Like a battering ram, the helmeted dummy crashes headfirst into the steel plate at 13 mph — barely the speed of a bicycle.
But the crunch of impact makes St. Louis University biomechanist Jack Engsberg wince and whistle.
Sensors embedded in the dummy’s head and neck show that the helmet would have saved a person from head trauma. But the spinal cord? Even at these speeds, Engsberg says, it would have snapped.
Engsberg and researchers in the university’s Physical Therapy department are designing a shield that would protect both the head and neck. With motorcycle deaths on the rise, the shield could be a boon for the safety conscious — even as some motorcyclists fight to repeal mandatory helmet laws.
However, it’s unclear how many self-respecting Harley riders would don the unwieldy device, a rigid exoskeleton that runs from head to waist. The shield is a molded fiberglass sheath, reinforced with steel rods that shepherd impact forces from a skullcap to the shoulders, bypassing the neck.
”Clearly, this prototype is not something that someone would wear,” Engsberg said.
There are some benefits to the design. Most helmets tightly wrap the head and, moreover, require the head to hold up the helmet. With the shield, on the other hand, there’s about an inch of space separating the head and the skullcap, offering greater freedom of movement. Engsberg said a refined version could be made more breathable with an apple-pie lattice of fiberglass strips.
He noted that motorcyclists could buy helmets and armored jackets — but that no one had protected the neck by uniting the two concepts.
Motor vehicle accidents cause nearly half of the estimated 11,000 annual spinal cord injuries in the United States, according to the National Spinal Cord Injury Database. Those who die from spinal cord injuries at the scene of an accident are not counted.
Over the last decade, motorcycle deaths per vehicle-mile traveled have almost doubled, even as automobile death rates have declined, according to the National Highway Transportation Safety Administration.
The researchers say the shield also could help horse riders. In a 1995 equestrian event, actor Christopher Reeve was thrown from his horse and landed on his head. He broke his neck and suffered a severe spinal cord injury even though he was wearing a helmet and protective vest.
It was also a horse-riding accident that motivated Washington University neurologist William Landau to design the shield, after his granddaughter was paralyzed in a fall.
”He said, ‘I’ve got to do something about this,”’ Engsberg said. Landau was awarded a 1998 patent for a ”brain and spinal cord protector.”
Landau later approached Engsberg, who runs a motion analysis laboratory at St. Louis University. The researchers recently smashed up eight Bell Zephyr motorcycle helmets, collecting data that would be compared with earlier tests on their prototype shield.
The researchers rely on two systems to gather data from the dummy. One uses six high-speed cameras, taking 250 frames per second, to build a 3-D model of the dummy as it drops. The other uses accelerometers, little titanium cubes that sense the sudden stopping of the head at decelerations 100 times gravity.
Before one test, Occupational Therapist Tim Shurtleff ratcheted the dummy up 5 feet high, using a pulley he borrowed from his own catamaran. John Standeven, an electrical engineer, gave the command. ”Three, two, one, go,” he said.
The dummy swooped low in its sling and slammed into the steel plate. For an instant, the neck visibly crimped. A plastic visor snapped off.
Engsberg clucked and shook his head. ”Doesn’t that hurt?”
By Eric Hand Of The St. Louis Post-Dispatch