No description available.

No description available.

No description available.

No description available.

Spinal cord injury results in life-long damage to sensory and motor functions. Recovery from these injuries is limited and often insufficient because the lack of stimulation from supraspinal systems results in further atrophy of the damaged neural pathways. Current studies have shown that repeated sensory activity obtained by applying stimulation enhances plasticity of neural circuits, and in turn increases the ability to create new pathways able to compensate for the damaged neurons. Functional electrical stimulation has been proven to show success in this form of rehabilitation, but it has its limitations. Stimulating neural pathways with electricity results in also stimulating surrounding neurons and muscle tissue. This results in attenuation of the intended effect. The use of optogenetics mitigates this issue, but comes with its own complications. Optogenetics is a growing method of neural stimulation which utilizes genetic modification to create light activated ion channels in neurons to allow for activation or suppression of neural pathways. In order to activate the neurons, light of the appropriate wavelength must be able to penetrate the nerves. Applying the light transcutaneously is insufficient, as the skin and muscle tissue attenuate the signal. The target nerve may also move relative to an external point on the body, creating further inconsistency. Specifically in the case of using a rat model, an external object will be immediately removed by the animal. This thesis seeks to address this issue for a rat model by designing a nerve cuff capable of both optical and electrical stimulation. This device will be scaled to fit the sciatic nerve of a rat and allow for both optical activation and inhibition of the neural activity. It will be wired such that each stimulus may be operated individually or in conjunction with each other. The simultaneous stimulation is required in order to validate the neural inhibition facet. The circuit itself will be validated through the use of an optical stimulation rig, using a photoreceptor in place of an EMG. The application of the cuff will be verified in a live naive rat. Aim 1: Design and build an implantable electrical stimulation nerve cuff for the sciatic nerve of rats. An electrical nerve cuff for the sciatic nerve of a rat will be designed and assembled such that it is able to reliably activate the H-reflex. For it to be used in a walking rat, the cuff must be compatible with a head mount in order to prevent the rat from being able to chew at the wiring or their exit point. The cuff will be controlled through a Matlab program that is able to output specified signals and compare these outputs directly with the resultant EMG inputs. Aim 2: Implement LEDs onto the cuff and perform validation experiments. Light delivery capability will be added to the cuff through the use of LEDs. The functionality of the cuff will be validated through tests on naive rats. If successful, only an electric stimulation will result in a muscle twitch. An optical stimulation should result in no twitches, which would then validate that no current is leaking from the nerve cuff, given that the rat does not express any light sensitive protein channels. Ultimately, with a rat expressing ChR2 opsins on the sciatic nerve, an activation of the nerve using a blue light of wavelength 470nm will result in activating an h-wave without an m-wave when optically stimulated. Similarly, using the nerve cuff with a rat expressing ArchT opsins will result in suppressing the h-wave from an electric stimulation once the sciatic nerve is illuminated with green light of a wavelength of 520 nm. / Bioengineering

No description available.

As many as 1.9 million sports-related concussions occur annually in youth sports in the United States (U.S.). Often considered a transient injury, research has begun to relate sports-related concussions to long-term neurodegeneration. Youth athletes are considered to be more vulnerable to concussion than their adult counterparts. The research presented in this dissertation was aimed at promoting player safety in youth football as it relates to concussion. Balance dysfunction is often cited as one of the most common symptoms associated with a concussion. Several postural control assessments were assessed in order to develop a youth-specific testing protocol. A cognitive, dual-task assessment was presented for clinician use in the management of sports-related concussion. On-field data collected from youth football players wearing instrumented helmets allowed for characterization of the biomechanics of head impacts and concussions for this population. A youth concussion risk function was developed using head impact data collected from youth football players with medically diagnosed concussions. The proposed testing standard for youth football helmets was assessed in the laboratory and related to on-field head impact data to determine how representative the standard is of youth football head impacts. Helmet safety standards and certifications operate on a pass-fail threshold that does not allow consumers to weigh the relative performance of helmets. A modification of the Summation of Tests for the Analysis of Risk (STAR) evaluation system was developed for youth football helmets. Data presented in this dissertation have direct application to the development of future helmet safety standards and potentially other safety applications as well. / Doctor of Philosophy / As many as 1.9 million sports-related concussions occur annually in youth sports in the United States (U.S.). Often considered a short-term injury, research has begun to relate sports-related concussions to long-term breakdowns in neurological processes. Youth athletes are considered to be more vulnerable to concussion than their adult counterparts. The research presented in this dissertation was aimed at informing player safety in youth football as it relates to concussion. Abnormal balance is often cited as one of the most common symptoms associated with a concussion. Several balance assessments were assessed in order to develop a youth-specific testing protocol. An assessment involving quiet standing while being subjected to a cognitive task was presented for clinician use in the management of sports-related concussion. On-field data collected from youth football players wearing instrumented helmets allowed for characterization of the biomechanics of head impacts and concussions for this youth population. A youth concussion risk function was developed that related linear and rotational head acceleration to risk of concussion. The proposed testing standard for youth football helmets was assessed in the laboratory and observed to assess the most severe head impacts a youth player may experience during participation in football. A modification of the Summation of Tests for the Analysis of Risk (STAR) evaluation system was developed for youth football helmets in order to give consumers more information about helmet performance beyond the pass-fail criteria of the helmet standards. Data presented in this dissertation have direct application to the development of future helmet safety standards and potentially other safety applications as well.

Equines have been used for utilized for manual labor, recreation, and companionship amongst many other valuable conveniences since their domestication. As the modern horse progressed from livestock to athlete, attention was paid to the body conformation to be used as an indicator of biomechanics and can dictate equine performance. Poor conformation can put physical limitations on the body and predispose the horse to injury and chronic disease. When not managed properly, these flaws can lead to injury, lameness, and premature retirement in sport horses. The distal limb is composed of tendons and ligaments that are all susceptible to tear or rupture. Protective wraps or boots are typically applied to the distal limb prior to exercise to prevent superficial injury from the environment or interference. However, these preventatives can trap heat against the skin which can have detrimental effects on the fibroblasts which can lead to failure. It was not until the early twentieth century that the idea of equine physiotherapy was adopted, and practices changed to meet remedial needs and create a sustainable, healthy equine athlete. Equine physiotherapy is a broad-spectrum term used to describe the therapeutic efforts made to keep the body in good health by means of prevention of injury to improve or maintain performance. Traditionally, therapeutics are administered by a veterinarian or trained professional in the event of an existing injury. In recent years therapeutics have been commercialized and are readily available for everyday preventative use. The most common readily available treatments being variations of pulsating electromagnetic fields (PEMF), vibration therapy, cryotherapy, and thermotherapy. When used prior to or after exercise, the therapeutics are designed to prepare the body for exercise and improve recovery by increasing circulation and down regulating the inflammatory response. The studies performed evaluate the efficacy of Rambo®Ionic (Horseware, Dundalk,Ireland), Lux Ceramic Therapy® (Schneider Saddlery Co., Inc., Ohio, USA), and Ice-Vibe® (Horseware, Dundalk,Ireland) therapeutic boots when applied to the distal limb as per manufacturer recommendation. The first study evaluated the therapeutic boots ability to alter performance performing gait analysis using the ALOGO™ MovePro (Alogo Technologies, Switzerland) stride sensor, blood analysis measuring serum concentrations of C reactive protein (CRP), basic fibroblast growth factor (bFGF) and tenascin-C (TN-C), and capturing thermal images of the distal limb using an HT-19 thermal imaging camera (HTI, La Vergne, TN). In this study, eight healthy horses were exercised for approximately ten minutes per day for five consecutive days. There was a ten-day washout period where the horse received no treatment between each period; there was a total of four periods. The second study only evaluated Rambo®Ionic (Horseware, Dundalk,Ireland) and Ice-Vibe® (Horseware, Dundalk,Ireland) therapeutic boots on seventeen healthy horses in the Virginia Tech equitation lesson program. There were three periods with five days of consecutive data collection and a ten-day washout period in between where the horses received no treatment. Gait analysis was measured using the ALOGO™ MovePro (Alogo Technologies, Switzerland) stride sensor and a blind behavioral analysis was performed to analyze behavioral changes under saddle in response to a rider. / Master of Science / Equines have been used for utilized for manual labor, recreation, and companionship amongst many other valuable conveniences since their domestication. As the modern horse progressed from livestock to athlete, attention was paid to the structure of the horse, otherwise known as conformation. Conformation is an indicator of physical movement and can dictate what uses the horse is best suited for. In undesirable cases, poor conformation can put physical limitations on the body and predispose the horse to injury and chronic disease. When not managed properly, these flaws can lead to injury, lameness, and premature retirement in sport horses. The distal limb is a particularly vulnerable structure. It is free of muscle and is comprised of tendons, ligaments, and mobile joints. A protective wrap or boot is typically applied to the distal limb prior to exercise which can have detrimental effects on the cellular components of the associated structures which can lead to failure. It was not until the early twentieth century that the idea of equine physiotherapy was adopted, and practices changed to meet remedial needs and create a sustainable, healthy equine athlete. Equine physiotherapy is a broad-spectrum term used to describe the therapeutic efforts made to keep the body in good health by means of prevention of injury to improve or maintain performance. Traditionally, therapeutics are administered by a veterinarian or trained professional in the event of an existing injury. In recent years therapeutics have been commercialized and are readily available for everyday preventative use. The most common readily available treatments being variations of pulsating electromagnetic fields (PEMF), vibration therapy, cryotherapy, and thermotherapy. When used prior to or after exercise, the therapeutics are designed to prepare the body for exercise and improve recovery by increasing circulation and down regulating the inflammatory response. The studies performed evaluate the efficacy of Rambo®Ionic (Horseware, Dundalk,Ireland), Lux Ceramic Therapy® (Schneider Saddlery Co., Inc., Ohio, USA), and Ice-Vibe® (Horseware, Dundalk,Ireland) therapeutic boots when applied to the distal limb as per manufacturer recommendation. The first study evaluated the therapeutic boots ability to alter performance performing gait analysis using the ALOGO™ MovePro (Alogo Technologies, Switzerland) stride sensor, blood analysis measuring serum concentrations of C reactive protein (CRP), basic fibroblast growth factor (bFGF) and tenascin-C (TN-C), and capturing thermal images of the distal limb using an HT-19 thermal imaging camera (HTI, La Vergne, TN). In this study, eight healthy horses were exercised for approximately ten minutes per day for five consecutive days. There was a ten-day washout period where the horse received no treatment between each period; there was a total of four periods. The second study only evaluated Rambo®Ionic (Horseware, Dundalk,Ireland) and Ice-Vibe® (Horseware, Dundalk,Ireland) therapeutic boots on seventeen healthy horses in the Virginia Tech equitation lesson program. There were three periods with five days of consecutive data collection and a ten-day washout period in between where the horses received no treatment. Gait analysis was measured using the ALOGO™ MovePro (Alogo Technologies, Switzerland) stride sensor and a blind behavioral analysis was performed to analyze behavioral changes under saddle in response to a rider.

Gait biomechanics have been studied extensively. Many existing studies, though, have been performed in a controlled laboratory setting, and assumed that measures obtained are representative of gait in a naturalistic environment (e.g., outdoors). Several environmental and psychological factors may contribute to differences between these environments, and identifying any such differences is important for generalizing results outside the laboratory. The purpose of this study was to test the implicit assumption that gait inside a research laboratory does not differ from gait outdoors, when a participant is unaware of data collection in the latter. Means and interquartile ranges (IQR) of several spatio-temporal and kinematic gait characteristics were obtained from 19 young adults during several gait conditions both inside a laboratory environment and outdoors. Four comparisons were made between the two environments, including conditions involving: 1) self-selected speeds, 2) matching outdoors self-selected speeds, 3) matching outdoors self-selected speeds while carrying a crate, and 4) matching outdoors hurried speeds. Spatio-temporal variables differed between the two environments in that self-selected walking speed was 1.7% slower inside the lab and cadence was 1.4-2.6% lower for all four comparisons. At heel contact, the foot was 4.4-8.1% more dorsiflexed inside the lab for all comparisons except in matching hurried outdoors walking speed. Minimum toe clearance was 6.5-16.2% lower outdoors for all four comparisons. It is unclear if these differences impair the ability to generalize gait study results to outside the laboratory. Nevertheless, some specific differences exist in gait between environments, and that research should recognize. / Master of Science

Falls due to slipping are a serious occupational concern. Slipping is estimated to cause 40-50% of all fall-related injuries. In 2011, falls resulted in 22% of injuries requiring days away from work. Epidemiological data indicates that older and obese adults experience more falls than young, non-obese individuals. An increasingly heavier and older workforce may be exacerbating the problem of slip-induced falls in the workplace. The purpose of this study was to examine the effects of obesity and age on slip severity and fall outcome following an unexpected slip. Four groups of participants (young obese, young non-obese, older obese, older non-obese) were exposed to an unexpected slip perturbation. Slip severity (slip distance, slip duration, average slip velocity and peak slip velocity) and slip outcome (fall or recovery) were compared between groups. Obese individuals experienced 8.25% faster slips than non-obese individuals in terms of average slip velocity (p=0.022). Obesity did not affect slip distance, slip duration or peak slip velocity. Obese individuals also experienced more falls; 33.3% of obese individuals fell compared to 8.6% of non-obese (p=0.005). Obese individuals were 8.24 times more likely to experience a fall than non-obese individuals, when adjusting for age, gender and gait speed. No age effects were found for slip severity or slip outcome. This study revealed that obese participants experienced faster slips and more falls than their non-obese counterparts. These results, along with epidemiological data reporting higher fall rates among the obese, indicate that obesity may be a significant risk factor for experiencing slip-induced fall. / Master of Science