Participant characteristics at baseline
| Characteristics | Flat, flexible school shoe (n=12) | Traditional school shoe (n=12) | Total (n=24) |
| Age, years | 14.3 (1.7) | 14.4 (1.8) | 14.4 (1.7) |
| Height, cm | 171.4 (10.2) | 166.0 (8.2) | 168.7 (9.5) |
| Body mass, kg | 68.1 (15.3) | 64.2 (8.0) | 65.6 (12.1) |
| Body mass index, kg/m2 | 23 (4.2) | 23.3 (2.2) | 23.2 (3.2) |
| Sex, male (%) | 11 (92) | 4 (33) | 15 (63) |
| Bilateral PFP, n (%) | 8 (67) | 10 (83.3) | 18 (75) |
| Duration of symptoms in months, median (IQR) | 15 (4-24) | 39 (24-54) | 24 (9-39) |
| Sports participation, yes (%) | 11 (92) | 9 (75) | 20 (83) |
| Physical activity participation, days/week | 4 (2.2) | 3 (2.1) | 4 (2.3) |
| Worst pain* | 6.1 (1.4) | 6.7 (1.9) | 6.4 (1.7) |
| Average pain* | 3.4 (1.4) | 3.7 (1.9) | 3.5 (1.6) |
| Classification of current school footwear†| 4.8 (3.0) | 7.3 (3.5) | 6.0 (3.4) |
Values are mean (SD) unless otherwise indicated.
*Worst & average pain measured on an 11-point numeric rating scale with 0 indicating no pain and 10 indicating worse pain imaginable over the past week.
†Classification of current school footwear performed using the minimalist index (scored from 0 to 25 with lower scores indicating greater minimalism and flexibility).
PFP, patellofemoral pain.