Abstract: An apparatus supporting “dry land” simulation of the diagonal stride cross-country skiing technique. The apparatus may include a roller ski comprising at least two wheel configured to roll on a surface and a stop connected to the roller ski. The stop may selectively engaging at least one of the surface and the at least two wheels in response to a force of at least a threshold magnitude urging the roller ski toward the surface to resist rearward roll of the roller ski on the surface. The resistance to rearward roll may vary with the force.