Achilles tendon injuries in runners can be chronic, debilitating injuries that last for months or even years. In my opinion, the challenge is not in rehabilitating the patient but in finding out the cause of the injury. All too often, I see runners who have been going to physical therapy for months and performing strengthening exercises at home, and yet they still are complaining of Achilles tendonitis. If the injury continues to be chronic and nagging in nature, then observing training patterns and running form becomes extremely crucial.

Discussing training patterns and running form can be a pages-long discussion. Here is one example of how focusing on stride rate can help reduce strain on the Achilles tendon. It is well established that step rate (cadence) is strongly associated with running-related injuries. Research has shown increasing a runner’s cadence to substantially reduce the loading to the hip and knee joints during running and may therefore prove beneficial in the prevention and treatment of common running-related injuries.1,2 Aiming for 180 steps per minute or higher has become a hot topic of debate in the running industry.3 Increasing one’s cadence may help prevent overstriding and in turn help decrease overuse injuries.

In a study published in the Journal of Applied Biomechanics, authors determined that increasing a runner’s cadence by 5 percent correlates to a decrease in overall strain on the Achilles tendon.4 The study also revealed that a forefoot strike pattern increased the strain on the Achilles tendon in comparison to a rearfoot strike pattern. I would expect to see this as the Achilles will become more active in a midfoot or forefoot strike pattern by contracting eccentrically to absorb impact. Over a period of time, as proven by Davis’s law, the Achilles tendon would adapt and become stronger. This study did have a small sample size, though. One would have to reduce the variables and compare runners who have been forefoot striking over the same given period of time as those who were rearfoot striking.4

In summary, in addition to focus on the rehabilitation of an Achilles tendon injury in runners, be sure to look at their stride rate or cadence. In my experience, most runners who think they have a quick turnover are running with average cadence of 160 steps per minute, which is well below the recommended cadence of 180 steps per minute.

References

1. Van Dyck E, Moens B, Buhmann J, et al. Spontaneous entrainment of running cadence to music tempo. Sports Med Open. 2015;1(1):15.

2. Heiderscheit BC, Chumanov ES, Michalski MP, Wille CM, Ryan MB. Effects of step rate manipulation on joint mechanics during running. Med Sci Sports Exerc. 2011;43(2):296–302

3. Latter P. The great cadence debate. Runners World. Available at http://www.runnersworld.com/race-training/the-great-cadence-debate . Published Sept. 21, 2012.

4. Lyght M, Nockerts M, Kernozek T, Ragan R. Effects of foot strike and step frequency on achilles tendon stress during running. J Appl Biomech. 2016; epub Mar 8.

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