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Faculty Advisor(s)

Philip Anloague, PT, DHSc, Joaquin Barrios, PT, PhD

Description

Purpose: The biomechanical properties of muscles and tendons are important in rehabilitation and sport performance but are not routinely assessed. Recently, the MyotonPro device has been used in the assessment of a specific aspect of soft tissue stiffness, the resistance in deformation to an external force, at the Achilles tendon. Interestingly, it remains unclear if this stiffness is related to decreased ankle joint dorsiflexion mobility, and further if limb dominance affects this relationship. Indeed, dorsiflexion mobility has been linked to lower extremity injury risk such as anterior knee pain and anterior cruciate ligament injury. Therefore, the primary purpose of this study was to assess the strength of correlation between Achilles tendon stiffness as assessed with the MyotonPro and weight bearing dorsiflexion (WBDF) mobility. We secondarily aimed to assess if the relationship varied by limb dominance. We hypothesized that a moderate strength correlation would be observed bilaterally.

Subjects: 28 healthy participants (27 right limb dominant, 22 females, age = 24.1±2.1 years, height = 1.70±0.9 m, weight = 70.4±12.1 kg) completed all testing.

Methods/Materials: Dominance was determined by asking subjects which leg they typically use when kicking a ball. Using parameters from the literature, the MyotonPRO was set up to deliver a 15 ms duration impulse under constant precompression force of 0.18 N. The subject was prone on a plinth with the feet hanging freely over the edge. With the tendon relaxed, three measures were taken with the probe applied over the most central point of the tendon, level with the medial malleolus. Next, WBDF was measured with the subject facing a wall with the test leg forward and the contralateral limb in-line behind the subject with the heel raised. The subject flexed the knee and brought the center of the patella as close to the wall as they could without raising the heel. Tibial advancement was measured with a digital inclinometer over the anterior midpoint of the tibia. Pearson product moment correlations were calculated for both limbs.

Results: The correlation coefficients between Achilles tendon stiffness and WBDF were r=-0.54 and -0.35 (p< 0.05) for the non-dominant and dominant limbs, respectively.

Conclusion: A direct relationship between Achilles tendon stiffness and WBDF mobility was observed, such that higher stiffness values were associated with decreased motion.

Clinical Relevance: The use of instrumentation to characterize the stiffness of the Achilles tendon using the principle of resistance to deformation from an external force is a recent advancement in the area of soft tissue assessment. These data suggest that greater stiffness and decreased ankle mobility are related. Given the interest in dorsiflexion mobility in the areas of injury risk and sport performance, clinicians may benefit from direct assessment of Achilles stiffness.

Publication Date

5-8-2025

Disciplines

Physical Therapy | Rehabilitation and Therapy

Comments

Presented on February 13, 2025 at APTA Combined Sections Meeting

The Relationship Between Dorsiflexion Mobility and Achilles Stiffness

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