Build up a mound of sand in the jumping pit straight down the center of the pit. Make it higher and wider towards the end. Make a standing jump and clear the mound of sand. This will force you to pull your legs up to avoid hitting the sand mound. Extend the legs for teh landing. If you are succesful, then extend the mound of sand so it becomes progressively more difficult to do this. This drill will get the jumper to bring their feet up in mid air.