The effects of CrossFit and minimalist footwear on Achilles tendon kinetics during running

Abstract

The aim of the current investigation was to comparatively assess the influence of barefoot, CrossFit, minimalist and conventional footwear on the loads experienced by the Achilles tendon during running. Twelve male runners (27.81 ± 7.02 years, height 1.77 ± 0.11 cm and body mass 76.22 ± 7.04 kg) ran at 4.0 m·s-1 in each of the four footwear conditions. Achilles tendon forces were calculated using a musculoskeletal modelling approach allowing the magnitudinal and temporal aspects of the Achilles tendon force to be quantified. Differences between footwear were examined using one-way repeated measures ANOVA. The results showed the peak Achilles tendon force was significantly larger when running barefoot (5.81 ± 1.21) and in minimalist footwear (5.64 ± 1.03 BW) compared to conventional footwear (5.15 ± 1.05 BW). In addition it was revealed that Achilles tendon impulse was significantly larger when running barefoot (0.77 ± 0.22 BW.s) and in minimalist footwear (0.72 ± 0.16 BW.s) in comparison to both conventional footwear (0.64 ± 0.15 BW.s). Given the proposed association between high Achilles tendon forces and tendon degradation, the outcomes from the current investigation indicate that CrossFit athletes who select barefoot and minimalist footwear for their running training may be at increased risk from Achilles tendon pathology in comparison to conventional footwear conditions.