The football dilemma

[alteran]

Take your bike away from your kid now.

From the American Association of Neurological Surgeons website...

The following 20 sports/recreational activities represent the categories contributing to the highest number of estimated head injuries treated in U.S. hospital emergency rooms in 2009.

Cycling: 85,389
Football: 46,948
Baseball and Softball: 38,394
Basketball: 34,692
Water Sports (Diving, Scuba Diving, Surfing, Swimming, Water Polo, Water Skiing, Water Tubing): 28,716
Powered Recreational Vehicles (ATVs, Dune Buggies, Go-Carts, Mini bikes, Off-road): 26,606
Soccer: 24,184
Skateboards/Scooters: 23,114
Fitness/Exercise/Health Club: 18,012
Winter Sports (Skiing, Sledding, Snowboarding, Snowmobiling): 16,948
Horseback Riding: 14,466
Gymnastics/Dance/Cheerleading: 10,223
Golf: 10,035
Hockey: 8,145
Other Ball Sports and Balls, Unspecified: 6,883
Trampolines: 5,919
Rugby/Lacrosse: 5,794
Roller and Inline Skating: 3,320
Ice Skating: 4,608

The top 10 sports-related head-injury categories among children ages 14 and younger:

Cycling: 40,272
Football: 21,878
Baseball and Softball: 18,246
Basketball: 14,952
Skateboards/Scooters: 14,783
Water Sports: 12,843
Soccer: 8,392
Powered Recreational Vehicles: 6,818
Winter Sports: 6,750
Trampolines: 5,025

These numbers are interesting but completely meaningless in the context of determining safety. Children are on bikes ALL THE TIME. A small minority of children play football for a couple hours a week only for a limited part of the year. It's just not comparable.

How many career cyclists are having difficulty walking from repetitive brain injury? Or killing themselves after having massive brain-trauma related issues? Anyone? Beuhler?

[Tom B.]

I always have trouble explaining that concept when discussing car safety. So many people think huge, indestructible behemoths are safer than cars that are designed to not survive an accident (i.e. to absorb the energy of impact).

I usually settle on "all that energy from the impact is going somewhere: either into crumpling the car, or the internal organs of the people in the car."

See also: Earnhardt, Dale. Watching it in real time, his wreck didn't look all that bad. The car didn't flip or fly apart -- it just went into the wall and skidded to a stop. And it killed him.

[gus]

They in fact do.

I meant football helmets, which are intended to be continually re-used.

I'm not sure about your math, but algebra in text notation always gives me headaches (plus I think you have a typo in there).

But regardless, you're assuming a perfectly inelastic collision, which of course is never the case. In other words, you're assuming an ideal case, where crumple zones and deforming materials aren't necessary.

You need to consider energy to fully appreciate the effects of the collision, as immediately post impact the head will continue to have kinetic energy. The goal is to reduce, as much as possible, that energy.

[uh_no]

I meant football helmets, which are intended to be continually re-used.

I'm not sure about your math, but algebra in text notation always gives me headaches (plus I think you have a typo in there).

But regardless, you're assuming a perfectly inelastic collision, which of course is never the case. In other words, you're assuming an ideal case, where crumple zones and deforming materials aren't necessary.

You need to consider energy to fully appreciate the effects of the collision, as immediately post impact the head will continue to have kinetic energy. The goal is to reduce, as much as possible, that energy.

This is in fact, not true.

I have assumed nothing about where the energy dissipates. I have only calculated the force applied to the head, which is the same regardless of the elasticity of the collision. Elasticity only speaks to the energy which may be extracted

Using the force combined with the energy lost in the materials (and consequently the energy remaining in the system), we can calculate how far the brain moves relative to the rest of the head.

For a concussion you would need 2 things (pseudo science warning!!!) enough energy to move the head enough to close the distance between the cranium and the brain, and enough force/acceleration so that the brain hits the cranium at speed. Since there is certainly ample energy to move the head the required distance (and we can do the calculation if you like...but regardless of the elasticity of the collision, there is clearly enough energy to move the head a fraction of an inch), all we must consider is the force.

So yes, if we were talking about much larger distances to move the target object, we would need to take energy and elasticity into account, but with ample energy and tiny distances, the force is the dominating measure

[ncexnyc]

You can't beat DBR. It's the only place I can come on a daily basis and get not only a math lesson, but a physics lesson as well

[rasputin]

You can't beat DBR. It's the only place I can come on a daily basis and get not only a math lesson, but a physics lesson as well

My head hurts from reading this thread.

[luburch]

I opened this thread and thought it was going to be a discussion on how Duke has become a football school with a basketball problem. Boy was I wrong.

[throatybeard]

would be interesting to see what percentage of the cycling head related injuries among children would have been mitigated by the proper use of a helmet.

Not that anecdotes prove anything: my sister, even whilst wearing a helmet, suffered a concussion and incurred a short hospital stay from riding her bike, and it was only when she showed how she wore it that we realized it was both too small and being worn too far back on the head.

I'll be the first to admit cycling is dangerous, having taken my share of spills, but i also wouldn't be surprised if the numbers are exaggerated by improper use of safety equipment.

This is neither here nor there w/r/t concussions, but I just decided Uh No is from a more British part of the former empire than the US.

[throatybeard]

See also: Earnhardt, Dale. Watching it in real time, his wreck didn't look all that bad. The car didn't flip or fly apart -- it just went into the wall and skidded to a stop. And it killed him.

You're absolutely right. That was...I'm at a loss for an adjective here. Insane?

I had some Duke people over to my house for the Duke-SJU game earlier in the day. It's been so long that I can't remember screen names, or who all it was. It was like Siedsma, Weks, Weks' little sister and her BFF. Tieguy, I think. Duke roughed up Saint John's, and Doherty's UNC team coughed it up at Clemson. It was the beginning of the end for the 2001 UNC team, but we didn't know that then. We were flipping back and forth during commercials. We just happened to tune in for the last couple laps of the Daytona 500.

We saw DE Sr die in turn 3, but we didn't know it at first. It just looked like no big deal in the grand scheme of NASCAR wrecks. Later, Prince Jr came out to make the announcement.

I'm not a huge NASCAR guy, (but I'm also not one of these condescending people who likes to poo on NASCAR). It's hard to say what that was like by analogy with another sport. The best I can come up with, and it isn't perfect, is Peyton Manning is killed on the field from head trauma during a Super Bowl. Or like, dies after the game from a hit.

I'll never forget the 1998 and 2001 Daytona 500s.

[uh_no]

This is neither here nor there w/r/t concussions, but I just decided Uh No is from a more British part of the former empire than the US.

do not colour me with such rubbish!