- Jan 3, 2011
- 65
- 196
It's all about the accelleration -- or decelleration in this case.
When your head hits a hard surface it decellerates to 0 m/s almost instantly (ok, you have some rebound effect and whatnot but let's simplify things). The fluid inside your skull provides a medium for a tiny bit of cushioning before the brain contacts bone. Mind you, water (and many fluids that are primarily water) is non-compressible so that fluid doesn't do much to absorb force.
Now, put any soft object between the head and hard surface. As the soft surface (for example the floor mats we use) compresses it both absorbs force and decellerates the head more-slowly. If the cushion is thick enough then the decelleration is gradual enough so that the brain does not end up being too banged around. That's good.
Take a motorcycle helmet. These things are designed to reduce the impact of your head hitting concrete while going quite fast. It's by no means a guarantee of safety but it does increase the odds in your favour. The exterior of the helmet is a hard shell, while the interior is lined with foam that 'crushes' when your head impacts it. This is a one-way trip for the interior foam. To maximize the cushioning effect the material is damaged in the process and then is no longer of the same cushioning factor afterwards. So toss that helmet after you've whacked it into the pavement or face more serious consequences next time it happens.
Now in the sports realm you have training headgear for people who do martial arts, and you will see them wearing it in olympic boxing. The added cushion around the skull will lessen the force of the opponent's blows. Again, this is only a mitigating factor and you can still get a concussion with one of these if you are hit hard enough while moving into the blow. But considering that the goal is to try and hit each other in the head the trade off of a more limited field of view and a 'heavier head' makes it a good choice for training purposes where you will have to absorb a lot of blows.
Now I don't have an opinion yet of whether helmets are a good idea or a bad one for cheerleaders. I can think of the "bad old days" of first teaching girls to do full-twisting layout basket tosses and the number of times I took elbows, knees, whatever to the face and head (I wouldn't have minded the helmet so much back then). Since that time I've become much better at teaching progressions in skills and other than the occasional, fluke catch things are good now. Being more focused on perfect basics rather than rushing forward for a new skill is a much better recipe for avoiding concussion than slapping on some head gear and just chucking it. So there, I guess I'm not an advocate of helmets and have an opinion after all.
When your head hits a hard surface it decellerates to 0 m/s almost instantly (ok, you have some rebound effect and whatnot but let's simplify things). The fluid inside your skull provides a medium for a tiny bit of cushioning before the brain contacts bone. Mind you, water (and many fluids that are primarily water) is non-compressible so that fluid doesn't do much to absorb force.
Now, put any soft object between the head and hard surface. As the soft surface (for example the floor mats we use) compresses it both absorbs force and decellerates the head more-slowly. If the cushion is thick enough then the decelleration is gradual enough so that the brain does not end up being too banged around. That's good.
Take a motorcycle helmet. These things are designed to reduce the impact of your head hitting concrete while going quite fast. It's by no means a guarantee of safety but it does increase the odds in your favour. The exterior of the helmet is a hard shell, while the interior is lined with foam that 'crushes' when your head impacts it. This is a one-way trip for the interior foam. To maximize the cushioning effect the material is damaged in the process and then is no longer of the same cushioning factor afterwards. So toss that helmet after you've whacked it into the pavement or face more serious consequences next time it happens.
Now in the sports realm you have training headgear for people who do martial arts, and you will see them wearing it in olympic boxing. The added cushion around the skull will lessen the force of the opponent's blows. Again, this is only a mitigating factor and you can still get a concussion with one of these if you are hit hard enough while moving into the blow. But considering that the goal is to try and hit each other in the head the trade off of a more limited field of view and a 'heavier head' makes it a good choice for training purposes where you will have to absorb a lot of blows.
Now I don't have an opinion yet of whether helmets are a good idea or a bad one for cheerleaders. I can think of the "bad old days" of first teaching girls to do full-twisting layout basket tosses and the number of times I took elbows, knees, whatever to the face and head (I wouldn't have minded the helmet so much back then). Since that time I've become much better at teaching progressions in skills and other than the occasional, fluke catch things are good now. Being more focused on perfect basics rather than rushing forward for a new skill is a much better recipe for avoiding concussion than slapping on some head gear and just chucking it. So there, I guess I'm not an advocate of helmets and have an opinion after all.