New study published in Research in Sports Medicine found there were significant differences between female and male feet. The authors took four hundred and twenty-four feet and four men's running shoe lasts (U.S. women 6.0-9.5), used for the manufacturing of women's shoes. These were scanned in three dimensions and six foot measures were quantified. Using a cluster analysis different foot types were classified then researchers compared last measures and specific foot type measures for eaxch classification. Findings revealed the differences in width measures between lasts and foot types varied substantially (0-9 mm). Width grading ws larger in lasts in comparison with average grading in feet (3.5-5.9 mm). The authors concluded the use of down-graded men's lasts for making women's shoes has to be questioned.
Krauss I, Valiant G, Horstmann T, Grau S. 2010 Comparison of female foot morphology and last design in athletic footwear--are men's lasts appropriate for women? Res Sports Med. 2010 Apr;18(2):140-56.