UC Davis system checks athletes’ knee ligaments
American River College freshman Nathan Miller jumps from a special force plate as UC Davis biomechanical engineer Judd Van Sickle prepares to measure how hard he comes down on the device. Van Sickle hopes to develop a quick, lowcost test to predict which athletes are most at risk for anterior cruciate ligament tears, a common but serious knee injury.
One after another, aspiring football and soccer players mounted a low blue bench, jumped off, then leaped up again, as high as they could.
Their landings were tracked by two video cameras, two computers and a special force plate that measured how hard they came down.
The man behind the high-tech gear last week in the American River College gym is hoping to develop a quick, low-cost screening test to spot athletes most at risk for a common – but serious – knee injury.
Judd Van Sickle, a biomechanical engineer with UC Davis' sports medicine performance program, is fascinated by tears to the anterior cruciate ligament because he thinks they're so preventable.
"It's a non-impact injury. It's not someone running into your knee. It's you turning and your ACL pops," Van Sickle said.
A torn ACL often requires surgery and a recovery that can cost an athlete a season or a year – sometimes knocking a high school player off a scholarship path.
Van Sickle's project is part research and part prevention. A few studies suggest the two things he's measuring – how hard an athlete lands and the position of the knees – correlate with vulnerability to ACL tears.
Athletes who land hard on the force plate, especially in relation to the force of their takeoff when they jump back up in the air, seem to be the ones likeliest to injure their knees, Van Sickle said. The harder landing indicates less control, and so less support for the knee.
The second indicator is whether the knees turn in on landing, in a sort of knock-kneed position, or are aligned directly above the feet. The inward turning knees could be a sign of poor hip stability or just improper technique, both leaving the knee more prone to injury.
Once he finishes writing the computer code that will give him a quick analysis of each student athlete's landing, Van Sickle will give American River College coaches a list of those who seem most prone to ACL problems.
"It's definitely helpful to detect those things," said Gil Bejarano, one of the community college's trainers. "This way we know what to strengthen for."
Bejarano and fellow trainer Anna August work with about 500 student athletes a year, and their most common injuries are to knee and ankle ligaments, August said.
The young people lined up for their team physicals on Thursday at American River College had their own tales of seeing teammates or relatives hobbled by knee injuries. Some had gotten detailed injury prevention advice in high school, others none.
Most ACL tears come in sports with lots of jumping and cutting, or rapid changes of direction. Basketball, soccer, volleyball and football are rich breeding grounds for ACL problems.
Proper turning techniques can lessen the risk of injury; so can strength and neuromuscular training, which build a better support structure for the knee.
The students Van Sickle pinpoints will get extra help in all those areas, August said.
That extra help – aimed at preventing injuries – will make it tougher to tell whether tests really did spot the most injury-prone players.
But Van Sickle said he'll get useful data anyway. He will track students who his tests indicate are less likely to tear an ACL. If those students end up getting injured at higher than expected rates, he'll know a more robust test is needed.
There are more detailed ways to look for potential knee problems, including skeletal reconstructions that involve a full, three-dimensional analysis of each athlete, Van Sickle said. Those take hours of computer processing time and equipment that costs around $100,000.
By contrast, the simple force plate and video testing system he is using takes just a few minutes. It should cost well under $100 per athlete.
He plans to collect data on more than 100 American River College student athletes as part of routine physicals they're required to take before playing.
It's a pilot program he hopes will grow, even though right now "I've got zero funding for this," Van Sickle said.
Among those hoping he succeeds is Joseph Iese, a freshman from Santa Cruz who has watched over the years as his father, mother and sister underwent knee surgery for ligaments torn during basketball games.
"I really don't want to have the surgery," Iese said. "I'll take all the help I can get."