The prevalence of obesity in children has increased dramatically during the past decades in Europe and understanding physical fitness and its components in children is critical to design and implement effective interventions.
The objective of the present study was to analyse the association between physical fitness (aerobic capacity, agility, power, flexibility and balance) and body mass index in pre-pubertal children. 30431 healthy schoolchildren (6 to 11 y) participated in this study. Children were grouped in weight status categories based on International cut-off centile curves.
Physical fitness was measured by 6 physical fitness tests: Leger test, agility shuttle, standing long jump, sit and reach, basketball forward throw and static balance. Significant differences in anthropometric characteristics and physical fitness were observed through age classes and between genders.
Obese girls and boys showed significantly lower physical fitness levels than their normalweighted counterparts in aerobic capacity (mean level reached: -44 and -39%, p<0.05), agility (mean time to complete the task: +7.5 and +9.2%, p<0.05), lower limb power (mean length of the jump: -11.2 and -13.8%, p<0.05) and balance (mean time in balance: -12.2 and -15.8%, p<0.05). As well, difference between weight status groups in aerobic capacity, agility and lower limbs power increased as a function of age, especially in boys.
On the other hand, obese girls and boys showed higher upper limbs power (mean length of the throw: +11.2 and +7.9%, p<0.05) and under-weighted girls and boys showed poorer upper limbs power (mean length of the throw: -7.7 and -7.4%, p<0.05) relative to their normal-weighted counterparts. Flexibility was only partially affected by weight status.
In conclusion, higher BMIs were associated with lower performance capabilities limiting proper motor skill development, which directly affects the ability of children to take on sports skills. Actions undertaken to promote children’s wellness and fitness should be prioritized and introduced early in life with the aim of enhancing physical fitness as well as preventing obesity.
