Normal values for maximal respiratory pressures in children and adolescents: A systematic review with meta-analysis

•MRP values increased with increasing age.•MEP values, both for girls and boys, were higher than the MIP values for all ages.•Boys had higher MIP and MEP values than girls, regardless of age group.•Large 95 % CI values were observed for MIP and MEP, mainly for the 12–19 age group.•For clinical practice, the nationality of the study should be considered.