Abstract: Jumps for horses comprise control means for altering with elapse of time at least one of the shape, configuration and position relative to the ground of the obstacle presented by the jump to the horse. Examples of obstacles presented of which at least one of the shape, configuration and position relative to the ground are caused to vary are an axially rotatable beam with a non-circular cross-section, water issued from a plurality of selectively controllable water jet nozzles, and a plurality of mutually parallel poles mounted to be driven in a direction perpendicular to their length along a closed loop, which itself moves along the ground.