In a prospective study, researchers may have shed new light on why some runners develop Achilles tendon injuries while others don't. The research suggested that specific ankle movements during running and higher weekly mileage may significantly influence the risk of developing Achilles tendinopathy.
Achilles tendinopathy is a common overuse injury marked by pain, swelling, and reduced function in the tendon that connects the calf muscles to the heel. While previous research has linked high running volume and certain movement patterns to injury risk, many earlier studies were small or retrospective.
In the recent study, part of the Healthy Aging in Industrial Environment Program 4, the researchers followed 911 adult participants for a period of 1 year, including 528 runners and 383 nonrunners. The participants underwent detailed biomechanical testing at baseline and were monitored using wearable devices and weekly injury reports. All cases of Achilles tendinopathy were confirmed by a physician.
Over the 12-month follow-up, 23 participants developed new Achilles tendon injuries. The condition was more common in runners (3.8%, n = 20) compared with nonrunners (0.8%, n = 3). One of the clearest findings involved weekly running distance. For every approximately 7.8-mile increase in weekly mileage, the risk of developing Achilles tendinopathy rose by 67%.
The researchers identified two ankle movement patterns during the stance phase of running that were strongly associated with injury risk. For instance, runners whose ankles generated stronger inward-rolling force during the stance phase of running were less likely to develop Achilles tendinopathy.
The researchers didn't find that foot strike patterns significantly influenced injury risk, thereby challenging common recommendations that runners should change how their foot hits the ground to prevent Achilles tendon–related injuries. Age and sex weren't statistically significant predictors after adjusting for other factors, although injured runners tended to be slightly older.
Because the study followed participants over time and confirmed diagnoses medically, the findings provided stronger evidence than previous cross-sectional reports. The researchers suggested that clinicians and coaches may consider monitoring both running volume and specific ankle mechanics when designing injury prevention strategies.
“Our study presents evidence that sufficient peak external rotation of the foot and peak ankle inversion moments during the stance phase of running may serve as a protective factor against Achilles tendinopathy. This finding challenges the conventional approach of limiting non-rearfoot-fall patterns in runners. Moreover, our research indicates that higher weekly running distances significantly elevate the risk of Achilles tendinopathy,” concluded lead study author Daniel Jandacka, of the Department of Human Movement Studies at the University of Ostrava in the Czech Republic, and colleagues.
Co–study author Scott Selbie reported being the owner of a company that owns the commercial software program Visual 3D, which was used for processing biomechanical data in this study. The study authors reported no other conflicts of interest.
