Experimental identification and analytical modelling of human walking forces: Literature review

Reduced bone mass in daughters of women with osteoporosis

Individuals with spinal cord injury (SCI) can face decades with permanent disabilities. Advances in clinical management have decreased morbidity and improved outcomes, but no randomized clinical trial has demonstrated the efficacy of a repair strategy for improving recovery from SCI. Here, we summarize recent advances in biological and engineering strategies to augment neuroplasticity and/or functional recovery in animal models of SCI that are pushing toward clinical translation. Advances in cellular regeneration and technical approaches to spinal cord repair are on the verge of being translated into clinical trials.

Spinal cord repair: advances in biology and technology.

When investigating the dynamics of three-dimensional multi-body biomechanical systems it is often difficult to derive spatiotemporally directed predictions regarding experimentally induced effects. A paradigm of 'non-directed' hypothesis testing has emerged in the literature as a result. Non-directed analyses typically consist of ad hoc scalar extraction, an approach which substantially simplifies the original, highly multivariate datasets (many time points, many vector components). This paper describes a commensurately multivariate method as an alternative to scalar extraction. The method, called 'statistical parametric mapping' (SPM), uses random field theory to objectively identify field regions which co-vary significantly with the experimental design. We compared SPM to scalar extraction by re-analyzing three publicly available datasets: 3D knee kinematics, a ten-muscle force system, and 3D ground reaction forces. Scalar extraction was found to bias the analyses of all three datasets by failing to consider sufficient portions of the dataset, and/or by failing to consider covariance amongst vector components. SPM overcame both problems by conducting hypothesis testing at the (massively multivariate) vector trajectory level, with random field corrections simultaneously accounting for temporal correlation and vector covariance. While SPM has been widely demonstrated to be effective for analyzing 3D scalar fields, the current results are the first to demonstrate its effectiveness for 1D vector field analysis. It was concluded that SPM offers a generalized, statistically comprehensive solution to scalar extraction's over-simplification of vector trajectories, thereby making it useful for objectively guiding analyses of complex biomechanical systems.

Vector field statistical analysis of kinematic and force trajectories (vol 46, pg 2394, 2013)

It has been asserted that speed alone is an effective indicator of the degree of gait abnormality. To determine the validity of this assertion, relationships between velocity and 18 other temporal gait parameters were determined in 25 patients with a first hemispheric stroke resulting in hemiplegia or hemiparesis of at least one month duration. Gait characteristics were recorded using footswitches connected to a portable computerized monitoring device. Velocity was found to be significantly correlated with cadence, mean cycle duration, mean cycle length, hemiplegic limb stance phase duration, nonhemiplegic limb stance phase duration and percent, nonhemiplegic limb swing phase percent, double support phase duration and percent, hemiplegic limb swing/stance phase ratio, nonhemiplegic limb swing/stance phase ratio, and swing phase symmetry ratio but not with the hemiplegic limb stance phase percent, hemiplegic limb swing phase duration and percent, nonhemiplegic limb swing phase duration, stance phase symmetry ratio, and overall asymmetry ratio. Velocity is related to most, but not all, of the other temporal measures of hemiplegic gait. A comprehensive gait evaluation should also include characterization of the degree of asymmetry and descriptions of individual phase durations and proportions (particularly hemiplegic stance and swing percentages).

Hemiplegic gait: Relationships between walking speed and other temporal parameters

Forefoot, rearfoot and shank coupling: effect of variations in speed and mode of gait.

Changes in foot and lower limb coupling due to systematic variations in step width.

The coronal and sagittal plane leg movements of 24 experienced male cyclists were assessed using video analysis while cycling on a Kingcycle windload simulator. The cyclists were grouped into those with a history of injury and an asymptomatic group on the basis of self-reported injury status. The ages, cycling experience, competition distances and competition speeds of the two groups were compared using Student's t-test. No significant differences (P < 0.05) were found for any of these variables. The maximum and minimum shank adduction, shank adduction velocities, knee flexion and ankle dorsiflexion values were also compared using Student's t-test. Significant differences were found at the point of maximum adduction (1.9 degrees; P = 0.019) and minimum dorsiflexion (4.9 degrees; P = 0.014). These differences indicated more dorsiflexion and greater abduction on the part of the symptomatic cyclists, supporting previous research that found that cyclists with a history of injury differ from those without a history of injury in the coronal plane leg movement patterns they adopt. Also, the most extreme medial position of the knee relative to the ankle occurred during knee extension. This supports the potential injury mechanism proposed by Francis (1986), which had previously only been examined using coronal plane kinematics.

/pdf/kinematics-of-cycling-in-relation-to-anterior-knee-pain-and-3a1wsp1zyi.pdf

Neil Messenger

Papers

Forefoot, rearfoot and shank coupling: effect of variations in speed and mode of gait.

Changes in foot and lower limb coupling due to systematic variations in step width.

Kinematics of cycling in relation to anterior knee pain and patellar tendinitis

Sequential therapy of anti-Nogo-A antibody treatment and treadmill training leads to cumulative improvements after spinal cord injury in rats.

Energetics of paraplegic walking