The Achilles is the strongest tendon in the body. It attaches your calf muscles to your heel bone and is critical for walking and standing. Achilles Tendonitis and tendinosis injuries are most common in runners, with as many as 60% of joggers complaining of pain. This tendon is also often a problem in those who participate in jumping sports and those who are sedentary. Physical Therapy for Achilles Tendonitis has excellent outcomes.
Most tendon injuries result from gradual wear and tear secondary to overuse and aging. Anyone can have a tendon injury, but people who make repetitive movements in their jobs, sports, or daily activities have higher incidents.
Physical Therapy for Achilles Tendonitis must first start with understanding the cause and ruling out other pathologies.
Contrary to what we believed for years, the actual pathology of most diagnosed with tendonitis, “itis”, means inflammation, is not inflammatory but a failed healing response.
Tendinosis
Achilles tendinosis is when very small tears form and degeneration occurs in the Achilles tendon. Most pain in the Achilles tendon is classified as tendinosis because the pain is related to tendon degeneration rather than inflammation. In addition, the tendon becomes weakened and loses its structure. Although aging may play a part in this process, repetitive minor trauma, such as overtraining and playing sports involving running or jumping, can also play a role.
Symptoms of Achilles tendinosis include:
- Pain & difficulty jumping and running
- Tenderness with a palpable lump
- *Morning Stiffness
- Weakness with heel raises
- Dull pain while walking
- Change in sports performance
What are the functions of tendons?
Tendons are thick, fibrous bands with poor blood supply. They have a vital role, overshadowed by focusing on muscles when training. Tendons are secret weapons because they function to save energy, control movements, and improve explosive power! Tendon health is so critical in sports because healthy tendons improve sports performance.
Anatomy of the calf/heel:
The calf comprises two muscles, the gastrocnemius and soleus.
The gastrocnemius is the muscle that we associate with our calf, and the soleus is hidden underneath. Both muscles enable heel raises (plantarflexion), and both taper into the Achilles tendon, attaching to the heel bone. The gastroc has more fast-twitch fibers for speed and originates above the knee. The soleus has mostly slow-twitch fibers and is critical in maintaining your balance in standing and normal walking. The soleus originated below the knee and is more active with heel raises when your knee is bent.
What causes injury to the Achilles Tendon?
Achilles tendonitis / tendinosis is linked to several different factors, including:
- Poor foot mechanics (hyper-pronation)
- Overtraining and inadequate rest
- Calf muscle tightness
- Calf muscle weakness
- Abnormal foot structure
- Improper footwear
- Decreased blood supply and tensile strength with aging
Poor training with inadequate rest is the number one cause of Achilles tendonitis. The second contributor is poor biomechanics. Other contributing factors can include poor/worn shoes, hormonal levels, medications, smoking, and age.
As we get older, there are changes in the mechanical properties of the tendon, similar to what occurs with disuse. Age causes a decrease in the percentage of water and turnover rate of collagen, affecting the recovery rate. Exercise can counteract changes that occur with age!
Biomechanics:
Excessive pronation is linked with almost all running overuse injuries, including an
increased risk of Achilles pain. Excessive pronation causes a whipping action in the Achilles tendon that, when exaggerated, leads to microtears and breakdown. Excessive pronation can be caused by genetics, born with flat feet, or acquired. Walking requires 10 degrees of dorsiflexion (shin bones over ankle). While running, you need at least 15 degrees. If you do not have the required motion in your ankle in calf to dorsiflexion, the movement will be made-up in the midfoot. This creates abnormal movement and stress on the Achilles, plantar fascia, knee, iliotibial band, and hip.
Pathology: The Source of Pain:
Patients with tendonitis were prescribed anti-inflammatories and were given steroid injections as it was believed that inflammation was the cause of pain. It was not until this past decade that researchers revealed that the inflammatory stage is short-lived.
The pain in tendinopathies appears to be related to the neurovascular (nerve and blood supply) growth seen in the tendon’s response to injury. Neurogenic inflammation (inflamed nerves) and pain neurotransmitters were found in high levels in painful tendons but not in normal tendons. Blood flow is also not detectable in normal tendons, but it is seen in injured tendons. The pathological change in the tendon can manifest clinically as tendon thickening or nodules.
A pathological tendon does not change over time. The abnormalities in structure remain. It is believed that exercise improves muscle function allowing the muscle to get stronger, but the pathological changes that occur remain.
Injury is most common in the mid‐portion of the Achilles tendon, but it also occurs at the bone–tendon junction, known as Insertional Achilles Tendonitis / Tendinosis. Insertional is perpetuated by compression. It is crucial to minimize additional compression on the tendon as it inserts into the calcaneal bone. Stretching of the Achilles causes compression, and the compressive force increases with increased dorsiflexion motion. Stretching is minimized in the early stage of healing for insertional tendon pathologies. They also take longer to heal than mid-portion tendinopathy.
Injury Levels of Tendinopathy:
Grade I: Mild strain, disruption of a few fibers. Mild to moderate pain, tenderness, swelling, stiffness. Expected to heal normally with conservative management.
Grade II: Moderate strain, disruption of several fibers. Moderate pain, swelling, difficulty walking normally. Expected to heal normally with conservative management but takes approximately 12 weeks for complete healing.
Grade III: Complete rupture, often characterized by a “pop,” immediate pain, inability to bear weight. Typically requires surgery to repair. Complete ruptures often have no painful warning signs.
Stages of Tendon Healing:
I. Inflammatory stage, lasting only a few days.
II. Repair Phase. This stage lasts less than 2 months.
III. Remodeling Phase. This last stage can last up to 12 months.
Tendon injury and Performance:
When your tendon injury is symptomatic, pain is your main symptom. It also causes changes in your motor response. The tendon is less stiff, causing an altered stretch-shortening cycle behavior. This is important because it affects explosive performance. You lose the extra spring-like power. Exercise for Achilles Tendonitis that targets strength is most important.
Weakness is the subsequent most prominent symptom. There is usually a marked 
reduction in heel raise strength, comparing symptomatic versus the asymptomatic ankle. An athlete should be able to perform over 20 uni-heel raises. When there is a tendon overuse injury, you will see compensatory movements (leaning and bending the knee), and some are unable even to perform one uni-heel raise.
Those with no pain but who have had a previous injury, exhibit changes in kinetics (rate of reaction), indicating permanent changes in biomechanics. Thus, individuals with previous injuries to their tendons, even though they no longer have any pain, have lost some of that explosive power that they once had.
Full symptomatic recovery does not ensure full recovery of the muscle-tendon junction.
There is a very high reinjury or recurrence rate. After 12 weeks of treatment, you still have a 10-86% chance of recurrence.
It is important to treat minor tendinopathy symptoms early with exercises for Achilles tendonitis that target “load control” instead of ignoring or just treating the symptoms.
What is “load control”?
Load control is the amount of stress that you place on the tendons. Jumping and running place higher stress levels on the Achilles tendon than cycling and swimming.
Why is there such a high rate of reoccurrence? It is All about Load & Biomechanics.
Overloading and underloading a tendon by doing too much or not using the tendons leads to tendon injury. An adequate load is what is needed to maintain a healthy tendon. Load is the amount of stress you put on the tendon. The Achilles tendon requires the load to be in weightbearing. If you continually stress the tendon with excessive pronation
The Effect of Loading on Tendon:
- Tendon responds by becoming larger
- Exercise increases circulation and increases collagen synthesis in tendon
The Effect of Immobilization on a Tendon:
- Body adapts to imposed demand
- Decrease tensile strength and stiffness
- Stiffness in tendinopathy is a sensation not a change in mechanical properties
- Causes contractures
- Effects can be minimized if the tendon/ligament is elongated when immobilized.
Tendon Rehabilitation:
Improving biomechanics, strengthening, and load management are the most effective treatment for Achilles Tendonitis /Tendinosis.
Restoring the functional capacity of the tendon is done by load modification and progressive exercise. Improvements in pain and function are noticed within four weeks of beginning an exercise rehab program.
Pain is the most important guide for exercise and returning to sport. Some pain with activity is acceptable and expected with tendon injuries. Using a pain scale of 0-10 (10 is emergency room pain), a level under a 5 is acceptable.
Pain levels:
0-2 = no risk of reinjury.
2-5 = acceptable
5-10 = unacceptable, and the exercise/activity needs to be modified.
Treatment of Achilles Tendinitis / Tendinosis
Monitor pain level during and 24 hr later.
- Reduce pain through load management
- Reduce stress: Heel lift
- Night splint to minimize the Achilles tightening because of the foot’s plantarflexed position when sleeping.
- Avoid compression for insertional tendinosis. (No aggressive stretching)
- Correct any biomechanical issues
Exercise for Achilles Tendinitis / Tendinosis:
Increase tendon load
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- Initially, start with isometrics because they will not cause pain.
- External load: Eccentric / Concentric
- Eccentric strength training through pain. Eccentric is strengthening as the muscle and tendon are elongating. It will cause some pain that is expected. But the pain immediately dissipates when the pressure is off. Pain level must stay below a 5/10, including 24 hrs. later.
- 90% effective for mid-tendon / 30% insertional
- The effect of repetitive stretching, with a “lengthening” of the muscle-tendon unit, may also have an impact on the capacity of the musculotendinous unit to effectively absorb load.
- due to alteration of the neovascularisation and accompanying nerves. The number of repetitions may damage the vessels and accompanying nerves
- Eccentric strength training through pain. Eccentric is strengthening as the muscle and tendon are elongating. It will cause some pain that is expected. But the pain immediately dissipates when the pressure is off. Pain level must stay below a 5/10, including 24 hrs. later.
Continued sports activity using a pain monitoring model
Pain/stiffness not allowed to increase from week to week
Gradually progress load
- Increase load / speed of movt
- Increase speed of running – increase load.
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- Proper training = Heavy less often and lighter more often.
Conclusion:
If recovery between your training sessions is inadequate, this leads to injury instead of recovery!
You should plan three recovery days between heavy activity. Only run the day after you feel good. Cross Train on the other days. This is very hard, as a runner myself to hear. You must remember that it is during recovery that you get stronger. If you do not allow for that time, then you are only shooting yourself in the foot.
Once you damage your tendons, it is very difficult to regain that explosive power and the tendon never returns to its original form. It is critical to recognize the first signs of tendon overuse and modify your activity before damage occurs!
