Association Between Objectively Measured Physical Activity and Plasma BDNF in Adolescents: DADOS Study.

Brain-derived neurotrophic factor (BDNF) is suggested to play a key role in moderating the benefits of physical activity (PA) on cognition. Previous research found that PA may have an impact on peripheral BDNF expression. The aim of our study was to analyze the association between objectively measured PA with circulating BDNF in a group of active adolescents. Two hundred thirty-four adolescents (132 boys) aged 13.9 ± 0.3 years old from the DADOS study were included in this cross-sectional analysis. PA was assessed by GENEActiv triaxial accelerometer. Participants wore the accelerometer on their non-dominant wrist for 6 consecutive 24-h days, including weekends. PA was expressed as the average (min/day) of light, moderate, and vigorous PA. Fasting plasma BDNF concentrations at rest were measured using an enzyme-linked immunosorbent assay. Partial correlations and linear regression analyses were performed with a significance level established at p < 0.05. No correlations were found between BDNF and PA variables. Plasma levels of BDNF at rest were not significantly associated with daily PA in either boys or girls (p > 0.05). Based on previous research and our own data, the association between daily PA and baseline levels of BDNF remains inconclusive. Further research is needed to shed light on the relationship between regular PA and BDNF in adolescents.

An examination of injuries in Spanish Professional Soccer League.

AIM: Objective of the study was to examine the injury incidence in the Spanish Professional Soccer League, and to analyse differences between competition and training. METHODS: Sport injuries data from 11 out of 22 Spanish second division soccer teams (301 players) were prospectively collected during the season 2008/2009. RESULTS: A total of 891 injuries (111 recurrence injuries) were identified during 161602.7 hours of exposure. Competition injury incidence was higher than training (38.8 vs. 3.8 injuries per 1000h; P<0.05). The higher injury incidence was located at lower extremities (4.82 per 1000 h), and mainly affected muscles and tendons (3.1 per 1000 h). Two out of three injuries were due to overuse (54% during competition and 72% during training), and mainly result in players were unable to full soccer participation for less than 7 days (64%). Training injury incidence was higher during the pre-season and tended to decrease throughout the season (P<0.05), while competition injury incidence increased progressively throughout the season (P<0.05). CONCLUSION: In our best knowledge, this is the first examination of injuries in Spanish professional soccer players. The main findings of the study suggest that competition is much more injurious than training, revealing a progressive decrease of training injury incidence and a progressive increase of competition injury incidence throughout the season. These data might be considered by clubs, coaches, and medical staff in order to design new strategies that reduce injury risk in Spanish Professional Soccer League.

Body adiposity index and incident hypertension: the Aerobics Center Longitudinal Study.

BACKGROUND AND AIM: The body adiposity index (BAI) has been recently proposed as a new method to estimate the percentage of body fat. The association between BAI and hypertension risk has not been investigated yet. The aim of our study was to evaluate the ability of BAI to predict hypertension in males and females compared with traditional body adiposity measures. METHODS AND RESULTS: The present follow-up analysis comprised 10,309 individuals (2259 females) free of hypertension from the Aerobics Center Longitudinal Study, who completed a baseline examination between 1988 and 2003. Body adiposity measures included BAI, body mass index (BMI), waist circumference, hip circumference, percentage of body fat and waist to hip ratio (WHR). Incident hypertension was ascertained from responses to mail-back surveys between 1990 and 2004. During an average of 9.1 years of follow-up, 872 subjects (107 females) became hypertensive. Hazard ratios (HRs) and 95% confidence intervals (95% CI) showed that males in the highest categories of all body adiposity measures showed a higher incident risk of hypertension (HRs ranged from 1.37 to 2.09). Females showed a higher incident risk of hypertension only in the highest categories of BAI, BMI and WHR (HRs ranged from 1.84 to 3.36). CONCLUSION: Our results suggest that in order to predict incident hypertension BAI could be considered as an alternative to traditional body adiposity measures.

Five year trends on total and abdominal adiposity in Spanish adolescents.

OBJECTIVE: To assess five years trends in total and abdominal fat in Spanish adolescents. DESIGN: Two cross-sectional studies: adolescents from the city of Zaragoza (Spain) assessed during 2001-2002 and 2006-2007. SUBJECTS: 399 adolescents in 2001-02 and 392 adolescents in 2006-07. MAIN OUTCOME MEASUREMENTS: Socio-economic status was assessed using the education level of both parents. A complete anthropometric assessment was performed in both surveys using the same methodology: weight, height, skinfold thickness (biceps, triceps, subscapular, suprailiac, thigh and calf) and circumferences (waist and hip). The body mass index (BMI) and the sum of 6 skinfold thicknesses were calculated. Body fat percentage (BF%) was also calculated by the formulas described by Slaughter et al. RESULTS: After adjusting for age and pubertal status, only females showed a significantly decrease in weight, BMI and waist circumference, and a significant increase in the sum of 6 skinfolds (all P < 0.05 and Cohen's d ≥ 0.25) in 2006-2007, when compared to values obtained in 2001-2002. Males did not show any significant change between the two surveys. Concerning centile values, a slight general reduction was observed in weight, BMI and waist circumference for both males and females. On the contrary, the sum of 6 skinfolds and the BF% were higher in 2006-2007 than in 2001-2002. CONCLUSION: According to these results, there might be a levelling-off in the trends of BMI, BF% and waist circumference in male adolescents from Zaragoza. In females, despite a trend towards higher body fat mass, there was a trend towards lower BMI and waist circumference values.

Five year trends on total and abdominal adiposity in Spanish adolescents / Tendencias durante cinco años en la grasa total y abdominal en adolescentes españoles

Objective: To assess five years trends in total and abdominal fat in Spanish adolescents. Design: Two cross-sectional studies: adolescents from the city of Zaragoza (Spain) assessed during 2001-2002 and 2006-2007. Subjects: 399 adolescents in 2001-02 and 392 adolescents in 2006-07. Main outcome measurements: Socio-economic status was assessed using the education level of both parents. A complete anthropometric assessment was performed in both surveys using the same methodology: weight, height, skinfold thickness (biceps, triceps, subscapular, suprailiac, thigh and calf) and circumferences (waist and hip). The body mass index (BMI) and the sum of 6 skinfold thicknesses were calculated. Body fat percentage (BF%) was also calculated by the formulas described by Slaughter et al. Results: After adjusting for age and pubertal status, only females showed a significantly decrease in weight, BMI and waist circumference, and a significant increase in the sum of 6 skinfolds (all P < 0.05 and Cohen's d ≥ 0.25) in 2006-2007, when compared to values obtained in 2001-2002. Males did not show any significant change between the two surveys. Concerning centile values, a slight general reduction was observed in weight, BMI and waist circumference for both males and females. On the contrary, the sum of 6 skinfolds and the BF% were higher in 2006-2007 than in 2001-2002. Conclusion: According to these results, there might be a levelling-off in the trends of BMI, BF% and waist circumference in male adolescents from Zaragoza. In females, despite a trend towards higher body fat mass, there was a trend towards lower BMI and waist circumference values (AU)

Objetivo: Evaluar las tendencias de cinco años de la grasa total y abdominal de adolescentes españoles. Diseño: Dos estudios transversales: adolescentes de la ciudad de Zaragoza (España) evaluados durante 2001-2002 y 2006-2007. Sujetos: 399 adolescentes en 2001-02 y 392 adolescentes en 2006-07. Principales variables estudiadas: El estado socioeconómico se evaluó usando el nivel educativo de ambos progenitores. Se realizó una evaluación antropométrica completa en ambos estudios con la misma metodología: peso, talla, grosor del pliegue (bíceps, tríceps, subescapular, suprailíaco, muslo y pantorrilla) y circunferencias (cintura y cadera). Se calcularon el índice de masa corporal (IMC) y la suma del grosor de 6 pliegues. También se calculó el porcentaje de grasa corporal (%GC) con las fórmulas descritas por Slaughter et al. Resultados: tras ajustar por edad y estado puberal, sólo las chicas mostraron un descenso significativo del peso, IMC y la circunferencia de la cintura, y un aumento significativo en la suma de los 6 pliegues cutáneos (todos ellos P < 0,05 y d de Cohen ≥ 0,25) en 2006-2007, en comparación con los valores obtenidos en 2001-2002. Los chicos no mostraron cambios significativos entre ambos estudios. Con respecto a los percentiles, se observó una reducción leve del peso, IMC y circunferencia de la cintura en chicos y chicas. Por el contrario, la suma de los 6 pliegues cutáneos y el %GC fueron mayores en 2006-2007 que en 2001-2002. Conclusión: de acuerdo con estos resultados, podría haber un resultado neutro en las tendencias del IMC, %GC y circunferencia de la cintura en los adolescentes varones de Zaragoza. En las chicas, a pesar de una mayor tendencia a una mayor grasa corporal, hubo una tendencia a unos menores valores de IMC y de circunferencia de la cintura (AU)

Associations of muscular and cardiorespiratory fitness with total and central body fat in adolescents: the HELENA study.

OBJECTIVE: to examine the association of healthrelated physical fitness with total and central body fat in adolescents. PARTICIPANTS/METHODS: the present cross-sectional study comprises 363 Spanish adolescents (186 female participants) aged 12.5-17.5 years. We assessed fitness by the 20-m shuttle run test (cardiorespiratory fitness); the handgrip strength, the standing broad jump and the Abalakov tests (muscular strength); and the 4 × 10-m shuttle run test (speed-agility). Total body fat was measured by dual energy x-ray absorptiometry (DXA), BodPod and sum of six skinfolds, and central body fat was measured by DXA at three regions (R1, R2 and R3) and waist circumference. RESULTS: the Abalakov, the standing broad jump, the 4 × 10-m shuttle run and the 20-m shuttle run tests were negatively associated with all markers of total and central body fat in men and women after controlling for age, pubertal status and objectively assessed physical activity (p<0.01). Handgrip strength test was positively associated with waist circumference (p<0.01). CONCLUSIONS: lower body muscular strength and cardiorespiratory fitness are negatively and consistently associated with total and central body fat in adolescents, whereas levels of upper body muscular strength were superior in adolescents with higher levels of central body fat.

Role of cardiorespiratory fitness on the association between physical activity and abdominal fat content in adolescents: the HELENA study.

We examined the role of cardiorespiratory fitness (CRF) on the association between physical activity (PA) and abdominal fat content in adolescents. Abdominal fat content was measured by waist circumference, waist-to-height ratio and dual energy X-ray absorptiometry (DXA) at 3 regions (R1, R2, and R3). PA and CRF were assessed by accelerometry and the 20 m-shuttle run test, respectively. Vigorous PA was inversely associated with waist circumference and waist-to-height ratio (ß from -0.149 to -0.197; p<0.05). In both CRF groups (i. e., low and high), vigorous and moderate-to-vigorous PA (also average PA in the low CRF group) were inversely associated with abdominal fat (i. e., R1, R2 and R3; ß from -0.146 to -0.244; p<0.05). This association did not differ according to CRF group (P for interaction >0.05), yet the percentage of variance in abdominal fat content, when assessed by DXA, explained by PA was slightly higher in adolescents with low CRF (3-8%) compared to those with high CRF (2-4%). The findings indicate that there is not a clear interaction effect of CRF in the association between PA and abdominal fat in adolescents, yet slightly stronger association was observed in the low fit group.

Secular trends in health-related physical fitness in Spanish adolescents: the AVENA and HELENA studies.

We analysed the secular trends in health-related physical fitness in Spanish adolescents between 2001-2002 and 2006-2007. Two representative population studies were conducted 5 years apart in adolescents (12.5-17.5 years) from Zaragoza (Spain) that participated in the AVENA study in 2001-2002 and in the HELENA-CSS study in 2006-2007. Both studies used the same tests to assess physical fitness: the handgrip strength, bent arm hang, standing broad jump, 4×10m shuttle run and 20m shuttle run tests. Performance in 4×10m shuttle run and 20m shuttle run tests was higher in 2006-2007 (Cohen's d ranging from 0.2 to 0.4, p<0.05), whereas performance in handgrip strength and standing broad jump tests was lower in 2006-2007 (Cohen's d ranging from 0.3 to 1.1, p<0.001). Adjustment for age, pubertal status, fat mass, fat free mass and parental education did not alter the results. The odds ratio (OR) of meeting the FITNESSGRAM Standards for healthy cardiorespiratory fitness was higher in 2006-2007 in both boys (OR, 95% CI: 2.123, 1.157-3.908) and girls (OR, 95% CI: 2.420, 1.377-4.255). The results indicate that levels of both speed/agility and cardiorespiratory fitness were higher in 2006-2007 than in 2001-2002, whereas muscular strength components were lower in 2006-2007.

Socioeconomic status influences physical fitness in European adolescents independently of body fat and physical activity: the HELENA study.

INTRODUCTION: The influence of socioeconomic status on health-related fitness is not clear. AIM: To examine the influence of socioeconomic status on health-related fitness in adolescents. METHODS: A total of 3,259 adolescents (15.0 +/- 1.3 y) from the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study (HELENA-CSS) participated in the study. Socioeconomic status was assessed by the family affluence scale (FAS). Speed-agility, muscular strength and cardiorespiratory fitness were assessed. Covariates included total body fat, physical activity and pubertal status. RESULTS: Adolescents with high FAS had significantly higher fitness levels than their peers of lower FAS categories except for speed-agility and handgrip in boys. Overall, the associations observed presented a medium to large effect size. CONCLUSION: These results suggest that socioeconomic status is positively associated with physical fitness in European adolescents independently of total body fat and habitual physical activity.

Socioeconomic status influences physical fitness in European adolescents independently of body fat and physical activity: the HELENA Study / El estatus socioeconómico influencia la condición física en adolescentes europeos. El estudio HELENA

Introduction: The influence of socioeconomic status on health-related fitness is not clear. Aim: To examine the influence of socioeconomic status on health-related fitness in adolescents. Methods: A total of 3,259 adolescents (15.0 ± 1.3 y) from the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study (HELENA-CSS) participated in the study. Socioeconomic status was assessed by the family affluence scale (FAS). Speed-agility, muscular strength and cardiorespiratory fitness were assessed. Covariates included total body fat, physical activity and pubertal status. Results: Adolescents with high FAS had significantly higher fitness levels than their peers of lower FAS categories except for speed-agility and handgrip in boys. Overall, the associations observed presented a medium to large effect size. Conclusion: These results suggest that socioeconomic status is positively associated with physical fitness in European adolescents independently of total body fat and habitual physical activity (AU)

Introducción: La influencia del estatus socioeconómico sobre la condición física en relación con la salud no está clara. Objetivo: Examinar la influencia del estatus socioeconómico sobre la condición física en relación con la salud en adolescentes. Metodología: Un total de 3259 adolescentes (15,0 ± 1,3 años) del "Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study" (HELENA-CSS) participaron en el estudio. El estatus socioeconómico fue medido con una escala de riqueza familiar "family affluence scale (FAS)". Se midieron velocidad-agilidad, fuerza muscular y capacidad aeróbica. Las covariables incluidas fueron grasa corporal total, actividad física y estadio madurativo. Resultados: Los adolescentes con alto FAS tuvieron significativamente mayores niveles de condición física que aquellos con bajo FAS exceptuando los tests de velocidad-agilidad y fuerza de prensión manual en chicos. En general, las asociaciones observadas presentaron un efecto del tamaño de la muestra (effect size) entre medio y largo. Conclusión: Estos resultados sugieren que el estatus socioeconómico esta positivamente asociado con la condición física en adolescentes Europeos independientemente de la grasa corporal total y el nivel de actividad física (AU)

Association of objectively assessed physical activity with total and central body fat in Spanish adolescents; the HELENA Study.

OBJECTIVES: To examine the association of objectively assessed physical activity (PA) with markers of total and central body fat in adolescents, and to determine whether meeting the current PA recommendations (> or = 60 min day(-1) of at least moderate intensity PA) is associated with reduced levels of total and central body fat. SUBJECTS/METHODS: A total of 365 Spanish adolescents aged 12.5-17.5 years participated in this cross-sectional study. PA was assessed by accelerometry and expressed as average PA (counts per minute), and min day(-1) of light, moderate, moderate to vigorous (MVPA) and vigorous PA. MVPA was dichotomized into < 60 min day(-1) and > or = 60. Total body fat was measured by DXA, BodPod and the sum of six skinfolds. Central body fat was measured by DXA at three regions (R1, R2 and R3), and waist circumference. RESULTS: All markers of central body fat were negatively associated with vigorous PA (P < 0.01) after controlling for sex, age and pubertal status. Abdominal adiposity measured at R1, R2 and R3 was also negatively associated with MVPA (P < or = 0.001), and with average PA (P < 0.01). All markers of total body fat were negatively associated with vigorous PA (P < 0.01), MVPA (P < 0.01) and average PA (P < 0.05). Adolescents engaged on at least 60 min day(-1) MVPA presented lower levels of total (P < 0.05) and central body fat (P < or = 0.01). CONCLUSIONS: The results suggest that vigorous PA may have a greater effect on preventing obesity in adolescents than does PA of lower intensity, whereas both average PA and at least moderate PA may have an impact on total and central body fat in youth.