The Achilles Tendon is the strongest and largest tendon in the body. In fact, it can withstand forces of up to 1,100 pounds of stress. The Achilles Tendon serves to transmit the force generated by the calf muscles to produce the push-off (plantar flexion) that is required for walking, running, and jumping.

The Achilles Tendon is named after the ancient Greek mythological hero Achilles. Legend tells us that this tendon was the only part of Achilles body that was vulnerable to attack, otherwise he was invulnerable. I am not sure about the truth behind this story, but I do know that if you ever ruptured your Achilles Tendon, it would definitely incapacitate you.

Despite its impressive strength, due to its poor blood supply, the Achilles Tendon is also extremely vulnerable to injuries that often end athletic careers. In fact:

• More than a third of the NFL players who sustained an Achilles tendon injury are never able to return to professional play.

• The NFL players who do return have an averaged a 50% reduction in their power ratings (4).

Fortunately, most injuries to the Achilles Tendon are not full tears and can be rehabilitated without the need for surgery.

RUNNING CONSIDERATIONS

The Achilles Tendon is an essential link in a runners kinetic Chain just consider the following functions this important structure serves in a runners gait (14):

• The Achilles Tendon has a spring like action storing and releasing energy. This spring action decreases the metabolic cost of movement by decreasing the workload placed on the bodies muscular support system.

• Energy that is stored in the Achilles Tendon during midstance of gait is used to initiate the swing phase of gait (propulsion phase). This drives the knee and the hip up and forward.

• The action of the Achilles greatly reduces strain on the hip flexors (iliopsoas, rectus femoris) and the hamstring muscles

ANATOMY OF THE ACHILLES TENDON

The Achilles Tendon is a co-joined tendon. It is where the two calf muscles, the gastrocnemius and soleus, join together to form a single band of tissue, which then becomes the Achilles Tendon. The lower end of the Achilles Tendon inserts into the calcaneus or heel bone. Keep in mind that both the gastrocnemius and soleus muscles are innervated by the tibial nerve (1).

The area of the Achilles Tendon (approximately 2 to 6 cm above its insertion into the calcaneus) is very dense and under constant tension. This area has the poorest blood supply, making it extremely susceptible to injury and very slow to heal when it is injured (1).

Myofascial Connections of the Achilles Tendon

From a myofascial perspective, the Achilles tendon has a wide range of connections. The “myo” in ‘myofascial’ refers to muscle. The medical definition of ‘fascia’ is, “a thin sheath of fibrous tissue enclosing a muscle or other organ”. A definition, based on current research, defines fascia as “the soft tissue component of the connective tissue system that permeates the human body, forming a whole body continuous three-dimensional matrix of structural support”. This definition is taken from the First International Fascia Congress (Dr. Robert Schleip, Dr. Thomas Findley).

It is important to understand the effects of these myofascial connections on the function of the Achilles Tendon, especially when working to resolve Achilles Tendon injuries. For example, although the Achilles Tendon attaches to the posterior aspect of the heel (calcaneus), it is also has fascial continuity with the plantar fascia that surrounds the heel, and to the fat pad located on the bottom of the foot. The clinical relevance is that excessive stretching or tightness of the Achilles Tendon can lead to an increased incidence of Plantar Fasciitis and several gait imbalances. The image above is an MRI of the foot, showing the connection between the plantar fascia and the Achilles Tendon (12).

Other significant connections include to the hamstring muscles (biceps femoris, semitendinosus, and semimembranosus). There are also direct fascial connections between the hamstrings and the gastrocnemius muscles. Consequently, tension within the hamstrings can be directly transferred into the calf muscles and then to the Achilles Tendon (1,12).

Also of note, is that hamstring tension can be related to a lack of gluteal activation. The gluteal muscles are the primary hip extensors. Without good gluteal activation, force will be transferred into the hamstrings, which act as secondary hip extensors.

Eventually this ongoing hamstring tension is transferred further down the kinetic chain, into the calf muscles and then into the Achilles Tendon (1,8,12).

Another interesting connection is the plantaris muscle (a weak plantar flexor). The plantaris originates on the back of the knee (lateral supracondylar ridge of the femur) and is a long thin muscle that passes between the gastrocnemius and soleus until it inserts directly into medial aspect of the Achilles Tendon (2,8). The Plantaris muscle is also innervated by the Tibial nerve.

When patients develop a trigger point or adhesion in the plantaris muscle, they may experience pain not only in the mid-calf muscle, but also feel referred pain into the medial aspect of the Achilles Tendon. Therefore, patients may believe they are experiencing Achilles Tendon pain, but in reality, they may be experiencing referred pain from the plantaris muscle.

It is interesting to note that when patients rupture the Achilles Tendon, the plantaris muscle may compensate and mask some of the clinical signs of the rupture.

TYPES OF ACHILLES TENDON INJURIES

In this blog, I speak in terms of the ‘Achilles Tendon injury’ rather than using terms such as Achilles Tendinitis. The term “tendonitis” is often misleading, since on examination (histopathological exam), signs of inflammation are often not present in cases of Achilles Tendon injury.

Inflammation

If inflammation does occur, it is often called a Paratenonitis. The paratenon is a sheath surrounding the Achilles Tendon, which works as an elastic envelope around the tendon, allowing the tendon to move freely between the surrounding tissue. Paratenonitis is often caused by overuse or repetitive strain and commonly occurs in triathletes and runners.

Injury of the Achilles Tendon may also occur due to Tendinosis, which refers to degeneration within the Achilles Tendon, often caused by a previous tear. This condition can be felt as a palpable tendon nodule very close to the heel. This nodule is formed by the accumulation of scar tissue.

Tears of the Achilles Tendon

A tear of the Achilles tendon is also a common diagnosis, and refers to the tearing or separation of the Achilles Tendon from the calcaneus (heel bone). As we mentioned earlier, the Achilles Tendon is very strong. However, even with this strength, the Achilles Tendon is the second most frequently ruptured tendon in the body. A complete rupture is where the tendon has completely separated from the calcaneus (heel bone). This can occur when either Paratenonitis and Tendinosis are not correctly treated and rehabilitated. Surgical intervention is the only solution for resolving a complete rupture of the Achilles Tendon (1).

Therapy for Achilles Injuries

Although more research needs to be conducted, there is good evidence to support the use of soft-tissue techniques in the treatment of Achilles Tendon injury (1,4,8,9).

Research has demonstrated that each case of Achilles Tendinopathy needs to be assessed and treated as a unique dysfunction specific to that individual. Certain cases only involve local structures while other cases involve a much larger kinetic chain. In MSR (Motion Specific Release) we use the terms Local Tensegrity and Global Tensegrity to denote issues limited to a localized area, or issues involving the larger kinetic chain. The concept of Tensegrity was first brought forward by Buckminster Fuller , and then expanded to the human body by Thomas Myers of Anatomy Trains.

The following two sections provide examples of possible structures involved in both local and global tensegrities. Which structures are addressed vary greatly based on the needs of each individual case.

Achilles Tendon Injury: Addressing Common Local Tensegrity Issues

Local Tensegrity applies to structures that are directly linked, or attached, to the Achilles Tendon. The connections can be myofascial, osseous, neurological, or vascular in nature. Affected local structures must be evaluated and treated for a successful resolution of the injury. Possible structures involved include:

Structure: Gastrocnemius and Soleus muscles

• Anatomical Significance: Co-joint structures that forms the Achilles Tendon (1).

• Achilles Tendon Relationship: Direct transference of tension into the Achilles tendon from the calf muscles (6,12).

Structure: Plantaris muscle

• Anatomical Significance: Inserts into medial aspect of Achilles tendon.

• Achilles Tendon Relationship: Weak plantar flexor that can mask orthopedic tests of Achilles Tendon (12). In addition, the plantaris muscle can refer pain into the medial Achilles Tendon.

Structure: Flexor Retinaculum

• Anatomical Significance: The tibial nerve innervates the triceps surae. The posterior tibial nerve passes through the tarsal tunnel of the ankle under the flexor retinaculum.

• Achilles Tendon Relationship: Thickening of the Flexor Retinaculum can cause compression on the posterior tibial nerve (Tarsal Tunnel Syndrome - TTS). Over-pronation can exacerbate both Achilles Tendinopathy and TTS.

Structure: Superior Fibular Retinaculum

• Anatomical Significance: Located between the Achilles Tendon and flexor hallucis longus (FHL) muscle (12).

• Achilles Tendon Relationship: Contributing factor in gait imbalances. FHL Tendinosis or Tenosynovitis (Dancers Tendonitis). Most common symptoms are posterior ankle or posterior-medial ankle pain. One of the common differential diagnosis’s for Dancers Tendonitis is Achilles Tendinopathy.

Structure: Tibialis Anterior

• Anatomical Significance: Gastrocnemius antagonist.

• Achilles Tendon Relationship: May affect triceps surae function through reciprocal inhibition. Triceps surae (from Latin meaning three heads) is the two-headed gastrocnemius and the soleus muscle (your calf muscles). Reciprocal inhibition is a neuromuscular reflex that inhibits opposing muscles.

Structure: Plantar Fascia

• Anatomical Significance: Direct fascial connection between the paratenon of the calcaneal tendon and the plantar fascia. Aging produces a decrease in the number of fibres linking the Achilles tendon to the plantar fascia (12).

• Achilles Tendon Relationship: Contributing factor in gait imbalances. Hyper-pronation is often related to Achilles Tendon pathology.

Structure: The subtalar joint

• Anatomical Significance: The gastrocnemius muscle crosses three joints – knee, ankle, and subtalar joints (1,2,8).

• Achilles Tendon Relationship: Alterations in the function of any of these joints will also have the immediate effect of increasing tension on the Achilles tendon.

Achilles Tendon Injury: Common Global Tensegrity Issues

Global Tensegrity refers to structures that are linked further out in the kinetic chain. They may impact, or even cause, the injury. Tension, restrictions, neurological compression or vascular changes within the Global Tensegrity may need to be addressed to achieve a full resolution of the injury. Possible structures include:

Structure: Hamstring muscles

• Anatomical Significance: Direct fascial connection into the Gastrocnemius muscles.

• Achilles Tendon Relationship: Tension in the hamstrings is transferred to the Gastrocnemius then directly into the Achilles Tendon (1). Note: There is a strong fascial band from semitendinosus to gastrocnemius muscle. Surgeons use this band for ACL reconstructive surgery (13).

Structure: Gluteus Maximus muscle

• Anatomical Significance: Primary hip extensor

• Achilles Tendon Relationship: Due to inhibition or delayed gluteus maximus activity, the hamstring muscles become dominant during hip extension, which can cause hamstring tension. Tension in the hamstrings easily cascades into the Gastrocnemius, and then the Achilles Tendon (1).

Structure: Gluteus Medius muscle

• Anatomical Significance: Primary hip abductor muscle. A weak gluteus medius is associated with an increased risk of lower extremity injury and gait imbalances (5). (+ Trendelenburg Gait)

• Achilles Tendon Relationship: A weak gluteus medius can lead to increased foot pronation. Increased foot pronation has been associated with an increased risk for Achilles Tendinopathy (5).

Structure: Adductor muscles

• Anatomical Significance: Antagonist of gluteus medius.

• Achilles Tendon Relationship: May decrease gluteus medius function, create pelvic instability, and cause gait imbalances, which then leads to increased foot pronation. This is initiated through reciprocal inhibition.

Structure: Iliopsoas muscle

• Anatomical Significance: Gluteus maximus antagonists.

• Achilles Tendon Relationship: May decrease gluteus maximus function through reciprocal inhibition.

Structure: Quadriceps muscle

• Anatomical Significance: Antagonist to hamstrings.

• Achilles Tendon Relationship: Tight restricted quadriceps cause tension in the hamstrings.

Structure: Hip, knee, ankle and subtalar joints.

• Anatomical Significance: Dysfunction in the hip affects the entire lower extremity, and can create gait imbalances. The gastrocnemius muscle crosses three joints – knee, ankle, and subtalar joints (1,2,8).

• Achilles Tendon Relationship: Alterations in the function of any of these joints will also have the immediate effect of increasing tension on the Achilles tendon.

RECOMMENDED FASCIAL BOOKS

Functional Atlas of the Human Fascial System - Carla Stecco https://amzn.to/3TE1EqP

Fascia: The Tensional Network of the Human Body https://amzn.to/3gQlUXB

Anatomy Trains - Thomas Myers Publications https://amzn.to/3Njsj9L

Fascia Stecco Publications - https://amzn.to/3FrWI3P

Fascia: The Tensional Network of the Human Body: The science and clinical applications in manual and movement therapy, 1e https://amzn.to/3SV2WN2

PHYSICAL EXAMINATION

The following videos demonstrate procedures that we commonly use in the examination of an Achilles injury.

Effective Ankle and Foot Examination

This video uses orthopaedic test to evaluate for some of the most common ankle and foot conditions we see in clinical practice. These conditions include: Ankle Sprains (inversion sprain), Cuboid Syndrome, Talar Dome Lesions, 5th Metatarsal Fracture, Syndesmosis damage, Achilles Tendon Tendinopathy, Morton's Neuroma, 2nd Metatarsal Stress Fracture, Plantar Fasciitis, and Bunions.

Lower Limb Neuro Examination

The lower limb neurological examination is part of the over all neurological examination process, and is used to assess the motor and sensory neurons which supply the lower limbs. This assessment helps to detect any impairment of the nervous system. It is used both as a screening and an investigative tool.

Peripheral Vascular Examination - Key Points

A peripheral vascular examination is a valuable tool used for ruling out signs of vascular-related pathology. The detection and subsequent treatment of PVD can potentially mitigate cardiovascular and cerebrovascular complications. In this video we go over some of the common procedures we perform in daily clinical practice. This video is available for the public on November 14/2022.

RECOMMENDED ORTHOPAEDIC REFERENCE BOOKS

Orthopaedic Physical Assessment – David J. Magee https://amzn.to/3zgu0za

Dutton'sOrthopaedic: Examination, Evaluation and Intervention, Fifth Edition https://amzn.to/3st1AOv

RELEASING RESTRICTIONS

It is essential to release any soft-tissue restrictions not just within the Achilles Tendon, but also the muscles, tendons, ligaments, and fascia. Conservative therapy can be very effective in achieving this. The following videos are examples of the type procedures we could use in cases of Achilles Tendon Injury to address both soft tissue and joint restrictions.

MSR Calf Muscle + Tom, Dick, and Harry Release: This video is about releasing both your superficial calf muscles (gastrocnemius and soleus) and the deeper muscles Tom, Dick, and Harry (TDH). Tom, Dick, and Harry stands for: T=Tibialis posterior, D=Flexor digitorum longus, an=posterior tibial artery and tibial nerve, and H=Flexor hallucis longus.

4 Point Dorsi Flexion Protocol - Motion Specific Release: Dorsiflexion is the movement at the ankle joint where the toes are brought closer to the shin. The muscles of the shins help your foot to clear the ground during the Swing Phase (concentric contraction) of your stride, and absorb much of the impact shock during running.

SR - 7 Point Ankle & Foot Mobilization: Improving joint mobility is critical if you are going to effectively address the body's full kinetic chain. In fact, we greatly reduce the effectiveness of any myofascial treatment if we don’t also address restrictions in joint mobility. The objective of joint mobilization is to reverse adverse physiological changes by promoting movement between capsular fibers.

RECOMMENDED REFERENCE BOOKS

Functional Anatomy: Anatomy, Kinesiology, and Palpation https://amzn.to/3f49Xgn

The Muscle and Bone Palpation Manual with Trigger Points, Referral Patterns and Stretching Joseph E. Muscolino – https://amzn.to/3SAh5Pl

Anatomy Trains: Myofascial Meridians for Manual Therapists https://amzn.to/3SCkhtZ

Joint mobilization/manipulation extremity and spinal techniques https://amzn.to/3DxqCCs

The Trigger Point Manual - https://amzn.to/3gFDDRu

Chinese Acupuncture and Moxibustion (4th Edition) - https://amzn.to/3TRDs3M

EXERCISES

Equally as important as soft-tissue therapy is the use of appropriate exercises. This is because there are some key physiological factors that you simply cannot get around.

One very important factor is the process of tissue remodelling. The tissues of the body remodel according to the forces that are placed upon them. Without the right combination of stretching, strengthening, and proprioceptive exercises, you cannot expect to obtain full resolution of an Achilles Tendinopathy.

The following exercise are examples of exercises that we may prescribe to our patient with an Achilles Tendinopathy. The specific exercises that we prescribe will vary from case to case.

Stretching Your Calf Muscles: Calf stretches for both your calf muscles the gastrocnemius and soleus. Only minor changes in technique can make a huge difference in increasing your calf flexibility.

Calf Muscle Release - Lacrosse Ball & Foam Roller - The gastrocnemius with the soleus, your calf muscles are the main plantar-flexors of the ankle joint. In addition the calf muscles are also powerful flexors of the knee joint.

Calf Strengthening - Eccentric Calf Raises & Pulsations: The Eccentric Calf Raise is a great way to increase calf strength, without causing further injuries. These dynamic calf-pulsations are ideal exercises for improving sports performance and power. This is an advanced exercise, so before attempting this exercise, make sure you can easily perform the standard Eccentric Calf Raises & Pulsations.

Improve Your Balance - Exercises for Beginners - Balance exercises are a fundamental aspect of training that should not be ignored in either Rehabilitation or Sports Performance training. Improve your balance with these simple exercises. Using our progression techniques you can ensure that you perform these exercises safely without increased risk of injury.

EQUIPMENT

Lacrosse balls at Amazon: https://amzn.to/3W1zE22

Yoga Blocks at Amazon: https://amzn.to/3zcjE3k

Yoga Mats at Amazon: https://amzn.to/3gzyfiO

DR. BRIAN ABELSON DC.

Dr. Abelson believes in running an Evidence Based Practice (EBP). EBP's strive to adhere to the best research evidence available, while combining their clinical expertise with the specific values of each patient.

Dr. Abelson is the developer of Motion Specific Release (MSR) Treatment Systems. His clinical practice in is located in Calgary, Alberta (Kinetic Health). He has recently authored his 10th publications which will be available later this year.

Make Your Appointment Today!

Make an appointment with our incredible team at Kinetic Health in NW Calgary, Alberta. Call Kinetic Health at 403-241-3772 to make an appointment today, or just click the MSR logo to right. We look forward to seeing you!

REFERENCES

1. Brian Abelson, Kamali Abelson, Release Your Pain: 2nd Edition Resolving Soft Tissue Injuries with Exercise and Active Release Techniques Rowan Tree Books Ltd.

2. Carlson, R.E., Fleming, L.L., Hutton, W.C., 2000. The biomechanical relationship between the tendoachilles, plantar fascia and metatarsophalangeal joint dorsiflexion angle. Foot Ankle Int. 21 (1), 18–25.

3. Cheng, H.Y., Lin, C.L., Wang, H.W., Chou, S.W., 2008. Finite element analysis of the plantar fascia under stretch: The relative contribution of windlass mechanism and Achilles tendon force. J. Biomech. 41 (9), 1937–1944.

4. Epidemiology and Outcomes of Achilles Tendon Ruptures in the National Football League. Foot & Ankle Specialist, 2009; 2 (6): 283 DOI: 10.1177/1938640009351138

5. Friel K, McLean N, Myers C, Caceres M. Ipsilateral hip abductor weakness after inversion ankle sprain. J Athl Train. 2006;41:74-78.

6. Milz, S., Rufai, A., Buettner, A., Putz, R., Ralphs, J.R., Benjamin, M., 2002. Three-dimensional reconstructions of the Achilles tendon insertion in man. J. Anat. 200 (Pt 2), 145–152.

7. O’Sullivan, K. Electromyographic analysis of the three subdivisions of gluteus medius during weight-bearing exercises. 2010. 2(17).

8. Shirley Sahrmann, Diagnosis and treatment of movement impairment syndromes, Mosby, 2002.

9. Silbernagel KG, Thomeé R, Eriksson BI, Karlsson J. Continued sports activity using a pain monitoring model during rehabilitation in patients with Achilles tendinopathy. Am J Sports Med. 2007;35(6):897‐905.

10. Snow, S.W., Bohne, W.H., DiCarlo, E., Chang, V.K., 1995. Anatomy of the Achilles tendon and plantar fascia in relation to the calcaneus in various age groups. Foot Ankle Int. 16 (7), 418–421.

11. Stecco, C., Corradin, M., Macchi, V., et al., 2013. Plantar fascia anatomy and its relationship with Achilles tendon and paratenon. J. Anat. 223 (6), 665–676.Six

12. Stecco, Carla; Stecco, Carla. Functional Atlas of the Human Fascial System E-Book (Page 350). Elsevier Health Sciences. Kindle Edition.

13. Uzun,Tuncay, Kucuker, Karalezli The fascial band from semitendinosus to gastrocnemius: the critical point of hamstring harvesting Acta Orthopaedica 2007; 78 (3): 361–363

14. McGill S. Low Back Disorders: Evidence-Based Prevention and Rehabilitation. Champaign, IL:Human Kinetics Publishing 2002:102.

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