Achilles Muscle Strain

Everyone’s talking about Kevin Durant’s devastating Achilles tendon Injury. But what is the Achilles tendon? Was this preventable? How long will it take to recover?

What is the Achilles: The Achilles tendon is a band of connective tissue that connects the calf muscles (Gastrocnemius and Soleus) to the heel bone (Calcaneus). Its primary function is force transmission between the muscle and bone to perform plantar flexion of the foot, or pointing of the foot towards the floor.

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Mechanism of Injury: The force of quickly pushing off of the foot requires the calf and Achilles to transmit force from the muscles to the heel, allowing propulsion. With Kevin’s prior calf strain having had 32 days to heal, is it likely that the calf muscle was no longer the weakest point in the kinetic chain. With immobility or disuse over even short periods of time, the Achilles tendon can remodel and become weaker relative to the strength it had before resting. His return to sport was likely too quick to allow the Achilles to return to its prior pre-injury strength, leading to overloading and subsequent rupture.

Clinically, most overuse tendon injuries are due to repetitive motion, which creates ‘‘microtrauma’’ that accumulates over time.1 Additional factors include muscular imbalance, muscular weakness, anatomical factors (leg length discrepancy etc.) and training errors.

Muscle strain injury/healing and how Physical Therapy can optimize healing:

By placing the injured muscle at rest for the first 4–6 days after the injury, the excessive scar formation and re-ruptures at the injury site can be best prevented.

At this point it is recommended that gradual mobilization, both active and passive, be started followed by a progressively intensified exercise program to optimize the healing. Healing is optimized by restoring strength of the injured muscle, preventing muscle atrophy, and loss of flexibility, all of which can follow prolonged immobilization. The rehabilitation program should consist of progressive agility and trunk stabilization exercises as well as exercise to lengthen (eccentric exercises) the injured skeletal muscle.

Proper progression of exercises, active and passive range of motion, Kinesiotaping, Active Release Technique, movement retraining, agility, plyometric training in addition to modalities such as ice, heat, ultrasound and electrical stimulation are all supported by the literature to optimize recovery after an Achilles tendon rupture.

What this means moving forward:

“…healed tendon has been shown in many studies to take upwards of a year to more closely approach the functional strength of uninjured tissue.” (T.W. Lin et al. / Journal of Biomechanics 37 (2004) 865–877

According to a 2011 study, “When players were compared with matched controls, an Achilles tendon rupture resulted in fewer games played ( P < .001), decreased play time ( P = .025), and worse performance statistics ( P < .001) at 1 year but not 2 years postoperatively ( P > .05). When individual sports were compared, NBA players were most significantly affected, experiencing significant decreases in games played, play time, and performance.3

Unfortunately for Kevin Durant, he will likely experience significant reductions in his performance next year. According to the literature he will likely require 2 years before his player efficiency returns to his preinjury levels. Hopefully this article brings to light the importance of a rehab in the world of sports medicine and the information can be useful for anyone suffering from musculoskeletal injuries.


  1. Hess, et al. Prevention and Treatment of Overuse Tendon Injuries. Sports Medicine. 1989;8(6): 371-384.
    2. T.W. Lin et al. Biomechanics of tendon injury and repair. Journal of Biomechanics. 2004;37(6): 865–877
  2. Trofa, DP. Professional athletes’ return to play and performance after operative repair of an Achilles tendon rupture. Am J Sports Med. 2017;45(12): 2864-2871

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