Background This study examines the effect of progressive increases in footwear minimalism on injury incidence and pain perception in recreational runners.

Methods One hundred and three runners with neutral or mild pronation were randomly assigned a neutral (Nike Pegasus 28), partial minimalist (Nike Free 3.0 V2) or full minimalist shoe (Vibram 5-Finger Bikila). Runners underwent baseline testing to record training and injury history, as well as selected anthropometric measurements, before starting a 12-week training programme in preparation for a 10 km event. Outcome measures included number of injury events, Foot and Ankle Disability (FADI) scores and visual analogue scale pain rating scales for regional and overall pain with running.

Results 99 runners were included in final analysis with 23 injuries reported; the neutral shoe reporting the fewest injuries (4) and the partial minimalist shoe (12) the most. The partial minimalist shoe reported a significantly higher rate of injury incidence throughout the 12-week period. Runners in the full minimalist group reported greater shin and calf pain.

Conclusions Running in minimalist footwear appears to increase the likelihood of experiencing an injury, with full minimalist designs specifically increasing pain at the shin and calf. Clinicians should exercise caution when recommending minimalist footwear to runners otherwise new to this footwear category who are preparing for a 10 km event.