Conceptual modeling of structural malalignments and ankle joint contact forces during walking.

Background: Structural malalignments, such as talar malalignments and hindfoot varus, are hypothesized to contribute to early ankle joint degeneration by altering joint contact force (JCF). These malalignments, common in individuals with chronic ankle instability (CAI), can modify the articular geometry of the ankle joint, potentially leading to abnormal joint loading patterns. This study leverages musculoskeletal modeling and simulation to conceptualize the effects of increasing severity of these malalignments on ankle JCF during walking.

The effects of age and task demand on dynamic mean ankle moment arm during walking.

Background: Older adults walk with a diminished foot and ankle push-off compared to younger adults and this difference may be a target for assistive devices. Dynamic mean ankle moment arm (DMAMA) is an aggregate measure of foot and ankle control that varies in younger adults across walking speeds and inclines.

Research Question: Does age affect DMAMA across a range of walking tasks designed to challenge power output from the ankle and foot?

Methods: We enrolled 12 healthy younger adults and 10 healthy older adults.

Questionnaires of self-perception poorly correlate with instability elicited by walking balance perturbations.

Rehabilitation to prevent falls should not only directly address intrinsic and extrinsic factors, but also the neuropsychology of falls to promote safe and independent mobility in our aging population. The purpose of this study was to determine the relation between falls self-efficacy and objective responses to a series of walking balance perturbations. 29 healthy younger adults and 28 older adults completed four experimental trials, including unperturbed walking and walking while responding to three perturbations: mediolateral optical flow, treadmill-induced slips, and lateral waist-pulls; and three self-reported questionnaires: Activity-specific Balance Confidence, Falls Efficacy Scale, and the Fear of Falling Questionnaire-Revised.

The aging Achilles tendon: model-predicted changes in calf muscle neuromechanics.

Forward propulsion depends on the forces generated by the triceps surae muscles and transmitted through the muscles' subtendons, which merge and twist to form the Achilles tendon (AT). As people age, the AT may undergo structural changes that could alter the subtendons' ability to transmit forces or function with some independence; prominent changes include increased tendon compliance and a proliferation of interfascicular adhesions compared to younger tendon. However, the effects of age-related changes on the subtendons are difficult to isolate in vivo.