Our results provide conclusive evidence for an increasingly widening gap of OW/OB children's gross motor coordination relative to NW peers across developmental time in the absence of targeted initiatives. Special attention is thus needed for OW/OB children, especially for those not practicing sports in a club environment, in terms of motor skill improvement to promote regular participation in physical activity.

Within the obesity literature, focus is put on the link between weight status and gross motor skills. However, research on fine motor skills in the obese (OB) childhood population is limited. Therefore, the present study focused on possible weight related differences in gross as well as fine motor skill tasks. Thirty-four OB children (12 ♀ and 22 ♂, aged 7-13 years) were recruited prior to participating in a multidisciplinary treatment program at the Zeepreventorium (De Haan, Belgium). Additionally, a control group of 34 age and gender-matched healthy-weight (HW) children was included in the study. Anthropometric measures were recorded and gross and fine motor skills were assessed using the Bruininks-Oseretsky Test of Motor Proficiency, second edition (BOT-2). Results were analyzed by independent samples t-tests, multivariate analysis of variance, and a chi-squared test. Being OB was detrimental for all subtests evaluating gross motor skill performance (i.e., upper-limb coordination, bilateral coordination, balance, running speed and agility, and strength). Furthermore, OB children performed worse in fine motor precision and a manual dexterity task, when compared to their HW peers. No group differences existed for the fine motor integration task. Our study provides evidence that lower motor competence in OB children is not limited to gross motor skills alone; OB children are also affected by fine motor skill problems. Further investigation is warranted to provide possible explanations for these differences. It is tentatively suggested that OB children experience difficulties with the integration and processing of sensory information. Future research is needed to explore whether this assumption is correct and what the underlying mechanism(s) could be.

Objective: This longitudinal study investigated the interrelationship between children's weight status and level of gross motor coordination over time, taking baseline physical activity (PA) into account as a possible mediator. Methods: Baseline measurements were collected in 2517 children (5-13 years, 52.8% boys), including (1) body height and weight to calculate body mass index (BMI) z-scores, (2) gross motor coordination using the K€ orperkoordinationstest f€ ur Kinder (KTK), (3) total PA estimated by a questionnaire. At follow-up, 754 participants (7-13 years, 50.8% boys) underwent anthropometric and KTK assessments again. Two hypothesized partial mediation models (i.e., KTK $ PA $ BMI z-score) were examined by multiple linear mixed models. Results: A lower performance on the KTK at baseline significantly predicted an increase in BMI z-score (B 5 20.003, P 5 0.027). Conversely, a higher baseline BMI z-score also predicted a decrease in KTK performance (B 5 21.792, P < 0.001). Since total PA at baseline was not significantly related to initial KTK performance (B 5 1.628, P 5 0.134) nor BMI z-score (B 5 25.312, P 5 0.130), its mediating effect was not further explored. Conclusions: Our results strongly suggest that children's weight status negatively influences future level of gross motor coordination, and vice versa. Prevention and intervention initiatives should consider this reciprocal causal relationship across developmental time.