Assessment of the elementary school students' schoolbag weight in the urban environment in Poland: A cross-sectional study carried out as a part of the 'Lightweight Schoolbag' and 'Let's Get the Kids Moving' projects.

Background: Carrying a properly weighted schoolbag is an important factor in preventing the occurrence of muscular skeletal disorder in early school age children.

Objective: The purpose of this cross- sectional observational study was to examine the schoolbag weight and to determine the percentage of children were carrying overloaded schoolbag.

Methods: The study group included pupils from five primary public schools in Wrocław, Poland.