An MRI study of long-distance runners presented recently at the Radiological Society of North America (RSNA) annual meeting suggests that the runners were able to regenerate the cartilage in their ankles and feet.

The runners participated in the Trans Europe Foot Race (TEFR) from April 19 to June 21, 2009. During the 4,487 km race that started in southern Italy and ending in the North Cape in Norway, the runners ran every day for 64 days without any day of rest.

Forty-four of the runners (66%) agreed to participate in the study, in which researchers using a mobile MRI truck followed them during the race to test their physical limits and adaptation. Each participant was scanned every 3 to 4 days—resulting in 15 to 17 MRI exams during the course of the race. The runners were also randomly assigned to additional examinations, and protocols were created for daily urine, blood, and other tests, explains a media release from RSNA.

The results showed that with the exception to the patellar joint, nearly all cartilage segments of knee, ankle, and hind-foot joints showed a significant degradation within the first 1,500 to 2,500 kilometers of the race, per the release.

“Interestingly, further testing indicated that ankle and foot cartilage have the ability to regenerate under ongoing endurance running,” says Uwe Schütz, MD, a radiologist and specialist in orthopedics and trauma surgery in the Department of Diagnostic and Interventional Radiology at the University Hospital of Ulm in Germany, and one of the participating researchers, in the release.

“The ability of cartilage to recover in the presence of loading impact has not been previously shown in humans. In general, we found no distance limit in running for the human joint cartilage in the lower extremities,” he adds.

The results of MRI scans on the runners’ soft tissues and bones also revealed a significant increase of the diameter of the Achilles tendon. However, Schütz notes in the release that no relevant damage to bone of soft tissues was found.

“The human foot is made for running,” he states.

The researchers also looked at how ultramarathon running affects the gray matter in the runners’ brains.

Baseline comparison of TEFR participants and controls revealed no significant differences in gray matter volume. At the end of the race, MRI of the brain revealed about a 6.1 percent loss of gray matter volume in the runners. After eight months, gray matter volume had returned to normal levels, the release explains.

Schütz states in the release that this is no cause for alarm, however.

“Despite substantial changes to brain composition during the catabolic stress of an ultramarathon, we found the differences to be reversible and adaptive,” he explains in the release. “There is no lasting brain injury in trained athletes participating in ultra-running.”

[Source(s): Radiological Society of North America, Science Daily]