I would rather take my chances jumping than take a helmet in the tibia.

The rule is also for the safety of the player being hurdled, who has a pretty good chance of getting kneed or kicked in the head and neck area.

This is what the NFHS's response was in 2012 to media inquiries on just this topic:

"In 2012, the committee had requests to change the hurdling rule and eliminate it as a foul. By definition: “Hurdling is an attempt by a player to jump (hurdle) with one or both feet or knees foremost over an opponent who is contacting the ground with no part of his body except one or both feet.” This is an Illegal Personal Contact Foul (NFHS Football Rule 9-4-3d) and carries a 15-yard penalty. Recently, national and local media have identified some of these plays at the collegiate and professional levels as “spectacular feats” and glorified the individual’s athletic ability instead of pointing out the heightened potential for harm. Little regard has been given to the fact that attempting to “hurdle” a defender increases the risk of injury to both the hurdler and tackler! The NFHS SMAC requested that this rule not be changed and backed up its request by showing several incidences where players were severely injured while attempting this act! The NFHS Football Rules Committee concurred with the SMAC and did not change the hurdling rule. In addition, to focus on the dangers associated with hurdling, it has been included as a Point of Emphasis for the 2012 season. The emphasis on this illegal act supports the committee’s ongoing attempt to minimize the risk of injuries in high school football. Coaches must teach their players of the inherent dangers associated with this illegal act, and game officials must call it when observed."

I don't think that can be predicted. The ball is eventually going to become dead by some means, and more often than not it'll be via tackling. Being hit waist high is a very safe way to get hit, although it's hard to predict how you'll then contact the ground following such a hit vs. any other type of tackle.

But the other point I don't think can be so easily predicted is the danger of hurdling vs. that of diving. The danger to the opponent is that a hurdler might come down on your head, bringing the whole weight of his body on it and endangering your neck. However, I think that'd be a relatively rare event compared to the times a runner on his feet or diving projects toward an opponent's head horizontally. The danger to the hurdler himself is his being undercut and upended and so having an awkward landing. However, is that greater than the danger from diving head first? In the latter case the head is projected toward opponents; in both cases the head might contact the ground. The runner trying to hold onto the ball, no matter how he leaves the ground, is at a disadvantage in not having the use of both arms, or possibly either arm, in bracing himself for a fall.

When the rate of catastrophic injury from diving approaches that of hurdling, the rule will be changed.

Is there a big enough sample from hurdling to even calculate a meaningful rate?

Good point. What do we see - 1 or 2 of these in a year? Has anyone ever witnessed or even heard of an injury caused by someone hurdling? I haven't.

Not only have I never seen an injury, I have not seen this attempted in any game I was working since 2008. This is mostly a situation that this happens on YouTube than in most games I am sure. It does not even happen in college very often either. I think that is one of the main reasons I think you do not see this called at the high school level.

Peace

MD Longhorn:
Apparently the Sports Medicine Advisory Committee has evidence of injuries that resulted from attempted hurdling.

I'm sure they do, but do they have the ratio of injuries per attempt?

It's a lot of work to collect these stats. The only case I'm aware of a football rules governing body's studying statistically the rate of injuries in certain circumstances was 40 yrs. ago with blocking below the waist on kick returns. Usually they just go by anecdotes, hunches, and a priori reasoning that certain practices are more dangerous than others.

I was answering the question:

"Has anyone ever witnessed or even heard of an injury caused by someone hurdling? "

The SMAC has heard of such and provided evidence to the NFHS.