Matching Items (11)

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Relating Reactive Stepping Characteristics to Falls in Older Community Dwelling Adults

Description

Background: Falls are a leading cause of injury in older adults with roughly 1 in 4 American's over the age of 65 experiencing a fall. Research that looks at reactive

Background: Falls are a leading cause of injury in older adults with roughly 1 in 4 American's over the age of 65 experiencing a fall. Research that looks at reactive stepping, or the steps a person takes when they encounter a loss of balance, is sparse. Whether a specific aspect of reactive stepping can be linked to falls has yet to be determined. Purpose: The purpose of this study was to determine which reactive stepping characteristics may be correlated with falls in from community dwelling older adults. Methods: 54 older adults (11 fallers & 43 non-fallers) underwent 3 "postural perturbations", in which they leaned back into the testers hands and were released, resulting in one or more reactive steps. Inertial sensors (APDM, inc.) were used to measure participant movement and Quantify reactive steps. Step length and step latency, which is the time it takes for an individual to perform a step, were the primary outcomes measured, along with time to stabilization, number of steps taken, and time until first foot strike. Results: Neither step length or step latency were significantly different in fallers compared to non-fallers (p=0.537 and p=0.431, respectively). However, four square step test was significantly different between the populations (p= 0.045). Conclusions: These results showed that four square step test may be more closely related to falls than step length or latency. When performing fall prevention training, or working with an individual at risk for falling, it may be more beneficial to focus on four square step test and the changes in direction associated with it, as opposed to other stepping characteristics in order to improve their fall risk.

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Date Created
  • 2018-05

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The Effect of an Exercise Program for Adults with Down Syndrome (ExDS) on Balance

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Individuals with Down Syndrome (DS) are subject to a spectrum of behavioral, cognitive and physical impairments. This population is more predisposed to comorbidity and typically has an increased risk of

Individuals with Down Syndrome (DS) are subject to a spectrum of behavioral, cognitive and physical impairments. This population is more predisposed to comorbidity and typically has an increased risk of inactivity resulting in a lower level of fitness. Previous studies on physical activity have shown that routine exercise has similar health benefits for those with DS as those individuals without a disability and in turn progresses their balance ability. Due to limited exercise program opportunities and studies that intentionally investigate the benefits of specific modes of exercise on the DS population, a community-based Exercise Program for Adults with DS (ExDS) was created with the goal of improving their physical and mental health and measuring changes in their balance capabilities throughout the program. ExDS partnered with Arizona State University (ASU) students to create biweekly customized workouts, that followed exercise prescription guidelines, consisting of an aerobic warm-up, main aerobic exercise bout, resistance training, balance training, and stretching for each participant with DS. Participant dynamic and static balance ability was measured using the Berg Balance Scale (BBS) during program pre- and post-assessments. The BBS composite score did not change and no significant improvement was seen in the p-values for each line item of the BBS from pre- to post-testing. For follow-up analyses, the participants with low treatment fidelity were removed. Follow-up analyses showed significant increases in BBS composite score and line item 13 from pre- to post-testing. Treatment fidelity was a limitation in this study and future studies should aim to increase fidelity and consistency of tester for pre- and post-testing. In conclusion, holistic exercise programming for adults with DS appears to benefit balance as long as treatment fidelity is high. It is unclear which mode of exercise had the greatest impact on changes in balance.

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Date Created
  • 2018-12

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Sit-to-stand task with physical and cognitive perturbations: A comparison of linear and nonlinear methods of analyzing postural data

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Variability is inherent in human movement, and poses a challenge to researchers attempting to measure balance. Human movement variability was analyzed using two methods: standard deviation and largest Lyapunov exponent.

Variability is inherent in human movement, and poses a challenge to researchers attempting to measure balance. Human movement variability was analyzed using two methods: standard deviation and largest Lyapunov exponent. The experiment was a sit-to-stand task with physical and cognitive perturbations. The physical perturbation consisted of stable and unstable platform conditions, while the cognitive perturbation consisted of a counting task. The data were collected from 24 healthy young adults. The purpose of this study was to compare the standard deviation and largest Lyapunov exponent as measures of stability, and to determine the Lyapunov exponent's sensitivity to cognitive perturbation. Evidence suggests that the Lyapunov exponent serves as a more accurate indicator of stability than standard deviation, and that it lacks sensitivity to the counting task.

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  • 2016-12

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Intervention Principles to Improve Postural Stability in Older Adults

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The purpose of this paper was to review existing literature on exercise interventions to improve postural stability in older adults in order to assist with the development of a novel

The purpose of this paper was to review existing literature on exercise interventions to improve postural stability in older adults in order to assist with the development of a novel intervention with the same function. A brief review of balance changes with aging is followed by a summary of the methods and findings of various interventions. Many types of interventions are discussed, including resistance training, balance training, t'ai chi, and whole body vibration. The studies show promising results, but none utilize the approach of the proposed intervention. This intervention being developed involves the use of a weighted vest to raise one's center of mass, creating a more unstable posture. Performing exercises or daily activities with the vest may improve balance by training muscles in unsteady conditions. The intervention principles to improve postural stability in older adults are beneficial to the foundation of future studies.

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Date Created
  • 2014-12

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The Effects of Acute Resistance Training (RT) and Assisted Cycle Therapy (ACT) on Balance and Gait in Adults with Down syndromeThe Effects of Acute Resistance Training (RT) and Assisted Cycle Therapy (ACT) on Balance and Gait in Adults with Down syndrome

Description

Down syndrome (DS) is caused by either an extra copy of chromosome 21 or by extra material on chromosome 21. This causes various levels of intellectual disability and issues with

Down syndrome (DS) is caused by either an extra copy of chromosome 21 or by extra material on chromosome 21. This causes various levels of intellectual disability and issues with gross motor skill development which can prevent these individuals from participating in activities of daily living (ADL) such as getting dressed, self-care, or grocery shopping. People with DS have a decreased ability to balance, an abnormal and slower gait pattern, difficulty adapting to new environments, and a lack of improvement in these areas with growth and development when compared to their neurotypical peers. The objective of this study was to determine the immediate effects of resistance training (RT) and assisted cycle therapy (ACT) on adults with DS’s balance ability and gait speed. Each participant completed one session of RT, ACT (stationary cycling with the assistance of a motor to maintain a cadence of at least 35% greater than their voluntary cycling speed), and no training in a randomly selected order. Balance and gait speed were measured by a Clinical Test of Sensory Interaction on Balance (CTSIB) (i.e., eyes open firm surface, eyes closed firm surface, eyes open foam surface, eyes closed foam surface) on a Balance Tracking System Board (Btracks board) and by a Timed Up and Go (TUG) test. A total of ten participants’ data was used for analysis. The measures of total path length (cm), anterior-posterior (AP) excursion, and medial-lateral (ML) excursion were used to analyze the CTSIB. The average time was used to analyze the TUG test. The results showed that the eyes closed foam surface balance task was the most challenging balance task for every participant in every intervention. Furthermore, the most improvement was evident in the eyes closed foam surface balance task from pre to post intervention in all of the interventions. Post hoc tests also indicated statistically significant improvements of path length from pre to post in the RT intervention with the eyes closed foam surface balance task as well as with AP excursion in the ACT intervention with the eyes closed foam surface balance task. Possible explanations for improvements from pre to post in the eyes closed foam balance task across all interventions will be discussed with respect to the length of the intervention, and the effect of strength, social and learned factors on balance in adults with DS.

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Date Created
  • 2020-12

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Evaluating the Effects of Ankle-Foot-Orthoses, Functional Electrical Stimulators, and Trip-specific Training on Fall Outcomes in Individuals with Stroke

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This dissertation aimed to evaluate the effectiveness and drawbacks of promising fall prevention strategies in individuals with stroke by rigorously analyzing the biomechanics of laboratory falls and compensatory movements required

This dissertation aimed to evaluate the effectiveness and drawbacks of promising fall prevention strategies in individuals with stroke by rigorously analyzing the biomechanics of laboratory falls and compensatory movements required to prevent a fall. Ankle-foot-orthoses (AFOs) and functional electrical stimulators (FESs) are commonly prescribed to treat foot drop. Despite well-established positive impacts of AFOs and FES devices on balance and gait, AFO and FES users fall at a high rate. In chapter 2 (as a preliminary study), solely mechanical impacts of a semi-rigid AFO on the compensatory stepping response of young healthy individuals following trip-like treadmill perturbations were evaluated. It was found that a semi-rigid AFO on the stepping leg diminished the propulsive impulse of the compensatory step which led to decreased trunk movement control, shorter step length, and reduced center of mass (COM) stability. These results highlight the critical role of plantarflexors in generating an effective compensatory stepping response. In chapter 3, the underlying biomechanical mechanisms leading to high fall risk in long-term AFO and FES users with chronic stroke were studied. It was found that AFO and FES users fall more than Non-users because they have a more impaired lower limb that is not fully addressed by AFO/FES, therefore leading to a more impaired compensatory stepping response characterized by increased inability to generate a compensatory step with paretic leg and decreased trunk movement control. An ideal future AFO that provides dorsiflexion assistance during the swing phase and plantarflexion assistance during the push-off phase of gait is suggested to enhance the compensatory stepping response and reduce more falls. In chapter 4, the effects of a single-session trip-specific training on the compensatory stepping response of individuals with stroke were evaluated. Trunk movement control was improved after a single session of training suggesting that this type of training is a viable option to enhance compensatory stepping response and reduce falls in individuals with stroke. Finally, a future powered AFO with plantarflexion assistance complemented by a trip-specific training program is suggested to enhance the compensatory stepping response and decrease falls in individuals with stroke.

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Date Created
  • 2019

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Physical Human-Bicycle Interfaces for Robotic Balance Assistance

Description

Riding a bicycle requires accurately performing several tasks, such as balancing and navigation, which may be difficult or even impossible for persons with disabilities. These difficulties may be partly alleviated

Riding a bicycle requires accurately performing several tasks, such as balancing and navigation, which may be difficult or even impossible for persons with disabilities. These difficulties may be partly alleviated by providing active balance and steering assistance to the rider. In order to provide this assistance while maintaining free maneuverability, it is necessary to measure the position of the rider on the bicycle and to understand the rider's intent. Applying autonomy to bicycles also has the potential to address some of the challenges posed by traditional automobiles, including CO2 emissions, land use for roads and parking, pedestrian safety, high ownership cost, and difficulty traversing narrow or partially obstructed paths.

The Smart Bike research platform provides a set of sensors and actuators designed to aid in understanding human-bicycle interaction and to provide active balance control to the bicycle. The platform consists of two specially outfitted bicycles, one with force and inertial measurement sensors and the other with robotic steering and a control moment gyroscope, along with the associated software for collecting useful data and running controlled experiments. Each bicycle operates as a self-contained embedded system, which can be used for untethered field testing or can be linked to a remote user interface for real-time monitoring and configuration. Testing with both systems reveals promising capability for applications in human-bicycle interaction and robotics research.

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Date Created
  • 2020

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Underbalancing and state policies: how China interacts with its East Asian neighbors

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East Asia in the aftermath of the Cold War might provide the most favorable case for realist theory due to historical rivalries, territorial disputes, economic competition, great power politics and

East Asia in the aftermath of the Cold War might provide the most favorable case for realist theory due to historical rivalries, territorial disputes, economic competition, great power politics and deep-rooted realist beliefs among politicians in the region. Yet the fundamental realist prediction of balance of power in the region has not materialized. Neither internal nor external balancing in their original senses is explicitly present. This poses a serious challenge to realism and more broadly, western international relations theories for understanding regional dynamics. Several explanations have been put forward in previous research, such as a total rejection of the applicability of realism for explaining East Asian politics, modifying realism by adding new variables, and focusing on domestic variables. Using a neoclassical realist term, underbalancing, this dissertation goes beyond neoclassical realist theory of underbalancing by reintroducing the distinction between external and internal balancing, which has direct implications for the resources needed for a balancing policy and external reactions to balancing policy. In particular, this approach emphasizes the effect of interaction between states on underbalancing. By doing so, it also highlights what is omitted by realism, namely, the agency of the targeted state at risk of being balanced. In other words, the policy of the state that is aware of its risk of being balanced could draw upon foreign policy tools it possesses to neutralize the balancing efforts from others. This notion of state policies influencing the outcome of balance of power is tested with post-Cold War East Asian politics. The cases included China-Japan and China-ASEAN strategic interactions after the Cold War. Based on materials from public media outlets, official documents and recently leaked U.S. diplomatic cables, this dissertation argues that China's policies towards neighboring states- policies expressed variously through cultural, diplomatic, economic and security initiatives- are indispensable to explain the fact of underbalancing in the region.

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Date Created
  • 2014

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Basins of attraction in human balance

Description

According to the CDC in 2010, there were 2.8 million emergency room visits costing $7.9 billion dollars for treatment of nonfatal falling injuries in emergency departments across the country. Falls

According to the CDC in 2010, there were 2.8 million emergency room visits costing $7.9 billion dollars for treatment of nonfatal falling injuries in emergency departments across the country. Falls are a recognized risk factor for unintentional injuries among older adults, accounting for a large proportion of fractures, emergency department visits, and urgent hospitalizations. The objective of this research was to identify and learn more about what factors affect balance using analysis techniques from nonlinear dynamics. Human balance and gait research traditionally uses linear or qualitative tests to assess and describe human motion; however, it is growing more apparent that human motion is neither a simple nor a linear task. In the 1990s Collins, first started applying stochastic processes to analyze human postural control system. Recently, Zakynthinaki et al. modeled human balance using the idea that humans will remain erect when perturbed until some boundary, or physical limit, is passed. This boundary is similar to the notion of basins of attraction in nonlinear dynamics and is referred to as the basin of stability. Human balance data was collected using dual force plates and Vicon marker position data for leans using only ankle movements and leans that were unrestricted. With this dataset, Zakynthinaki’s work was extended by comparing different algorithms used to create the critical curve (basin of stability boundary) that encloses the experimental data points as well as comparing the differences between the two leaning conditions.

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Date Created
  • 2016

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Critical evaluation and optimization of a hypocycloid wiseman engine

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In nearly all commercially successful internal combustion engine applications, the slider crank mechanism is used to convert the reciprocating motion of the piston into rotary motion. The hypocycloid mechanism, wherein

In nearly all commercially successful internal combustion engine applications, the slider crank mechanism is used to convert the reciprocating motion of the piston into rotary motion. The hypocycloid mechanism, wherein the crankshaft is replaced with a novel gearing arrangement, is a viable alternative to the slider crank mechanism. The geared hypocycloid mechanism allows for linear motion of the connecting rod and provides a method for perfect balance with any number of cylinders including single cylinder applications. A variety of hypocycloid engine designs and research efforts have been undertaken and produced successful running prototypes. Wiseman Technologies, Inc provided one of these prototypes to this research effort. This two-cycle 30cc half crank hypocycloid engine has shown promise in several performance categories including balance and efficiency. To further investigate its potential a more thorough and scientific analysis was necessary and completed in this research effort. The major objective of the research effort was to critically evaluate and optimize the Wiseman prototype for maximum performance in balance, efficiency, and power output. A nearly identical slider crank engine was used extensively to establish baseline performance data and make comparisons. Specialized equipment and methods were designed and built to collect experimental data on both engines. Simulation and mathematical models validated by experimental data collection were used to better quantify performance improvements. Modifications to the Wiseman prototype engine improved balance by 20 to 50% (depending on direction) and increased peak power output by 24%.

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Date Created
  • 2011