A Neuromechanical Model of Reduced Dorsiflexor Torque During the Anticipatory Postural Adjustments of Gait Initiation.

Anticipatory postural adjustments (APAs) precede gait initiation and function to accelerate the center of mass forward and towards the initial stance leg. Impairments in APA generation, such as those seen in people with Parkinson's disease (PD), can impact the quality of the first step. An initial burst of activity in the dorsiflexor muscle (tibialis anterior) of the stepping leg is an important contributor to the posterior excursion of the center of pressure that accelerates the center of mass forward during an APA.

Improving regions of deviation gait symmetry analysis with pointwise T tests.

The regions of deviation method has been proposed as a technique for identifying regions of the gait cycle where joint motion deviates from normal (Shorter et al., 2008). The original statistical analysis distinguished only peak values during stance and swing.

Quantifying complexity and variability in phase portraits of gait.

Background: Injuries to the lower extremity often cause limitations to joint motion and alter movement patterns of limb segments during gait. We hypothesized that complexity and variability of limb segment motion during gait would increase in both limbs due to unilateral injury. Using simulated injury to generate asymmetric gait, we developed new methods to quantify changes in the complexity and variability of limb segment angular phase portraits.

Differences in gait complexity and variability between children with and without developmental coordination disorder.

We used elliptical Fourier analysis (EFA) to examine potential differences in the complexity and variability of gait of children with (N=10) and without (N=10) Developmental Coordination Disorder (DCD). Children with DCD generated movement patters with larger variability and complexity than typically developing (TD) children. In addition, children with DCD exhibited greater asymmetry in their movement patterns compared to TD children.

Quantifying variability in phase portraits: application to gait ontogeny.

We describe new Fourier- and shape-based methods for quantifying variation in phase-portraits, and re-analyze previously-published ontogenetic and adult data [Clark, J. E., & Phillips, S.