title: A multilevel analysis of health-related physical fitness. The Portuguese sibling study on growth, fitness, lifestyle and health.
abstract: This study investigates biological, behavioural and sociodemographic correlates of intra-pair similarities, and estimates sibling resemblance in health-related physical fitness (PF). The sample comprises 1101 biological siblings (525 females) aged 9-20 years. PF components and markers were: morphological [waist circumference (WC) and %body fat (%BF)], muscular [handgrip strength (GS) and standing long jump (SLJ)], motor [50-yard dash (50YD) and shuttle run (SR)], and cardiorespiratory (1-mile run). Biological maturation was assessed; physical activity (PA), TV viewing and socioeconomic status (SES) information was obtained. On average, older and more mature subjects are better performers in all PF components; PA was negatively associated with SR, while SES was negatively associated with SLJ and SR. A pattern was observed in the intraclass correlations (ρ) wherein same sex siblings demonstrate greater resemblance for most PF components (sister-sister: 0.35≤ ρ≤0.55; brother-brother: (0.25≤ρ≤0.60) than brother-sister pairs (BS) (0≤ρ≤0.15), except for %BF (ρBB>ρSS>ρBS), and the 1-mile run (ρSS>ρBS>ρBB). In conclusion, behavioural and sociodemographic correlates play different roles in siblings PF expression. Further, a significant familial PF resemblance was observed with different trends in different sibling types, probably due to variations in shared genetic factors and sociodemographic conditions.
authors.affiliation: CIFI2D, Faculty of Sport, University of Porto, Porto, Portugal.
authors.forename: Sara
authors.initials: S
authors.lastname: Pereira
authors.affiliation: Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, United States of America.
authors.forename: Peter
authors.initials: P
authors.lastname: Todd Katzmarzyk
authors.affiliation: CIFI2D, Faculty of Sport, University of Porto, Porto, Portugal.
authors.forename: Thayse Natacha
authors.initials: TN
authors.lastname: Gomes
authors.affiliation: CIFI2D, Faculty of Sport, University of Porto, Porto, Portugal.|Department of Physical Education, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil.
authors.forename: Michele
authors.initials: M
authors.lastname: Souza
authors.affiliation: CIFI2D, Faculty of Sport, University of Porto, Porto, Portugal.|Federal University of Technology-Paraná (UTFPR), Campus Curitiba, Curitiba, Brazil.
authors.forename: Raquel Nichele
authors.initials: RN
authors.lastname: Chaves
authors.affiliation: CIFI2D, Faculty of Sport, University of Porto, Porto, Portugal.|Department of Physical Education, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil.
authors.forename: Fernanda Karina
authors.initials: FK
authors.lastname: Dos Santos
authors.affiliation: CIFI2D, Faculty of Sport, University of Porto, Porto, Portugal.
authors.forename: Daniel
authors.initials: D
authors.lastname: Santos
authors.affiliation: Department of Public Health Sciences, University of Chicago, Chicago, IL, United States of America.
authors.forename: Donald
authors.initials: D
authors.lastname: Hedeker
authors.affiliation: CIFI2D, Faculty of Sport, University of Porto, Porto, Portugal.
authors.forename: José
authors.initials: J
authors.lastname: Maia
mesh_terms: D000293:Adolescent; D041923:Adolescent Development; D002648:Child; D002657:Child Development; D005260:Female; D018737:Hand Strength; D000070497:Healthy Lifestyle; D006801:Humans; D008297:Male; D010809:Physical Fitness; D011174:Portugal; D035781:Siblings; D055105:Waist Circumference; D055815:Young Adult