Achilles Tendinopathy and Calf Loading for Runners

Achilles tendonitis/tendinopathy is one of the most common issues we see with our runners. Our tendons facilitate movement by transferring forces generated by muscles to the skeleton. They deform under load to store and return strain energy, making them critical during locomotion. The Achilles is the largest, strongest, and thickest tendon in the body, and experiences 5-7x your body weight per step during running.

PATHOLOGY

The Achilles tendon is made up of collagen, which is a substance full of protein which makes up connective tissues. In healthy tendons, those strands of collagen lay in long, straight strands in an organized fashion (imagine a box of uncooked Spaghetti pasta).

When repetitively pushed beyond its capacity and strength limits, the tendon can become painful due to many deep cellular processes. Overloading of the tendon leads to degeneration and disorganization of healthy collagen in the structure, which triggers an inflammatory response. If left unaddressed, the cycle of poor quality tissue repair, inflammation, and pain continues, leading to further deformation of the tendon (imagine a bowl of cooked Spaghetti pasta).

Achilles issues most commonly occur in the middle portion of the achilles, but occasionally can occur at the insertion (heel bone) as well. Luckily, the solution to healing both mid portion and insertional tendinitis is very similar.

THE SOLUTION

Optimal heavy, but controlled loading of the calf and tendons act like your hair straightener or comb that straighten those long fibers of collagen back longitudinally. This does take time and consistency and does not happen overnight. True strengthening gains can take 6-8 weeks, however most tendinopathies take 3 or more months to completely heal, and continued adherence to the appropriate exercise program is essential well after that 3 month period!

A physical therapist guided rehabilitation program will generally consist of heavy controlled loading with isometric, concentric and eccentric exercises. It is critical that plyometric and power exercises be implemented into the program as the tendon begins to tolerate more load. In many cases, changes in running gait and even changing footwear can reduce impact forces on the tendon and maximize running efficiency.

THE GOOD NEWS

Because the goal is to strengthen and fortify the tendon, complete rest is often contraindicated meaning you can often continue to run through some reasonable amount of discomfort, as long as a calf loading strengthening program is implemented. How much pain is ok and how much loading for a painful tendon is always something you should manage with your physical therapist and not alone. A good rule of thumb is that on a 10 point pain scale (where 0 is no pain, and 10 is the worst pain), pain during a run should not increase by more than 2 pain points.

And for you runners out there running healthy without a tendon issue in sight - don’t neglect the importance of loading those calves to prevent issues down the road! If we can create a better capacity to tolerate load, we can avoid having to dig you out of a deep hole.

OUR FAVORITE CALF EXERCISES

A variety of concentric, eccentric and isometric exercises, involving heavy loading are critical to building a healthy, strong achilles tendon. Here is a list of our favorite calf loading exercises that add additional challenge to the traditional body weight heel raise.

THE BASICS

Single Leg Heel Raise with Load- with Straight and Bent Knee
- Purpose: This exercise aims to strengthen the calf muscles. When performed on a straight knee, this exercise activates both parts of the calf muscle ( the gastroc and soleus). On a bent knee, lesser known but equally important soleus is isolated. It is essential to strength both parts of the calf in isolation in order to properly load the the calves.
- How to:
  - Place one hand lightly on a wall for support
  - In the opposite hand, hold a heavy weight (think 10-20#)
  - Transfer weight to one leg, keep the knee straight and push up onto the toes
  - Repeat this exercise while keeping the knee bent
Isometric Heel Raise with load
- Purpose: Isometrics do not have to be easy! A static hold of the heel raise challenges the endurance of the calf muscles.
- How to:
  - Hold a heavy dumbbell or kettlebell in one hand
  - Holding onto the wall or back of a chair for support, transfer your weight onto one leg and push up onto your toes. Hold for 10 -15 seconds at the end range of motion. Don’t let that heel fall towards the floor!

OUTSIDE THE BOX

Dynamic Calf Exercises
- Purpose: These exercises challenge the calf muscles dynamically, by requiring not only recruitment of the gastroc-soleus complex, but also requires core stability, balance and power. See videos of 2 farmer’s carry variations on toes above.
- How to: Farmer’s Carry March
  - Grab a heavy kettlebell or dumbbell to carry in one hand
  - Squeeze shoulder blades together and keep tension in the shoulders, while simultaneously “stacking” your rib cage over your pelvis (keep the core engaged and trunk upright)
  - Slowly march one leg forward at a 90 degree angle, and push up onto the toe of the standing leg and hold for 1 second
  - Slowly lower down on the calf of the standing leg
  - Switch legs and continue for about 10 repetitions on each side
  - Repeat this series with the weight in the opposite hand
- How to: Farmer’s Carry on toes
  - Grab 2 heavy kettlebells or dumbbells to carry in each hand
  - Squeeze shoulder blades together and keep tension in the shoulders, while simultaneously “stacking” your rib cage over your pelvis (keep the core engaged and trunk upright)
  - Push up onto both toes and take slow, controlled steps up and down a long hallway or gym floor

Plyos: Pogo Hops
- Purpose: Plyos are a vital piece of performance training for runners. It increases our springiness making us more economical, powerful and resistant to injury. See our last blog post on training power and plyometrics here. These particular plyos emphasize stiffness in the hip and knee and springy-ness from the foot and calf.
- How to:
  - Stand on two legs with a slight bend in the knees
  - Power up off of the ground from the toes
  - Keeping the knees and hips relatively stiff, spring back off those toes into the next pogo hop
  - To increase the challenge, perform on a single leg, or hold a dumbbell or kettlebell in each hand

Postural Endurance Exercise: Straight Arm Pull Down with Single Leg Heel Raise
- Purpose: This exercise mimics optimal running posture and can help to train postural muscle endurance while also working on single leg calf strength.
- How to:
  - Obtain a staggered stance with one knee bent and the foot placed on the weight bench, the other leg slightly behind, toes facing forward
  - With elbows straight, pull down on a band towards your hips (anchored in a doorframe) while squeezing the shoulder blades together and keeping the ribs stacked over your pelvis
  - On the back leg, push up onto the toes and hold for one second, slowly lower back down and repeat 10 times
  - Switch the position of the feet and repeat