Exercise Progression to Incrementally Load the Achilles Tendon

Abstract

Purpose 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. Methods 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. Results 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. Conclusion 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.

Functional Ankle Range of Motion but Not Peak Achilles Tendon Force Diminished With Heel-Rise and Jumping Tasks After Achilles Tendon Repair

“…It is possible that individuals in this study could have modified their heel-rise or jumping strategy bilaterally in response to their Achilles rupture, reducing the effect of presence of rupture in this analysis. Compared with previously published data in healthy participants, 4 the participants included in this study had similar or slightly increased peak Achilles tendon load (percentage difference based on means from repaired side in this group to controls: heel-rise, 28%; CMJ, 10%; DJ, 27%; hop, 7%) and similar or reduced Achilles tendon impulse (percentage difference based on means from repaired side in this group to controls: heel-rise, 2%; CMJ, -33%; DJ, -59%; hop, -32%). Additionally, although all participants underwent open surgical repair and some form of postoperative rehabilitation, surgical technique and rehabilitation were not standardized.…”

“…Lower limb kinematics and kinetics were calculated by means of a constrained kinematic model using a previously described approach. 4 Briefly, a generic musculoskeletal model (gait 2392) 34 was scaled using each participant’s bodyweight and markers placed over anatomic landmarks. After scaling body segments of each participant, we moved these models into the anatomic position by fitting the experimental data collected during a standing trial using best practices.…”

Experimental recommendations for estimating lower extremity loading based on joint and activity

“…Participants completed a battery of exercises that are clinically relevant for treating Achilles tendon injuries, as described in a previous paper from our group (Baxter et al, 2021). From this battery, we selected a subset of exercises that would provide a wide range of lower extremity loading for our later analysis.…”

“…Participants completed a battery of exercises that are clinically relevant for treating Achilles tendon injuries, as described in a previous paper from our group (Baxter et al, 2021).…”

Workflow assessing the effect of Achilles tendon rupture on gait function and metatarsal stress: Combined musculoskeletal modeling and finite element analysis

“…4 Concerning the load of the AT, at full speed run, the peak load of the AT is about 12.5 times the body weight, during jumping or shuttle run, the peak load of the AT can reach 3-5 times the body weight. 5 AT is highly sensitive to mechanical stimuli, therefore regular exercise can increase the diameter of the AT, while less activity results in a decrease in the diameter. 6 The increase in elastic modulus and stiffness after training indicates that the AT will undergo adaptive changes after training to withstand higher stress.…”