Anthropometric Indices and Some Aspects of Physical Fitness in Croatian Adolescents by Gender.

. The main purpose of this study was to explore the body-mass index and waist circumference associated with physical fitness by gender. In this cross-sectional study, we included 1036 adolescents (55.4% girls) from eight randomly selected secondary schools within the city of Zagreb (Croatia). Body-mass index and waist circumference were objectively measured. Physical fitness included three tests: (1) 1 min sit-ups, (2) standing long jump and (3) a sit-and-reach test. Associations were calculated using linear regression models. Boys had higher body-mass index and waist circumference values, compared to girls ( < 0.001). They also performed better in 1 min sit-ups and the standing long jump tests ( < 0.001), while girls obtained higher values in the sit-and-reach test ( < 0.001). In boys, body-mass index and waist circumference were associated with 1 min sit-ups and the standing long jump. In girls, waist circumference was also associated with 1 min sit-ups and the standing long jump, while body-mass index was only associated with this standing long jump. Our study shows that anthropometric indices have non-linear associations with physical fitness tests in a large sample of Croatian adolescents. Screening for thinness and obesity to predict the level of physical fitness should be of a great interest.