Effects of minimalist and maximalist footwear on Achilles tendon load in recreational runners

The current investigation aimed to comparatively examine the effects of minimalist, maximalist and conventional footwear on Achilles tendon forces (ATF) during running. Twelve male runners (age 23.11 +/- 5.01 years, height 1.78 +/- 0.10 cm and body mass 77.13 +/- 7.89 kg) ran at 4.0 m/s in the three footwear conditions. ATF's were calculated using Opensim software allowing the magnitudal and temporal aspects of the ATF to be quantified. Differences between footwear were examined using one-way repeated measures ANOVA. The results showed the peak ATF was significantly larger in minimalist footwear (5.97 +/- 1.38 body weight (BW)) compared to maximalist (5.07 +/- 1.42 BW). In addition it was revealed that ATF per mile was significantly larger in minimalist (492.31 +/- 157.72 BW) in comparison to both maximalist (377.31 +/- 148.06 BW) and conventional (402.71 +/- 125.51 BW) footwear. Given the relationship between high ATF and Achilles tendon degradation, the current investigation indicated that minimalist footwear may increase runners risk for Achilles tendon injury.