how riding helmets protect your head
Stephanie Bonin, PhD, PE, a forensic engineer who studies injury biomechanics, works for the Southern California firm MEA Forensic. A former event rider and self-described nerdy horse person who loves computer modeling, she studies brain injuries and helmet protection. Her presentation at the inaugural Horse Industry Safety Summit, held April 23 at the University of Kentucky’s Spindletop Hall, in Lexington, reviewed how helmets protect a rider’s head.

In her research with MEA, Bonin examines how the human head responds to injury and evaluates the “crush” observed in a helmet to see what the head and brain experienced upon impact. Her research contributes to the concussion database by capturing head impact kinematics (a branch of classical mechanics that describes the motion of points, objects, and groups of objects without considering the forces that caused the motion), correlating kinematics to clinical diagnoses, and improving helmet protection.

“What is the head experiencing during a fall, and how do we know what to design a helmet for?” she said “What is the starting point? We have to understand what happens in order to make changes in helmet design.”

Bonin said brain injuries are typically classified as either focal (which includes hematomas, hemorrhages, contusions, skull fractures, and edema) or diffuse (which includes concussion and indicates that the injury happened throughout the brain tissue). These injuries can be caused by:

  • Linear acceleration (which is likely to cause issues such as skull fracture, epidural hematoma, or contusions secondary to skull fracture); and/or
  • Rotational acceleration (which is likely to case issues including concussion and diffuse axonal injury).

Both types of acceleration cause brain strain.

She said studying linear acceleration helps scientists and doctors understand the trauma a person must experience for the injury to result in a concussion. She described how, in the automotive industry, researchers use test dummies with accelerometers to record acceleration during impact. Then, they use the accelerometer data to correlate dummy acceleration to injury.

“We’re measuring 10 milliseconds of acceleration,” Bonnin said. “Mouth guards are another way to gather data; our top teeth are coupled to our skulls, so you get data collection.”

Bonin said riding helmets are designed to reduce peak linear accelerations (“The hard, outer shell keeps things from penetrating the skull, and foam absorbs energy,” she said), and some manufacturers are starting to produce helmets designed to reduce rotational acceleration, as well.

“Equestrian helmet standards do not require rotational acceleration reduction—yet,” she said. “However, multi-directional impact protection system technology, or MIPS, is used in helmet design in other applications, such as bicycle and motorcycle helmets. With MIPS helmets, the liner moves relative to the inner surface relative to the outer surface. MIPS systems have been shown to reduce rotational energy and therefore, they add additional protection against brain injury.”

Bonin’s next steps in furthering equestrian helmet research include testing rotation management systems, correlating tests to real life impacts, and collecting data on rider falls. She is also interested in creating “point clouds” (simply, a set of data points) of racetracks using 3-D virtual cameras so she can evaluate at the virtual environment by overlaying video with 3-D rider models.

Karin Pekarchik, senior extension associate for distance learning within UK’s Biosystems and Agricultural Engineering Department, served on the planning committee for the Horse Industry Safety Summit.

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