Does your chronic tendon pain seem relentless and unyielding, refusing to fade away? Is the prolonged healing process causing despair and disruption? Tendon injuries are an excruciating burden, often leading to a protracted recovery journey.
Exploring the Tendon Terrain
Tendons are the critical facilitators of movement, serving as the bridge between muscles and bones. These hardworking structures transfer the force generated by our muscles, helping us experience the bounce, elasticity, and dynamism that underlie all movement. Think of them as the tyres on a car — they don't generate power but efficiently transfer it to initiate motion.
Tendons are essentially composed of cells called tenoblasts and tenocytes, enveloped by an extracellular matrix. The extracellular matrix consists of collagen and elastin fibres. Collagen provides strength and rigidity; elastin provides the necessary elasticity and recoil for dynamic movement. Despite their crucial role, tendons are delicate structures — they lack abundant blood vessels, making them prone to inflammation and poor healing.
Understanding Tendon Injury Types
Reactive Tendinopathy occurs as a reaction to a sudden increase in activity load. The tendon cannot manage this increase effectively, leading to inflammation and pain. Pain most often arises 2–4 weeks after an activity escalation.
Dysrepair Tendinopathy commonly develops between 6 and 12 weeks of unregulated loading of a painful tendon. Pain and stiffness will ease initially with exercise but worsen as you continue. The Achilles will take longer to warm up after rest.
Degenerative Tendinopathy occurs when the condition has been mismanaged for 3–6 months. All activities cause pain, including standing and walking. If not well managed, the tendon may tear or rupture.
The Healing Mechanism of Tendons
The healing process involves three overlapping stages. Initially, inflammation takes the lead — initiating tissue clean-up and regeneration. It is important to note that re-aggravating the injury restarts this process. The proliferation phase follows, with an increase in tenocytes at the injury site. The final maturation stage involves remodelling of the new tissue — this phase can last weeks to months.
Why Tendons Take So Long
One of the main reasons tendon injuries are slow to heal is their poor blood supply, depriving them of the nutrients and oxygen needed for swift recovery. Unregulated overload and repeated stress exacerbate the injury, causing chronic inflammation and triggering a persistent pain cycle.
The body's attempt at healing — neovascularisation (growth of new blood vessels) — can be a double-edged sword. While it increases nutrient and oxygen delivery, it can lead to overgrowth of blood vessels and nerves into the tendon substance, increasing sensitivity and contributing to pain rather than resolving it.
Most importantly, improper management and repeated overuse — continuing to train through pain without adequate recovery — can exacerbate the injury, inflating the inflammation and preventing the healing phases from completing. These factors push the body into a chronic state of injury.
Exercise Types for Tendon Rehabilitation
Isometric exercises (sustained holds like calf raise holds) involve maintaining muscle tension without movement. This controlled strain force prompts the tendon to recondition at a tolerable load and has been shown to reduce tendon pain acutely.
Eccentric exercises (slowly lowering from a calf raise) place greater strain on the tissue, prompting it to recondition to a greater degree. These are generally recommended after isometric exercises are tolerable.
Plyometric exercises (jumping, hopping) are employed during the maturation phase to build tolerance and create a shield against future injury.
References:
Cook, J. L., & Purdam, C. R. (2009). Is tendon pathology a continuum? British Journal of Sports Medicine.
Alfredson, H., et al. (1998). Heavy-load eccentric calf muscle training for chronic Achilles tendinosis. American Journal of Sports Medicine.
Rio, E., et al. (2015). Isometric exercise for patellar tendinopathy. British Journal of Sports Medicine.
From Pain to Performance — The Orthopaedic Sleeve Society (TOSS)