The barefoot performance of Callaghan Zero means that some users accustomed to conventional footwear (which typically offers positive drop and impact cushioning and stabilizing performance) may require an adaptation/transition period to this type of footwear. This group of users is advised to progress in footwear type: using transition footwear (70%-80%) in the first phase, minimalist footwear (80%-90%) in the second phase, and barefoot footwear (90%-100%) in the third phase. The duration of these phases may depend on individual factors and varies for each user.