Cartilage in the ankle and foot can regenerate during long-distance running, according to a study presented at this week´s annual meeting of the Radiological Society of North America (RSNA).
Researchers used a mobile MRI scanner to study the effects of ultra-endurance running in 44 athletes taking part in the Trans Europe Foot Race (TEFR) in 2009. The athletes ran for 64 consecutive days, starting in southern Italy and ending in the North Cape in Norway. They covered 4,487 kilometres (2,788 miles) during the event, which took place from 19 April to 21 June.
Each participant was scanned every three to four days, resulting in 15 to 17 MRI exams over the course of the race. There were also other examinations, and daily urine, blood and other tests.
The results revealed that, with exception of the patellar joint, nearly all cartilage segments of knee, ankle and hind-foot joints showed significant degradation within the first 1,500 to 2,500 kilometers of the race, RSNA reported.
“Interestingly, further testing indicated that ankle and foot cartilage have the ability to regenerate under ongoing endurance running,” said Dr. Uwe Schütz, a radiologist and specialist in orthopaedics and trauma surgery at the University Hospital of Ulm in Germany. “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.”
MRI scans also showed a significant increase of the diameter of the Achilles tendon, but no relevant damage to bone or soft tissues, Dr. Schütz said, adding: “The human foot is made for running.”
Separately, the researchers looked at how ultramarathon running affects brain volume. They found that runners experienced a 6.1% loss of grey matter volume, but this had returned to normal levels after eight months.
The finding on grey matter volume loss while running is not cause for alarm, according to Dr. Schütz.
“Despite substantial changes to brain composition during the catabolic stress of an ultramarathon, we found the differences to be reversible and adaptive,” he said. “There is no lasting brain injury in trained athletes participating in ultra-running.”