The Relationship Between Obesity Status and Body Image Dissatisfaction on Gross Motor Skill Development and Cardiorespiratory Fitness in Children Aged 6–12 Years Old

Background: The harmonious development of gross motor skills (GMSs) is vital for children, fostering their physical, cognitive, and socio-emotional growth. This study aimed to achieve three primary objectives: (1) to establish standardized reference values for all GMS tests conducted; (2) to examine the impact of overweight and obesity on factors influencing the development of GMSs and cardiorespiratory fitness (CRF); and (3) to investigate the relationship between GMSs and CRF levels and body image dissatisfaction among Canadian children from the province of Québec. Methods: The study encompassed 3144 children aged 6 to 12 years (1535 boys and 1609 girls) recruited from 24 elementary schools situated in five urban areas. Anthropometric measurements included body mass, body height, and body mass index (BMI). Physical performance was assessed using a maximal aerobic power test and 12 GMS tests, which comprised two segmental speed tests, four agility tests, two static balance tests, one simple reaction time test, and three coordination tests. Body perception and body image dissatisfaction were evaluated using a silhouette scale featuring two sets of nine drawings depicting a spectrum of body shapes ranging from very thin to obese. Results: Standardized normative values were established for each GMS test. GMSs demonstrated continuous improvement throughout childhood, albeit with a deceleration in progress during later developmental stages. At comparable age, boys generally outperformed girls on tests demanding greater strength, speed, or endurance, whereas girls exhibited superior performance in balance and hand–foot coordination tasks ( p ≤ 0.05). However, segmental speed remained equivalent between sexes ( p > 0.05). GMS and CRF were significantly influenced by obesity status. Children with a normal BMI demonstrated superior performance compared to their overweight or obese counterparts, particularly in tests requiring body mass displacement ( p ≤ 0.05). Conversely, socioeconomic status exhibited no significant impact on body perception in boys ( p = 0.106), but it was a notable factor among 6–8-year-old girls from lower socioeconomic backgrounds ( p = 0.045). Conclusions: Obesity status is linked to diminished GMS performance, especially in tasks involving body mass movement. These findings underscore the importance of early intervention strategies to encourage an active lifestyle and promote a healthy body composition in children.