Science and Engineering vs Concussions Abstract
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- Introduction
- The Physics Behind the Hit
- Can the NFL prevent concussions
- Fixing the Helmet
| Merrick Lester Bautista
Science and Engineering vs Concussions Abstract NFL players often sustain one or more concussions throughout their career. These concussions have been shown to lead to neurodegenerative diseases like chronic traumatic encephalopathy (CTE) which have eventually led to some players committing suicide. Concussions are caused by trauma to the head which causes rapid acceleration or deceleration of the head causing the brain to bounce around in the skull, damaging the brain and nerves. As force is decreased over longer distances, football helmets provide padding to increase the time of collision and reduce the force of trauma. The NFL has tried to simply avoid these concussions by not allowing players to hit within the head and neck area of opposing players. However this has led to more problems, for players target lower and have been causing more ACL injuries. Engineering and science seems to be the only way to help prevent further concussions. Many designers are creating different types of helmets to absorb the linear acceleration of football hits to reduce the trauma on the player’s head. Research is also being done beyond sports to find biomarkers and diagnostic tools that can better recognize concussions. With this push using engineering and science, one day there will be a deeper understanding in the cause, diagnosis, and treatment of concussions. Introduction Junior Seau was one of the most respected and idolized National Football League (NFL) players of his time; not only did the legendary 10-time All-Pro and 12-time Pro Bowl linebacker make his impact on the field for the University of Southern California Trojans, San Diego Chargers, and New England Patriots with his charismatic play, but his positive energy continued outside of football games and touched the hearts of fans everywhere. Thus when news of his sudden suicide emerged, everyone was in utter disbelief as to how this 43-year old joyful fan-favorite had committed the ultimate act of depression [1]. However when the National Institutes of Health (NIH) diagnosed him with chronic traumatic encephalopathy (CTE), a neurodegenerative disease commonly found in individuals who suffer multiple concussions and hits to the head, a guilty feeling spread throughout fans everywhere who had not realized that every bone-crushing hit they cheered for was actually slowly killing Junior Seau in front of their very eyes [2]. Seau was not the first to suffer a CTE; according to Boston University, there have been more than forty players to suffer CTE’s from playing football. Seau was also not the first to commit suicide due to a CTE; Dave Duerson and Ray Easterling also had similar cases and committed suicide earlier in the decade[3]. Appropriately, more than four thousand former players have sued the NFL for hiding and downplaying the harmful effects of concussions. In August 2013, the NFL and the plaintiffs agreed to a $765 million dollar settlement which would give money to concussed athletes who had been diagnosed with neurological disorders and would provide for future research into concussions [4]. To further prevent degenerative disorders from concussions, the NFL recently enacted an expansive concussion assessment tool and a myriad of rule adjustments, yet the threat of concussions still looms in the NFL and seems to be impossible to eliminate.
What is a concussion? The Third International Conference on Concussion in Sport defined it as “a complex pathophysiological process affecting the brain induced by traumatic biomechanical forces” [13]. They are usually caused by traumas to the head, commonly through sports. The tricky part of diagnosing concussions is that they do not necessarily appear with visible signs. It is quite possible to get a concussion without having marks on the head and without losing consciousness. To test for this impaired brain function, doctors ask mentally stimulating questions like reciting the alphabet backwards or to remember a sequence of words. While one concussion should not cause extensive brain damage, repeated brain trauma like that in football can be devastating [5]. [Figure 1: Concussion Physics]
A concussion is due to a rapid change in acceleration or deceleration of the brain. The brain is not securely held within the skull; instead it is separated from the skull by a layer of cerebrospinal fluid. Thus whenever a person is in motion and suddenly stops, their brain, according to Newton’s first law of motion, will continue in its current motion until stopped by an outside force as seen in Figure 1. While the cerebrospinal fluid can normally slow the brain down and protect the brain from hitting the skull, football hits come with such an extreme deceleration of the brain and the cerebrospinal fluid is not enough to prevent the brain from crashing into the cranium, the inside of the skull. As the brain essentially “bounces” around in the skull, neurological abilities get impaired and concussion symptoms are evident [6]. Helmets are the primary safety mechanism to prevent concussions. The large surface area of helmets is actually able to reduce the pressure on the head from forces since pressure is the force over the area it is applied to, P = F/A. Newton’s second law of motion states force is a product of mass times acceleration, F = ma. Acceleration in this formula can be substituted with (Vf2 – Vi2)/2d where Vf is the final velocity, Vi is the initial velocity, and d is the distance traveled during acceleration. This formula makes sense as the faster a ball is initially thrown, the more force it will apply to its final target at a certain distance. On the other hand, a ball thrown with the same velocity but with a further target will apply less force once it arrives at its target. With the substitution for acceleration, this would make a new formula for force, F = (m/2d) x (Vf2 – Vi2). One way to reduce force would therefore be to reduce the mass of the player or to decrease the final velocity. Impractically this would mandate NFL players to lose weight and to not run as fast as possible during football games. A more feasible factor is to increase d, the distance during acceleration. The soft cushioning is able to slow down the head and increase the distance of deceleration during huge hits and collisions on the field in order to reduce the force applied to the head. On the other hand, “brick wall tackles” in which a runner at full speed runs into a standing, squared up defensive player create such a small distance for deceleration and often leaves the victim dazed and confused for a few seconds [7]. This same difference in force can be observed in cars; riders in a vehicle smoothly stopping for a red light will feel little compared to the passengers of a vehicle in which the driver had to suddenly stomp on his breaks to avoid a dog crossing the road. [Figure 2: School of Hard Knocks] Can the NFL prevent concussions? Football is a dangerous game. The sport consists of eleven fast, strong guys trying to forcefully hit and tackle one guy with the ball and ten other guys hitting and blocking as necessary to prevent the other team from getting to the ball carrier. The NFL has heavily developed “defenseless player” rules throughout the last few years, especially after the nightmare collision between DeSean Jackson of the Philadelphia Eagles and Dunta Robinson of the Atlanta Falcons in the 2011 NFL season. These rules prevent hitting the heads of receivers in the process of catching or quarterbacks in the process of throwing. As these players are focusing on other tasks, they have no opportunity to protect their own head or neck area and are thus very susceptible to concussions or other head injuries. [Figure 3: DeSean Jackson and Dunta Robinson video] A few key points need to be noted in Figure 3. First of all, DeSean Jackson was not even hit on the head; however the deceleration due to the hit was so extreme that the whiplash effect may have caused a concussion without head-to-head contact. Second, Dunta Robinson as the defender was also hurt, as he was leading with the helmet. He could have very well suffered a concussion due to the collision as well. The last thing to note is that the announcers also admit that they have no idea how to solve the concussion issue plaguing the NFL, but it needs to be done. Unfortunately to prevent these collisions, NFL players are now aiming lower at the knees. [Figure 4: Randall Cobb injury] Figure 4 is an example of the adjustment defensive players are making. Green Bay Packers receiver Randall Cobb, instead of getting a concussion, ended up with a fractured fibula. Recently Washington Redskins safety Brandon Meriweather said, “You’ve got to tear people’s ACLs” [8]. While his word choice wasn’t the greatest, many NFL players agree with him. Hitting up high and possibly causing a concussion is an automatic yellow penalty flag whereas hitting low and possibly tearing an ACL is still considered a legal hit. However a torn ACL takes a year minimum to recover from and many players never return to their original form. Thus, simply telling the players to not hit in the head or neck area is leading to other sever problems as well.
So what options do the NFL have to fix this issue? One option is to change the helmet. One problem with the current NFL helmet is that it lacks any defense against rotational acceleration. During football hits, the head experiences linear and rotational acceleration. The linear acceleration, or the straight line hit, is significantly reduced by the current helmet and the cushioning mentioned earlier. However rotational acceleration is caused when the head is hit off-center and as the head spins, the brain will also twist and turn, pulling axons and causing nerve strains which also leads to concussions and the current NFL helmet cannot prevent this. Bill Simpson, long time auto safety expert, decided to make a helmet to account for this rotational acceleration. As seen in Figure 5, the helmet’s main feature is a plastic layer that goes onto the player’s head, but rotates within the helmet. Thus when rotational acceleration occurs, the harder outside shell can rotate independently of the plastic shell inside the helmet. According to lab tests, it can reduce brain rotation by 40 to 50%. Other innovators also agree rotational acceleration is the key issue. Peter Halldin, a biomedical engineer, has created a solution he calls MIPS, the Multidirectional Impact Protection System (MIPS). MIPS is a plastic layer that lies between the player’s head and the helmet itself, providing the head with extra rotational acceleration protection during a hard hit. The technology is actually already being implemented in helmets for snowboarding and skiing, and perhaps it will one day be incorporated into NFL helmets [14]. [Figure 5: The Helmet that Might Save Football] Conclusion Concussions not only affect NFL players, and researchers today are still trying to create better diagnostic tools that could not only aid NFL players but also anyone else with concussion symptoms. Currently the diagnosis for concussions are difficult because there are no known biomarkers or any other indicators in the body and they do not appear on imaging tests [15]. Fortunately breakthroughs are being made in these areas. Recently the University of Rochester and the Cleveland Clinic found increased concentrations of a certain protein, S100B, in the blood of football players who had received more hits to the head. If this proves to be an accurate biomarker then when S100B is found inside the brain, a medical doctor could then conclude the person has a concussion. Specialized scans like diffusion tensor imaging are also being researched and developed to detect images as seen in Figure 6 [16]. If a pattern is found among these images, this could develop into a tool to accurately diagnose concussions. Hopefully, engineering and science can lead to a breakthrough in preventing concussions. Engineering is already paving the way towards better helmets whereas further biological research is helping doctors more accurately diagnose and understand concussions. Physicists are also researching the impacts of football hits to help the NFL and other sports leagues understand the causes of concussions and to assist them on preventing concussions. Perhaps with the contributions from all of these fields, one day athletes will be able to play the game they love without any fear of concussions and we as fans will not have to witness another tragedy like Junior Seau’s. References
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