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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.

The aims of this study were to identify differences between the sexes in extra-curricular participation in sports and to determine its association with body fat and socio-demographic factors in Spanish adolescents. A total of 2165 adolescents (1124 males and 1041 females) aged 13.0-18.5 years from the AVENA Study participated. Participants filled in an ad hoc questionnaire for extra-curricular participation in sports, which was the dependent variable. Independent variables were: age, percent body fat, and father's and mother's educational level and occupation. Chi-square tests and logistic regression were applied. Bivariate analysis showed for male adolescents that age and father's occupation were related to extra-curricular participation in sports. In addition, body fat and mother's education and occupation (all P < 0.05) were related to extra-curricular participation of in sports for female adolescents. Logistic regression analysis showed that the likelihood of involvement in extra-curricular participation in sports was 5.3-fold (3.86-7.38) higher for males than females. Age and father's education in both males and females were independently associated with extra-curricular participation in sports. In summary, Spanish male adolescents were shown to engage in more extra-curricular sports than females. In addition, age and father's education (in both sexes) were associated with the participation of their offspring in extra-curricular sports during adolescence.

The objective of this study is to analyse the association of objectively assessed physical activity (PA) with muscular strength and fat-free mass in adolescents, and to determine whether meeting the current PA recommendations is associated with higher levels of muscular strength and fat-free mass. The present cross-sectional study comprised 363 Spanish adolescents (180 females) aged 12.5-17.5 years. PA was assessed by accelerometry and expressed as average PA (counts/min), and min/day of inactive, light, moderate, vigorous and moderate to vigorous PA (MVPA). MVPA was dichotomized into < 60 min/day and > or = 60. Upper body muscular strength was measured with the handgrip strength test, and lower body muscular strength was measured with the standing broad jump, squat jump, counter movement jump and Abalakov tests. Fat-free mass was measured by DXA. We observed positive associations between vigorous PA and all the lower body muscular strength tests except for the counter movement jump in males. PA was not associated with fat-free mass in both males and females. Male adolescents engaged in at least 60 min/day MVPA performed better in the standing broad jump test. In conclusion, the findings of the present study suggest that only vigorous PA is associated with muscular strength, particularly lower-body muscular strength in male adolescents.

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.