What Maximum Ankle Torque is Appropriate for Training Patients with Non-insertional Achilles Tendinopathy?

Background and Purpose: The capacity of the Achilles tendon during a 1-repetition eccentric maximum contraction is largely unknown. This study examined the maximum ankle torque during a concentric/ eccentric heel raise/lowering task and while running in healthy individuals and participants with chronic Achilles tendinopathy. These findings were applied to a 10-week training program for a patient with chronic Achilles tendinopathy. Methods: A total of 13 subjects (9 healthy and 4 with Achilles tendinopathy) participated in this study. Subjects were asked to perform a maximum eccentric contraction wearing a weighted vest while collecting 3-dimensional biomechanical variables. Subjects also ran along an instrumented runway to assess torque at the ankle joint. All participants completed VISA-A Outcomes: On the VISA-A, subjects with Achilles tendinopathy (AT) scored on average 28 points less than the healthy controls and were 27% weaker. The peak ankle torque during a single leg lowering task and running was 3.1 Nm/kg and appeared similar between controls and participants with chronic AT. Findings of the study when applied in a 10-week high load eccentric rehabilitation program demonstrated improved tendon characteristics and VISA-A score. Conclusion: Unhealthy tendons likely can tolerate high loads during rehabilitation and AT programs should consist of progressive resistive exercises instead of movements that emphasize repetitions