i use down and ups and i found that they work. Start in a press up position, then get up and run 5 meters and go down in the press up position again facing the side you came from. then up again and back to the start....emphasis should be on being explosive in the first 3 steps...increase the distance to 10 meters and time speed over first 5 meters...increase to 15 meters and time speed over first 10 meters ..increase to 25 meters and time first 15 meters...player should do about 8 down and ups in the shorter distance and 4 in the longer distances without stopping...remember emphasis should be on reaching maximum speed with minimum steps..(explosiveness)....one can find the right running technic videos on youtube.