Dirks, Rachel C.Richard, Jeffrey S.Fearon, Angela M.Scott, AlexanderKoch, Lauren G.Britton, Steven L.Warden, Stuart J.2025-05-202025-05-202013-03-11Dirks RC, Richard JS, Fearon AM, et al. Uphill treadmill running does not induce histopathological changes in the rat Achilles tendon. BMC Musculoskelet Disord. 2013;14:90. Published 2013 Mar 11. doi:10.1186/1471-2474-14-90https://hdl.handle.net/1805/48283Background: The purpose of this study was to investigate whether uphill treadmill running in rats created histopathological changes within the Achilles tendon consistent with Achilles tendinosis in humans. Methods: Twenty-six mature rats selectively bred for high-capacity running were divided into run and cage control groups. Run group rats ran on a treadmill at a 15° incline for a maximum duration of 1 hr/d, 5 d/wk for 9 weeks at increasing speeds, while rats in the cage control group maintained normal cage activity. After 9 weeks, Achilles tendons were harvested for histological processing and semi-quantitative histopathological analysis. Results: There were no significant group differences within each of the individual histopathological categories assessed (all p ≥ 0.16) or for total histopathological score (p = 0.14). Conclusions: Uphill treadmill running in rats selectively bred for high-capacity running did not generate Achilles tendon changes consistent with the histopathological presentation of Achilles tendinosis in humans.en-USAttribution 4.0 InternationalAnimal modelTendinitisTendinopathyTendinosisOveruseArticle