The achillies tendon is formed in two separate mechanisms. The first is the converging of the gastrocnemius and soleus aponeurosis 12cm above the calcaneal insertion. The Second is the with gastrocnemius aponeurosis inserting directly into the soleus aponeurosis. The achillies tendon has a round shape proximately, however flatten in the distal 4cm before insertion. The fibers of the tendon spiral approximately 90deg to allow for maximal elongation and energy storage release on propulsion.
The tendon is enveloped in a para-tendon consisting of two layers which originate from the deep fascia of the leg.
Tendons are stiff, resilient, high tensile strength incorporating anatomical structures which can stretch up to 4% before damage may occur. A number of theories resonate with the development of achillies tendon injury, the most prominent being overuse stress, however, other theories include; poor vascularity, poor flexibility, gender, genetics, metabolic factors and endocrine factors.
Achillies tendinopathy is a common degenerative injury among athletes who are involved in a lot of running. Development of the condition can occur due to a number of issues including; muscle power and tendon elasticity imbalance, a sudden increase in training intensity or duration and inadequate warm up or stretching before the completion of an explosive activity (B). Achillies tendinopathy in middle-long distance runners compared to both white collar and blue collar workers has been found to be statistically significant p <0.001 (Kujala, Sarna, & Kaprio, 2005).
The morphology of healthy tendons has been shown to be of different make-up in a normal tendon, however appears to be indistinguishable when pathology is present within the tendon.
When trying to best diagnose a suspect achillies tendinopathy, a full history should be received covering past treatment, medication, medical conditions, training patterns, past training patterns and footwear use. Palpation of the achillies tendon at insertion mid portion, origin and surrounding tissues should be complete and in many circumstances the use of US or MRI may be appropriate to confirm the diagnosis.
It is suspected that tendon degeneration begins long before symptoms begin and may even remain asymptomatic in some cases. Early diagnosis is of practical relevance particularly in high performance sport. Despite popular belief (Hirschmuller, et al., 2012)found there to be no significant link between gender and achillies tendinopathy development.
Cook and Purdam, 2010 , has described tendinopathy to be on a continuum which incorporates 3 inter-weaving stages and suggests that each may be required to be managed differently depending where on the continuum the pathology resides.
Reactive Tendinopathy: Is a non-inflammatory response to compressive or acute tensile forces which develops a thickening and therefore increased cross section of the tendon, usually due a sudden increase in activity which an individual may not be used too. There is no change in the vascularity of the tendon matrix and collagen is mostly maintained at this point.
Tendon Disrepair: Is seen as a tendon which will make an attempt to repair, as seen in the reactive tendon but suffers from increase matrix breakdown and collagen separation. The placement of this within the spectrum will generally be associated with high intensity or repetitive load over a long duration. It is still somewhat possible to reverse anatomical and physiological changes at this point.
Tendon Degeneration: Is clearly identified by changes to the matrix and cells within the tendon. The ability of the tendon to reverse any possible pathology has diminished and some cell apoptosis has occurred. Through imaging these is visualization of extensive changes around the area of concern.
When clinically managing a patient it is important to address their expectations of performance and return to sport by supplying them with a modified and sensible training plan or referring them to someone who may be able to develop a program like this for them. The activity which is believed to have instigated the problem should be ceased in the acute stages so that collagen fibers can repair and rehabilitation activities involving loading the achillies can begin to stimulate the remodeling process.
(Kader, Saxena, Movin, & Maffull, 2002) found that an eccentric loading program had a statistically significant outcome in the rehabilitation of the achillies tendon, over that of a concentric loading program. When looked at from a sport specific point of view concentric based training is the primary educated tool for most training program outside of rehabilitation and therefore the eccentric stage of movement are neglected hence we can revisit that debate of imbalance in power of the muscles vs elasticity of the tendon and ability to absorb heavy load under stress.

The achillies tendon, differentiating from other tendons, has been shown to respond to loading regimes which target the specific demands of the mid or insertional aspects of the tendon. The loads are required to be of significant stressors for the area of pathology and encourage the development of strength due to the nature of achillies tendinopathy being cause mostly via inadequate rest from repetitive load over a long duration.
The use of a 12-15mm heel raise (inclusive of heel drop of shoe) has been found to be clinically significant, however, has not been found to be evidently substantial as an offloading mechanism. The use of cryotherapy aims to reduce the metabolic rate of the achillies tendon, decreasing extravasation of blood and protein from new capillaries found in the tendon as well as producing an analgesic effect.
It is suggested that surgical intervention or opinion be sort after 6months of non-effective conservative treatment, however it should also be mentioned that poor outcomes are regularly seen for those patients with long standing issues, therefore to manage the risk of undertreating a patient it may be worth referring them for surgical opinion much earlier.
Furthermore, adequate dorsiflexion range of motion is essential during gait (both walking and running), walking stairs and as part of landing mechanics. Dorsiflexion during landing activities of specific sports is required for the absorption and dissipation of the high Ground Reaction Forces encounted upon ground contact. If dorsiflexion range of motion is inadequate, it can be inferred that increased loading of the plantarflexor complex. Ankle injuries account for approximately 20-30% of all sporting injuries, this is inclusive of any soft tissue which crosses the ankle joint ala achillies tendon. Inadequate dorsiflexion has been noted to increase the risk of ankle joint sprain, fractures or musculoskeletal injuries during sport.

Jackson McCosker
Director /Chief Editor

Bibliography
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Hirschmuller, A., Frey, L., Konstantindis, H., Baur, H., Dickhuth, N., Sudkamp, P., & Helwig, P. (2012). Prognostic Valus of Achillies Tendon Doppler Sonography in Asymptomatic Runners. American College of Sports Medicine, 199 – 205.

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Kujala, U., Sarna, S., & Kaprio, J. (2005). Cumulative Incidence of Achillies Tendon Rupture and Tendinopathy in Male Former Elite Runners. Clinical Journal of Sports Medicine, 133 – 134.

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Maffuli, N., Kenward, M., Testa, V., Capasso, G., Regine, R., & King, J. (2001). Clinical Diagnosis of Achillies Tendinopathy with Tendinosis. Clinical Journal of Sports Medicine, 11 – 15.

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