An article of footwear includes a fitting system with an upper member that is supported by the upper and a strand guide that is supported by the sole structure. The strand guide is flexible and flexes in concert with the sole structure. The strand guide has a guide surface. The fitting system further includes a tensioning system with a flexible strand that is configured to bias the upper member toward the strand guide. The flexible strand has a first section coupled to the upper member and a second section extending through the sole structure. The second section abuts the guide surface. The second section is configured to slide across the guide surface as a result of flexure of the strand guide. The first section and the upper member are configured to move relative to the sole structure as a result of sliding of the second section across the guide surface.