Tendon Pain Is a Signal, Not Just a Symptom: What Causes It and When Physio Helps

⚠ Clinical Note

This article is for educational purposes only. It is based on current clinical practice guidelines and peer-reviewed research and is not a substitute for personalised medical advice, diagnosis, or treatment. If you are experiencing severe, sudden, or rapidly worsening symptoms - or symptoms described in this article as urgent - seek immediate medical attention. For all other concerns, consult a qualified healthcare professional before starting any exercise or treatment program.

Key Facts

✔ Achilles tendinopathy affects 4–7% of the general population; runners face a 40–52% cumulative lifetime incidence of the condition. [1]
✔ Progressive tendon loading exercise is the Grade A first-line treatment for both Achilles and rotator cuff tendinopathy - complete rest is not recommended and may slow recovery. [1,2]
✔ Imaging is not required to diagnose tendinopathy, and clinical guidelines advise against it as the initial investigation; structural changes on a scan do not reliably predict how much pain a person experiences. [2,3]
✔ Inflammatory markers are elevated in tendinopathic tissue in the majority of studies that have measured them - the widespread belief that tendinopathy lacks inflammation is not supported by systematic review evidence. [4]
✔ Systemic factors including type 2 diabetes, postmenopausal hormonal changes, and dyslipidaemia lower the mechanical load threshold of tendons, making some people significantly more vulnerable even without unusual mechanical demand. [5]
✔ For lower-limb tendinopathies, pain up to 5/10 during loading exercise may be acceptable; symptoms should settle within a few hours and should not progressively worsen. [6,7]

30-Second Summary

Tendons become painful when repeated mechanical load exceeds their adaptive capacity - a process that involves structural changes, inflammation, and neurogenic sensitisation of nerves that grow into the tendon substance. [3,4,9] The key to management is progressive loading, not rest, carried out within a pain monitoring framework that uses pain level and next-morning stiffness as practical feedback signals. [1,6,7] Recovery varies between individuals and can be influenced by biological, functional, psychosocial, and broader health factors. [1,5]

Introduction

People with tendon pain often wonder whether they should stop activity altogether. The answer is not always intuitive, particularly when symptoms change with work, exercise, or daily movement. This article explains what the supplied research and guidelines say about tendon pain and load.

Understanding tendinopathy from structural, biological, and neurological perspectives can help make sense of confusing symptoms. This article covers the biology of tendon pain, systemic and mechanical contributors, and the recommendations in the supplied guidelines. It also explains where advice must be tailored to the tendon location and the individual presentation.

What Is Tendinopathy?

A tendon connects muscle to bone and transfers force under repeated loading. When load accumulates faster than the tendon can adapt, the repair process can gradually break down. [6,8]

That breakdown follows a three-stage progression. In the reactive stage, the tendon responds to an abrupt load increase with a cellular thickening that is largely reversible if load is managed promptly. If load continues to exceed capacity, the dysrepair stage follows: collagen fibres become disorganised, proteoglycans accumulate between them, and the tendon loses structural integrity without yet showing irreversible damage. The degenerative stage involves established areas of structural failure - disorganised collagen, new blood vessel ingrowth, and cell death in parts of the tendon - though the surrounding healthy tissue can still adapt positively with the right stimulus. [6,8]

The shift in terminology from "tendinitis" to "tendinopathy" reflected a recognition that this is more than acute inflammation. That recognition was correct in what it highlighted, but it also produced an overcorrection that the research has since challenged. A systematic review of 53 studies across 2,306 tendinopathic tendon specimens found signs of inflammation in 39 studies, including inflammatory cells or increased inflammatory markers. [4] The review challenges the belief that tendinopathy is uniformly non-inflammatory.

What the initial focus on inflammation didn't account for is a distinct neurogenic dimension. A healthy tendon has no nerve supply within its substance - nerves run in the outer sheath only. In chronically painful tendons, nerve fibres sprout inward, and the pain-sensing receptors on those fibres become sensitised: a key glutamate receptor (NMDAR1) is upregulated approximately nine-fold in painful tendons compared with non-painful ones. [3]

Structural damage and pain severity do not always correlate closely in chronic presentations. [3] Neurogenic changes have been identified across multiple tendon sites. [9] For readers whose pain is at the elbow or wrist, elbow and wrist pain: what's driving it covers how these mechanisms present in that region.

Why Do Tendons Become Painful?

Common mechanical contributors include a rapid increase in training volume, a return to sport after time away, or sustained repetitive work without adequate recovery. Repetitive loading can contribute to tendon micro-injury and degenerative change. [8]

But not everyone who overloads a tendon develops tendinopathy, and some people develop it with what appears to be modest load. The threshold at which a tendon fails is shaped significantly by systemic health. A 2026 review in the Journal of Orthopaedic Surgery and Research identified four pathogenic axes through which systemic factors reduce tendon resilience. [5] Advanced glycation end-products - which accumulate when blood glucose is poorly controlled - irreversibly cross-link collagen fibres, reducing the tendon's mechanical load capacity. [5] Postmenopausal oestrogen decline is associated with a 48% higher incidence of rotator cuff tendon injury compared with women without oestrogen deficiency, reflecting oestrogen's role in maintaining tendon matrix. [5]

Dyslipidaemia alters tenocyte metabolism and matrix composition. The accumulation of senescent cells with age generates a chronic pro-inflammatory local environment through senescence-associated secretory signalling, compounding mechanical vulnerability. Taken together, these systemic factors lower the load threshold - the same external demand that a metabolically healthy tendon handles well can be enough to overload one that is metabolically or hormonally compromised. [5]

This is an illustrative case. Consider a woman in her 50s who began a daily 5-kilometre walking programme after a health check revealed early elevated cholesterol. Within six weeks she developed Achilles pain. Her load was not unusual by any standard training measure, but postmenopausal oestrogen decline and dyslipidaemia had likely already lowered her tendon's load threshold - making a modest, new load sufficient to exceed it. [5]

Other contributing factors include fluoroquinolone antibiotics such as ciprofloxacin, which directly impair tenocyte function and substantially increase the risk of tendinopathy and rupture. Repeated corticosteroid injections weaken tendon structure over time and are not an appropriate long-term management strategy. [8]

What Does Tendon Pain Feel Like?

The most recognisable feature of tendinopathy is its loading pattern. Pain or stiffness is typically worst in the first few minutes of activity - morning stiffness that eases with gentle movement - and often returns after sustained loading or the following morning. [6,7]

The pain is localised. It concentrates at a specific, palpable point along the tendon rather than across a diffuse region, and is provoked by activities that load that tendon. [1,2,6] The push-off phase of walking or running for the Achilles, stair descent for the patellar tendon, overhead movement for the rotator cuff, and gripping and wrist extension for the lateral elbow are examples of tendon-specific loading demands. [1,2,6]

For Achilles tendinopathy, where morning stiffness and pain with heel raises are characteristic, Achilles tendon pain causes and symptoms covers the full clinical picture for that tendon in detail. [1]

Certain features are not typical of tendinopathy and require clinical assessment: constant pain at rest, pain that wakes a person from sleep, marked swelling or warmth over the tendon, or a sudden, complete loss of function. These may point to other pathology - including tendon rupture, inflammatory arthropathy, or infection - and should not be managed as routine tendinopathy. [1,2]

Treatment Options

The consistent conclusion across clinical practice guidelines for multiple tendon sites is that progressive loading exercise is the first-line treatment. For Achilles tendinopathy, the 2024 JOSPT Clinical Practice Guideline gives a Grade A recommendation to tendon loading exercise as first-line treatment. [1] This includes eccentric, concentric, isometric, and plyometric variations, selected according to the stage and current irritability of the tendon. For rotator cuff tendinopathy, the 2025 JOSPT guideline gives a Grade A recommendation to active rehabilitation combining motor control training and progressive resistance exercise as the initial approach. [2]

Loading can follow a staged progression. Isometric and isotonic strengthening, energy-storage work, and return-to-activity loading are among the approaches described in the clinical-reasoning literature. [6,7] The starting point and rate of progression should follow the tendon’s symptom response rather than a fixed timeline. [1,6]

The pain monitoring framework helps guide how much load is appropriate at each session. For lower-limb tendinopathies, pain up to 5/10 during and after training may be acceptable; symptoms should settle within a few hours and should not progressively worsen over the programme. [6,7] This approach makes it possible to load the tendon progressively without waiting for it to be completely symptom-free. [6]

The evidence on what does not work is also worth stating directly. Complete rest is not indicated - it removes the stimulus for tendon adaptation and results in deconditioning without addressing the underlying problem. [1,6] Corticosteroid injections offer short-term symptom relief but are not superior to exercise at medium-term follow-up. [2] For rotator cuff tendinopathy specifically, subacromial decompression surgery provides no clinically meaningful benefit over sham surgery in well-powered trials. [2]

RHECORE’s Pain & Injury Management programme is designed with reference to the general principles outlined in the guideline cited below and does not guarantee any specific clinical outcome. Both guidelines also include education about load management and the pain monitoring framework. [1,2] Understanding why the tendon responds to load the way it does is a therapeutic component of education alongside exercise-based care. [1,2]

Self-Management

The most immediately useful action for tendon pain is modifying load rather than eliminating it. Continuing activity within a comfortable range keeps the tendon engaged and prevents the deconditioning that comes with complete rest. For lower-limb tendinopathies, the 5/10 pain guide and symptom response described in the Treatment section can help monitor loading; other tendon sites need an individualised approach. [6,7]

When the tendon is acutely irritable, isometric loading may form part of a symptom-guided programme. The specific exercise and dose should be selected for the affected tendon and presentation rather than copied from a general article. [6,7]

If systemic factors are present, attending to them is part of the rehabilitation picture. For people with type 2 diabetes, the review suggests that exercise supporting glycaemic control may reduce the harmful effects of advanced glycation end-products on tendon health. [5] For people with elevated adiposity or dyslipidaemia, the metabolic dimension of tendon vulnerability is worth discussing with a GP alongside the physical rehabilitation plan. [5]

Ice may provide short-term comfort, but it should not substitute for load management as the primary strategy. [7,8]

When to See a Physiotherapist

Tendon pain that limits usual activity or does not improve with sensible load modification warrants clinical assessment. [1,2] A physiotherapist can assess the presentation, contributing load patterns and biomechanics, identify systemic factors that may require a broader approach, and design a loading programme appropriate for that specific tendon and presentation. [1,2]

Some presentations need more prompt attention. A sudden, complete loss of function in the affected area may indicate tendon rupture rather than tendinopathy and warrants prompt medical assessment. [8] Constant pain at rest unrelated to activity levels, or significant visible swelling and warmth over the tendon, also warrant assessment without delay.

Pain emerging during or shortly after a course of fluoroquinolone antibiotics is also worth raising with a clinician. [1,8]

Key Takeaways

• Tendon pain involves inflammation and neurogenic sensitisation of nerve fibres that grow into the tendon substance - not just structural damage, which explains why scan findings do not always predict how much pain a person has. [3,4,9]
• Progressive loading, not rest, is the primary treatment; for lower-limb tendinopathies, a pain-monitoring framework can help guide progression. [1,6,7]
• Systemic factors - including diabetes, postmenopausal hormonal changes, and age-related cellular changes - can lower the tendon's load threshold and are worth identifying alongside the mechanical assessment. [5]
• Recovery varies between people and is influenced by biological, functional, psychosocial, and broader health factors. [1,5]
• For rotator cuff tendinopathy, subacromial decompression surgery does not provide clinically important benefits compared with placebo surgery in the guideline evidence base. [2]

References

1. Merry K, de Vos RJ, van der Vlist AC, et al. Achilles pain, stiffness, and muscle power deficits: midportion Achilles tendinopathy revision – 2024. *Journal of Orthopaedic & Sports Physical Therapy.* 2024.
2. Desmeules F, Roy J-S, MacDermid JC, et al. Rotator cuff tendinopathy diagnosis, nonsurgical medical care and rehabilitation: a clinical practice guideline. *Journal of Orthopaedic & Sports Physical Therapy.* 2025.
3. Spang C, Alfredson H, et al. Tendon pain – what are the mechanisms behind it? *Scandinavian Journal of Medicine & Science in Sports.* 2022.
4. Millar NL, Murrell GAC, McInnes IB. A systematic review of inflammatory cells and markers in human tendinopathy. *BMC Musculoskeletal Disorders.* 2020.
5. Lin Y, Liu Z, Peng L, et al. Beyond local injury: pathogenic roles of metabolic, endocrine, and aging-associated systemic factors in tendinopathy and novel therapeutic strategies. *Journal of Orthopaedic Surgery and Research.* 2026;21:297.
6. Cook JL, Purdam CR. Tendinopathy: evidence-informed physical therapy clinical reasoning. *Journal of Orthopaedic & Sports Physical Therapy.* 2015;45(11):816–818.
7. Malliaras P, Cook JL, et al. Tendinopathy – Sport Health feature. *Sport Health* (Sports Medicine Australia). 2014.
8. Docheva D, Müller SA, Majewski M, et al. Spectrum of tendon pathologies: triggers, trails and end-state. *International Journal of Molecular Sciences.* 2020;21(3):844.
9. Spang C, Backman LJ, et al. Is neurogenic inflammation involved in tendinopathy? A systematic review. *BMJ Open Sport & Exercise Medicine.* 2023;9(1):e001494.