Bidirectional, prospective associations between physical activity, fundamental motor skills, and physical fitness in preschool children

Background Evidence regarding longitudinal associations between physical activity (PA), fundamental motor skills, and physical fitness in young children is scarce and mixed. This study aimed to investigate bidirectional associations between intensity-specific PA and fundamental motor skills and physical fitness in 3–4-year-old preschoolers over 18 months. Methods We included 821 children (3.8 years, 53.5% boys) from the Active Learning Norwegian Preschool(er)s study who were measured at baseline and 18 months later. PA was measured with ActiGraph GT3X + accelerometers, fundamental motor skills were evaluated using 9 skills as indicators of locomotor skills, object control skills, and balance skills, and fitness was measured through tests of upper- and lower-body muscular strength (handgrip and standing long jump) and motor fitness (4 × 10 shuttle-run test). Structural equation modelling (SEM) with latent change-scores was used to investigate the bidirectional, prospective associations for PA with fundamental motor skills and physical fitness. Results Vigorous PA (VPA) and total PA (TPA) were bidirectionally, and favourably, associated with locomotor skills and motor fitness. Moderate PA (MPA) and moderate-to-vigorous PA (MVPA) showed a positive association with balance skills, and MPA, VPA, MVPA, and TPA were prospectively and positively associated with object control skills, handgrip strength, and standing long jump, but not vice versa. Sedentary behaviour (SED) showed a bidirectional, negative association with locomotor skills, and a negative association with object control skills and all fitness measures. Conclusion Although we found a few bidirectional associations for PA with locomotor skills and motor fitness, our results suggest that promoting MVPA in early childhood can have a positive impact on children’s development of fundamental motor skills and physical fitness.