By Emily Delzell
Women who run barefoot with a midfoot or forefoot strike pattern have higher Achilles tendon (AT) loads—and, potentially, a higher risk of tendinopathy—than rearfoot strikers, according to research e-published May 3 in the Annals of Biomedical Engineering.
Movement scientists at the University of Wisconsin in La Crosse and East Carolina University in Greenville, NC, analyzed computer modeling data on gastrocnemius and soleus muscle forces in 19 healthy female runners (11 rearfoot strikers, eight mid- or forefoot strikers) who ran barefoot.
Peak AT force occurred significantly earlier in stance phase among nonrearfoot strikers, contributing to a statistically significant increase (15%) in AT loading rate. Nonrearfoot strikers also had a significantly greater AT impulse (11%) with each step and a nearly significant greater AT impulse per mile run, equating to an additional 47.7 body weights for each mile run.
The authors concluded barefoot and minimalist runners with nonrearfoot strike patterns, particularly those with a history of Achilles tendon pain or injury—and women, who are vulnerable to estrogen’s inhibitory effects on collagen renewal— should modify footwear or training programs accordingly.
Almonroeder T, Willson JD, Kernozek TW. The effect of foot strike pattern on achilles tendon load during running. Ann Biomed Eng 2013 May 3. [Epub ahead of print]