An article of footwear having a medial side and a lateral side, the article of footwear defining a lateral axis that extends transversely relative to a longitudinal axis between the medial side and the lateral side, the article of footwear configured to receive a foot, the article of footwear comprising: an upper having a strobel member that is configured to extend underneath the foot; and a sole structure that is operably coupled to the upper, the sole structure extending along the lateral axis, the sole structure including an outsole that includes: a base with an upper surface that faces the upper and a lower surface that faces away from the upper surface, and a first stepped projection that projects in a plurality of first steps from the lower surface, the plurality of first steps defined by a plurality of first tread surfaces and a plurality of first riser surfaces, and a second stepped projection that projects in a plurality of second steps from the lower surface, the plurality of second steps defined by a plurality of second tread surfaces and a plurality of second riser surfaces, the second stepped projection being spaced away from the first stepped projection, the base being resiliently flexible and moveable between a neutral position and a flexed position, the base configured to move the strobel member of the upper between a smooth position and a wavy position due to movement between the neutral position and the flexed position, the strobel member being in the smooth position when the base is in the neutral position, the strobel member being in the wavy position when the base is in the flexed position. an upper having a strobel member that is configured to extend underneath the foot; and a sole structure that is operably coupled to the upper, the sole structure extending along the lateral axis, the sole structure including an outsole that includes: a base with an upper surface that faces the upper and a lower surface that faces away from the upper surface, and a first stepped projection that projects in a plurality of first steps from the lower surface, the plurality of first steps defined by a plurality of first tread surfaces and a plurality of first riser surfaces, and a second stepped projection that projects in a plurality of second steps from the lower surface, the plurality of second steps defined by a plurality of second tread surfaces and a plurality of second riser surfaces, the second stepped projection being spaced away from the first stepped projection, the base being resiliently flexible and moveable between a neutral position and a flexed position, the base configured to move the strobel member of the upper between a smooth position and a wavy position due to movement between the neutral position and the flexed position, the strobel member being in the smooth position when the base is in the neutral position, the strobel member being in the wavy position when the base is in the flexed position. a base with an upper surface that faces the upper and a lower surface that faces away from the upper surface, and a first stepped projection that projects in a plurality of first steps from the lower surface, the plurality of first steps defined by a plurality of first tread surfaces and a plurality of first riser surfaces, and a second stepped projection that projects in a plurality of second steps from the lower surface, the plurality of second steps defined by a plurality of second tread surfaces and a plurality of second riser surfaces, the second stepped projection being spaced away from the first stepped projection, the base being resiliently flexible and moveable between a neutral position and a flexed position, the base configured to move the strobel member of the upper between a smooth position and a wavy position due to movement between the neutral position and the flexed position, the strobel member being in the smooth position when the base is in the neutral position, the strobel member being in the wavy position when the base is in the flexed position.