Fall Prevention Training for Service Members With an Amputation or Limb Salvage Following Lower Extremity Trauma.

Introduction: Recent military conflicts have resulted in a significant number of lower extremity injuries to U.S. service members that result in amputation or limb preservation (LP) procedures.

Military training alters the fractal behavior of step width.

Non-linear analyses have been successfully applied to gait with evidence that fractal behavior of gait-related variables provide insights into function. Specifically, shifts in the fractal behavior of step width from pink toward white noise reflects a loss of complexity and diminished adaptive capacity and functionality. We previously reported an apparent difference in the fractal behavior of step width during treadmill walking between Service members with transtibial amputations and able-bodied civilian.

Common fall-risk indicators are not associated with fall prevalence in a high-functioning military population with lower limb trauma.

Background: Persons with lower limb trauma are at high risk for falls. Although there is a wide range of measures used to assess stability and fall-risk that include performance measures, temporal-spatial gait parameters, and nonlinear dynamic stability calculations, these measures are typically derived from fall-prone populations, such as older adults. Thus, it is unclear if these commonly used fall-risk indicators are effective at evaluating fall-risk in a younger, higher-functioning population of Service members with lower limb trauma.

Developing and Establishing Biomechanical Variables as Risk Biomarkers for Preventable Gait-Related Falls and Assessment of Intervention Effectiveness.

The purpose of this review is to position the emerging clinical promise of validating and implementing biomechanical biomarkers of falls in fall prevention interventions. The review is framed in the desirability of blunting the effects of the rapidly growing population of older adults with regard to the number of falls, their related injuries, and health care costs. We propose that biomechanical risk biomarkers may be derived from systematic study of the responses to treadmill-delivered perturbations to both identify individuals with a risk of specific types of falls, such as trips and slips as well as quantifying the effectiveness of interventions designed to reduce that risk.

Assessments of trunk postural control within a fall-prevention training program for service members with lower limb trauma and loss.

Background: Trunk postural control (TPC) is critical in maintaining balance following perturbations (i.e., avoiding falls), and impaired among persons with lower extremity trauma, contributing to elevated fall risk.

Treadmill-belt width, but not feedback from the lower visual field, influences the noise characteristics of step width time series.

Step kinematic variability, which has been associated with gait-related fall risk, is thought to be attributed to neuromotor noise. Altered neuromotor control of step kinematics would be expected to manifest as changes in the noise-related characteristics of the step kinematic time series. This study determined the effects of eliminating feedback from the lower visual field and reducing treadmill-belt width on the noise characteristics of step width time series and statistical measures of step width variability during treadmill walking.

Task-Specific Perturbation Training Improves the Recovery Stepping Responses by Women With Knee Osteoarthritis Following Laboratory-Induced Trips.

Trip-specific training improves the kinematics of trip-specific compensatory stepping response (CSR) in the laboratory and reduces prospectively measured trip-related fall-rate of middle age and older women. We examined whether one session of trip-specific perturbation training could improve recovery step kinematics in women with knee osteoarthritis (OA), a condition known to increase fall risk. Seventeen women with self-reported symptomatic knee OA (age 61.

Ensuring accurate estimates of step width variability during treadmill walking requires more than 400 consecutive steps.

Falls to the side are associated with significant morbidity, including increased risk of hip and radius fracture. Although step width variability, as measured by standard deviation, has been hypothesized to be associated with falls to the side, there is little supporting evidence. The extent to which such a relationship could be reliably established, however, is dependent on the accuracy with which step width, and thus step width variability, is measured.

A single session of trip-specific training modifies trunk control following treadmill induced balance perturbations in stroke survivors.

Background: Individuals with stroke are at significant risk of falling. Trip-specific training is a targeted training approach that has been shown to reduce falls in older adults and amputees by enhancing the compensatory stepping response required to prevent a fall. Still, individuals with stroke have unique deficits (e.

Performance of an attention-demanding task during treadmill walking shifts the noise qualities of step-to-step variation in step width.

Background: The fractal scaling evident in the step-to-step fluctuations of stepping-related time series reflects, to some degree, neuromotor noise.

Research Question: The primary purpose of this study was to determine the extent to which the fractal scaling of step width, step width and step width variability are affected by performance of an attention-demanding task. We hypothesized that the attention-demanding task would shift the structure of the step width time series toward white, uncorrelated noise.

Trip-specific training enhances recovery after large postural disturbances for which there is NO expectation.

Purpose: Informed consent usually provides foreknowledge of experimental methods that can potentially increase expectation of stimuli and, therefore, influence the response. We determined the effects of increased expectation and trip-specific training on the recovery response following a treadmill-delivered, trip-specific disturbance. To deliver unexpected disturbances, subjects were deceived during the informed consent process.

Bilateral early activity in the hip flexors associated with falls in stroke survivors: Preliminary evidence from laboratory-induced falls.

Objective: Falls are the most common and expensive medical complication following stroke. Hypermetric reflexes have been suggested to impact post-stroke balance but no study has evaluated reflex amplitudes under real conditions of falls in this population. Our objective was to quantify the early reflexive responses during falls induced in the laboratory.

Characteristics and adaptive strategies linked with falls in stroke survivors from analysis of laboratory-induced falls.

Falls are the most common and expensive medical complication in stroke survivors. There is remarkably little information about what factors lead to a fall in stroke survivors. With few exceptions, the falls literature in stroke has focused on relating metrics of static balance and impairment to fall outcomes in the acute care setting or in community.

Relating minimum toe clearance to prospective, self-reported, trip-related stumbles in the community.

Background: Individuals with transtibial amputation are at increase risk of falling. The absence of an ankle joint and the associated musculature in these individuals can reduce clearance between the prosthetic foot and ground during the swing phase of gait, which may increase the risk of stumbling and in turn falling.

Objectives: To associate minimum toe clearance during gait in the laboratory with community-based, trip-related stumbles by individuals with transtibial amputation using conventional feet.

Knee osteoarthritis negatively affects the recovery step following large forward-directed postural perturbations.

The reasons for higher fall risk of people with osteoarthritis (OA) compared to people without OA are not known. It is possible that following a loss of balance OA may negatively affect the recovery stepping response. Stepping responses have not been reported for people with knee OA.

Age-related differences in the maintenance of frontal plane dynamic stability while stepping to targets.

Older adults may be vulnerable to frontal plane dynamic instability, which is of clinical significance. The purpose of the current investigation was to examine the age-related differences in frontal plane dynamic stability by quantifying the margin of stability and hip abductor moment generation of subjects performing a single crossover step and sidestep to targets that created three different step widths during forward locomotion. Nineteen young adults (9 males, age: 22.

Active dorsiflexing prostheses may reduce trip-related fall risk in people with transtibial amputation.

People with amputation are at increased risk of falling compared with age-matched, nondisabled individuals. This may partly reflect amputation-related changes to minimum toe clearance (MTC) that could increase the incidence of trips and fall risk. This study determined the contribution of an active dorsiflexing prosthesis to MTC.

Expectation of an upcoming large postural perturbation influences the recovery stepping response and outcome.

Tripping during locomotion, the leading cause of falls in older adults, generally occurs without prior warning and often while performing a secondary task. Prior warning can alter the state of physiological preparedness and beneficially influence the response to the perturbation. Previous studies have examined how altering the initial "preparedness" for an upcoming perturbation can affect kinematic responses following small disturbances that did not require a stepping response to restore dynamic stability.

Obesity as a Factor Contributing to Falls by Older Adults.

The growth of the worldwide population of older adults presents significant challenges, many inter-related, that range from the health of individuals to the health of national economies. In the US, more than one-third of older adults may be obese, a condition that may independently increase the risk for mobility impairment, fall-related injury and, possibly, costs of post-injury treatment and care. The effectiveness of conventional exercise-based fall prevention programs is significant but smaller than both the annual rate of falling of older adults and rate of growth of this population, who are at greatest risk for injurious falls.

Exercise-based fall prevention: can you be a bit more specific?

Trip-specific perturbation training reduces trip-related falls after laboratory-induced trips and, prospectively, in the community. Based on an emerging body of evidence, we hypothesize that using task-specific perturbation training as a stand-alone approach or in conjunction with conventional exercise-based approaches will improve the effectiveness of fall prevention interventions significantly.

The influence of age on the thresholds of compensatory stepping and dynamic stability maintenance.

The purpose of this study was to investigate the effects of age on compensatory-stepping thresholds and dynamic stability maintenance in response to postural disturbances. It was hypothesized that, with older age, anterior but not posterior stepping thresholds would be reduced. Thirteen young adults (31.

Task-specific fall prevention training is effective for warfighters with transtibial amputations.

Background: Key factors limiting patients with lower extremity amputations to achieve maximal functional capabilities are falls and fear of falling. A task-specific fall prevention training program has successfully reduced prospectively recorded trip-related falls that occur in the community by the elderly. However, this program has not been tested in amputees.

Frontal plane margin of stability is increased during texting while walking.

Injurious falls associated with cell phone use during ambulation are increasingly common. Studies examining texting while walking suggest this task alters the attentional component of walking to the extent that safety may be compromised. Here, we quantified the extent to which frontal plane dynamic stability while walking was affected by the cognitive and physical demands of texting.

An apparent contradiction: increasing variability to achieve greater precision?

To understand the relationship between variability of foot placement in the frontal plane and stability of gait patterns, we explored how constraining mediolateral foot placement during walking affects the structure of kinematic variance in the lower-limb configuration space during the swing phase of gait. Ten young subjects walked under three conditions: (1) unconstrained (normal walking), (2) constrained (walking overground with visual guides for foot placement to achieve the measured unconstrained step width) and, (3) beam (walking on elevated beams spaced to achieve the measured unconstrained step width). The uncontrolled manifold analysis of the joint configuration variance was used to quantify two variance components, one that did not affect the mediolateral trajectory of the foot in the frontal plane ("good variance") and one that affected this trajectory ("bad variance").