Mark Pryer, Senior Applied Performance Coach
The foot is the first and most important point of contact between the body and the ground, and its function is vital for athletic performance. The calf muscle is attached to the calcaneus (heel) through a rigid fibrous attachment called the Achilles tendon, which plays a role in transmitting force during sprinting and jumping tasks, where being explosive is of utmost importance. However, tendinous injuries are commonplace and can happen in several different ways, with differing timelines to return to play depending on the physician’s protocol used.
Pathology and Mechanism of injury:
The first mechanism of injury is chronic disrepair caused by inflammation. Chronic degradation of the Achilles tendon complex is the most common finding in spontaneous tendon ruptures (2). Degradation can occur via chronic tendinosis/tendinitis that is allowed to progress unabated. In addition, there are several other factors that play a role, including sub-optimally conditioned musculotendinous unit, age, gender, changes in training pattern, poor technique, previous injuries, and footwear.
Achilles ruptures typically are acute and are classically produced by a single high-load impact. For example, a backpedal to rapid stop before moving into a sprint. An ATR (achilles tendon rupture) is associated with sudden or violent dorsiflexion of the ankle (4). Moreover, an acceleration-deceleration mechanism has been reported in up to 90% of sports-related ATRs. Limited range of motion at the ankle combined with a flat foot can predispose an athlete to be at a higher likelihood of Achilles rupture.
Return to play:
The primary goal of immediate post-surgical rehab is the removal of all swelling around the joint. Swelling can disrupt muscular firing patterns in the area and lead to inefficient movement. The secondary goal is the restoration of individual physiological norms for range of motion, with the passive range of motion (PROM) coming before active range of motion (AROM). The normal range of motion for ankle joint dorsiflexion was established as 0 to 16.5 degrees non-weight-bearing and 7.1 to 34.7 degrees weight-bearing (1).
In the weight room, initial strength work will consist of isometric work and progress to typical strength exercises such as calf raises, as the range of motion is restored and tissues are healing. In rehab the gold standard is gait, and everything is compared to the tissue loads that are experienced during walking, sprinting, and jumping. Athletes progress based on healing timelines, as well as where they are on the Walk→ Jog→ Run→ Sprint continuum. Plyometrics are compared to force production/absorption requirements on walk/jog/run/sprint cycle.
For example, If an athlete is cleared to perform pogos they should be able to progressively begin to start jogging. Force absorption and redirection is crucial for a seamless return to play. During gait, the lower extremities absorb the vertical, horizontal, and rotational forces in order to propel the body forward through space. At a walking pace (2 m/s), forces typically are around 1-1.5 times body weight and increase to 2.2 times body weight with a faster running speed (7 m/s). During maximal sprinting the body will experience up to 4x its body weight in forces for elite sprinters (6,7). For plyometrics-between 2.7- 4.6+ times, bodyweight impact forces can be seen on athletes commonly depending on the jump employed, with a single leg and drop jumps reporting significantly higher ground reaction forces (8).
Unfortunately, due to the nature of the injury and the structures involved, the timeline for return to play on an Achilles rupture can be extensive. There are two main schools of thought on the process, a standard return to play and the more recent development of an accelerated return to play.
In a traditional Achilles rehabilitation, the timeline can stretch up to 9+ months with the first block of time coinciding with immobilization of the foot and ankle using a walking boot. In an accelerated rehab protocol, timelines are greatly reduced, typically lying within a 12-16 week span. Previous research has shown that within the first 3 months of rehab is when most of the lengthening of the graft occurs, and further lengthening can occur up to 60 months post-surgery (3).
In the accelerated protocol the subjects were instructed to only wear the walking boot during mobilization, whereas in the traditional protocol the subjects wore the boot constantly, only removing it to wash the injury site. The verdict is still out, however, researchers noted that on an accelerated timeline patients started running sooner (by 4 weeks on average!) despite less lengthening of the Achilles tendon (stated as a result of no full immobilization period at the onset of rehab)(3,5). Decision making on the choice in protocol should be made in conjunction with your physician.
Here is a sample of simple return to play exercises commonly used in achilles return to play protocols.
- Baggett BD, Young G. Ankle joint dorsiflexion. Establishment of a normal range. J Am Podiatr Med Assoc. 1993 May;83(5):251-4. doi: 10.7547/87507315-83-5-251. PMID: 8135911.
- Järvinen, Markku & Józsa, László & Kannus, P & Järvinen, Teppo & Kvist, M & Leadbetter, W. (1997). Histopathological findings in chronic tendon disorders. Scandinavian journal of medicine & science in sports. 7. 86-95. 10.1111/j.1600-0838.1997.tb00124.x.
- Porter, M. D., & Shadbolt, B. (2014). Randomized controlled trial of accelerated rehabilitation versus standard protocol following surgical repair of ruptured achilles tendon. ANZ Journal of Surgery, 85(5), 373–377. https://doi.org/10.1111/ans.12910
- Tarantino, D., Palermi, S., Sirico, F., & Corrado, B. (2020). Achilles Tendon Rupture: Mechanisms of Injury, Principles of Rehabilitation and Return to Play. Journal of functional morphology and kinesiology, 5(4), 95. https://doi.org/10.3390/jfmk5040095
- Arunakul, M., Pholsawatchai, W., Arunakul, P., & Pitakveerakul, A. (2021). Conventional VS accelerated rehabilitation protocol following reattachment of Achilles tendon for insertional achilles tendinopathy. Foot & Ankle International, 42(9), 1121–1129. https://doi.org/10.1177/10711007211003871
- Nilsson J, Thorstensson A. Ground reaction forces at different speeds of human walking and running. Acta Physiol Scand. 1989 Jun;136(2):217-27. doi: 10.1111/j.1748-1716.1989.tb08655.x. PMID: 2782094
- Hierholzer, Kaela M., "The Effects of Increasing Running Speed on vGRF and Asymmetry" (2020). Electronic Theses and Dissertations. Paper 3648. https://dc.etsu.edu/etd/3648
- Wallace BJ, Kernozek TW, White JM, Kline DE, Wright GA, Peng HT, Huang CF. Quantification of vertical ground reaction forces of popular bilateral plyometric exercises. J Strength Cond Res. 2010 Jan;24(1):207-12. doi: 10.1519/JSC.0b013e3181c3b841. PMID: 19924006.