Maintaining Tendon Health: How to Keep Your Tendons Resilient from Injury

I have found tendon pain to be one of the hardest and most stubborn injuries to treat. Not only for my clients, but for me personally as well. I have dealt with a myriad of tendon pain including my elbow, achilles, and groin. They can be a source of persistent pain that limits our daily and recreational activities.

Because I’ve experienced multiple tendon injuries myself, I have done a lot of research on how to maintain healthy, strong tendons throughout our lifespan and also how to treat them if they get injured. This article will discuss the structure and function of tendons, how to develop strong and resilient tendons, risk factors for tendon injury, nutrition and supplementation to support healthy tendons, and treatment options for injured tendons.

Tendon Structure and Function

Tendons, composed mainly of Type I collagen, along with proteoglycans, elastin, and glycoproteins, form a strong extracellular matrix. Acting as "mechanical bridges," these stiff, strong tissues connect muscles to bones, efficiently transmitting the force of muscle contractions to create movement without significant deformation.

How to Develop Strong and Healthy Tendons

Tendons, mainly Type I collagen with proteoglycans, elastin, and glycoproteins, contain tenoblasts (collagen producers) and mature tenocytes. Tendons strengthen when they are subjected to sufficient mechanical force, such as from muscle contractions during resistance and plyometric training, which stimulates tenoblasts to produce more collagen.

Resistance Training

Resistance training, involving muscle contractions against external loads, applies mechanical tension through tendons to bones. This tension prompts tendon cells (tenoblasts) to produce and organize collagen fibers. Unlike disorganized scar tissue, resistance training encourages the alignment of collagen with each repetition.

To transmit forces equally throughout the tendon, incorporate either heavy, slower resistance training or prolonged isometric exercises into your program. Short, rapid contractions may only stress the strongest parts of the tendon, potentially leaving weaker areas vulnerable due to "stress shielding." Lifting heavier weights naturally slows the movement, increasing the crucial time under tension for both muscles and tendons.

If heavy lifting isn't feasible, light isometric holds sustained for 10 to 30 seconds can provide a similar stimulus to the tendons. Isometric holds are particularly beneficial for individuals who cannot tolerate heavy resistance training.

Plyometric Training

Plyometric training harnesses the muscle-tendon unit's stretch-shortening cycle to boost stiffness and power through fast stretch and contraction exercises like jumping and throwing. In this process, the tendon functions as a spring, accumulating and then releasing energy. Plyometrics contribute to improved tendon stiffness, thickness, and the capacity for energy storage.

However, akin to heavy resistance training, plyometrics are not universally applicable. The rapid nature of these movements primarily stresses the strongest regions of the tendon, potentially leaving weaker areas susceptible to injury and rupture. Establishing a solid base in resistance training is advisable before incorporating plyometrics, as it necessitates a gradual progression and may not be appropriate for everyone.

Nutrition and Supplements for Healthy Tendons

Besides resistance training, diet and nutrition are other crucial components to keeping tendons healthy and strong. Exercise creates the stimulus for adaptations in our tissue. Rest and proper nutrition fuel the recovery process.

As with most cases, there isn't one specific diet that is superior to others for developing healthy tendons. It consists of a diet rich in whole foods and the proper amount of protein intake. There are also supplements available when nutrition from diet alone is not enough.

Protein Intake

Protein intake is probably the most effective metric to track regarding proper nutrition for recovery and muscle growth. It is just as important for collagen synthesis as well.

Protein provides the building blocks for the tissues in our body to grow. You need to consume the right amount of protein to fuel muscle and collagen synthesis. The minimum amount of protein to consume per day is 0.8 grams per pound of body weight.

Where you get your protein from doesn’t matter as much as the amount of protein you are getting per day. Whether it’s from animal products or a plant-based diet, as long as you get at least 0.8 grams of protein per pound of body weight each day, you will be on the right track.

Supplements

It can be hard to consume all the nutrients we need from food alone. That’s where supplementation can play a role. However, you don’t want to rely solely on supplements. They are a supplement to our diet. Try to get as much nutrition from food as possible and supplement where needed.

• Protein Shakes: Prioritize daily protein intake, aiming for 0.8 gram per pound of body weight. Whey protein supplementation is recommended due to its high leucine content, which stimulates protein synthesis. Plant-based protein is a suitable alternative for vegetarians or those with dairy sensitivities.

• Hydrolyzed Collagen Powder (Collagen Peptide Hydrolysate): Collagen supplementation, beyond whey or plant protein, is crucial for collagen synthesis. While bone broth is a great dietary source, mammals store heavy metals in their bone marrow. To limit your exposure to heavy metal consumption, hydrolyzed collagen powder or peptides from animal skin (fish or bovine) are safer alternatives. Studies indicate that 15-30 grams of collagen with resistance training improves collagen production more than training alone. Plant-based options with Vitamin C also support collagen production, though they lack gelatin.

• Vitamin C: While most diets provide enough Vitamin C to avoid scurvy, it's also vital for collagen synthesis, which is crucial for healing bones, tendons, and ligaments. Supplementing with small amounts of Vitamin C (e.g., 50 mg with 15 g of collagen) can boost amino acids in the blood, aiding this process.
  

How Do Tendons Get Injured?

Even with proper resistance training, nutrition, and rest, tendon injuries can still occur. These "overuse injuries," or tendinopathies, differ from tendon ruptures (complete tears). Tendinopathy is a gradual process. A common example is a new runner developing Achilles pain after suddenly increasing their running frequency. While this example is simple, tendinopathy development involves various factors and exists on a continuum.

Tendinopathy as a Continuum

Tendinopathy, a pathological alteration of tendon structure and function, is often mistakenly called tendinitis. Unlike tendinitis, tendinopathy lacks an inflammatory response, making rest and anti-inflammatory drugs ineffective treatments. It develops across three stages—reactive, dysrepair, and degenerative—due to either excessive or insufficient stress on the tendon. Overloading is common, but chronic underloading in sedentary individuals can also cause similar tendon changes.

• Reactive Tendinopathy: Reactive tendinopathy is a rapid, non-inflammatory tendon thickening caused by acute overload. Instead of normal stiffness adaptation, excessive stress leads to increased proteoglycans and water, reducing stress and adapting to compression. Common in younger individuals with sudden training increases, it can resolve with reduced load or sufficient rest.

• Tendon Dysrepair: Tendon dysrepair, similar to reactive tendinopathy but with more matrix breakdown, involves continued cell proliferation and collagen disorganization, potentially with increased vascularity. Common in overloaded tendons of young individuals, though possible at any age, it's difficult to differentiate from reactive tendinopathy. More pronounced tendon thickening might be present. Diagnostic imaging is necessary to identify structural changes or increased vascularity.

• Degenerative Tendinopathy: Chronic tendon overload or underload leads to degenerative tendinopathy, characterized by cell death and collagen disorganization within the tendon. Diagnostic imaging is necessary to see these changes. This condition, primarily affecting older individuals but possible in younger chronically overloaded ones, has little chance of reversal and carries a high risk of rupture under significant load. Variability exists within the tendon, with degenerative areas alongside other stages and normal tissue.

  
  

Risk Factors for Developing Tendon Injury

Tendon injuries primarily result from the stress placed upon them, whether excessive load without adequate recovery or insufficient load causing weakness. Contributing risk factors are categorized as extrinsic (acting on the body) like overload and underload, and intrinsic (acting within the body) such as age and gender. 

Extrinsic Risk Factors

The primary external risk factors for tendon injuries are load management and individual biomechanics. Overloading occurs through repetitive high stress without adequate rest, often stemming from training errors with excessive high-intensity days. Conversely, chronic underloading due to sedentary behavior or stress shielding also weakens tendons.

Biomechanical factors, including anatomy, posture, neuromuscular control, and flexibility, collectively contribute to tendon injury risk. Anatomical predispositions can make certain tendons more vulnerable to compressive loads. When combined with poor posture, tightness, and impaired neuromuscular control, these factors can lead to chronic tendon overload from both tensile and compressive forces.

Intrinsic Risk Factors

Intrinsic risk factors act systemically from within the body and can include age, gender, lipid levels, and medication.

Age: With age, tendons experience a decline in their adaptive capabilities due to alterations in cellular structure and a reduced capacity for regeneration. Specifically, collagen fibers become disorganized, and collagen production diminishes. These changes compromise the tendon's viscoelastic properties and overall strength, thereby elevating the risk of injury.

Gender: Women are more prone to tendon injuries due to estrogen fluctuations. Higher estrogen levels, particularly during the luteal phase, inhibit a protein that stiffens tendons. Conversely, decreased estrogen during menopause loosens tendons. Both increased and decreased estrogen levels increase women's susceptibility to tendon injury.

Lipid Levels: Lipid levels also play a role in developing tendon injuries. The higher the lipid levels, the more susceptible tendons are to injury. Higher lipid levels may indicate that someone is not metabolically healthy, which can affect how tissue heals and regenerates.

Medications: Certain medications negatively affect tendon health. Fluoroquinolone antibiotics (like ciprofloxacin) and angiotensin-II inhibitors (blood pressure drugs like Sartan drugs) increase the risk of tendon rupture. Excess exogenous testosterone also harms tendons by decreasing collagen, making them brittle and prone to rupture, similar to the effects of aging.

Treatment Options for Tendinopathy

Conservative approaches like physical therapy and injections are the primary treatments for most tendinopathies. While surgery is sometimes necessary, the majority of tendon issues improve with non-surgical management. This discussion will cover fundamental physical therapy treatment strategies and an overview of available injection options.

Physical Therapy Treatment Strategies

• Time off from the aggravating activity. This is not time off forever, but you have to take some time off from the activity that is causing the pain. The amount of time off will depend on:

  • Baseline level of pain

  • Type of activity

  • Frequency of the activity

  • Individual factors

• Load the tendon in a controlled, progressive manner.

  • Start with isometrics and progress to isotonic exercises as tolerated.

  • Blood flow restriction in the acute phase to enhance tendon healing.

• Address impairments elsewhere in the body.

  • Strengthen weak muscles.

  • Increase soft tissue mobility in tight areas.

  • Address movement patterns and posture.

• Modalities can be used as an adjunct to the loading program and addressing impairments elsewhere.

  • Shockwave therapy.

  • Red light therapy.

  • Dry needling.
    

Tendon pain recovery is a gradual process spanning several months. While complete symptom resolution takes time, you don't necessarily need to cease all activities during this period, though some symptoms may persist. Consistency and patience with this approach are crucial for successfully overcoming your tendon injury. This is the guidance I provide my patients and follow personally.

Injection Options

When physical therapy fails to resolve tendon pain, injections are a treatment option considered after unsuccessful conservative management. Before opting for an injection, consider this: 

• Consider injections only after three months of consistent physical therapy and a loading program without any improvement. If there's some improvement but not full pain resolution, wait another three months before considering an injection.

• Injections for tendinopathy should supplement physical therapy and loading, not replace them. Addressing the underlying cause is crucial to prevent recurrence, even if injection provides temporary relief.
  

There are a number of options that include traditional injections such as corticosteroids and newer technologies like peptides and stem cells. I will briefly discuss each option and present my opinion on each of them.

Corticosteroid (Cortisone) Injections: Cortisone injections, synthetic hormones mimicking cortisol, suppress the immune system to reduce musculoskeletal pain. While often effective for short-term pain relief (around 8 weeks), they primarily mask the pain. Chronic use carries risks, including tendon tissue degradation and reported cases of rupture after multiple injections. Due to the short-term relief and risk of tissue damage, it is not one I usually recommend.

Platelet-Rich Plasma (PRP) Injections: PRP injections for tendons involve concentrating plasma from the patient's blood and injecting it into the painful area to stimulate healing. The effectiveness of PRP varies due to inconsistent preparation methods (single or double spin, leukocyte-rich or poor plasma). While some evidence supports PRP for upper extremity tendon issues, often alongside physical therapy, its use in the lower extremity is less clear, possibly because lower extremity tendons are harder to immobilize post-injection, potentially reducing PRP retention.

Prolotherapy Injections: Prolotherapy involves injecting a hypertonic dextrose solution into painful tendons to stimulate healing. While results are similar to PRP, it appears more effective for upper extremity tendons than lower extremity tendons. For upper extremity tendinopathies, prolotherapy combined with physical therapy is recommended; however, I am less inclined to suggest it for lower extremity issues.

Peptides: Peptides, particularly those boosting growth hormone like BPC-157, are used for pain and recovery in functional and longevity medicine. While increased growth hormone doesn't directly improve tendon collagen, it raises IGF-1 from the liver, which does benefit tendons. Despite anecdotal reports of positive effects, caution is warranted as most peptide studies are in mice, and growth hormone-stimulating peptides don't directly alter tendon properties. Therefore, peptide therapy isn't a primary tendon treatment but can be considered alongside comprehensive rehab due to potential indirect benefits from improved recovery and training tolerance. These injections should always be done under supervision of a trained physician. 

Stem Cells: Stem cell injections are a newer technology that is being used to help regenerate tissue. Stem cells are FDA approved in the United States for certain uses. They are gaining popularity, especially in the athletic world, for treatment of musculoskeletal injury. I urge you to do your own research and talk to a healthcare professional about your options. There are cases of clinics using stem cells that were not FDA approved that led to serious injury of their patients. 

TL;DR: Guidelines to Keep Tendons Healthy and Strong

• Prevention is key for keeping tendons healthy and pain-free.

• Train tendons effectively: Use isometric exercises or slow, heavy resistance training.

• Allow adequate rest and recovery between intense training sessions.

• Support your tendons with proper nutrition:

  • Aim for one gram of protein per pound of body weight per day. (I.e., a 170-pound individual needs 170 grams of protein per day).

  • Consider supplements:

    • Protein shakes: Help achieve adequate protein intake. Whey protein is often recommended, but plant-based options are also available.

    • Hydrolyzed collagen powder: Look for sources from animal skin/hide to reduce heavy metal exposure. Aim for 10-15 grams per day.

    • Vitamin C: Usually adequately achieved through diet.

• Conservative care is the foundation for tendon issues:

  • Initially, rest from aggravating activities.

  • Begin low-load isometric strengthening exercises.

  • Work on neuromuscular control, posture, strength, and flexibility as needed.

• Injection Options: Consider these points:

  • Dry needling can be a helpful first-line option to help create a healing response without injecting material into the tendon.

  • PRP and prolotherapy may be best options for upper extremity tendons.

  • Corticosteroid injections should be a last resort due to short-term effects and potential long-term damage to tendons.

• Regenerative injections (Peptide therapy, Stem cell therapy, Exosome therapy) all have the goal of increasing tissue healing. There isn't a lot of robust human data to definitively support their use for tendons, but anecdotally, some people seem to get good results.

In conclusion, nurturing healthy and resilient tendons is a proactive endeavor that combines thoughtful training, consistent nutrition, and mindful attention to your body's signals. Understanding the nuances of tendon structure, the benefits of specific exercises, and the importance of adequate recovery empowers you to minimize your risk of injury and maximize your athletic potential. However, should tendon pain arise or linger, remember that early intervention and expert guidance can make all the difference in your recovery journey. Don't let tendon pain sideline you any longer. Take the first step towards lasting relief and a return to your active life by scheduling a comprehensive evaluation today. Let's work together to get you back to doing what you love, stronger and healthier than before.