Exercise Progression to Incrementally Load the Achilles Tendon.

The purposes of our study were to evaluate Achilles tendon loading profiles of various exercises and to develop guidelines to incrementally increase the rate and magnitude of Achilles tendon loading during rehabilitation. Eight healthy young adults completed a battery of rehabilitation exercises. During each exercise, we collected three-dimensional motion capture and ground reaction force data to estimate Achilles tendon loading biomechanics. Using these loading estimates, we developed an exercise progression that incrementally increases Achilles tendon loading based on the magnitude, duration, and rate of tendon loading. We found that Achilles tendon loading could be incrementally increased using a set of either isolated ankle movements or multijoint movements. Peak Achilles tendon loads varied more than 12-fold, from 0.5 bodyweights during a seated heel raise to 7.3 bodyweights during a forward single-leg hop. Asymmetric stepping movements like lunges, step ups, and step downs provide additional flexibility for prescribing tendon loading on a side-specific manner. By establishing progressions for Achilles tendon loading, rehabilitative care can be tailored to address the specific needs of each patient. Our comprehensive data set also provides clinicians and researchers guidelines on how to alter magnitude, duration, and rate of loading to design new exercises and exercise progressions based on the clinical need.