Longitudinal Changes in Running Economy Following Minimalist Footwear and Running-Retraining Interventions Over 12 Months.

PURPOSE: The objective of this study was to compare the long-term effects of running retraining and minimalist footwear on running economy (RE), foot and ankle adaptations, and running biomechanics over a 12-month period. METHOD: In this randomized controlled trial, 61 habitual rearfoot runners were allocated to 3 groups: minimalist footwear (n = 19), running-retraining (n = 18), and control (n = 24). Participants were evaluated at baseline, 2, 6, and 12 months. Outcome measures included RE and biomechanics assessed on a treadmill at self-selected comfortable speed, as well as foot and ankle characteristics. RESULTS: RE improved over time in all groups, with no clear between-group differences at any time point. RE significantly improved from baseline in both the minimalist group (+4.9% at 6 mo and +9.3% at 12 mo; P = .03 and P < .001, respectively) and the running-retraining group (+5.6% at 6 mo and +10.5% at 12 mo; P < .001 for both). The control group showed an improvement in RE (+4.7%) at 12 months compared to baseline (P = .01). No significant changes were observed in foot and ankle characteristics in any group across the follow-up period. CONCLUSION: RE improved similarly across all groups, suggesting that neither running retraining nor transitioning to minimalist footwear provides additional benefits beyond the control condition over a 12-month period. Although descriptive trends indicated greater improvements in the intervention groups, substantial interindividual variability highlights the need to identify responders to these interventions in future studies.