BACKGROUND & OBJECTIVE
Previous research suggests that transitioning from traditional running shoes to minimalist shoes causes increases in foot intrinsic and extrinsic muscles size and strength. However, no studies have compared the properties of different foot structures depending on habitual running footwear. Therefore, the objective of this study was to determine the association between habitual running shoe type and the morphology of foot soft tissues (intrinsic and extrinsic foot muscles, plantar fascia, Achilles tendon and heel pad) in healthy recreational runners.
A total of 38 runners participated in this study. To be included, they had to be aged between 18 and 50 years, run at least 10km per week, run with the same shoes since at least 6 months and be injury-free. Participants were divided into 4 different groups depending on their habitual footwear: (1) neutral cushioned shoes (n=11); (2) motion control cushioned shoes (n=10); (3) minimalist shoes (n=7); (4) neutral cushioned shoes and custom-made insoles (n=10). Using ultrasound imaging, thickness and cross-sectional area of intrinsic and extrinsic foot muscles were assessed, along with the plantar fascia, Achilles tendon and heel pad. Tissue characteristics were compared between groups to assess their relationship with habitual footwear.
Runners using minimalist shoes showed: