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Faculty Advisor(s)

Joaquin Barrios, PT, DPT, PhD


Background/Purpose: Chronic ankle instability is a common sequelae to the lateral ankle sprain. Individuals with CAI have a higher risk of developing osteoarthritis and reporting lower quality of life scores. Biomechanical variations have been observed in individuals with CAI during ambulation and landing. To the authors’ knowledge there are no studies investigating the biomechanical profile of the SLS in individuals with CAI. The purpose of this study was to compare the biomechanics of the SLS in individuals with unilateral CAI. We hypothesized that inter-limb biomechanical differences would be observed in individuals with unilateral CAI.

Methods: Participants were recruited from a university setting and provided informed consent. Individuals were included if they reported a history of at least 1 ankle sprain >3 months prior to participation and scored >10/37 on the Identification of Functional Ankle Instability scale. Participants were excluded if they had an ankle sprain within the last 3 months, had a history of LE surgery, or had any current LE or spinal injury. Weight-bearing dorsiflexion ROM was assessed bilaterally using established methods. Participants performed the SLS with their stance limb on the force plate, arms crossed, and their non-stance limb knee flexed to 90 degrees with their thigh vertical. A trial was 3 continuous repetitions to maximum depth at a speed of 60 bpm to a metronome. Five SLS trials were collected bilaterally. Variables of interest included peak hip, knee, and ankle sagittal and frontal plane joint angles and internal moments, as well as peak vertical ground reaction force.

Results: There was approximately 3 degrees less in WB DF ROM (p=0.050) and peak DF angle on the involved limb (p=0.010). The peak plantarflexion moment was approximately 13% less (p=0.008).

Conclusion: Individuals with CAI demonstrated reduced ankle DF during both clinical ROM assessment and motion analysis of SLS. Frontal plane mechanics did not differ between limbs.

Clinical Relevance: The clinical assessment of WB DF coincided with reduced DF mechanics during the SLS. These data suggest that interventions to increase DF ROM may improve SLS symmetry. Clinicians can use WB DF as an assessment to assist in identifying ROM deficits that may be related to motion analysis abnormalities.

Publication Date



Physical Therapy | Rehabilitation and Therapy


Poster presented at the Combined Sections Meeting of the American Physical Therapy Association, Denver, CO, February 2020.

Frontal and Sagittal Plane Lower Extremity Mechanics during Single-Limb Squatting in Chronic Ankle Instability