That actually depends on the jumper. If they are not in a position to use increased speed in a jump, you will more often than not tank the jump and fly into the bar, rather than improve the jump. Telling an athlete to run faster to jump higher is a very common problem I see coaches do when the athlete does not have the strength or coordination to do it based on their current level of development. You have to know the athletes strengths and weaknesses before giving a blanket statement for how to improve.
