Comparison of foot loading and foot strike pattern in women running in minimalist and conventional sports shoes

Background: At present, most runners use conventional sports shoes to protect and absorb the impacts that may cause overloading of the feet and joints. On the other hand, some runners tend to run almost barefoot or in minimalist footwear that may lead to foot strike pattern changes. Objective: The aim of this study was to analyse and to compare the foot strike pattern and foot loading when running in conventional running shoes (CRS) and minimalist running shoes (MRS) in a group of recreational women runners. Methods: A group of 14 experienced recreational women runners participated in this research. A Pedar-X system (Novel, Munich, Germany) was used to analyse the interaction of the foot with the ground while running in different type of shoes from as it relates to vertical force and plantar pressure distribution. The participants ran over a distance of 100 m with their habitual foot strike pattern in minimalist and also in conventional running shoes and data was always obtained while running along a straight 50 m long section (v = 3.33 ± 0.2 m ⋅ s -1 ). For assessment of the temporal and kinetics variables differences, the Wilcoxon test and the unpaired t-tests were used. Results: Recreational women runners showed statistically significant shift of the plantar pressures towards the forefoot when running in MRS compared to CRS (p = .047). Duration of swing phase in MRS and in CRS was similar (p = .291). When running in MRS, foot loading during initial contact was significantly higher than when running in CRS. Loading in the area of midfoot and forefoot was significantly higher in MRS too. Conclusions: Runners shifted their foot strike pattern forward when running in MRS; running in MRS may increase the foot loading and we recommend the use of minimalist footwear only after adequate foot strengthening and adaptation to avoid possible risk of foot injuries.