title: Associations of Fat Mass and Fat-Free Mass with Physical Fitness in 4-Year-Old Children: Results from the MINISTOP Trial.
abstract: Physical fitness is a powerful marker of health in youth. Studies in adolescents and adults suggest that higher fat mass is related to worse physical fitness. However, there is limited knowledge whether fat mass and fat-free mass are associated with physical fitness already in preschoolers. Baseline data from the MINISTOP (Mobile-based INtervention Intended to STop Obesity in Preschoolers) trial was utilized for this cross-sectional analysis. Body composition was assessed using air-displacement plethysmography. Fat mass index [fat mass (kg)/height² (m)] and fat-free mass index [fat-free mass (kg)/height² (m)] were used to provide height-adjusted measures of body composition. Physical fitness was measured using the PREFIT (FITness testing in PREschool children) battery, which assesses cardiorespiratory fitness, upper-body and lower-body muscular strength as well as motor fitness. In total, this study included 303 children (168 boys and 135 girls), who were on average 4.48 ± 0.15 years old. Higher fat mass index was associated with worse cardiorespiratory fitness (standardized β = -0.17, p = 0.002), lower-body muscular strength (β = -0.17, p = 0.003) and motor fitness (β = -0.21, p < 0.001) in regression analyses adjusted for age, sex and mutually adjusted for fat-mass index and fat-free mass index. Conversely, higher fat-free mass index was associated with better cardiorespiratory fitness (β = 0.18, p = 0.002), upper-body muscular strength (β = 0.39, p < 0.001), lower-body muscular strength (β = 0.22, p < 0.001) and motor fitness (β = 0.17, p = 0.004). Thus, fat mass and fat-free mass in preschoolers appear to have joint but opposite associations with physical fitness, an important marker for current and future health.
authors.affiliation: PROmoting FITness and Health through Physical Activity Research Group (PROFITH), Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, 18071 Granada, Spain. pontus.tm.henriksson@gmail.com.|Department of Clinical and Experimental Medicine, Faculty of Health Science, Link&#246;ping University, 581 53 Link&#246;ping, Sweden. pontus.tm.henriksson@gmail.com.
authors.forename: Pontus
authors.initials: P
authors.lastname: Henriksson
authors.affiliation: PROmoting FITness and Health through Physical Activity Research Group (PROFITH), Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, 18071 Granada, Spain. cristina.cadenas.sanchez@gmail.com.
authors.forename: Cristina
authors.initials: C
authors.lastname: Cadenas-Sanchez
authors.affiliation: Department of Health Sciences, University of Jyvaskyla, 40014 Jyvaskyla, Finland. marja.h.leppanen@gmail.com.
authors.forename: Marja H
authors.initials: MH
authors.lastname: Leppänen
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Huddinge, Sweden. christine.delisle.nystrom@ki.se.
authors.forename: Christine
authors.initials: C
authors.lastname: Delisle Nyström
authors.affiliation: PROmoting FITness and Health through Physical Activity Research Group (PROFITH), Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, 18071 Granada, Spain. ortegaf@ugr.es.|Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Huddinge, Sweden. ortegaf@ugr.es.
authors.forename: Francisco B
authors.initials: FB
authors.lastname: Ortega
authors.affiliation: Marshfield Clinic Research Foundation, Marshfield, WI 54449, USA. pomeroy.jeremy@mcrf.mfldclin.edu.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Pomeroy
authors.affiliation: PROmoting FITness and Health through Physical Activity Research Group (PROFITH), Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, 18071 Granada, Spain. ruizj@ugr.es.|Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Huddinge, Sweden. ruizj@ugr.es.
authors.forename: Jonatan R
authors.initials: JR
authors.lastname: Ruiz
authors.affiliation: Department of Clinical and Experimental Medicine, Faculty of Health Science, Link&#246;ping University, 581 53 Link&#246;ping, Sweden. marie.lof@ki.se.|Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Huddinge, Sweden. marie.lof@ki.se.
authors.forename: Marie
authors.initials: M
authors.lastname: Löf
mesh_terms: D050154:Adiposity / Q000208:ethnology; D015415:Biomarkers; D001823:Body Composition; D015992:Body Mass Index; D001846:Bone Development; D000072599:Cardiorespiratory Fitness; D002652:Child Behavior / Q000208:ethnology; D002657:Child Development; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D024510:Muscle Development; D053580:Muscle Strength; D063766:Pediatric Obesity / Q000000981:diagnostic imaging / Q000208:ethnology / Q000209:etiology / Q000517:prevention & control*; D010809:Physical Fitness; D010993:Plethysmography, Whole Body; D012044:Regression Analysis; D057185:Sedentary Behavior / Q000208:ethnology; D013548:Sweden
chemical_list: D015415:Biomarkers
keywords: air-displacement plethysmography; body composition; cardiorespiratory fitness; motor fitness; muscular strength; preschool