Solving the Brain Crisis in Sports

The physicality in contact sports such as American football is the aspect of the game that is most appealing to a large portion of fans. Contact sports have always been considered dangerous, but only recently have the negative long-term effects of head injuries in sports been completely understood. Several ex-NFL players have been developing serious mental health issues linked to neurodegeneration. Neurodegenerative diseases, such as Alzheimer’s or ALS, have no known cures and are characterized by memory loss and eventually death. In addition, multiple high profile players, such as Junior Seau, have committed suicides, which is thought to be the result of head trauma-induced depression [1].

After noting the trend of declining brain health in ex-football players, physicians began to test the brains of deceased players to find that several players developed the neurodegenerative disease chronic traumatic encephalopathy (CTE), a disease that is linked exclusively to individuals who experience severe head trauma or repeated concussions.

Th​rough extended research scientists have concluded that these mental health side effects also occur frequently in collegiate football players, and that younger athletes who begin playing tackle football before the age of 12 significantly increase their risk of developing neurological disorders later in life [2]. Findings also show that these terrifying ailments are not exclusive to football, but occur almost as often in other sports in which players receive repeated impact to the head such as hockey, lacrosse and boxing. As the understanding of how and why these brain injuries occur gets better, engineers have begun to use that knowledge to develop safer head protection to save the minds of athletes everywhere.

Football players sustain concussions when they experience large amounts of force to their head, which accelerates the head and brain rapidly. These forces occur most often when one player hits another player in the head. The two types of acceleration created by contact are linear acceleration and rotational acceleration, and the greater acceleration, the greater danger [3].

Acceler​ation of the brain causes the brain to “bounce” around in the skull cavity, meaning that the movement of the brain lags behind the movement of the skull when impacted. This “bouncing around” in the skull creates tension in the blood vessels that connect the brain and skull, which stretches brain tissue and causes brain damage [4]. Linear acceleration (Figure 2) is caused by a straight hit to the center of a player’s head, and can cause skull fractures in addition to the stretching of tissue that causes concussions. Rotational acceleration (Figure 3) is caused by an off-center hit to the head that spins the head around its center of gravity. This type of acceleration causes the brain tissue to stretch and twist simultaneously. Therefore, most researchers agree that rotational acceleration is the more dangerous form of the two [3].

On average a hit that creates a concussion generates about 95 g’s of force. A single g of force represents the regular force of gravity that keeps a person grounded, meaning that a player sustaining a concussion experiences a force at least 95 times greater than gravity. The average hit delivered by a football player of any skill level is 103 g’s, and when a professional player delivers an off-center hit that creates rotational generation, that hit can generate up to 190 g’s of force due to the increased torque caused by the head’s rotation [5]. Given such physical forces it is not hard to see why concussions are so prevalent in the sport.

But it is not as easy to prevent them. Many safe helmet technologies focus solely on softening the force of linear acceleration by including larger and thicker padding that spreads out the force generated by a direct hit, but the padding does nothing to decrease the force generated by rotational acceleration. In order to best address the ongoing issue of concussions and head trauma, researchers must develop technology that effectively reduces the force received from both head-on and off-center hits to the player’s head.

Football equipment manufacturing giants such as Riddell and Xenith have received much criticism in the past decade about the safety of their helmets that has pushed the companies to improve their products. While these companies have increased their helmets’ safety ratings by adding a few extra safety measures, they still seem to fall short. Most companies that improve their safety ratings do so simply by adding thicker layers of vinyl nitrile padding to their helmets, or developing helmet shells that redirect linear impact to areas of the helmet that are not directly impacted. Both of these precautions reduce the amount of linear acceleration the player’s head experiences, but they can cause other complications, and neither addition combats rotational acceleration. Adding more padding creates heavier helmets, which in turn create more force behind a hit, and redirecting impact does not reduce total impact force, but rather spreads the same amount of force to different areas of the head [6][7].

While large sports equipment manufacturers have implemented smaller scale safety precautions to their helmets, two independent research teams have created their own technologies in an effort to create the safest football helmet. Architected Materials and researchers at UCLA have developed a microlattice material to be placed in helmets to reduce impact and track collisions, while Swedish company MIPS is using helmet technology that features a flowing plastic layer currently used in their bike helmets in an attempt to reduce rotational acceleration.

Microlattice

Designed as a continuous padding throughout the helmet, the microlattice developed in UCLA Material Science laboratories with the help of Architected Materials seeks to prevent concussions and head trauma by absorbing impact energy rather than distributing it. The material gets its name from its ordered crisscross structure, similar to that of a crystal lattice (Figure 6). The lattice’s structure and composition make it breathable and extremely light, offering better airflow through the helmet and limiting the mass that will make impact upon other helmets.
The material has out-performed the traditional vinyl nitrile helmet padding in several impact tests, and can be manufactured quickly and inexpensively. The lattice material also acts as a sensor that transmits data specific to a collision, allowing engineers to identify how to improve the design of the structure. The material is relatively new, so the lab has yet to release hard data detailing exactly how much the microlattice can reduce impact forces. However, preliminary tests do show substantial promise in the material, and the NFL recently awarded the design team $500,000 to continue their research due to the microlattice’s perceived potential [8][9].

The Multidirectional Impact Protection System (MIPS) attempts to protect the brain by mimicking the natural protection system used in human skulls. In between the brain and the skull is a layer of cerebrospinal fluid that acts as a barrier of protection by allowing the brain to move around slightly without being strictly bound to the skull. When a person’s head is accelerated in one direction, the fluid allows the brain to slide smoothly in the skull to minimize the stretching of brain tissue. MIPS mimics this natural characteristic by adding a layer of plastic to the helmet that allows the outer shell to rotate with the impact force and keep the head relatively stationary [10]. By keeping the head in place while the shell of the helmet moves with the acceleration force, the MIPS helmet is the first design that combats the dangerous rotational acceleration in addition to linear acceleration.

MIPS currently only sells bike helmets, but the Swedish company has been testing their technology in football helmet prototypes, and the results are encouraging. One laboratory test comparing the MIPS helmet to a standard football helmet showed that the MIPS model reduced the rotational acceleration of a 170 g hit from 14,100 radians per second squared to 6,400 radians per second squared, over a 50% reduction. If the helmet can continue to produce these results, MIPS could set the standard for safe helmet tech-nology in the coming years [6].

What Comes Next?

Contact-heavy sports are currently at a crossroads when it comes to safety. In the NFL ex-players are suing the league for failing to give players adequate warning about the dangers the game imposes, and recent NFL players like Chris Borland are retiring in the prime of their careers to prevent any further damage to their mental health [1]. At the smaller scale, parents are forbidding their children from ever attempting to play football because of the stigma the sport has received surrounding brain safety. Professional and collegiate football players are at the center of the head safety discussion because of their accessibility to the media and their high profile names, but this issue spans the horizons of almost every sport. From hard-contact helmet sports like lacrosse and hockey to seemingly contactless sports such as volleyball, the issue of concussions and brain health affects everyone from professional to youth athletes and worries parents and players alike. The microlattice and Multidirectional Impact Protection System technologies have proven potential and currently lead the way in the innovation of safer helmets, but engineers and product designers continue to work diligently to create products that will save athlete’s brains and keep sports alive.