04 April 2026 : Clinical Research
Effect of School Backpack Weight on Shape of Children's Feet
Sabina Lizis
ABCDEF 1, Justyna Leszczak ADEF 1, Ewa Puszczałowska-Lizis ADEF 1*
DOI: 10.12659/MSM.952039
Med Sci Monit 2026; 32:e952039
Table 6 Sex-related comparison of differences in foot shape characteristics recorded in first and second examination.
| Sex | Difference (first examination – second examination) | Statistics | ||||
|---|---|---|---|---|---|---|
| χ̄±SD | Min–Max | Q25 | Me | Q75 | ||
| Foot length of the right foot [cm] | ||||||
| Girls | 0.04±0.10 | −0.20–0.30 | 0.00 | 0.00 | 0.00 | Z=−1.21=0.225 |
| Boys | 0.09±0.22 | −0.20–1.30 | 0.00 | 0.00 | 0.10 | |
| Foot length of the left foot [cm] | ||||||
| Girls | 0.08±0.16 | 0.00–1.00 | 0.00 | 0.00 | 0.10 | Z=−0.02=0.982 |
| Boys | 0.08±0.14 | 0.00–0.70 | 0.00 | 0.00 | 0.10 | |
| Foot width of the right foot [cm] | ||||||
| Girls | 0.13±0.13 | −0.10–0.50 | 0.00 | 0.10 | 0.20 | Z=1.80=0.072 |
| Boys | 0.12±0.21 | −0.10–1.20 | 0.00 | 0.10 | 0.20 | |
| Foot width of the left foot [cm] | ||||||
| Girls | 0.19±0.17 | −0.20–0.70 | 0.10 | 0.20 | 0.30 | Z=1.59=0.111 |
| Boys | 0.14±0.15 | −0.20–0.50 | 0.00 | 0.10 | 0.20 | |
| Clarke’s angle of the right foot [°] | ||||||
| Girls | −2.21±2.11 | −7.00-0.00 | −4.00 | −2.00 | 0.00 | Z=−1.05=0.292 |
| Boys | −1.78±1.96 | −6.00-1.00 | −3.00 | −1.00 | 0.00 | |
| Clarke’s angle of the left foot [°] | ||||||
| Girls | −2.43±2.24 | −8.00-0.00 | −4.00 | −2.00 | 0.00 | Z=−1.26=0.207 |
| Boys | −1.86±1.99 | −10.00-1.00 | −3.00 | −1.50 | 0.00 | |
| Heel angle γ of the right foot [°] | ||||||
| Girls | 0.26±0.57 | −2.00–2.00 | 0.00 | 0.00 | 1.00 | Z=−0.05=0.964 |
| Boys | 0.33±0.73 | −1.00–3.00 | 0.00 | 0.00 | 1.00 | |
| Heel angle γ of the left foot [°] | ||||||
| Girls | 0.39±0.67 | −1.00–3.00 | 0.00 | 0.00 | 1.00 | Z=0.47=0.638 |
| Boys | 0.41±0.86 | −1.00–4.00 | 0.00 | 0.00 | 1.00 | |
| Hallux valgus angle α of the right foot [°] | ||||||
| Girls | 0.07±2.13 | −6.00–6.00 | 0.00 | 0.00 | 1.00 | Z=0.10=0.924 |
| Boys | −0.26±2.06 | −7.00-3.00 | 0.00 | 0.00 | 1.00 | |
| Hallux valgus angle α of the left foot [°] | ||||||
| Girls | 0.33±2.53 | −7.00–7.00 | 0.00 | 0.00 | 2.00 | Z=−0.42=0.676 |
| Boys | 0.05±2.24 | −8.00-4.00 | 0.00 | 0.00 | 1.00 | |
| Angle of the varus deformity of the fifth toe β of the right foot [°] | ||||||
| Girls | 1.02±1.65 | −2.00–7.00 | 0.00 | 0.00 | 2.00 | Z=0.17=0.862 |
| Boys | 0.98±1.96 | −3.00–10.00 | 0.00 | 0.00 | 1.00 | |
| Angle of the varus deformity of the fifth toe β of the left foot [°] | ||||||
| Girls | 1.59±2.93 | −6.00–12.00 | 0.00 | 1.00 | 3.00 | Z=0.70=0.484 |
| Boys | 1.07±2.91 | −14.00–8.00 | 0.00 | 0.50 | 2.00 | |
| χ̄ –arithmetic mean value; SD – standard deviation; Min – minimum value; Max – maximum value; Q – lower quartile; Me – median; Q – upper quartile; t – value of the test for independent variables statistics; Z – value of the Mann-Whitney U test statistics; – probability value. | ||||||