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 5 Comparison of foot shape characteristics in first and second examination in boys.
| Exam | χ̄±SD | Min–Max | Q25 | Me | Q75 | Statistics |
|---|---|---|---|---|---|---|
| Foot length of the right foot [cm] | ||||||
| 1 | 21.67±1.44 | 19.00–24.90 | 20.70 | 21.50 | 22.50 | t=−3.35=0.001* |
| 2 | 21.77±1.47 | 19.20–24.00 | 20.08 | 21.60 | 23.00 | |
| Foot length of the left foot [cm] | ||||||
| 1 | 21.68±1.39 | 19.10–24.90 | 20.80 | 21.50 | 22.50 | t=−4.37<0.001* |
| 2 | 21.76±1.41 | 19.20–25.00 | 20.80 | 21.55 | 22.50 | |
| Foot width of the right foot [cm] | ||||||
| 1 | 8.00±0.57 | 6.60–9.30 | 7.60 | 8.00 | 8.40 | t=−4.43<0.001* |
| 2 | 8.13±0.58 | 6.70–9.60 | 7.60 | 8.00 | 8.50 | |
| Foot width of the left foot [cm] | ||||||
| 1 | 8.09±0.58 | 6.80–9.50 | 7.70 | 8.05 | 8.50 | Z=−7.13<0.001* |
| 2 | 8.24±0.56 | 7.30–9.50 | 7.80 | 8.25 | 8.60 | |
| Clarke’s angle of the right foot [°] | ||||||
| 1 | 34.74±9.78 | 7.00–50.00 | 30.00 | 38.00 | 40.00 | Z=5.21<0.001* |
| 2 | 32.97±10.32 | 5.00–50.00 | 27.00 | 35.00 | 40.00 | |
| Clarke’s angle of the left foot [°] | ||||||
| 1 | 32.57±10.42 | 6.00–47.00 | 25.00 | 36.00 | 40.00 | Z=5.49<0.001* |
| 2 | 30.71±10.58 | 4.00–47.00 | 24.00 | 34.50 | 38.00 | |
| Heel angle γ of the right foot [°] | ||||||
| 1 | 16.21±1.60 | 14.00–20.00 | 15.00 | 16.00 | 17.00 | Z=2.97=0.003* |
| 2 | 16.53±1.76 | 13.00–20.00 | 15.00 | 16.00 | 17.00 | |
| Heel angle γ of the left foot [°] | ||||||
| 1 | 16.38±1.76 | 12.00–22.00 | 15.00 | 16.00 | 17.00 | Z=3.32=0.001* |
| 2 | 16.79±1.95 | 12.00–22.00 | 15.00 | 16.50 | 18.00 | |
| Hallux valgus angle α of the right foot [°] | ||||||
| 1 | 3.10±4.01 | −7.00–12.00 | 2.00 | 4.50 | 7.00 | t=0.96=0.342 |
| 2 | 2.84±4.65 | −8.00–15.00 | 0.00 | 3.00 | 6.00 | |
| Hallux valgus angle α of the left foot [°] | ||||||
| 1 | 4.26±5.07 | −13.00–15.00 | 2.00 | 4.50 | 7.00 | Z=1.12=0.262 |
| 2 | 4.31±5.64 | −14.00–15.00 | 0.00 | 4.00 | 8.00 | |
| Angle of the varus deformity of the fifth toe β of the right foot [°] | ||||||
| 1 | 16.19±4.56 | 3.00–25.00 | 14.00 | 15.50 | 19.00 | t=0–3.82<0.001* |
| 2 | 17.17±4.74 | 5.00–27.00 | 15.00 | 17.00 | 20.00 | |
| Angle of the varus deformity of the fifth toe β of the left foot [°] | ||||||
| 1 | 15.69±5.80 | 0.00–27.00 | 13.00 | 15.50 | 20.00 | t=0–2.79=0.007* |
| 2 | 16.76±5.90 | 1.00–28.00 | 13.00 | 17.50 | 21.00 | |
| 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 dependent variables statistics; Z – value of the Wilcoxon signed-rank test statistics; – probability value. * | ||||||