AHPRC Research Pilot Awardees

Ischemic Conditioning Improves Leg Function Post Stroke

PI: Dr. Allison Hyngstrom, Chair and Associate Professor of Physical Therapy; 

Co-PI: Dr. Matthew Durand, Assistant Professor of Physical Medicine and Rehabilitation, Medical College of Wisconsin

Abstract: After stroke, the nervous system cannot fully activate the affected musculature which leads to force generating deficits and changes in the vascular response to exercise. These impairments contribute to increased muscle fatigability (the acute, exercise induced reaction in force) post stroke which limits task endurance for activities such as walking. The purpose of this study is to examine if a non-invasive intervention, called ischemic conditioning (IC), can improve muscle fatigability through increased neural activation of the paretic leg musculature and the peripheral vascular response to exercise. Briefly, IC is a non-invasive stimulus which is triggered by using a blood pressure cuff to briefly occlude blood flow to the tissue of interest (the paretic leg), making the tissue transiently ischemic. In healthy individuals, the IC stimulus is known to increase the excitability of motor systems and improve arterial endothelial cell function and local regulation of blood flow, but the effects of IC in individuals with stroke are unknown. In 15 individuals with chronic stroke, we will measure sub-maximal knee extension contraction task duration at baseline and in response to a single session of IC or IC Sham. Interpretive measures of knee extensor strength, muscle activation, the regulation of peripheral blood flow to the knee extensors, and popliteal artery endothelial function will also be made. Compared to baseline and IC Sham measurements, we anticipate that IC will improve neuromuscular fatigability (increased task duration) and will be accompanied by increased strength, magnitude of muscle activation, and peripheral blood flow and endothelial function. Our interdisciplinary and interinstitutional team will be the first to quantify the effects of IC, a non-invasive, cost-effective intervention, on motor and vascular function in chronic stroke. Future studies conducted at the AHPRC will investigate the neural and humoral mechanisms of IC and the efficacy of IC compared with other walking adjuncts. 

 

The Role of Vascular Dysfunction in Fatigue in Adults with Prediabetes and Type 2 Diabetes

PI: Dr. Kathleen Lukaszewicz, Clinical Assistant Professor of Physical Therapy 

Co-PI: Dr. Jonathon Senefeld, Postdoctoral Research Associate, Exercise Science, Physical Therapy

Abstract: Type 2 diabetes (T2D) is a chronic metabolic disorder characterized by hyperglycemia with an increasing prevalence worldwide. Exercise is the cornerstone of management of T2D and is most efficacious if applied during the prediabetes stage when glycemia is elevated below the diabetic threshold. Adherence to exercise training is commonly limited in clinical populations due to excessive fatigability during exercise. Our laboratory demonstrated that across the diabetic spectrum, from prediabetes to T2D, people with this disease have greater fatigability of lower limb muscles than controls. In a study of only people with T2D, greater exercise fatigability was associated with reduced blood flow to the exercising muscle. Thus, our working hypothesis is that vascular dysfunction limits blood flow delivery during exercise causing greater fatigability in both people with T2D and in people in the earliest disease stage (i.e. prediabetes). Aim 1 will compare leg blood flow in response to a dynamic fatiguing task of the lower limb in people across the spectrum of the disease, including age and BMI-matched controls, people with prediabetes and diabetes. Aim 2 will assess vascular reactivity of small skeletal muscle arterioles extracted from human muscle biopsies to make a direct measurement of the ability of the blood vessel to respond to stimuli that would normally occur during exercise. This is a unique technique only performed on human muscle tissue by one other laboratory worldwide with the current body of knowledge on blood flow mechanisms relying on indirect assessments in vivo. By using isolated human arterioles from skeletal muscle, we can chemically manipulate the tissue in ways not possible in vivo. These outcomes will provide necessary pilot data for a clinical trial that can be conducted in the AHPRC and will translate into the development of exercise programs specific to the needs of people with T2D and prediabetes. 

 

Recovery from Concussion: Longitudinal Tracking of Sensorimotor Adaptations in Student Athletes

PI:  Dr. Robert A. Scheidt, Professor of Biomedical Engineering

Co-PI: Dr. Carolyn Smith, Clinical Assistant Professor of Physical Therapy 

Co-PI: Dr. Lee Ann Mrotek, Research Professor of Biomedical Engineering

Co-PI: Dr. James B. Hoelzle, Professor of Psychology

Abstract: Sport-related concussion (SRC) transiently degrades memory and attention, which can lead to persistent cognitive and sensorimotor performance deficits. Near-term objectives of our research are to: (1) understand how SRC impacts the neural mechanisms of sensorimotor memory and attention that enable skilled motor performance; (2) quantify how those mechanisms change over time; and (3) develop a quick, sideline test of SRC severity that cannot be intentionally falsified. Long-term, we seek to apply our results to optimize SRC recovery on an individual-by-individual basis by applying physical and mental exercise as medicine. 

This project will achieve three objectives addressing the AHPRC's special emphasis on concussion research while fostering a new collaboration between Biomedical Engineering's Neuromotor Control Laboratory, Psychology's Neuropsychology and Personality Laboratory and MU Athletics. Objective 1 establishes partnership with MU Athletics to evaluate the sensorimotor and cognitive performance of concussed student-athletes using procedures based on those established by our prior work. This partnership will be built on respect for the student-athletes, their time, and their academic and athletic obligations. Objective 2 will enhance the sensitivity and efficiency of our procedures by integrating a novel and cognitively-challenging movement task that also permits streamlining of data collection. Objective 3 will establish the validity of the sensorimotor concussion testing by verifying our assertion that our novel test of SRC severity cannot be intentionally falsified. This work is timely and necessary  because current sideline and clinical assessments of SRC lack sensitivity and validity. 

The proposed work is important because it fills a knowledge gap related to how sensorimotor memory and attention recover in the days immediately following SRC. It is also important because we will test the extent to which baseline results of our novel assessment of concussion severity can be intentionally manipulated to mask SRC severity. 

 

Optimizing Performance and Minimizing Risk of Injury in Student-Athletes

PI: Dr. Kristof Kipp, Associate Professor of Exercise Science 

Co-PI: Dr. Janelle Cross, Assistant Professor of Orthopaedic Surgery, Medical College Of Wisconsin

Co-I: Dr. Iqbal Ahamed, Professor of Mathematics, Statistics, & Computer Science

Co-I: Dr. Gary Krenz, Professor of Mathematics, Statistics, & Computer Science

Co-I: Dr. Dong Hye Ye, Assistant Professor of Electrical and Computer Engineering

Co-I: Dr. Yaguang Zhu, Assistant Professor of Communication Studies 

Abstract: Two major goals of sports training and competition are to optimize athlete performance and minimize risk of injury. The goals of this project are to leverage player-tracking and wearable technologies to 1) compare player-tracking data against biomechanical loads experienced by the body, 2) compare longitudinal player-tracking data against seasonal changes in objective and subjective measures of physical function, and 3) investigate different models used to evaluate longitudinal changes in player-tracking data and objective and subjective measures of physical function. The first goal of this project will answer whether trunk-mounted accelerometer data adequately reflects the impact loads borne by the lower extremity during a variety of movement tasks. The second goal of this project will help determine whether player-tracking data can be used to predict current and future knee joint function and pain in male and female athletes. The third goal will provide a distinct set of evidence-based guidelines that prescribe best practices for calculating and analyzing longitudinal player-tracking data for the purposes of optimizing competition performance and minimizing risk of injury.