Over time, the strain on the tendon causes structural changes within the tendon.
Overuse of the Achilles tendon can occur with activities such as:
- Increasing your speed or walking/running long distances too quickly
- Suddenly adding strenuous hills or stair climbing to your exercise routine
- Doing too much too soon after taking time away from exercising
- A sudden or violent contraction of the calf muscles, such as during an all-out sprint
- Running/walking too much.
Factors that may increase your risk of getting Achilles tendinopathy include:
- improper or badly worn footwear
- inflexibility of the calf muscles
- improper training program
- increased age
Symptoms of tendinopathy may include:
- Tenderness (usually just above the heel)
- stiffness that gradually eases as the tendon is warmed-up
- pain after activity that gradually worsens
- pain along the tendon during and/or after running/walking
- swelling or thickening in the area of the Achilles tendon
Conservative treatment for mid portion Achilles tendinopathy has been proven effective. One of the most supported conservative treatments is a specific exercise program described by Alfredson in 1998. Alfredson's model of eccentric heel drop exercises emphasizes the need for patients to complete an exercise protocol of 180 heel drops per day (3 sets of 15 with knee extended and knee bent to 45 degrees twice per day) despite pain in the tendon. If the patient experiences no tendon pain doing this program, the load is increased until the exercise provokes pain. This 12 week program has been proven successful in approximately 90% of those with mid-portion Achilles tendinopathy.
In 2014 Stevens and Tann challenged this protocol by modifying the regime to a repetition volume that was tolerable to each participant. The new protocol used the same exercises as Alfredson but instructed the participants to do as many reps as was tolerable. Furthermore, they were told to exercise to discomfort but not excessive pain. Stevens and Tann compared this modified protocol to the standard 180 reps per day protocol over a 6 week period and found no difference between the groups, with both groups demonstrating improved function and reduced mid portion tendon pain. They concluded that patient tolerance of the exercise should be considered when determining proper dosage of eccentric heel drop exercises to address mid-portion Achilles tendinopathy.
Stevens, M., & Tan, C.-W. (2014, February). Effectiveness of the Alfredson protocol compared with lower repetition-volume protocol for midportion achilles tendinopathy: A randomized controlled trial. JOSPT, 44(2), 59-67.
Alfredson H, Pietlia T, Lorentzon R. Heavy Load eccentric calf muscle training for the treatment of chronic Achilles tendinosis. Am J Sports Med, 1998:26, p. 360-366.