05. Plasma osmolality increased only in the eunatremic runners (pre: 290 ± 3; post: 295 ± 6 mmol∙kg-1; p < 0.05). Plasma volume decreased more in the hyponatremic compared to eunatremic runners (-4.4 ± 2.0 vs. -3.2 ± 1.4%, p < 0.05). Lastly, dietary sodium intake was lower in the hyponatremic runners compared to eunatremic (789 ± 813 vs. 906 ± 672 mg; p < 0.05). The incidence of hyponatremia among the athletes was relatively low, possibly due to race conditions.

3.
J Strength Cond Res ; 33(9): 2388-2397, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28737590

RESUMO

Methenitis, S, Spengos, K, Zaras, N, Stasinaki, A-N, Papadimas, G, Karampatsos, G, Arnaoutis, G, and Terzis, G. Fiber type composition and rate of force development in endurance- and resistance-trained individuals. J Strength Cond Res 33(9): 2388-2397, 2019-The purpose of the study was to investigate the relationship between muscle fiber composition and the rate of force development (RFD) in well-trained individuals with different training background. Thirty-eight young men with different training background participated: 9 endurance runners, 10 power-trained individuals, 9 strength-trained individuals, and 10 sedentary individuals. They performed maximal isometric leg press for the measurement of RFD. Body composition (dual x-ray absorptiometry) and vastus lateralis fiber type composition were also evaluated. When all participants were examined as a group, moderate correlations were found between the percent of type II muscle fibers and RFD between 100 and 600 milliseconds (r = 0.321-0.497; p ≤ 0.05). The correlation coefficients were higher for the cross-sectional area (CSA) and the %CSA of type II and IIx muscle fibers (r = 0.599-0.847; p < 0.001). For the power group, RFD up to 250 milliseconds highly correlated with % type IIx muscle fibers and type IIx fiber CSA (r = 0.670-0.826; p ≤ 0.05), as well as with %CSA of type IIx fibers (r = 0.714-0.975; p ≤ 0.05). Significant correlations were found between the relative RFD (·kg lower extremities lean mass) and CSA-%CSA of type II and IIx fibers for the power group (r = 0.676-0.903; p ≤ 0.05). No significant correlations were found between muscle morphology and RFD for the other groups. In conclusion, the present data suggest that there is a strong link between the type IIx muscle fibers and early RFD and relative RFD in power-trained participants. Type II fibers seem to be moderately linked with RFD in non-power-trained individuals.


Assuntos
Treino Aeróbico , Força Muscular , Músculo Quadríceps/citologia , Músculo Quadríceps/fisiologia , Treinamento de Resistência , Adulto , Composição Corporal , Humanos , Contração Isométrica , Masculino , Fibras Musculares de Contração Rápida/citologia , Corrida/fisiologia , Levantamento de Peso/fisiologia , Adulto Jovem
4.
Front Nutr ; 5: 10, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29479531

RESUMO

Objective: The aim of the study was to evaluate physical fitness (PF) and identify its anthropometric and lifestyle determinants in a sample of Greek schoolchildren. Methods: The study sample consisted of 335,810 schoolchildren (♂: 51.3%, 6-18 years old). Students' anthropometric parameters and PF levels-assessed via the Eurofit test battery-were measured by trained physical education teachers and evaluated according to the available norms, while their lifestyle habits were assessed through a questionnaire. Results: In all applied PF tests, students' performance was negatively associated with the presence of obesity and central obesity, defined through international criteria for body mass index and waist to height ratio, respectively. According to multiple logistic regression analysis, the presence of overweight/obesity [odds ratio (OR): 4.43, 95% confidence interval (CI): 3.98-4.93], low adherence to the MD (KIDMED ≤ 3) (OR: 1.27, 95% CI: 1.09-1.48), and increased time spent in sedentary activities (>2 h per day) (OR: 1.16, 95% CI: 1.03-1.29) were positively associated with poor PF, after adjusting for age and sex. In contrast, for every 1 day increase in the weekly frequency of engagement in athletic activity, the probability of poor PF decreased by 26% (OR: 0.74, 95% CI: 0.72-0.77). In a similar model, the presence of central obesity emerged as an even stronger possible predictor of poor PF (OR: 5.20, 95% CI: 4.66-5.78), compared to the presence of general obesity. Conclusion: Higher general or abdominal adiposity, as well as the adoption of a low-quality diet and a sedentary lifestyle, is strongly associated with low PF levels during childhood.

5.
Eur J Clin Nutr ; 72(3): 420-427, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29238038

RESUMO

BACKGROUND/OBJECTIVES: Children consume various fluids to meet dietary water intake needs. However, the contribution of different fluid types on hydration is unclear. The purpose of this study was to develop fluid intake patterns and examine their association with hydration, as indicated by 24-h urine osmolality. SUBJECTS/METHODS: Two hundred ten (105 girls) healthy children (height: 1.49 ± 0.13 m, weight: 43.4 ± 12.6 kg, body fat: 25.2 ± 7.8%) recorded their fluid intake for two consecutive days, and collected their urine for 24-h during the 2nd day, while conducting their normal daily activities. Urine samples were analyzed for specific gravity and osmolality. Factor analysis with principal components method was applied to extract dietary patterns from six fluid groups. Linear regression analysis evaluated the associations between the extracted dietary patterns and hydration based on 24-h urine osmolality. RESULTS: The analysis revealed the following six components: 1, characterized by consumption of milk and fresh juice, but not packaged juice; 2, by regular soda and other drinks, but not water; 3, by fresh juice and other drinks; 4, by packaged juice, but not regular soda; 5, by water and milk; and 6, by fresh juice. Component 5 was negatively correlated with urine osmolality (P = 0.001) indicating better hydration, whereas component 2 was positively correlated with urine osmolality (P = 0.001). CONCLUSIONS: A drinking pattern based on water and milk was associated with better hydration, as indicated by lower urine osmolality, whereas drinking regular soda and other drinks but not water was associated with inferior hydration.


Assuntos
Bebidas/estatística & dados numéricos , Água Corporal/fisiologia , Dieta/estatística & dados numéricos , Adolescente , Animais , Criança , Estudos de Coortes , Desidratação/urina , Feminino , Humanos , Masculino , Leite , Concentração Osmolar , Gravidade Específica , Urinálise , Água
6.
Int J Sport Nutr Exerc Metab ; 28(1): 75-81, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29035599

RESUMO

The purpose of this article is to assess the hydration status of elite young sailing athletes during World Championship competition. Twelve young, elite, male, Laser Class sailors (age: 15.8 ± 1.1 y, height: 1.74 ± 0.1 m, weight: 65.1 ± 1.5 kg, body fat: 12.5 ± 3.1%, training experience: 7.0 ± 1.2 y) participated in this descriptive study. After three-day baseline bodyweight measurements, hydration status was assessed via pre- and post-race body weights, urine-specific gravity, and thirst ratings via a visual analog scale during four consecutive days of racing. Measurements and data collection took place at the same time each racing day, with mean environmental temperature, humidity, and wind speed at 23.0 ± 0.8°C, 64-70%, and 9 ± 1 knots, respectively. Average racing time was 130 ± 9 min. Body weight was significantly decreased following each race-day as compared to prerace values (Day 1: -1.1 ± 0.2, Day 2: -2.5 ± 0.1, Day 3: -2.8 ± 0.1, and Day 4: -3.0 ± 0.1% of body weight; p < 0.05). The participants exhibited dehydration of -2.9 ± 0.2 and -5.8 ± 0.2% of body weight before and after the fourth racing day as compared to the three-day baseline body weight. Urine-specific gravity (pre-post → Day 1: 1.014-1.017; Day 2: 1.019-1.024; Day 3: 1.021-1.026; Day 4: 1.022-1.027) and thirst (pre-post → Day 1: 2.0-5.2; Day 2: 3.2-5.5; Day 3: 3.7-5.7; Day 4: 3.8-6.8) were also progressively and significantly elevated throughout the four days of competition. The data revealed progressive dehydration throughout four consecutive days of racing as indicated by decreased body weight, elevated urine concentration, and high thirst.


Assuntos
Atletas , Desidratação , Esportes/fisiologia , Sede , Perda de Peso , Peso Corporal , Humanos , Masculino , Navios , Urinálise , Adulto Jovem
7.
Front Nutr ; 4: 40, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28868290

RESUMO

BACKGROUND: Low levels of caffeine ingestion do not induce dehydration at rest, while it is not clear if larger doses do have an acute diuretic effect. The aim of the present investigation was to examine the acute effect of low and high levels of caffeine, via coffee, on fluid balance in habitual coffee drinkers (at least one per day) at rest. METHODS: Ten healthy adults (eight males and two females; age: 27 ± 5 years, weight: 89.5 ± 14.8 kg, height: 1.75 ± 0.08 m, and body mass index: 29.1 ± 4.4 kg m-2) ingested 200 mL of water (W), coffee with low caffeine (3 mg kg-1, LCAF), or coffee with high caffeine (6 mg kg-1, HCAF) on three respective separate occasions. All sessions were performed at 09:00 in the morning in a counterbalanced, crossover manner, at least 5 days apart. Subjects remained in the laboratory while urine samples were collected every 60 min for 3 h post ingestion. RESULTS: Absolute caffeine consumption was 269 ± 45 and 537 ± 89 mg for the LCAF and HCAF, respectively. Coffee ingestion at the HCAF trial induced greater diuresis during the 3-h period (613 ± 101 mL, P < 0.05), when compared to W (356 ± 53 mL) and LCAF (316 ± 38 mL). In addition, cumulative urinary osmotic excretion was significantly greater in the HCAF (425 ± 92 mmol, P < 0.05), as compared to the W (249 ± 36 mmol) and LCAF (177 ± 16 mmol) trials. CONCLUSION: The data indicate that caffeine intake of 6 mg kg-1 in the form of coffee can induce an acute diuretic effect, while 3 mg kg-1 do not disturb fluid balance in healthy casual coffee drinking adults at rest.

8.
Eur J Nutr ; 56(3): 1211-1217, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26864199

RESUMO

PURPOSE: Hypohydration has been suggested as a predisposing factor for several pathologies including cardiovascular diseases (CVD). While CVD are the leading cause of death worldwide, no study has investigated whether acute hypohydration affects endothelial function and cardiovascular function. METHODS: Ten young, healthy males participated in this crossover study (age: 24.3 ± 2.3 year; weight: 80.8 ± 5.3 kg; BMI: 24.3 ± 0.4 kg m-2). Each subject completed two measurements of endothelial function by flow-mediated dilation (FMD) in euhydrated and hypohydrated state separated by 24 h. Following baseline assessment of hydration status and FMD, the subjects completed 100 min of low-intensity intermittent walking exercise to achieve hypohydration of -2 % of individual body mass. For the rest of the day, a standardized, low water content diet was provided. The following morning, hydration markers and endothelial function were recorded. RESULTS: Hypohydration by -1.9 ± 0.1 % of body mass resulted in decreased plasma volume by -3.5 ± 1.8 % and increased plasma osmolality by 9 ± 2 mmol kg-1 (P < 0.001). FMD as a response to hypohydration decreased by -26.8 ± 3.9 % (P < 0.05). CONCLUSION: The data suggested that a small degree of hypohydration induced by moderate exercise and fluid restriction significantly impaired endothelial function.


Assuntos
Desidratação/fisiopatologia , Endotélio Vascular/fisiopatologia , Absorciometria de Fóton , Doença Aguda , Adulto , Glicemia/metabolismo , Pressão Sanguínea , Composição Corporal , Índice de Massa Corporal , Peso Corporal , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/fisiopatologia , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Estudos Cross-Over , Desidratação/sangue , Desidratação/complicações , Exercício Físico , Feminino , Humanos , Masculino , Concentração Osmolar , Triglicerídeos/sangue , Adulto Jovem
9.
Eur J Nutr ; 55(5): 1985-7, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27357837
10.
Eur J Nutr ; 55(3): 907-15, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25905541

RESUMO

AIM: Urine color (UC) is a practical tool for hydration assessment. The technique has been validated in adults, but has not been tested in children. PURPOSE: The purpose of the study was to test the validity of the urine color scale in young, healthy boys and girls, as a marker of urine concentration, investigate its diagnostic ability of detecting hypohydration and examine the ability of children to self-assess UC. METHODS: A total of 210 children participated (age: 8-14 years, body mass: 43.4 ± 12.6 kg, height: 1.49 ± 0.13 m, body fat: 25.2 ± 7.8 %). Data collection included: two single urine samples (first morning and before lunch) and 24-h sampling. Hydration status was assessed via urine osmolality (UOsmo) and UC via the eight-point color scale. RESULTS: Mean UC was 3 ± 1 and UOsmo 686 ± 223 mmol kg(-1). UC displayed a positive relationship as a predictor of UOsmo (R (2): 0.45, P < 0.001). Based on the receiver operating curve, UC has good overall classification ability for the three samples (area under the curve 85-92 %), with good sensitivity (92-98 %) and specificity (55-68 %) for detecting hypohydration. The overall accuracy of the self-assessment of UC in the morning or the noon samples ranged from 67 to 78 %. Further threshold analysis indicated that the optimal self-assessed UC threshold for hypohydration was ≥4. CONCLUSIONS: The classical eight-point urine color scale is a valid method to assess hydration in children of age 8-14 years, either by researchers or self-assessment.


Assuntos
Desidratação/diagnóstico , Desidratação/urina , Urina , Adiposidade , Adolescente , Biomarcadores/urina , Índice de Massa Corporal , Peso Corporal , Criança , Cor , Feminino , Humanos , Masculino , Concentração Osmolar , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
11.
BMC Pregnancy Childbirth ; 15: 66, 2015 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-25885759

RESUMO

BACKGROUND: To investigate the association between gestational weight gain, maternal age and lifestyle habits (e.g., physical activity, smoking, and alcohol consumption) during pregnancy, with Body Mass Index of the offspring at the age of 8. METHODS: Α random sample of 5,125 children was extracted from a national database and matched with their mothers. With the use of a standardised questionnaire, telephone interviews were carried out for the collection of information like: maternal age at pregnancy, gestational weight gain (GWG), exercise levels, smoking and alcohol consumption. The Body Mass Index (BMI) status of the offspring at the age of 8 was calculated from data retrieved from the national database (e.g., height and weight). RESULTS: The odds for being overweight/obese at the age of 8 for 1 kg GWG, for smoking, and for mild exercise during pregnancy compared to sedentary was 1.01 (95%CI: 1.00, 1.02), 1.23 (95%CI: 1.03, 1.47) and 0.77 (95%CI: 0.65, 0.91), respectively. Further analysis revealed that offspring of women who exceeded the Institute of Medicine (IOM) maternal weight gain recommendations were at an increased risk of obesity (OR: 1.45; 95%CI, 1.26, 1.67) compared with offspring of women with GWG within the recommended range. Maternal age and alcohol consumption were not associated with the outcome (p > 0.05). CONCLUSION: GWG, physical activity and smoking status during pregnancy were significantly associated with obesity for the offspring at the age of 8. Health care professionals should strongly advise women to not smoke and to perform moderate exercise during pregnancy to prevent obesity in the offspring in later life.


Assuntos
Estilo de Vida , Atividade Motora , Obesidade , Efeitos Tardios da Exposição Pré-Natal , Fumar , Ganho de Peso , Adulto , Índice de Massa Corporal , Criança , Feminino , Grécia/epidemiologia , Inquéritos Epidemiológicos , Humanos , Mães/psicologia , Obesidade/diagnóstico , Obesidade/epidemiologia , Obesidade/etiologia , Obesidade/psicologia , Gravidez , Complicações na Gravidez/epidemiologia , Complicações na Gravidez/fisiopatologia , Complicações na Gravidez/psicologia , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Efeitos Tardios da Exposição Pré-Natal/psicologia , Fatores de Risco , Comportamento Sedentário , Fumar/efeitos adversos , Fumar/fisiopatologia , Fumar/psicologia , Circunferência da Cintura
12.
J Strength Cond Res ; 29(12): 3447-52, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24513625

RESUMO

Although there are many studies demonstrating a high percentage of adult athletes who start exercise in suboptimal hydration state, limited data concerning hydration levels in athletic youth exist. The purpose of this study was to identify the hydration status of elite young athletes of different sports, during a typical day of training. Fifty-nine young elite male athletes from different sports (basketball, gymnastics, swimming, running, and canoeing) participated in the study (age: 15.2 ± 1.3 years; years of training: 7.7 ± 2.0). Hydration status was assessed in the morning, before and immediately after practice. Data collection took place at the same time of the day, with mean environmental temperature and humidity at the time of the measurements at 27.6 ± 0.9° C and 58 ± 8%, respectively. All athletes trained for approximately 90 minutes, and they were consuming fluids ad libitum throughout their practice. Over 89% of the athletes were hypohydrated (urine specific gravity [USG] ≥1.020 mg·dl) based on their first morning urine sample. Pretraining urine samples revealed that 76.3% of the athletes were hypohydrated, whereas a significant high percent remained hypohydrated even after training according to USG values ≥1.020 mg·dl (74.5%) and urine color scale: 5-6 (76.3%). Mean body weight loss during training was -1.1 ± 0.07%. We concluded that the prevalence of hypohydration among elite young athletes is very high, as indicated by the USG and urine color values. The majority of the athletes was hypohydrated throughout the day and dehydrated even more during practice despite fluid availability.


Assuntos
Desidratação/urina , Condicionamento Físico Humano/fisiologia , Equilíbrio Hidroeletrolítico , Esportes Juvenis/fisiologia , Adolescente , Basquetebol/fisiologia , Água Corporal , Criança , Ingestão de Líquidos , Ginástica/fisiologia , Humanos , Masculino , Corrida/fisiologia , Gravidade Específica , Natação/fisiologia , Urinálise , Perda de Peso
13.
J Athl Train ; 48(6): 741-7, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23952038

RESUMO

CONTEXT: Hydration has been shown to be an important factor in performance; however, the effects of mild dehydration during intense cycling are not clear. OBJECTIVE: To determine the influence of mild dehydration on cycling performance during an outdoor climbing trial in the heat (ambient temperature = 29.0°C ± 2.2°C). DESIGN: Crossover study. SETTING: Outdoor. PATIENTS OR OTHER PARTICIPANTS: Ten well-trained, male endurance cyclists (age = 28 ± 5 years, height = 182 ± 0.4 cm, mass = 73 ± 4 kg, maximal oxygen uptake = 56 ± 9 mL·min(-1)·kg(-1), body fat = 23% ± 2%, maximal power = 354 ± 48 W). INTERVENTION(S): Participants completed 1 hour of steady-state cycling with or without drinking to achieve the desired pre-exercise hydration level before 5-km hill-climbing cycling. Participants started the 5-km ride either euhydrated (EUH) or dehydrated by -1% of body mass (DEH). MAIN OUTCOME MEASURE(S): Performance time, core temperature, sweat rate, sweat sensitivity, and rating of perceived exertion (RPE). RESULTS: Participants completed the 5-km ride 5.8% faster in the EUH (16.6 ± 2.3 minutes) than DEH (17.6 ± 2.9 minutes) trial (t1 = 10.221, P = .001). Postexercise body mass was -1.4% ± 0.3% for the EUH trial and -2.2% ± 0.2% for the DEH trial (t1 = 191.384, P < .001). Core temperature after the climb was greater during the DEH (39.2°C ± 0.3°C) than EUH (38.8°C ± 0.2°C) trial (t1 = 8.04, P = .005). Sweat rate was lower during the DEH (0.44 ± 0.16 mg·m(-2)·s(-1)) than EUH (0.51 ± 0.16 mg·m(-2)·s(-1)) trial (t8 = 2.703, P = .03). Sweat sensitivity was lower during the DEH (72.6 ± 32 g·°C(-1)·min(-1)) than EUH (102.6 ± 54.2 g·°C(-1)·min(-1)) trial (t8 = 3.072, P = .02). Lastly, RPE after the exercise performance test was higher for the DEH (19.0 ± 1.0) than EUH (17.0 ± 1.0) participants (t9 = -3.36, P = .008). CONCLUSIONS: We found mild dehydration decreased cycling performance during a 5-km outdoor hill course, probably due to greater heat strain and greater perceived intensity.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Desidratação , Teste de Esforço/métodos , Adulto , Índice de Massa Corporal , Temperatura Corporal , Estudos Cross-Over , Ingestão de Líquidos , Febre , Frequência Cardíaca , Temperatura Alta , Humanos , Masculino , Oxigênio/metabolismo , Resistência Física/fisiologia , Esforço Físico/fisiologia , Sudorese
14.
Pediatr Exerc Sci ; 25(3): 394-406, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23877385

RESUMO

We aimed to model endurance, explosive power, and muscle strength in relation to body mass index (BMI) and physical-fitness tests in Greek children aged 7-10 years old. In the present large epidemiological study, anthropometric measurements and physical-fitness tests (i.e., multistage shuttle run, vertical jump, standing long jump, small ball throw and 30-m sprint) from 141,169 children were analyzed. Age- and sex-specific normative values for physical fitness tests were expressed as tabulated percentiles using the LMS statistical method. The correlation coefficients between BMI and performances were negative and significant for both sexes (p < .01) in all physical-fitness tests. The only exception was a positive correlation between ball throw and BMI (p < .01). Only 2.9% and 4.0% of boys and girls respectively, passed the upper quartiles in all tests. The performance in speed may serve as a predictive factor explaining, at least in part, the performance in aerobic endurance and explosive power in children aged 7-10 years. The presented population-based data for physical-fitness tests revealed that only a small percentage of these children are in the upper quartiles in all tests. Furthermore, the data suggests that speed performance can be used to predict physical fitness.


Assuntos
Índice de Massa Corporal , Força Muscular/fisiologia , Resistência Física/fisiologia , Aptidão Física/fisiologia , Esportes/fisiologia , Fatores Etários , Desempenho Atlético , Distribuição de Qui-Quadrado , Criança , Estudos Transversais , Exercício Físico/fisiologia , Feminino , Grécia , Humanos , Modelos Lineares , Masculino , Valores de Referência , Reprodutibilidade dos Testes , Medição de Risco , Fatores Sexuais , Análise e Desempenho de Tarefas
15.
Int J Sport Nutr Exerc Metab ; 23(3): 245-51, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23166200

RESUMO

UNLABELLED: There is a lack of studies concerning hydration status of young athletes exercising in the heat. PURPOSE: To assess preexercise hydration status in young soccer players during a summer sports camp and to evaluate body- water balance after soccer training sessions. METHODS: Initial hydration status was assessed in 107 young male soccer players (age 11-16 yr) during the 2nd day of the camp. Seventy-two athletes agreed to be monitored during 2 more training sessions (3rd and 5th days of the camp) to calculate dehydration via changes in body weight, while water drinking was allowed ad libitum. Hydration status was assessed via urine specific gravity (USG), urine color, and changes in total body weight. Mean environmental temperature and humidity were 27.2 ± 2 °C and 57% ± 9%, respectively. RESULTS: According to USG values, 95 of 107 of the players were hypohydrated (USG ≥ 1.020) before practice. The prevalence of dehydration observed was maintained on both days, with 95.8% and 97.2% of the players being dehydrated after the training sessions on the 3rd and 5th days, respectively. Despite fluid availability, 54 of the 66 (81.8%) dehydrated players reduced their body weight (-0.35 ± 0.04 kg) as a response to training, while 74.6% (47 out of the 63) further reduced their body weight (-0.22 ± 0.03 kg) after training on the 5th day. CONCLUSION: Approximately 90% of the young soccer players who began exercising under warm weather conditions were hypohydrated, while drinking ad libitum during practice did not prevent further dehydration in already dehydrated players.


Assuntos
Atletas , Desidratação/prevenção & controle , Ingestão de Líquidos/fisiologia , Futebol/fisiologia , Adolescente , Peso Corporal , Criança , Temperatura Alta , Humanos , Umidade , Modelos Lineares , Masculino , Prevalência , Estações do Ano , Manejo de Espécimes , Inquéritos e Questionários , Equilíbrio Hidroeletrolítico/fisiologia
16.
Med Sci Sports Exerc ; 44(1): 175-9, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21685819

RESUMO

UNLABELLED: It has been suggested that mouth rinse and/or ingestion of fluids during exercise may have a beneficial effect on performance. However, the existing results are controversial. PURPOSE: We hypothesized that pharyngeal receptor activation through ingestion of a small amount of water could enhance performance better than mouth rinse in dehydrated subjects. METHODS: Ten healthy trained male cyclists (weight = 78.2 ± 2.2 kg, age = 25.9 ± 1.0 yr, body fat = 15.6% ± 1.6%, VO2max = 53.8 ± 4.8 mL · kg(-1) · min(-1)) completed three time-to-exhaustion cycling tests at 75% of their maximum power output after being dehydrated by 2% of their total body weight. Dehydration was induced by a 2-h moderate-intensity exercise (70% of maximum HR), which included 30-min intervals alternating between jogging and cycling in the heat (31 °C). All subjects repeated the protocol in random order on three separate occasions: a) mouth rinse with 25 mL of plain water before and every 5 min of the trial (MR), b) ingestion of 25 mL of plain water before and every 5 min (DR), and c) control (CON), where no fluids were provided. Blood and urine samples were collected at the beginning of the dehydration phase, before the performance test, and at the end of the experimental protocol. RESULTS: A significantly greater time to exhaustion was recorded in the DR trial compared with MR and CON trials (21.9 ± 1.2 vs 18.7 ± 1.3 and 17.7 ± 1.1 min, respectively, P < 0.05). There were no differences in mean HR, maximum lactate concentration, or RPE between the three trials (P > 0.05). CONCLUSIONS: The results demonstrated that ingestion of even a small amount of water increased exercise time in dehydrated subjects possibly through activation of pharyngeal receptors.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo , Desidratação/fisiopatologia , Ingestão de Líquidos/fisiologia , Adulto , Desidratação/terapia , Fadiga/prevenção & controle , Frequência Cardíaca/fisiologia , Humanos , Ácido Láctico/sangue , Ácido Láctico/urina , Masculino , Consumo de Oxigênio/fisiologia , Resistência Física/fisiologia , Adulto Jovem
17.
Cardiol Res Pract ; 2011: 248626, 2010 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-20981278

RESUMO

We studied the association of physical activity and adherence to the Mediterranean diet, in total antioxidant capacity (TAC). A random sample of 1514 men and 1528 women was selected from Attica region. Physical activity was assessed with a translated version of the validated "International Physical Activity Questionnaire" (iPAQ), and dietary intake through a validated Food Frequency Questionnaire (FFQ). Adherence to the Mediterranean diet was assessed by the MedDietScore that incorporated the inherent characteristics of this diet. TAC was positively correlated with the degree of physical activity (P < .05). TAC was also positively correlated with MedDietScore (r = 0.24, P < .001). Stratified analysis by diet status revealed that the most beneficial results were observed to highly active people as compared to inactive, who also followed the Mediterranean diet (288 ± 70 µmol/L, 230 ± 50 µmol/L, resp.), after adjusting for various confounders. Increased physical activity and greater adherence to the Mediterranean diet were associated with increased total antioxidant capacity.

18.
J Athl Train ; 44(2): 117-23, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19295955

RESUMO

CONTEXT: Sodium replacement during prolonged exercise in the heat may be critically important to maintaining fluid and electrolyte balance and muscle contractility. OBJECTIVE: To examine the effectiveness of sodium-containing sports drinks in preventing hyponatremia and muscle cramping during prolonged exercise in the heat. DESIGN: Randomized crossover study. PATIENTS OR OTHER PARTICIPANTS: Thirteen active men. INTERVENTION(S): Participants completed 4 trials of an exercise protocol in the heat (30 degrees C) consisting of 3 hours of exercise (alternating 30 minutes of walking and cycling at a heart rate of 130 and 140 beats per minute, respectively); a set of standing calf raises (8 sets of 30 repetitions); and 45 minutes of steep, brisk walking (5.5 km x h(-1) on a 12% grade). During exercise, participants consumed fluids to match body mass loss. A different drink was consumed for each trial: carbohydrate-electrolyte drink containing 36.2 mmol/L sodium (HNa), carbohydrate-electrolyte drink containing 19.9 mmol/L sodium (LNa), mineral water (W), and colored and flavored distilled water (PL). MAIN OUTCOME MEASURE(S): Serum sodium, plasma osmolality, plasma volume changes, and muscle cramping frequency. RESULTS: During both HNa and LNa trials, serum sodium remained relatively constant (serum sodium concentration at the end of the protocol was 137.3 mmol/L and 136.7 mmol/L, respectively). However, a clear decrease was observed in W (134.5 +/- 0.8 mmol/L) and PL (134.4 +/- 0.8 mmol/L) trials compared with HNa and LNa trials (P < .05). The same trends were observed for plasma osmolality (P < .05). Albeit not significant, plasma volume was preserved during the HNa and LNa trials, but a reduction of 2.5% was observed in the W and PL trials. None of the volunteers experienced cramping. CONCLUSIONS: The data suggest that sodium intake during prolonged exercise in the heat plays a significant role in preventing sodium losses that may lead to hyponatremia when fluid intake matches sweat losses.


Assuntos
Ingestão de Líquidos , Teste de Esforço , Temperatura Alta/efeitos adversos , Sódio/administração & dosagem , Equilíbrio Hidroeletrolítico/fisiologia , Adulto , Aldosterona/análise , Aldosterona/metabolismo , Análise de Variância , Glicemia/análise , Volume Sanguíneo , Composição Corporal , Índice de Massa Corporal , Regulação da Temperatura Corporal , Frequência Cardíaca/fisiologia , Humanos , Hiponatremia/prevenção & controle , Masculino , Contração Muscular/fisiologia , Concentração Osmolar , Valores de Referência , Sensibilidade e Especificidade , Sódio/metabolismo , Desequilíbrio Hidroeletrolítico/prevenção & controle , Adulto Jovem
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