The work, developed by researchers from different institutions, including the Faculty of Human Motricity (University of Lisbon), the School of Sport and Leisure of Melgaço, and the higher schools of education in Lisbon, Coimbra and Bragança, analysed children from 3 and 6 years old.

Research has shown that, at these ages, children who live with siblings at home, regardless of age and sex, have better values ??for total motor skills, which may indicate “a tendency to develop better motor skills in the future”.

"Regardless of the need for further clarification on this matter, it is important that families and the various agents that work with children take into account the possible effects that being an only child can have on motor development", write the authors.

The siblings influence on the children's motor competence levels was demonstrated with a battery of tests that analyzes and evaluates three major groups of movements: stabilizers or postures (lateral jumps, for example), more locomotive movements (long jump and shuttle run)) and more manipulative and interacting movements (throwing or kicking a ball).

The researchers note that "the number of families with only children has increased steadily in recent years, resulting in a childhood without sibling relationships" and that several studies have already linked the existence of older siblings with positive changes in the physical activity of younger siblings over time.