Christian C. Evans

Exercise prevents weight gain and alters the gut microbiota in a mouse model of high fat diet-induced obesity.

Background Diet-induced obesity (DIO) is a significant health concern which has been linked to structural and functional changes in the gut microbiota. Exercise (Ex) is effective in preventing obesity, but whether Ex alters the gut microbiota during development with high fat (HF) feeding is unknown. Objective Determine the effects of voluntary Ex on the gastrointestinal microbiota in LF-fed mice and in HF-DIO. Methods Male C57BL/6 littermates (5 weeks) were distributed equally into 4 groups: low fat (LF) sedentary (Sed) LF/Sed, LF/Ex, HF/Sed and HF/Ex. Mice were individually housed and LF/Ex and HF/Ex cages were equipped with a wheel and odometer to record Ex. Fecal samples were collected at baseline, 6 weeks and 12 weeks and used for bacterial DNA isolation. DNA was subjected both to quantitative PCR using primers specific to the 16S rRNA encoding genes for Bacteroidetes and Firmicutes and to sequencing for lower taxonomic identification using the Illumina MiSeq platform. Data were analyzed using a one or two-way ANOVA or Pearson correlation. Results HF diet resulted in significantly greater body weight and adiposity as well as decreased glucose tolerance that were prevented by voluntary Ex (p<0.05). Visualization of Unifrac distance data with principal coordinates analysis indicated clustering by both diet and Ex at week 12. Sequencing demonstrated Ex-induced changes in the percentage of major bacterial phyla at 12 weeks. A correlation between total Ex distance and the ΔCt Bacteroidetes: ΔCt Firmicutes ratio from qPCR demonstrated a significant inverse correlation (r2 = 0.35, p = 0.043). Conclusion Ex induces a unique shift in the gut microbiota that is different from dietary effects. Microbiota changes may play a role in Ex prevention of HF-DIO.

Monitoring community mobility with global positioning system technology after a stroke: a case study.

Background: Stroke survivors often experience difficulty returning to activities and places they deem important to their social, leisure, and occupational aspirations. The extent to which stroke survivors return to community mobility and their ability to navigate and access locations they deem meaningful have not been objectively measured. Purpose: We used global positioning system technology (GPSt) to measure the community mobility of a person poststroke, and assess the relationship between GPSt measures and clinical measures of mobility. Methods: The participant was a 56-year-old man who sustained a right pontine stroke. At discharge from rehabilitation, his Six-Minute Walk Test distance was 73 m. He was fitted with a GPS unit and an accelerometer attached to a single belt and instructed to wear the devices at all times when out of bed. After identifying 10 locations that were important to his goals, he was monitored for 5 separate 1-week periods, on the first, fifth, and ninth weeks and at 6 and 12 months after discharge. Results: During the first 10 weeks, he averaged 7.6 target visits (70%) and 26.7 trips per week. At 1 year, his Six-Minute Walk distance score was 287.5 m. Accelerometry data revealed that he remained primarily sedentary. Target visits and trips per week did not change substantially over the course of 1 year, and compliance wearing the GPS unit was variable. Conclusions: Given the limited correlation in gait speed and distance with target attainment and trips, these outcomes likely measure different constructs for this subject. GPSt may offer insights into participation for stroke survivors following rehabilitation.

Automated Extraction of Community Mobility Measures from GPS Stream Data Using Temporal DBSCAN

Inferring community mobility of patients from GPS data has received much attention in health research. Developing robust mobility (or physical activity) monitoring systems relies on the automated algorithm that classifies GPS track points into events (such as stops where activities are conducted, and routes taken) accurately. This paper describes the method that automatically extracts community mobility measures from GPS track data. The method uses temporal DBSCAN in classifying track points, and temporal filtering in removing noises (any misclassified track points). The result shows that the proposed method classifies track points with 88% accuracy. The percent of misclassified track points decreased significantly with our method (1.9%) over trip/stop detection based on attribute threshold values (10.58%).

Detecting Stop Episodes from GPS Trajectories with Gaps

Given increased access to a stream of data collected by location acquisition technologies, the potential of GPS trajectory data is waiting to be realized in various application domains relevant to urban informatics—namely in understanding travel behavior, estimating carbon emission from vehicles, and further building healthy and sustainable cities. Partitioning GPS trajectories into meaningful elements is crucial to improve the performance of further analysis. We propose a method for detecting a stay point (where an individual stays for a while) using a density-based spatial clustering algorithm where temporal criterion and gaps are also taken into account. The proposed method fills gaps using linear interpolation, and identifies a stay point that meets two criteria (spatial density and time duration). To evaluate the proposed method, we compare the number of stay points detected from the proposed method to that of stay points identified by manual inspection. Evaluation is performed on 9 weeks of trajectory data. Results show that clustering-based stay point detection combined with gap treatment can reliably detect stop episodes. Further, comparison of performance between using the method with versus without gap treatment indicates that gap treatment improves the performance of the clustering-based stay point detection.

Community mobility after stroke: a systematic review

Abstract Background Stroke is the leading cause of severe disability and many survivors report long-term physical or cognitive impairments that may impact their ability to achieve community mobility (CM). Purpose: To determine the extent to which people with chronic stroke achieve CM compared to age-matched norms or non-neurologically impaired controls. Methods The StrokEDGE outcome measures were searched to identify validated tools that included >25% of items addressing CM. MEDLINE, CINAHL, Google Scholar, PubMed, PEDro and the Cochrane databases were searched from 2001 to 2015 with the identified outcome measures cross-referenced against search terms related to stroke and CM. Inclusion criteria: utilized a validated CM outcome measure, chronic (>3 months post) stroke survivors, and randomized controlled trial, observational or cohort study design. One reviewer screened the studies and performed data extraction and three performed quality appraisal. Fourteen studies met all inclusion criteria. Results Stroke survivors have impaired CM as demonstrated by 30–83% of normative or non-stroke subject CM scores. As time post-stroke increased, CM improved only slightly. Factors found to correlate with the CM were age, education, general well-being, emotional state, motor function and coordination, independence in activities of daily living, balance, endurance and driving status. Limitations of this review include a relatively high functioning cohort, no meta-analysis and reliance on outcome measures not specifically designed to measure CM. Conclusion Survivors of stroke may experience a significant decrease in CM compared to people without neurological injury. Rehabilitation addressing motor function, coordination, independence in activities of daily living, balance and endurance may be important for achieving higher levels of CM. Outcome measures directly addressing CM are needed.

Exercise prevents high fat diet-induced bone loss, marrow adiposity and dysbiosis in male mice

High fat diets can have detrimental effects on the skeleton as well as cause intestinal dysbiosis. Exercise prevents high fat (HF) diet-induced obesity and also improves bone density and prevents the intestinal dysbiosis that promotes energy storage. Previous studies indicate a link between intestinal microbial balance and bone health. Therefore, we examined whether exercise could prevent HF-induced bone pathology in male mice and determined whether benefits correlate to changes in host intestinal microbiota. Male C57Bl/6 mice were fed either a low fat diet (LF; 10 kcal% fat) or a HF diet (60 kcal% fat) and put under sedentary or voluntary exercise conditions for 14 weeks. Our results indicated that HF diet reduced trabecular bone volume, when corrected for differences in body weight, of both the tibia (40% reduction) and vertebrae (25% reduction) as well and increased marrow adiposity (44% increase). More importantly, these effects were prevented by exercise. Exercise also had a significant effect on several cortical bone parameters and enhanced bone mechanical properties in LF but not HF fed mice. Microbiome analyses indicated that exercise altered the HF induced changes in microbial composition by reducing the Firmicutes/Bacteriodetes ratio. This ratio negatively correlated with bone volume as did levels of Clostridia and Lachnospiraceae. In contrast, the abundance of several Actinobacteria phylum members (i.e., Bifidobacteriaceae) were positively correlated with bone volume. Taken together, exercise can prevent many of the negative effects of a high fat diet on male skeletal health. Exercise induced changes in microbiota composition could represent a novel mechanism that contributes to exercise induced benefits to bone health.

The Effectiveness of a Home Exercise Program for a Young Athlete with Schmorl's Nodes: A Case Report

Background and Purpose: Adolescent soccer players are often prone to low back pain and one source of low back pain incurred by adolescents is Schmorl’s nodes, or endplate disc herniations. Patients with low back pain due to Schmorl’s nodes are often given home exercise programs to manage their symptoms and increase their core stability. The purpose of this case report is to describe the treatment and outcome for a young athlete with Schmorl’s nodes causing low back pain and lower extremity weakness. Case Description: A 12 year-old female soccer player with a history of low back pain was referred to physical therapy with a diagnosis of Schmorl’s nodes. Following 8 weeks of physical therapy, the patient was then discharged to a home exercise program. The patient underwent a 7-week home exercise program involving core strengthening exercises designed to decrease her low back pain and help her return to playing soccer with one-hundred percent effort. Outcomes: The patient completed her 7-week home exercise program. Following intervention, the patient demonstrated improvements in lower extremity and core strength as well as improvements in athletic performance. The intervention did not result in significant changes in the patient’s low back pain. Discussion: Home exercise programs are effective in the management of low back pain in young athletes. However, the effectiveness of a home exercise program for adolescent athletes with Schmorl’s nodes is not well established. The home exercise program in this case was effective in increasing the patient’s strength, but not at decreasing the patient’s pain. More research is needed to determine the best physical therapy treatment and optimal home exercise program for adolescents with Schmorl’s nodes.