Tendinopathy: How Eccentric Training and Injection Options Really Work

When your tendon hurts-not just a quick twinge, but a persistent, dull ache that lingers after running, jumping, or even walking-you’re not just dealing with inflammation. You’re dealing with tendinopathy. It’s not a simple strain. It’s a degenerative breakdown of the tendon’s structure, often caused by repeated overload without enough recovery. And the good news? Most cases don’t need surgery. The better news? There’s solid science behind what actually works-and what doesn’t.

Why Eccentric Training Is the Gold Standard

For over 25 years, eccentric training has been the go-to treatment for tendinopathy, especially for Achilles and patellar tendons. Unlike traditional strengthening, which focuses on shortening the muscle (concentric), eccentric training works when the muscle is lengthening under load. Think of it like slowly lowering yourself into a squat or lowering your heel from a raised position. This controlled lengthening puts just the right kind of stress on the tendon to trigger repair.

Studies show that after 12 weeks of consistent eccentric training, people with Achilles tendinopathy see a 60-65% improvement in pain and function, measured by the VISA-A score. For patellar tendinopathy, the VISA-P score jumps from around 42 to over 80 in those who stick with it. That’s not just feeling better-it’s returning to running, jumping, and playing sports without fear.

The most common protocol for Achilles tendinopathy is the Alfredson heel drop: stand on the edge of a step, rise up on both feet, then lower the affected foot slowly over 3-5 seconds. Do 3 sets of 15 reps, twice a day, with your knee straight (targets the calf muscle) and then bent (targets the deeper soleus muscle). For patellar tendinopathy, single-leg decline squats on a 25-degree board are the standard. You lower slowly, then use both legs to stand back up.

It’s not easy. About 68% of people report high pain levels in the first two weeks. But here’s the key: the pain shouldn’t go beyond a 5/10 during exercise. If it hits 7/10 or lingers more than 24 hours, you’re overdoing it. This isn’t about pushing through pain-it’s about finding the sweet spot where the tendon adapts without breaking down further.

Heavy Slow Resistance: A Simpler Alternative?

Not everyone can tolerate the sharp pain of traditional eccentric training. That’s where heavy slow resistance (HSR) comes in. Instead of focusing only on the lowering phase, HSR uses controlled movements both up and down-3 seconds up, 3 seconds down-using weights around 70% of your one-rep max. You do 3 sets of 15 reps, three times a week.

A 2015 study comparing HSR to eccentric training for Achilles tendinopathy found both methods led to nearly identical improvements in pain and function. But here’s the twist: HSR had an 87% adherence rate. Eccentric training? Only 72%. Why? Because HSR feels less punishing at first. The pain spike isn’t as intense, making it easier to stick with.

For people who struggle with consistency, HSR might be the better long-term choice. It’s also easier to scale-add more weight as you get stronger, rather than just increasing reps or sets. And it works just as well for other tendons, like the rotator cuff, where eccentric-only protocols have been less reliable.

Isometric Exercises: The Quick Pain Reliever

If you need to play a game, train, or just walk without pain right now, isometric exercises are your best friend. These are static holds-no movement. For Achilles, stand on your toes and hold the position for 45 seconds. For patellar, sit with your leg straight and squeeze your quad hard for 45 seconds. Do this 5 times a day.

A 2015 study showed isometrics reduce pain by 50% within just 45 minutes. That’s faster than any injection. It doesn’t fix the tendon long-term, but it gives you a window to move without fear. Many athletes use this before activity to get through training or competition. It’s not a cure, but it’s a powerful tool to manage symptoms while you build strength with eccentric or HSR training.

Injection Options: What Actually Helps-and What Doesn’t

Corticosteroid injections are common. They work fast. Many people feel 30-50% better within a few weeks. But here’s the catch: they’re a band-aid. A 2013 BMJ study followed patients for a year. Those who got steroid shots had a 65% chance of needing another treatment within six months. Those who did eccentric training? Only 35% needed more help.

Steroids weaken the tendon over time. They reduce pain by suppressing inflammation, but they don’t rebuild tissue. In fact, repeated injections increase the risk of tendon rupture. That’s why most sports medicine guidelines now say: avoid them for midportion Achilles and patellar tendinopathy. They might be okay for short-term relief in insertional cases, but even then, they’re not first-line.

Platelet-rich plasma (PRP) gets a lot of hype. You’ve probably heard it’s “your own healing cells” injected into the tendon. Sounds amazing, right? But the data doesn’t back it up. A 2020 review of 18 studies found PRP only improved outcomes by 15-20% over placebo. That’s barely better than a sugar shot. And it costs hundreds to thousands of dollars. For most people, it’s not worth the price.

Shockwave therapy has better evidence. It’s not an injection, but it’s often grouped with them. Studies show it helps about 60% of people with chronic Achilles tendinopathy after 3-6 sessions. It’s less painful than eccentric training, but it’s also less effective long-term. Best used if you can’t tolerate exercise, or as a supplement-not a replacement.

Why So Many People Fail

You’ve heard it works. You’ve seen the studies. So why do so many people give up?

First, they don’t do it long enough. Twelve weeks is the minimum. Most people quit at week 6 because they don’t see results. But tendon remodeling takes time. Ultrasound scans show real structural changes-better collagen alignment, increased stiffness-only after 8-12 weeks. If you stop early, you’re wasting your effort.

Second, they do it wrong. A 2021 study found self-managed patients made technique errors 40% more often than those working with a physical therapist. A slight tilt in the decline squat, a rushed heel drop, or not lowering slowly enough-these mistakes mean the tendon doesn’t get the right stimulus. You need feedback. Use a mirror. Record yourself. Or better yet, get one session with a therapist to nail the form.

Third, they ignore pain signals. Many think “no pain, no gain” applies here. It doesn’t. You need to train at a 7-8/10 pain tolerance-not zero. That’s a big shift from old advice. Pain during exercise is normal. Pain that lasts all day or wakes you up at night? That’s a red flag.

What Works Best Together

The most successful outcomes come from combining approaches. Start with isometrics for immediate relief. Then layer in eccentric or HSR training for long-term healing. Use a smartphone app like Tendon Rehab to track progress and get form feedback. Apps boost adherence from 65% to 85%.

If you’re an athlete, pair this with load management. Don’t suddenly go from 5K runs to 10K. Don’t add more jumps without increasing recovery. Tendons need time to adapt. Gradual progression is everything.

And don’t underestimate the mental side. Chronic tendon pain is frustrating. It makes you anxious about moving. That fear can keep you stuck. Working with a therapist who understands both the physical and psychological side of tendinopathy makes a huge difference.

The Future of Tendinopathy Treatment

The field is moving beyond one-size-fits-all protocols. Researchers are now using ultrasound and MRI to map where exactly the tendon is damaged and how stiff it is. This helps match people to the right load-some need more intensity, others need less.

A 2022 study showed tailoring exercises to individual tendon tolerance improved outcomes by 25%. That’s huge. We’re moving toward precision rehab. Soon, we might use blood markers or genetic profiles to predict who responds best to eccentric training versus HSR.

New drugs are in early trials. Tendon-activating peptides (TAP-421) are being tested to stimulate tendon cells directly. But these are years away. For now, the best treatment is still movement-controlled, consistent, and patient.

What to Do Right Now

If you have tendinopathy:

• Start with isometrics for quick pain relief (45-second holds, 5x/day).
• Choose either eccentric training or heavy slow resistance-don’t do both at once.
• Do it 6-7 days a week for at least 12 weeks. No shortcuts.
• Keep pain between 2-5/10 during exercise. Stop if it hits 7/10 or lasts longer than 24 hours.
• Use an app or video to check your form.
• Avoid corticosteroid injections unless you’re in extreme pain and have tried everything else.
• Work with a physical therapist at least once to confirm your technique.

It’s not glamorous. It’s not fast. But if you stick with it, most people return to their favorite activities without pain. And once you’re back, keep the exercises going-just less often. Prevention is easier than cure.