A ski or a snowboard is in the form of a board-type gliding device. By reference to the width of the gliding device, at least one recess is provided in its middle portion extending in its depth direction from the top face of the gliding device in the direction towards the running surface facing and disposed in its longitudinal direction essentially parallel with the longitudinal direction of the gliding device with a view to causing a cross-sectional weakening. At least one manually adjustable adjusting device is provided, which is designed to produce an individually adjustable change in the load-dependent deformability of the cross-sectional shape or to produce an individually adjustable limit to the maximum permissible load-dependent cross-sectional deformation of the gliding device. Further, a ski or a snowboard is provided with a manually adjustable adjusting device which is designed to act as a spreading device for producing an individually adjustable increase in the width of the recess on the one hand and to act as a pulling device to produce an individually adjustable decrease in the width of the recess on the other hand.