title: A methodological approach to short-term tracking of youth physical fitness: the Oporto Growth, Health and Performance Study.
abstract: In this paper, three different statistical approaches were used to investigate short-term tracking of cardiorespiratory and performance-related physical fitness among adolescents. Data were obtained from the Oporto Growth, Health and Performance Study and comprised 1203 adolescents (549 girls) divided into two age cohorts (10-12 and 12-14 years) followed for three consecutive years, with annual assessment. Cardiorespiratory fitness was assessed with 1-mile run/walk test; 50-yard dash, standing long jump, handgrip, and shuttle run test were used to rate performance-related physical fitness. Tracking was expressed in three different ways: auto-correlations, multilevel modelling with crude and adjusted model (for biological maturation, body mass index, and physical activity), and Cohen's Kappa (κ) computed in IBM SPSS 20.0, HLM 7.01 and Longitudinal Data Analysis software, respectively. Tracking of physical fitness components was (1) moderate-to-high when described by auto-correlations; (2) low-to-moderate when crude and adjusted models were used; and (3) low according to Cohen's Kappa (κ). These results demonstrate that when describing tracking, different methods should be considered since they provide distinct and more comprehensive views about physical fitness stability patterns.
authors.affiliation: a Department of Physical Education, Center of Sports , Federal University of Santa Catarina , Florianópolis , Brazil.|b CAPES Foundation , Ministry of Education of Brazil , Brasília , Brazil.
authors.forename: Michele
authors.initials: M
authors.lastname: Souza
authors.affiliation: c Department of Radiology , Michigan State University , East Lansing , MI , USA.
authors.forename: Joey
authors.initials: J
authors.lastname: Eisenmann
authors.affiliation: d Department of Physical Education , Federal University of Technology of Paraná , Curitiba , Brazil.
authors.forename: Raquel
authors.initials: R
authors.lastname: Chaves
authors.affiliation: e CIFI2D, Faculty of Sport , University of Porto , Porto , Portugal.
authors.forename: Daniel
authors.initials: D
authors.lastname: Santos
authors.affiliation: e CIFI2D, Faculty of Sport , University of Porto , Porto , Portugal.
authors.forename: Sara
authors.initials: S
authors.lastname: Pereira
authors.affiliation: f Exercise Hemodynamic Laboratory, School of Physical Education and Sport , University of São Paulo , São Paulo , Brazil.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Forjaz
authors.affiliation: e CIFI2D, Faculty of Sport , University of Porto , Porto , Portugal.
authors.forename: José
authors.initials: J
authors.lastname: Maia
mesh_terms: D000293:Adolescent; D000072599:Cardiorespiratory Fitness; D002648:Child; D015444:Exercise; D005080:Exercise Test; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D053580:Muscle Strength; D010809:Physical Fitness; D012420:Running
keywords: Stability; adolescents; change; fitness