Retail is a tough business as more sales move online. Running stores are not immune as it is becoming easier and easier to purchase running shoes and apparel online.
The secret of retail is location, which really means TRAFFIC. So much of a running store's costs are fixed --- namely, rent. Therefore, the more traffic you can drive to the space the better. A local running store to me recently divided its space into a running store and a new bike shop. The strategy is sound to help bring in new customers to the same space.
However, I have a few other ideas that could help the next generation of running stores be the most profitable on their block.