The Achilles tendon is a common injury site for distance runners. Is there a greater risk of injury when running uphill or downhill?
Not according to a new study by researchers at Brigham Young University (BYU) in the United States.
Former BYU track star Katy Andrews Neves and exercise science professors Bill Myrer, Wayne Johnson and Iain Hunter found that the Achilles tendon is capable of adapting to uphill and downhill running better than previously believed.
The study involved 20 female runners who were asked to run for 10 minutes on each of three randomly ordered grades (-6%, 0 and +6%) on an instrumented treadmill. Each run was completed on a different day, with at least 48 hours between each round.
Knowing that the Achilles becomes more pliant and thinner from exercise, the researchers used Doppler ultrasound imaging to examine the thickness and stretch on Achilles tendons before and after each trial. Ten high-speed cameras recorded the motion of the runners, collecting data from 16 reflective markers placed on their lower extremities, the university reported.
The results, published in the Journal of Sports Science and Medicine, showed that although downhill running resulted in the largest peak force on the runners, there were no significant differences in Achilles tendon thickness changes between running grades. This means that there is no increased risk for Achilles injury when running up or downhill – as long as runners transition slowly to downhill running in order to adapt to the greater forces.
“Over time, runners adapt to the forces placed on their body, so even when the forces are higher (running downhill), if the adaptation process is gradual, the injury risk drops,” Neves explained. “Our bodies are amazing and are very good at adapting to the conditions we put them in.”