Understanding the Alfredson Protocol: The Science and Benefits of Eccentric Training

Eccentric heel drops — the cornerstone of the Alfredson Protocol for Achilles tendinopathy rehabilitation.

Introduction

Few injuries test an athlete’s patience quite like tendinopathy. Unlike a dramatic broken bone or a stress fracture — injuries with clear timelines and well-understood surgical solutions — tendon disorders are slow, stubborn, and maddeningly persistent. They creep in gradually, progressing from a mild morning stiffness to a deep, burning ache that refuses to subside.

For runners, basketball players, volleyball athletes, and weekend warriors alike, chronic achilles tendinopathy can mean months of frustration, failed treatments, and the looming threat of surgical intervention.

Yet in the late 1990s, a Swedish orthopedic surgeon named Dr. Håkan Alfredson introduced a deceptively simple treatment approach that would go on to reshape how the medical world thinks about tendon rehabilitation. Working at the University of Umeå in Sweden, Dr. Alfredson developed an eccentric calf-lowering exercise protocol — now universally known as the Alfredson Protocol — that challenged the conventional wisdom of rest-based tendon management. His landmark 1998 study demonstrated that patients who performed a structured program of painful eccentric heel drops experienced dramatic improvements in function, pain reduction, and return to activity, often avoiding surgery entirely.

In this article, we will explore the Alfredson Protocol in depth: what it entails, the science of eccentric muscle contraction, the biological mechanisms that make it effective, its benefits beyond Achilles tendinopathy, how it compares to other treatments, and practical guidance for those considering the program.

What Is the Alfredson Protocol?

The Alfredson Protocol is a structured, high-volume eccentric loading program originally designed for midportion achilles tendinopathy — the most common location for chronic tendon pain, occurring in the body of the tendon approximately 2 to 6 cm (1-3 inches) above its insertion at the calcaneus (heel of foot). The protocol is built around one principal exercise: the eccentric heel drop.

The program calls for a total of 180 eccentric heel drops per day, divided into two variations:

• Straight-knee heel drops: 3 sets of 15 repetitions — targeting the gastrocnemius muscle (the larger, more superficial calf muscle).
  
• Bent-knee heel drops: 3 sets of 15 repetitions — targeting the soleus muscle (the deeper calf muscle that crosses only the ankle joint).
  

Both variations are performed twice daily (morning and evening), yielding the protocol’s signature 180-repetition daily volume. The exercise is performed on the edge of a step or raised platform: the patient rises onto the toes of both feet, shifts weight to the affected leg, and then slowly lowers the heel below the level of the step over a count of approximately three to five seconds. The concentric (upward) phase is performed using the non-affected leg to return to the start position, ensuring the affected tendon is loaded only eccentrically.

The original program spans 12 weeks, though many clinicians and researchers now acknowledge that benefits can continue to accrue well beyond this time frame. One of the protocol’s most distinctive — and initially controversial — features is the instruction to exercise into discomfort. Patients are told to continue performing the heel drops even when they experience mild to moderate pain during the movement. Only severe or disabling pain is considered grounds for stopping. This “loading into pain” philosophy was a radical departure from the prevailing approach of rest and activity avoidance that dominated tendon management at the time.

Key Protocol Summary Exercise: Eccentric heel drops off a step edge Volume: 3 × 15 reps (straight knee) + 3 × 15 reps (bent knee), twice daily = 180 reps/day Duration: 12 weeks minimum (Anderson Performance has the way to decrease this to under a few weeks) Pain rule: Continue through mild-to-moderate discomfort; stop only for severe pain Progression: Add external load (weighted backpack) when body-weight repetitions become pain-free

Understanding Eccentric Training

To appreciate why the Alfredson Protocol works, it is essential to understand the mechanics of eccentric muscle contraction and how it differs from the other two primary types of muscle action.

All skeletal muscle contractions fall into three categories:

• Concentric contraction: The muscle shortens while generating force. Example: the upward phase of a bicep curl, when the bicep contracts to lift the weight.
  
• Isometric contraction: The muscle generates force without changing length. Example: holding a weight motionless at a fixed angle.
  
• Eccentric contraction: The muscle lengthens while generating force, effectively acting as a brake against an external load. Example: the lowering phase of a bicep curl, or — critically — lowering the heel below a step against the pull of gravity.
  

Eccentric contractions are biomechanically unique for several reasons. During an eccentric action, the muscle can produce 20–60% more force per motor unit compared to a concentric contraction at the same velocity. This is because the elastic properties of the muscle-tendon unit contribute to force production as the cross-bridges within the sarcomeres are mechanically stretched. Fewer motor units need to be recruited to produce a given level of force, making eccentric loading highly efficient from a neuromuscular standpoint — and also capable of imposing very high mechanical loads on the tendon itself.

This high-load, controlled-lengthening stimulus is precisely what gives eccentric training its therapeutic power in tendinopathy. Tendons are viscoelastic structures composed primarily of Type I collagen fibers arranged in parallel bundles. They remodel and adapt in response to mechanical loading — a principle known as mechanotransduction.

Eccentric loading, by virtue of the large tensile forces it applies along the tendon’s longitudinal axis, provides a potent stimulus for collagen remodeling, fiber realignment, and improved tensile strength at the cellular level. In essence, eccentric training tells the tendon to rebuild itself in a stronger, more organized configuration.

The Science Behind the Benefits

The clinical effectiveness of the Alfredson Protocol is supported by over two decades of research. Several interconnected biological mechanisms explain why eccentric loading is so effective for chronic tendinopathy.

Tendon Remodeling and Collagen Synthesis

Chronic tendinopathy is characterized not by inflammation in the traditional sense, but by a healing response limited by muscle activation and force absorption. Histological studies reveal disorganized collagen architecture, increased ground substance (proteoglycans and glycosaminoglycans), and a shift from strong, organized Type I collagen toward weaker Type III collagen. Reactivating and re-stimulating via direct current and eccentric loading has been shown to reverse this process by stimulating fibroblast activity and promoting the production of Type I collagen. Over weeks and months, this leads to more organized fiber alignment, increased cross-linking between collagen fibrils, and improved structural integrity of the tendon.

Neovascularization Disruption

A symptom, not a problem. One of the theories for why chronic tendinopathy is painful relates to neovascularization — the abnormal ingrowth of new blood vessels (and their accompanying nerve fibers) into the damaged tendon. These neo-vessels, visible on color Doppler ultrasound, are associated (correlated) with increased pain signaling. At Anderson Peformance we further deliniate the story by suggesting that the neovascularization is not the CAUSE but rather a symptom of the continued dysfunction.

Research has demonstrated that eccentric loading may help disrupt these abnormal vascular and neural structures, reducing the source of pain. Studies using ultrasound imaging have shown a measurable reduction in neovascularization following 12-week eccentric protocols. While many people interpret this as eccentric reversing the condition, rather we believe that when the tendon no longer needs additional blood flow and nerve function, it reverses itself.

Neuromuscular Adaptation

Eccentric training doesn’t just change the tendon — it retrains the neuromuscular system. Chronic tendinopathy is associated with altered motor control, reduced proprioception, and compensatory movement patterns that can perpetuate the problem.

Eccentric exercises improve the coordination of the muscle-tendon unit, enhance proprioceptive feedback, and restore normal force-absorption mechanics. This improved neuromuscular control helps protect against re-injury and improve functional performance.

Pain Modulation

There is growing evidence that eccentric exercise exerts direct effects on pain processing.

Chronic tendinopathy is associated with central sensitization — a state in which the central nervous system amplifies pain signals, causing pain that is disproportionate to the degree of tissue damage. Meaning it hurts more than it is actually damaged.

Eccentric loading may help “reset” this pain processing system, reducing central sensitization and normalizing pain thresholds. The repeated, controlled exposure to loading also functions as a form of graded exposure therapy, gradually desensitizing the patient’s pain response.

Long-Term Outcomes: The Evidence

The long-term durability of eccentric training results is supported by several longitudinal studies. A notable 5-year follow-up study by van der Plas and colleagues, published in the British Journal of Sports Medicine (2012), tracked patients who had completed an eccentric training program for midportion Achilles tendinopathy. The results were compelling:

Outcome Measure	Baseline	5-Year Follow-Up	Change
VISA-A Score (0–100 function scale)	49.2	83.6	+34.4 points
Patients completely pain-free	0%	39.7%	—
Sagittal tendon thickness	8.05 mm	7.50 mm	−0.55 mm

These findings demonstrate that eccentric training not only produces meaningful clinical improvements, but that those improvements are largely maintained or even continue to progress years after the initial treatment period.

The reduction in tendon thickness over five years is particularly noteworthy, as it suggests genuine structural remodeling rather than mere symptom suppression.

Benefits of Eccentric Training Beyond Achilles Tendinopathy

While the Alfredson Protocol was originally developed for midportion Achilles tendinopathy, the principles of eccentric loading have been successfully applied to a wide range of tendon disorders throughout the body. The underlying biology of tendinopathy — disorganized collagen, failed healing, neovascularization — is remarkably consistent across anatomical sites, making eccentric training a broadly applicable intervention.

• Patellar tendinopathy (jumper’s knee): Eccentric decline squat protocols have become a mainstay treatment for patellar tendon pain, particularly in volleyball and basketball athletes. Single-leg eccentric squats on a 25-degree decline board are the standard exercise.
  
• Lateral epicondylitis (aka tennis elbow aka pickleball elbow): Eccentric wrist extension exercises using a light dumbbell or a specialized device like the FlexBar have shown strong evidence for reducing pain and improving grip strength in chronic lateral elbow tendinopathy.
  
• Proximal hamstring tendinopathy: Eccentric hip extension and Nordic hamstring exercises are increasingly used for high hamstring pain, which is common in distance runners and sprinters.
  
• Rotator cuff tendinopathy: Slow eccentric shoulder external rotation and elevation exercises have demonstrated benefit for supraspinatus and infraspinatus tendinopathy, particularly in overhead athletes.
  

Beyond rehabilitation, eccentric training has substantial benefits for general athletic performance.

Research has consistently shown that eccentric-focused training builds greater tensile strength in tendons and muscles, increases muscle fascicle length (a key factor in sprint speed and injury resilience), and reduces the risk of muscle strain injuries. The Nordic hamstring exercise — a purely eccentric movement — has been shown to reduce hamstring injury rates by up to 51% in professional soccer players. These benefits have led to the widespread adoption of eccentric training across volleyball, soccer, running, basketball, and track and field rehabilitation and performance programs.

Advantages Over Other Treatment Approaches

Eccentric training’s position as a first-line treatment for chronic tendinopathy becomes even clearer when compared to alternative approaches:

Treatment Approach	Advantages	Limitations
Eccentric training (Alfredson Protocol)	Strong evidence base; promotes structural remodeling; low cost; minimal side effects; empowers self-management	Requires discipline and consistency; results take 6–12 weeks; may be uncomfortable
Corticosteroid injections	Rapid short-term pain relief	No structural healing; potential long-term harm (tendon weakening, increased rupture risk); diminishing returns with repeated injections
Rest alone	Reduces acute irritation	Leads to deconditioning; tendons do not remodel without mechanical loading; high recurrence rates upon return to activity
Surgical intervention	Can address structural pathology directly	Invasive; longer recovery (3–6+ months); surgical risks; not usually superior to conservative management

One of the most compelling advantages of eccentric training is its cost-effectiveness and accessibility.

The protocol requires nothing more than a step or raised surface and, eventually, a weighted backpack for progression. It can be performed at home without supervision once the technique is learned, making it accessible to patients regardless of geography, income, or insurance status. Research consistently reports a low adverse event profile — the most common “side effect” is temporary exercise-induced soreness, which is expected and generally self-limiting.

Arguably the most important aspect of eccentric training is that it empowers you to treat your own achilles pain.

The Evolution: Heavy Slow Resistance Training In recent years, heavy slow resistance (HSR) training has emerged as a complementary evolution of eccentric-only protocols. HSR programs incorporate both the concentric and eccentric phases of exercises like calf raises using heavy loads and slow tempos (typically 3 seconds up, 3 seconds down). Studies by Beyer et al. (2015) suggest that HSR produces comparable clinical outcomes to the Alfredson Protocol, with the added benefit of higher patient satisfaction due to lower overall training volume. Many clinicians now view HSR and eccentric training as complementary tools within a broader tendinopathy rehabilitation framework.

Practical Considerations and Modifications

For those considering the Alfredson Protocol, proper execution and realistic expectations are essential for success.

How to Perform the Alfredson Heel-Drop Exercise

1. Starting position: Stand with the balls of both feet on the edge of a step, staircase, or sturdy raised platform. Hold a railing or wall for balance. Rise up onto your toes using both legs.
   
2. Shift weight: Transfer all of your body weight onto the affected leg.
   
3. Eccentric lowering (straight knee): With the knee fully straight, slowly lower the heel below the level of the step over a count of 3–5 seconds. You should feel a stretch and load through the calf and Achilles tendon.
   
4. Return: Use the non-affected leg (or both legs) to push back up to the starting position. Do not use the affected leg concentrically.
   
5. Complete 3 sets of 15 repetitions with the knee straight.
   
6. Repeat with a bent knee: Perform the same movement with the knee of the affected leg slightly bent (approximately 20–30 degrees) to shift the load onto the soleus. Complete 3 sets of 15 repetitions.
   
7. Perform the entire sequence twice daily — once in the morning and once in the evening.
   

Eccentric heel drops: lower the heel below step level with controlled speed, loading the achilles tendon during the lengthening phase.

Progressing Load

As the exercises become pain-free with body weight alone, load should be progressively increased. The most common method is holding hand weights in one hand, starting 10lbs and increasing in 10lb increments as tolerated. Some patients and clinicians also use a Smith machine or leg press to apply controlled resistance. The principle is straightforward: the tendon must be continually challenged with increasing load to drive ongoing adaptation.

The “Do-As-Tolerated” Approach

While the original Alfredson Protocol prescribes a rigid 180-repetition daily volume, more recent research has questioned whether this high volume is strictly necessary. Stevens and Tan, writing in the Journal of Orthopaedic & Sports Physical Therapy (JOSPT), proposed a “do-as-tolerated” approach in which patients perform eccentric exercises based on their individual pain response and tolerance rather than adhering to a fixed repetition count. Their findings suggest that comparable clinical outcomes can be achieved with fewer repetitions, potentially improving patient compliance — a significant consideration, given that the demanding nature of 180 daily repetitions is one of the most commonly cited reasons for protocol dropout.

Consistency and Patience Are Essential Results from eccentric training are not immediate. Most patients begin to notice meaningful improvements in pain and function between 6 and 12 weeks into the program. Some individuals may require longer — up to 6 months — particularly in cases of long-standing tendinopathy. Premature abandonment of the protocol is one of the most common reasons for treatment failure. Staying consistent with the daily routine, even when progress feels slow, is critical to achieving the structural tendon changes that underpin lasting recovery.

When to Seek Professional Guidance

While the Alfredson Protocol can be self-administered, professional guidance is strongly recommended in several scenarios:

• If the pain worsens significantly or fails to improve after 6 weeks of consistent training
  
• If the tendon pain is at the insertion point (where the tendon meets the heel bone) rather than the midportion, as insertional Achilles tendinopathy may require a modified protocol
  
• If there is a history of tendon rupture, fluoroquinolone antibiotic use, or systemic inflammatory disease
  
• If the patient is unsure of the diagnosis — conditions such as posterior ankle impingement, retrocalcaneal bursitis, or partial tendon tears can mimic tendinopathy but require different management
  
• If the patient is a competitive athlete with time-sensitive return-to-play demands, where a tailored rehabilitation plan may be more appropriate than the standard 12-week protocol
  

Conclusion

More than 25 years after its introduction, the Alfredson Protocol remains one of the most thoroughly studied and widely recommended conservative treatments for chronic midportion Achilles tendinopathy and my go to recommendation if you want to try something on your own without any guidance. Its use of eccentric training is effective and has multiple benefits.

The protocol’s legacy extends far beyond the Achilles tendon. The principles of eccentric loading have transformed the management of tendinopathy throughout the body, from patellar tendons to rotator cuffs, and have become a cornerstone of injury prevention and athletic performance enhancement in sports ranging from professional soccer to recreational running. The emergence of complementary approaches like heavy slow resistance training has only broadened the clinical toolkit, offering patients and practitioners more options within the same evidence-based framework.

For anyone struggling with chronic tendon pain, the Alfredson Protocol offers something rare in medicine: a treatment that is simple, accessible, cost-effective, and supported by a robust body of evidence. It demands patience, consistency, and a willingness to work through discomfort — but the rewards, as decades of research and clinical experience have confirmed, are well worth the effort.

“The tendon adapts to what you ask of it. The key is to ask the right question — and eccentric loading is, for many patients, exactly the right question.”

If you have tried the Alfredson Protocol or any eccentric training program for chronic achilles tendon issues and didn’t see results, let us know! Anderson Performance knows what to do and can evaluate you as an individual, not just as a protocol.

If you simply want faster results, we have found how to reduce the Alfredson protocol timeline by over 60% in most cases. Give us a call!

Disclaimer This article is intended for educational and informational purposes only and does not constitute medical advice, diagnosis, or treatment. The information provided should not be used as a substitute for professional medical guidance. Always consult a qualified healthcare provider before beginning any new exercise program or treatment protocol, particularly if you have a pre-existing medical condition, are recovering from injury, or are taking medication. Individual results may vary, and what is appropriate for one person may not be suitable for another.