Each year, more than 400,000 people in the United States undergo surgery to repair a torn anterior cruciate ligament (ACL). While the procedure can restore stability to the knee, many patients continue to experience weakness, balance problems and difficulty returning to daily activities.
According to Moein Koohestani, a Ph.D. student in the Division of Kinesiology, the reason may lie beyond the knee itself. ACL injuries can disrupt how the brain communicates with the muscles that control movement, something traditional rehabilitation does not always address.
Koohestani studies how the nervous system adapts after an ACL injury and how those changes may contribute to lingering movement problems. By examining how the brain controls the muscles around the knee, he hopes to better understand what happens in the body during recovery.
“It’s not just physical,” Koohestani says. “A knee injury can break down how the brain interacts with the muscles.”
In his lab, participants perform tasks that allow researchers to measure both brain and muscle activity. These include holding knee contractions at different force levels and balancing on one leg. Some tests also introduce mental challenges designed to mimic real-world situations where people must move while also thinking and making decisions.
“These tasks help us to understand how the nervous system adjusts after injury and how that brain–muscle interaction changes during movements,” he says.
The findings could help clinicians develop more effective rehabilitation strategies that address both physical strength and neurological recovery.
“This research can help clinicians optimize rehabilitation approaches to help people better recover, avoid re-injury, and feel more confident returning to daily life and sports,” Koohestani says.
