title: Influence of activity patterns in fitness during youth.
abstract: The aim of this study was to analyze longitudinal associations between cardiorespiratory fitness, physical activity and body mass index in a 4-year longitudinal study. 170 students (97 girls and 73 boys) aged at baseline from 11 to 17 years were followed. Students performed 20-m-SR; physical activity patterns and parents' education were evaluated using a standard questionnaire. Body mass index was categorized according to established cut points. In a multilevel analysis using MLwIN, 2 level structures were defined: first for individuals and second for time observations. In a longitudinal 2 level analysis, cardiorespiratory fitness was -negatively associated with body mass index for girls and boys, respectively (p<0.05; R2=0.63; 0.62), especially with obesity category (p<0.01; R2=0.58; 0.60). In girls, independent associations were observed between CRF and PA categories regarding participation "almost every day" in organized (p<0.05; R2=0.50) and non-organized sports outside school (p<0.05; R2=0.52) and participation in sports competitions (p<0.05; R2=0.51). In boys, associations were found only with participation in sports competitions (p<0.05; R2=0.50). The results highlight the importance of youth participation in organized activities and competitive sports over time to achieve health-related fitness benefits.
authors.affiliation: Faculty of Sports, Research Centre in Physical Activity, Health and Leisure, University of Porto, Portugal. luisa.aires@gmail.com
authors.forename: L
authors.initials: L
authors.lastname: Aires
authors.forename: G
authors.initials: G
authors.lastname: Silva
authors.forename: C
authors.initials: C
authors.lastname: Martins
authors.forename: M P
authors.initials: MP
authors.lastname: Santos
authors.forename: J C
authors.initials: JC
authors.lastname: Ribeiro
authors.forename: J
authors.initials: J
authors.lastname: Mota
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000502:physiology*; D015992:Body Mass Index; D002320:Cardiovascular Physiological Phenomena; D002648:Child; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010809:Physical Fitness / Q000502:physiology*; D011174:Portugal; D012143:Respiratory Physiological Phenomena; D012574:Schools; D013177:Sports / Q000502:physiology