Barisch-Fritz et al, “Evaluation of the Rule-of-Thumb: Calculation of the Toe Allowance for Developing Feet”, Footwear Science, 2016, Volume 8, Number 3, Pages 113-127:
- boys’ foot length didn’t increase after age 15
- girls’ foot length didn’t increase after age 13
- fastest growth in boys: 7-8 years, 10-12 years
- growth varied a lot individually