Twelve months of minimalist shoes or of running retraining did not make habitual heel-strikers clearly more economical than controls: in a randomised trial of 61 rearfoot runners, running economy improved in all three groups (by 9.3% with minimalist shoes, 10.5% with retraining and 4.7% in controls at 12 months) with no clear difference between groups at any time point, and foot and ankle measures did not change; from the abstract

Abran and colleagues compared the long-term effects of moving to minimalist footwear and of running retraining with doing neither, in habitual rearfoot runners followed for a year.

They randomised 61 runners to minimalist shoes (19), retraining (18) or control (24) and measured running economy and running mechanics on a treadmill at a comfortable self-chosen speed, and foot and ankle characteristics, at baseline and after 2, 6 and 12 months. Economy improved over time in every group, with no clear difference between groups at any time point.

Within groups, the minimalist group improved by 4.9% at 6 months (P = .03) and 9.3% at 12 months (P < .001), the retraining group by 5.6% and 10.5% (P < .001 for both), and the control group by 4.7% at 12 months (P = .01). Foot and ankle characteristics did not change significantly in any group.

The authors conclude that neither intervention adds economy beyond the control condition over a year; the intervention groups trended toward larger gains, but individual responses varied widely, and they call for work identifying responders.