Influence of School Backpack Load as a Variable Affecting Gait Kinematics among Seven-Year-Old Children

This article investigates schoolchildren’s ability to carry an additional load using a backpack (BP). According to scientific research, there is no precise limit to the maximum backpack load, which varies from 10% to 15% of body weight (BW). The purpose of this study was, therefore, to evaluate the influence of an additional external load carried using a backpack on gait kinematics among seven-year-old children in Poland, including assessment of the gender differences. The study was conducted among 26 (13 boys and 13 girls) primary school children aged seven years. The children walked at their preferred speed, under four conditions: with no load (0% BW) and with 10%, 15% and 20% BW. Spatiotemporal parameters were measured using the 2 m Footscan® platform system and photocell Sectro timing system. The children walked more slowly under an additional load. Their step length and single support time decreased. Their base of support, step time and double support time increased. There was no significant effect on their stride length or gait cycle time. The gait kinematic changes were most evident between 10% BW and greater loading. The results highlight how children’s gait is affected by carrying additional external loads, which should not exceed 10% BW. That limit is appropriate for both genders

Sample of a single MRI slice with final segmentation of the four chosen muscles.

<p>Legend: Glut min–gluteus minimus muscle, Glut med–gluteus medius muscle, Glut max–gluteus maximus muscle, Pir–piriformis muscle. All anatomical objects defined by closed contours were filled in by selected colors.</p

Concordance and intra-class correlations between volume measurements made by two independent raters (1 and 2) in LBLP patients and healthy volunteers.

<p>Concordance and intra-class correlations between volume measurements made by two independent raters (1 and 2) in LBLP patients and healthy volunteers.</p

Comparison of the mean values for the four pelvic muscles volume (symptomatic v. non-symptomatic side of the LBLP group).

<p>Comparison of the mean values for the four pelvic muscles volume (symptomatic v. non-symptomatic side of the LBLP group).</p

Overall scatter of volume measurements in [cm³] performed by two independent raters (1 and 2) in healthy volunteers.

<p>Overall scatter of volume measurements in [cm³] performed by two independent raters (1 and 2) in healthy volunteers.</p

Differences in the frequency of LBLP patients with a smaller volume of the left muscles compared to the right muscles.

<p>Differences in the frequency of LBLP patients with a smaller volume of the left muscles compared to the right muscles.</p

Clinical description of the analyzed group.

<p>Clinical description of the analyzed group.</p

Overall scatter of volume measurements in [cm³] performed by two independent raters (1 and 2) in LBLP patients.

<p>Overall scatter of volume measurements in [cm³] performed by two independent raters (1 and 2) in LBLP patients.</p

Samples of a single MRI slice with contouring of the four segmented muscles (axial view).

<p>Legend: Glut min–gluteus minimus muscle, Glut med–gluteus medius muscle, Glut max–gluteus maximus muscle, Pir–piriformis muscle. Muscles were contoured in ITK-SNAP where the structures were outlined slice-by-slice by pointing and clicking with a mouse. The program connected the consecutive points with lines.</p