Achilles Tendinitis is a common injury we see in runners and as individuals get older. This doesn’t really come as a surprise as we mentioned in our plantar fasciitis blog. During the push-off phase of running, the plantar fascia and Achilles tendon are exposed to a force seven-times our bodyweight. In addition to increased demand, as we age the Achilles tendon actually becomes weaker. Thankfully our bodies are truly amazing and have built in safety mechanisms, unfortunately they can’t always keep up with repetitive trauma and poor movement patterns we tend to adopt.

The Achilles tendon is made up of the tendons from the gastrocnemius (big sexy calf muscle) and the soleus (the fan looking muscle behind the gastroc).  The two combine to form the thick Achilles tendon and insert on the back of the heel.

The Achilles tendon is made of primarily two types of collagen: type 1 and type 3. In a healthy Achilles tendon 95 percent of the collagen is made up of type 1, which is stronger and more flexible than type 3. In addition to the type 1 collagen, the Achilles is unique in that when the gastroc and soleus meet the tendon actually starts to twist, eventually rotating a full 90 degrees before attaching at the back of the heel.  This allows the Achilles to function like a spring, absorbing energy during the early phase of running and returning by elastic recoil after the propulsion phase, allowing for more efficient running.


Although the body is designed to help prevent injury to the Achilles, it is still very common due to overuse and poor movement strategies. Many individuals can become frustrated, brush it off and/or don’t get the treatment they need causing the issue to become a chronic problem. Many times runners don’t give the tendon adequate time to heal before progressing their training programs. During the healing process the body brings in specialized repair cells called fibroblasts to begin making collagen. In the early phase of tendon healing the fibroblasts mainly produce type 3 collagen, which is weaker and inflexible compared to the type 1 collagen that makes up the majority of a healthy Achilles tendon. However, as the healing progresses, fibroblasts increase and shift production from type 3 collagen to type 1 collagen.

Research is continuing to find that load is one of the best ways to create change in tendons leading them to adapt. It used to be common to say rest is good for tendinous injuries, but that is no longer the case. The best way is starting with isometric loads and progress to eccentric loads. Doing eccentric loading of the Achilles tendon has been shown to be effective in the treatment of Achilles tendonitis. However, it was found that there is a difference in the amount prescribed for recreational runners vs competitive runners. Recreational runners responded well to the traditional 3 sets of 15 reps, while competitive runners averaging more than 50 miles per week responded better to 4 sets of 50-80 reps.

 Start position of achilles eccentric exercise.

Start position of achilles eccentric exercise.

 Slow lowering on the injured leg, eccentrically loading the achilles.

Slow lowering on the injured leg, eccentrically loading the achilles.

Achilles eccentric exercises are performed by standing on a step or something lifted, using both feet to raise up, then at the top take away the good leg and slowly lower the heal to the ground on the injured leg. Once at the bottom, bring the uninjured leg back and rise up using both feet and repeat. In addition to eccentric loads, strengthening of the flexor digitorum helps to reduce the strain placed on the Achilles since they work together during the propulsion phase. Besides strengthening exercises, hands on manual therapy is also beneficial in helping to stimulate healing, increasing blood flow, and fibroblast to the injured tissue.  


At TROSS we strive to provide our patients with the best care possible. We use a combination of evidence based care and clinical experiences to best serve our patients.  We have received training in a variety of techniques in order to be better equipped to serve each individual patient. TROSS proudly serves the Cottleville, St. Peters, St. Charles, O’Fallon, and St. Louis communities.