The level of Motor Competence (MC) is a determining factor in the adherence of children and young people to increased physical activity. The objective was to explore the applicability of the Body Mass Index (BMI) and the Tri-ponderal Index (TPI) to assess the (MC) in schoolchildren aged 7 to 14 years (54 girls and 49 boys). Anthropometric variables of weight, height, BMI and PTI were evaluated. MC was measured with two tests from the Körperkoordinationstest Für Kinder (KTK) battery, Lateral Transposition (TL) and Lateral Leap (SL). Tests for normality, differences between groups were applied. There were no differences between both sexes(p>0.05), nutritional status according to BMI(p=0.079); on the contrary, in ITP there were significant differences(p= 0.010) between normal weight (10.43±2.67rep) with obesity and between overweight with obesity (p<0.05). In the SL there were differences between normal weight with obesity and between overweight with obesity (p<0.0). The results of the study suggest that ITP could be a better indicator of nutritional status compared to BMI; moreover, an elevated ITP can negatively influence motor skills during childhood and youth. It is necessary to insist on promoting healthy habits to maintain a healthy weight.