Simple within-stride changes in treadmill speed can drive selective changes in human gait symmetry.

Millions of people walk with asymmetric gait patterns, highlighting a need for customizable rehabilitation approaches that can flexibly target different aspects of gait asymmetry. Here, we studied how simple within-stride changes in treadmill speed could drive selective changes in gait symmetry. In Experiment 1, healthy adults (n = 10) walked on an instrumented treadmill with and without a closed-loop controller engaged.

The human preference for symmetric walking often disappears when one leg is constrained.

We hypothesized that minimization of metabolic power could drive people to walk asymmetrically when one leg is constrained We studied healthy young adults and independently constrained one or both step lengths to be markedly shorter or longer than preferred using visual feedback When one leg was constrained to take a shorter or longer step than preferred, asymmetric walking patterns were less metabolically costly than symmetric walking patterns When one leg was constrained to take a shorter or longer step than preferred and the other leg was allowed to move freely, most participants naturally adopted an asymmetric gait People may prefer to walk asymmetrically to minimize metabolic power when the function of one leg is constrained during fixed-speed treadmill walking ABSTRACT: The bilateral symmetry inherent in healthy human walking is often disrupted in clinical conditions that primarily affect one leg (e.g. stroke).

Ankle power biofeedback attenuates the distal-to-proximal redistribution in older adults.

Background: Compared to young adults, older adults walk slower, with shorter strides, and with a characteristic decrease in ankle power output. Seemingly in response, older adults rely more than young on hip power output, a phenomenon known as a distal-to-proximal redistribution. Nevertheless, older adults can increase ankle power to walk faster or uphill, revealing a translationally important gap in our understanding.

Biomechanical effects of augmented ankle power output during human walking.

The plantarflexor muscles are critical for forward propulsion and leg swing initiation during the push-off phase of walking, serving to modulate step length and walking speed. However, reduced ankle power output is common in aging and gait pathology, and is considered a root biomechanical cause of compensatory increases in hip power generation and increased metabolic energy cost. There is a critical need for mechanistic insight into the precise influence of ankle power output on patterns of mechanical power generation at the individual joint and limb levels during walking.

More push from your push-off: Joint-level modifications to modulate propulsive forces in old age.

Introduction: Compared to young adults, older adults walk with smaller propulsive forces and a redistribution to more proximal leg muscles for power generation during push-off. Despite this deficit in propulsive function, older adults can increase push-off intensity when encouraged to via real-time biofeedback. However, the specific joint-level modifications used by older adults to enhance propulsive force generation has yet to be elucidated.

Does dynamic stability govern propulsive force generation in human walking?

Before succumbing to slower speeds, older adults may walk with a diminished push-off to prioritize stability over mobility. However, direct evidence for trade-offs between push-off intensity and balance control in human walking, independent of changes in speed, has remained elusive. As a critical first step, we conducted two experiments to investigate: (i) the independent effects of walking speed and propulsive force () generation on dynamic stability in young adults, and (ii) the extent to which young adults prioritize dynamic stability in selecting their preferred combination of walking speed and generation.

The independent effects of speed and propulsive force on joint power generation in walking.

Walking speed is modulated using propulsive forces (F) during push-off and both preferred speed and F decrease with aging. However, even prior to walking slower, reduced F may be accompanied by potentially unfavorable changes in joint power generation. For example, compared to young adults, older adults exhibit a redistribution of mechanical power generation from the propulsive plantarflexor muscles to more proximal muscles acting across the knee and hip.

Area-based determination of bone loss using the glenoid arc angle.

In patients with anterior glenohumeral instability, the most commonly observed osseous defect involves the anterior portion of the inferior glenoid. The amount of glenoid bone loss guides surgical treatment, with progressively larger defects not being amenable to arthroscopic soft-tissue procedures. Currently, there is no universally accepted method of quantifying glenoid bone loss.

Electromyographic predictors of residual quadriceps muscle weakness after anterior cruciate ligament reconstruction.

Background: Despite the high prevalence of residual quadriceps muscle weakness after anterior cruciate ligament reconstruction, specific predictive factors have not been identified.

Hypothesis: Electromyographic analysis is a better predictor of residual muscle weakness than is preoperative strength.

Study Design: Prospective cohort study.