Tendinopathy 101: From Tendonitis to Tendinosis

Tendinopathy is one of the most misunderstood and mistreated soft tissue issues in both athletic and general populations. While it’s often casually referred to as “tendonitis,” the deeper science tells a more complex—and critical—story. To treat it properly and prevent recurrence, we need to understand the pathology, not just the pain.

What is Tendinopathy?

The term tendinopathy is a broad umbrella that refers to any disease or dysfunction of a tendon. It encompasses two main categories:

  • Tendonitis – an acute inflammatory condition
  • Tendinosis – a chronic degenerative condition without inflammation

Historically, most tendon pain was labelled “tendonitis,” implying that inflammation was the root cause. But research over the past two decades has shown that most chronic tendon injuries lack inflammatory cells and instead exhibit signs of collagen disorganisation, vascular growth (neovascularization), and cellular disruption. That’s where the term “tendinosis” comes in—and why proper diagnosis matters.

The Difference: Tendonitis vs. Tendinosis

Tendonitis is an acute condition, usually lasting days to a few weeks. It typically occurs after a sudden increase in load or repetitive movement—especially in untrained tissues. Inflammation, pain, and swelling are present.

Tendinosis is the result of chronic overload over weeks, months, or even years. It’s a degenerative condition where the tendon’s structure deteriorates: collagen fibers fray, matrix proteins break down, and the tendon becomes less elastic and more painful under tension.

Key differences:

  • Inflammation: Present in tendonitis, absent in tendinosis
  • Time course: Acute vs. chronic
  • Cellular changes: Tendinosis shows disorganized collagen and vascular disruption
  • Treatment: Anti-inflammatory strategies vs. progressive loading and remodeling

How Tendinopathy Develops

Tendons are designed to handle tensile loads, transmitting muscular force to bones efficiently. However, they adapt slowly compared to muscles. When loading exceeds the tendon’s capacity—without adequate time for adaptation—microtrauma accumulates. This disrupts the extracellular matrix and begins the degenerative cycle.

Contributing factors include:

  • Sudden increase in training volume or intensity
  • Poor biomechanics and movement patterns
  • Inadequate recovery or sleep
  • Weak kinetic chain or poor eccentric control
  • Underlying systemic inflammation or metabolic dysfunction

Why This Matters for Coaches and Clients

Many people misdiagnose or mismanage tendon pain, defaulting to rest or ice—or worse, cortisone injections that offer short-term relief but long-term damage. As a coach, understanding tendinopathy helps guide clients through safe and evidence-based strategies that actually heal tissue, not just reduce symptoms.

Rehab and Training Principles

The gold standard for tendinosis treatment is progressive mechanical loading. Rest is rarely the answer. Instead, load modification and structured progression are key.

Evidence-based stages of rehab include:

  1. Isometric loading: Used early to reduce pain and activate the tendon with minimal strain
  2. Slow concentric-eccentric loading: Improves tendon strength and structure
  3. Heavy slow resistance (HSR): Builds tensile strength and improves collagen remodeling
  4. Plyometric or sport-specific reintroduction: Only after the tendon can handle load

Supporting strategies also include:

  • Improving mobility and alignment in related joints (e.g. hip stability in patellar tendinopathy)
  • Targeting eccentric strength deficits in both the muscle-tendon unit and the kinetic chain
  • Correcting energy system deficits that affect tendon recovery (e.g. aerobic base)

Nutrition, Sleep, and Systemic Recovery

Recovery from tendinopathy isn’t just mechanical. Nutritional and systemic support is crucial:

  • Vitamin C for collagen synthesis
  • Gelatin + Vitamin C pre-loading before rehab training
  • Anti-inflammatory diets (omega-3s, curcumin) to reduce systemic stress
  • Sleep as the most powerful tissue recovery tool

Without these elements, mechanical loading alone won’t resolve deeper dysfunctions.

When to Refer Out

Chronic tendinopathy may require imaging (ultrasound, MRI) or collaboration with a physiotherapist, sports physician, or orthopedic specialist. Red flags include:

  • Night pain or constant pain not related to load
  • Rapid worsening despite proper rehab
  • Suspected rupture or full-thickness tear

Treat the Tendon, Not Just the Pain

Tendinopathy is more than “just tendonitis.” It’s a spectrum of tendon pathology that requires intelligent, patient, and progressive intervention. As a coach or athlete, your job isn’t to chase soreness or avoid pain—it’s to build tissue that lasts. That starts with education, load literacy, and lifestyle integration.

Train smart. Recover smarter. And remember—the goal is not just less pain, but more function.

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