Association between health behaviors and cardiorespiratory fitness in adolescents: results from the cross-sectional MoMo-study.

Purpose: The aim of this study was to analyze the association between adolescent and familial health behavioral factors and cardiorespiratory fitness in German adolescent boys and girls.

Methods: This study is based on a large nationwide cross-sectional study and its substudy on physical activity and fitness of children and adolescents ("Motorik-Modul"). For 1,328 adolescents between 11 and 17 years of age, data on cardiorespiratory fitness (Physical working capacity 170, PWC(170)) and familial and adolescent health behavioral factors were collected. Health behavior was assessed using psychometric questionnaires (socioeconomic status, pubertal stage, daily physical activity, sports-club time, parental physical activity habits, etc.). A hierarchical multiple regression model was used to quantify the association between relative PWC(170) values and health behavior.

Results: The relationship between adolescents' health behavioral factors and cardiorespiratory fitness was stronger than the relationship between age, social status, familial health behavior and cardiorespiratory fitness. Familial health behavioral factors explained 4.1% and 2.1% of variance in cardiorespiratory fitness in girls and boys, respectively. Adolescents' health behavioral factors explained 15.2% of variance in girls and 25.7% of variance in boys. For both girls (β = .273) and boys (β = .400), being normal weight had the greatest effect on relative PWC(170) values.

Conclusions: The difference in explained variance in cardiorespiratory fitness by familial and adolescents' health behavioral factors between girls and boys indicates that different predictors for cardiorespiratory fitness are important for girls and boys. Hence, sex specific research and interventions aimed at improving familial and adolescent health behavior may be important.