The Achilles tendon is the most commonly injured tendon and ruptures can be among the most debilitating injuries in sports. Recovery can take up to 9 – 12 months, and many athletes are unable to recover or return to pre-injury athleticism. According to a report from Sports Illustrated, 36% of NBA and NFL athletes who suffered a rupture to the Achilles tendon never returned to professional sports. Multiple studies have demonstrated the difficulty with regaining calf strength and endurance following an Achilles tendon repair following complete rupture. The ability to complete a single leg heel raise has long been a gold standard to measure calf strength and endurance. Even after 1 year following surgery, strength and endurance has been found to be approximately 75% of the non-injured limb. There are many potential causes for this lack of strength. For example, it was evident that many patients have increased tendon length, providing sub-optimal length-tendon relationships to maximize muscle force. Therefore, most protocols limit the amount of dorsiflexion stretching the first 8 weeks of recovery. However, even in the presence of normal tendon length, there are still evident strength deficits. One explanation is the difficulty of proper muscle recruitment of the gastrocsoleus complex during muscle strengthening. Most protocols begin light plantarflexion strengthening at approximately 8 weeks following surgery; allowing adequate healing of the surgically repaired tendon. I have seen protocols that allow theraband and cautious isotonic strengthening to begin as early as 6 weeks post-op.
Strengthening in this phase of rehabilitation is critically important. When done optimally, patients will be able to effectively activate the gastrocsoleus complex,enabling them to regain neuromuscular control and strength. This is very similar to doing quad activation work in the early stages of rehabilitation following ACL reconstruction. However, optimal gastrocsoleus activation is difficult and without effective muscle activation, the patients progress will be significantly hindered due to lack of strength development. This will potentially have major implications on the progress of the rehabilitation months down the road.
When beginning the strengthening phase of rehabilitation, patients have significant weakness and when doing certain exercises they will inherently demonstrate compensatory movements or muscle activation patterns that lessen the beneficial effects of the exercise. A very common exercise done in the early stage of strengthening is a sitting heel raises as it lessens the tensile stress on the achille’s tendon by shortening the gastrocnemius. When done correctly, this gives the patient a chance to begin light strengthening and activation of the soleus in a closed kinetic chain fashion that is more functional than open kinetic chain exercises such as theraband strengthening. One problem with this exercise, however, is that in the presence of significant weakness and atrophy of the soleus, many compensatory muscles will perform the movement.
The main compensation that I have seen is utilizing the hip flexors and simply raising their knee instead of pressing their foot into the ground to activate the plantarflexors. When visually observing, it is impossible to see a difference between a patient using primarily hip flexors vs. correctly utilizing their plantarflexors as both with cause similar lower extremity movements including raising their heel off the ground.
One is able to objectively observe this when having a patient doing sitting heel raises on a BodiTrak pressure mat. Below are screenshots of the patient doing the exercise and observing the vertical ground reaction forces. As you can see in the first example (Fig. 1), his ground reaction force (GRF) was routinely well below his resting ground reaction force (1). This indicated that he is not actively plantarflexing. Instead, he is likely utilizing his hip flexors to raise his lower extremity and therefore causing passive plantarflexion and decreased GRF. Figure 2 shows him doing the exercise after some cueing from the physical therapist to keep his ground reaction force above baseline as he goes through the exercise by using a phrase such as “keep the orange line above 1 as you lift your heel.” As you can see, he routinely created a higher ground reaction force with this exercise, indicating he is pressing into the ground and therefore effectively utilizing his plantarflexors as the exercise intended.
Fig 1 (Poor Plantarflexion): Line “1” indicates his baseline GRF at rest. In this picture, the peaks are at rest and the valleys are when he was performing the heel raise. This indicates decrease in GRF during the exercise which means he is not performing active plantarflexion.
Fig 2 (Active Plantarflexion): Line 1 indicates his baseline GRF at rest. In this picture, the peaks occurred while performing the heel raise and the valleys are during rest. This indicates active plantarflexion during the exercise
When visually observing, it is impossible to see a difference between a patient using primarily hip flexors vs. correctly utilizing their plantarflexors as both with cause similar lower extremity movements including raising their heel off the ground.
Without this type of information and ability to utilize BodiTrak for biofeedback, there would have been no way to determine if he is performing the exercise correctly and activating the plantarflexors outside of using EMG. Instead, when we would assume we are beginning the initial strengthening of the Achilles tendon, we are actually not providing any type of muscle activation or strengthening benefit as he is creating passive plantarflexion. This would have deleterious effects on his overall progress and delaying his recovery significantly.
Adam Halseth is a sports medicine and orthopedic physical therapist at the Orthopedic Institute in Sioux Falls, SD. He is TPI Medical Level 3 certified. Adam works with athletes from a variety of sports backgrounds and all ability levels. He graduated from physical therapy school at the Mayo Clinic School of Health Sciences. He has since developed a passion with rotational athletes and has worked extensively with professional and amateur golfers and collaborates with some of the top golf medical professionals in the nation including those on the LPGA and PGA tours.
Email Adam at email@example.com
Bostick, G. P., Jomha, N. M., Suchak, A. A., & Beaupre, L. A. (2010, June). Factors Associated with Calf Muscle Endurance Recovery 1 Year After Achilles Tendon Rupture Repair. Journal of Orthopaedic and Sports Physical Therapy, 40(6), 345-351.
Silbernagel, a. G., Willy, R., & Davis, I. (2012, June). Preinjury and Postinjury Running Analysis With Measurements of Strength and Lendon Length in a Patient With a Surgically Repaired Achilles Tendon Rupture. Journal of Orthopaedic and Sports Physical Therapy, 42(6), 521-529.