One of the biggest recent sports stories involved then-Golden State Warrior Kevin Durant. In game five of the NBA Finals, Kevin went down with an Achilles tendon injury.1 The interesting situation here is that Durant had also been nursing a calf injury for the previous few weeks that actually kept him out of the first four games of the NBA Finals.
As people looked for answers to what had happened, Bob Meyers, president of basketball operations for the Warriors, spoke at a press conference after the game. He stated: "The initial injury was a calf injury. This is not a calf injury." Myers said, "I'm not a doctor, I don't know how those are related or not, but it's a different injury."2
This is a great opportunity to discuss the general public's lack of knowledge of lower extremity anatomy, biomechanics, movement patterns and how they are all related. One of the most frustrating things for me in active practice is how little education our patients are given about their own bodies, including the feet, ankles, legs and knees. It's time to break down the Achilles tendon and calf relationship, as almost all health care providers deal with this area frequently in clinical practice.
Anatomy 101: The Calf, Achilles and How Overpronation Relates
The calf is often referred to as sura, which is the Latin word. It is the back portion or posterior compartment of the leg. The two largest muscles (the gastrocnemius and soleus) are known together as the calf muscles and they both attach to the calcaneus bone via the Achilles tendon.3
Understanding the anatomy of the calf is pretty simple, but let's complicate things a bit. If you recall, we all have three functional arches on the bottom of each foot: the medial longitudinal arch, the lateral longitudinal arch and the transverse (metatarsal) arch. These three arches form the plantar vault and are the basis for stability of the human foot.
The arches are formed by the plantar fascia and the bone-to-bone ligaments (like the spring ligament). When the arches are working well, the foot is allowed to move fluidly into regular pronation, regular supination and proper weight-bearing during standing and the gait cycle.
Up to 99 percent of the population display excessive pronation – their arches flatten out too much and fall toward the ground.4 Because this phenomenon happens so frequently in the patients who come to us for care, it is easy to see daily.
When the feet are overpronating, the three arches drop more than they should. As the foot falls to the ground, the tibia bone must inwardly rotate as a compensatory mechanism. The inward rotation of the tibia then causes the femur to rotate inward (medially) as well.
The excessive pronation has now set up a biomechanical situation whereby the dropping of the arches and inward rotation of both the tibia and femur bones stress the inner ankles and knees. As one of the consequences, the gastrocnemius and soleus muscles overcontract, even at rest.
Muscles that are essentially getting overworked are very susceptible to injury and damage. We can see this damage range from a calf strain or pulled leg muscle all the way to Achilles tendonitis, Achilles tendon tears or complete ruptures.
It's not just that the gastrocnemius, soleus and Achilles tendons are located too close to one another. The physical relationship is compromised by the biomechanical fact that excessive foot pronation can and will negatively affect the forces coming up from the heel and ankle into the Achilles tendon and calf. This relationship is what most people don't understand.
When an Achilles Tendon / Calf Injury Presents, What Can You Do?
So the question arises: What can I do in my clinic when an Achilles tendon / calf injury patient presents? Here are some smart options.
- Evaluate the lower extremity properly! Have the patient take off their shoes and socks and stand in front of you in anatomical position. You will clearly see how flat their feet are (look for the five signs of foot pronation). Often, you will see the tibia and femur bones internally rotating, and notice how tight and hypertonic the calf muscles and Achilles are on one or both sides.
- Utilize appropriate physiotherapy modalities like cold laser, ultrasound, EMS and/or a host of other modalities to help the patient, whether they are acute or chronic. Soft-tissue techniques (ART, Graston, etc.) are also very useful in helping those muscles and soft tissues improve.
- Administer chiropractic adjustments to all 26 foot bones, the tibia, femur and fibula. Since most patients presenting to our clinics are excessive foot pronators, the listings of all these bones are in quite a predictable pattern. It is easy to know what to look for and how to adjust it.
- Utilize custom, three-arch, flexible foot orthotics. Once your plantar fascia stretches past a certain point, the arches fall and the foot will continue to flatten out. Having the right type of orthotics support all three arches gives the foot, and therefore the body, a stable base of support. Without support, the overpronation will continue to stress the calf muscles and the Achilles.
- Ensure the patient is using proper footwear. Athletic, dress and casual shoes must be inspected by you, the doctor, so you can assess if they work well with the custom orthotics and provide solid support for the patient. Many patients wear shoes that help create stress to the ankle and knees. Some shoes are so awful that they won't even work with any orthotics.
- Give home care instructions that can include stretching and strengthening exercises of the calf and foot. Discuss appropriate activities to keep the patient active, but do not aggravate their condition. You may have to take a patient out of their sport short term while you get them stabilized and make sure their feet are well-supported.
Evaluating Pronation Is the Key
You may never see a patient / athlete the caliber of Kevin Durant, but your patients deserve to be treated like they are superstars. Please take the time to look at their feet, ascertain their pronation degree and treat them properly. Foot support is key or else the overpronation pattern will continue, stressing the ankle, knee and all muscles located in that area. Plus, your adjustments of the ankle and knee will never truly hold unless the three arches are supported properly.
References
- Bengel C. "Kevin Durant Injury Update: Warriors Star Undergoes Surgery for Ruptured Achilles Tendon." CBSSports.com, June 12, 2019.
- "Kevin Durant Suffered Achilles Injury, Warriors GM Bob Myers Announces." NBC Sports Bay Area, June 10, 2019.
- Picture of the Calf Muscle. WebMD.com - Anatomy: https://www.webmd.com/fitness-exercise/picture-of-the-calf-muscle#1.
- Overpronation. FootLevelers.com: https://www.footlevelers.com/why-custom-orthotics/overpronation.
Dr. Kevin Wong, earned a BS in exercise physiology from the University of California – Davis and his DC degree from Palmer Chiropractic College West. He practices in Orinda, Calif., and serves the Lamorinda, Berkeley, Walnut Creek and many other East San Francisco Bay Area communities. He is an expert on foot analysis, walking and standing postures, and orthotics, and lectures nationwide on spinal and extremity adjusting.