A sole structure for an article of footwear comprising: a sole plate including a midfoot region , and the sole plate further including a forefoot region and a heel region ; wherein the sole plate has a foot-facing surface with ridges extending longitudinally in the midfoot region and in the at least one of a forefoot region or a heel region ; wherein the sole plate has a ground-facing surface with grooves extending longitudinally in correspondence with the ridges ; wherein the ridges and the grooves are configured such that a thickness of the sole plate from the foot-facing surface to the ground-facing surface varies at a transverse cross-section of the sole plate through the ridges , or varies along a length of at least one of the ridges , or varies at both the transverse cross-section and along the length of the at least one of the ridges ; wherein the ridges and the grooves extend only in the midfoot region and the forefoot region ; wherein the sole plate has an undulating profile at any transverse cross-section of the sole plate through the ridges ; wherein the transverse cross-section is a first transverse cross-section of the sole plate in the midfoot region ; wherein the undulating profile of the sole plate at the first transverse cross-section includes a first set of multiple waves having crests at the ridges and having troughs between respective adjacent ones of the ridges ; wherein the undulating profile of the sole plate at a second transverse cross-section in the forefoot region includes a second set of multiple waves having crests at the ridges and having troughs between respective adjacent ones of the ridges ; wherein waves of the first set each have a first wavelength; and wherein waves of the second set each have a second wavelength greater than the first wavelength. a sole plate including a midfoot region , and the sole plate further including a forefoot region and a heel region ; wherein the sole plate has a foot-facing surface with ridges extending longitudinally in the midfoot region and in the at least one of a forefoot region or a heel region ; wherein the sole plate has a ground-facing surface with grooves extending longitudinally in correspondence with the ridges ; wherein the ridges and the grooves are configured such that a thickness of the sole plate from the foot-facing surface to the ground-facing surface varies at a transverse cross-section of the sole plate through the ridges , or varies along a length of at least one of the ridges , or varies at both the transverse cross-section and along the length of the at least one of the ridges ; wherein the ridges and the grooves extend only in the midfoot region and the forefoot region ; wherein the sole plate has an undulating profile at any transverse cross-section of the sole plate through the ridges ; wherein the transverse cross-section is a first transverse cross-section of the sole plate in the midfoot region ; wherein the undulating profile of the sole plate at the first transverse cross-section includes a first set of multiple waves having crests at the ridges and having troughs between respective adjacent ones of the ridges ; wherein the undulating profile of the sole plate at a second transverse cross-section in the forefoot region includes a second set of multiple waves having crests at the ridges and having troughs between respective adjacent ones of the ridges ; wherein waves of the first set each have a first wavelength; and wherein waves of the second set each have a second wavelength greater than the first wavelength. <EOS>