The Effect of Football Helmet Padding Pressure on the Effect of Force of Impact

Student Picture

Researched by Camdon A.
2004-05




PURPOSE

The purpose of this experiment was to determine if air pressure in a football helmet’s padding affects the force of impact.

I became interested in this idea after the football team I played on had won our championship game. I wondered if playing football that season had made any effect on my brain, good or bad.

The information gained from this experiment could possibly be helpful for football players and coaches in all different leagues, letting them know the effect their helmet has on possible brain injury.


HYPOTHESIS

My first hypothesis was that the impact force would decrease as air pressure inside the padding increased from 0 mm Hg (totally empty) up to 200 mm Hg (maximum tested).

My second hypothesis was that the impact force would increase as air pressure inside the padding increased above 75 mm Hg.


I based my hypothesis on the answer my football coach gave to the question, “Is the air pressure in the padding for comfort or for fit?” My coach answered, “It is for both. It depends on what the player wants. Some people like it as pumped up as they can get it, other like it as empty as possible.”

 
EXPERIMENT DESIGN

The constants in this study were: the helmet being tested, size of mannequin head, way tested, force/speed of helmet at impact, the temperature at which the experiment was conducted, the measure being used, accelerometer probe being used, and the software that read the probe.

The manipulated variable was the pressure in the football helmet.

The responding variable was “g” force or force of impact.

To measure the responding variable I used a Vernier Accelerometer probe attached to a computer running Logger Pro 3.0 software, which reads “g” force of the impact/ collision


MATERIALS


QUANTITY ITEM DESCRIPTION
1
Vernier accelerometer probe
1
computer running Logger Pro 3.0 software
2
football helmet
1
hand pump (off of a blood pressure cuff)
1
pulley
1
Mannequin head
25
Feet of 1/8inch rope
1
roll of masking tape



 PROCEDURES

1. Tie a rope securely to the base of the pulley.
2. Pass the rope over a strong support 3 meters above floor.  Pull the rope so the pulley is positioned securely about 3 meters above the floor. 
3. Take a helmet and tie it to a second rope.
4. Run this rope though the pulley so the weight can be raised and lowered easily.
5. Attach the Vernier accelerometer probe to the computer with Logger Pro software.
6. Place the Vernier accelerometer probe inside the mannequin head shape by drilling a hole in the top of it and stuffing the probe inside of the hole.
7. Using bulb pump from a sphygmomanometer attached to a sports ball needle, add air to the internal protective pad in the football helmet.  The pressure should read 0 mm Hg.
8. Put the mannequin head shape into the helmet in an upright position on a flat surface that the masking tape can fasten the mannequin head into a position where it is not tilted or uneven when it is placed on the flat surface.
9. Be sure it is positioned exactly under the other helmet.
10. Check helmet for correct fit.
11. Hold the rope so the helmet is in a fixed position, suspended 2.0 meters in the air directly above the helmet with the mannequin head. The empty helmet must not be swinging. 
12. Release the rope so the weight will hit the helmet and mannequin head. 
13. Record what the Vernier accelerometer probe reads in “meters per second squared” for that individual helmet brand at the moment of impact.
14. Repeat steps 10-13 for a total of 10 trials. 
15. Repeat steps 8-14 for each pad pressure.

 
RESULTS

The original purpose of this experiment was to determine if air pressure in a football helmet’s padding affects the force of impact.


The results of the experiment showed that the impact impulse raised as the air pressure inside the helmet increased. The maximum impact was similar on average for all pressure levels.

See my table and graph


 CONCLUSION

My first hypothesis was that the impact force would decrease as air pressure inside the padding increased from 0 mm Hg (totally empty) up to 200 mm Hg (maximum tested).

My second hypothesis was that the impact force would increase as air pressure inside the padding increased above 75 mm Hg


The results indicate that my first hypothesis should be rejected.
The results indicate that my second hypothesis should be accepted.

Because of the results of this experiment, I wonder if not having the padding in the helmet helps with the impact force.

If I were to conduct this project again I would b sure to do so in a more controlled manor. I also would find a something different do set the probe into instead of using a Styrofoam mannequin head. I believe that the Styrofoam head had a bad affect on the results of this experiment



Collision

Collision, “an encounter between particles resulting in exchange or transformation of energy”, consists of five major attributes. They are motion, momentum, acceleration, impact impulse, and force. 

Motion
Change of position with respect o others.

Momentum
“The product of a body’s mass and linear velocity; the force of motion” momentum can only be changed by changing the body’s mass or velocity. Gravity has nothing to do about it. It is a commonly used term in spots meaning strength or speed gained thought the development of events. This is what gives us football games and finder binders, specifically inertia or “resistance” to change in path and speed.

Acceleration
When force is applied is produces acceleration. “The rate of change of velocity with respect to time; change of velocity”

Impact impulse
Impact impulse is “The product of force and the duration of time in which it acts”. It is equal to the change in momentum of the body.

Force
“A strength or energy exerted or brought to a bear”. Commonly referred to as a push or pull on an object.


Helmets

Helmets are coverings made of a hard material (leather, metal, plastic) that protect the head from being inflicted by damage. There are many types of helmets such as sport, military, construction, firefighting, police, mining, and even astronomical activities.

Sport helmets

In all reality there is no big difference in a sport helmet from any other helmet. Just like others they are made out of hard materials and are used to protect the head from damage. 

Sports

Sport injuries are acquired in football. In football the majority of injury is to the head, neck, or spine (11.3%).  Most of these injuries happen during practice when players are doing the same thing over and over again. Only thirty-nine percent of injury happens in games. Twenty-nine percent of injury is general trauma to the head. Coach Powell of a 1991 Dallas Texas football team stated, “It is impossible to prevent all injuries in sports although good medical care and preventative techniques can help reduce the risk.”


The Nervous System

Because of the importance of the brain, when things go wrong it can be a very serious problem. The brain can be damaged by an accident, illness or disease. Traumatic injury- a skull fracture, for example, may drive bone splinters into the brain or cause part of the skull to be pushed on the cerebrum. If damage occurs to certain parts of the brain it may cause paralysis, loss of motor function, or the loss of sensation (anesthesia). In some cases only part of the brain is damaged but if too much is damaged it will cause death. In cases that only part of the brain is damaged the function that the damaged brain part controls will not work. However, he or she may be able to retrain or relearn the brain and body so that another part of the brain takes over control of the ability that was lost.


Summary

Helmets are used to protect the head from encountering damage to the nervous system from impact. Impact implies all acceleration, motion, and forces. Without this protection much damage could be done to the brain, causing injury and even death.

BIBLIOGRAPHY


Carroll, Bob.    "Football,” World Book Encyclopedia, 2001. p. 354- 368

Dr. Alvin Virgina, and Silverstein, Robert. The Nervous System.  Brookfield, Connecticut: Twenty- first Century Books. P 34-36

“Force,” World Book Encyclopedia, 2002 p. 369

The American Heritage College Dictionary Third Edition. p. 530, 680, 879.


ACKNOWLEDGEMENTS

I would like to thank the following people for helping make my project possible:

  • My parents for helping me with gathering materials and transportation for my experiment.
  • My teacher for providing me with materials he had for my experiment, giving up his time for my project, and keeping me on tract the best he could through out the time I worked on my project.
  • Vernier for there cooperation with the accelerometer probe that they made possible for me to barrow.
  • My football coach for allowing me to barrow two helmets for my testing.


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