Matching Items (5)

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An Adaptive Physical Activity Intervention for Inactive Adolescents: A Single Case Design

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An increasingly sedentary population in the United States, specifically with adolescents, is putting youth at risk of future health related trauma and disease. This single-case design study, Walking Intervention Through

An increasingly sedentary population in the United States, specifically with adolescents, is putting youth at risk of future health related trauma and disease. This single-case design study, Walking Intervention Through Text Messaging for Adolescents (WalkIT-A), was used to intervene with a 12-year old, physically inactive male, in an attempt to test the efficacy of a 12-week physical activity program that may help reduce health risks by increasing number of steps walked per day. The components of the intervention consisted of a FitBit Zip pedometer, physical activity education, text messages, monetary incentives, and goal setting that adapted personally to the participant. Mean step count increased by 30% from baseline (mean = 3603 [sd = 1983]) to intervention (mean = 4693 [sd = 2112]); then increased slightly by 6.7% from intervention to withdrawal (mean = 5009 [sd = 2152]). Mean "very active minutes" increased by 45% from baseline (mean = 8.8 [sd = 8.9]) to intervention (mean = 12.8 [sd = 9.6]); then increased by 61.7% from intervention to withdrawal (mean = 20.7 [sd = 8.4]). Weight, BMI, and blood pressure all increased modestly from pre to post. Cardiovascular fitness (estimated VO2 max) improved by 12.5% from pre (25.5ml*kg-1*min-1) to post (28.7ml*kg-1*min-1). The intervention appeared to have a delayed and residual effect on the participant's daily steps and very active minutes. Although the idealistic ABA pattern did not occur, and the participant did not meet the target of 11,500 daily steps, a positive trend toward that target behavior in the latter 1/3rd of the intervention was observed. Results suggest the need for an extended intervention over a longer period of time and customized even further to the participant.

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Date Created
  • 2014-12

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Accuracy of Commercially-Available Accelerometers For Measuring Steps

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Over the last decade, the ability to track daily activity through step counting devices has undergone major changes. Advanced technologies have brought about new step counting devices and new

Over the last decade, the ability to track daily activity through step counting devices has undergone major changes. Advanced technologies have brought about new step counting devices and new form factors. The validity of these new devices is not fully known. The purpose of this study was to validate and compare the step counting accuracy of commercially available hip- and wrist-worn accelerometers. A total of 185 participants (18-64 years of age) were analyzed for this study, with the sample composed nearly evenly of each gender (53.5% female) and BMI classification (33% overweight, 31.9% obese). Each participant wore five devices including hip-worn Omron HJ-112 and Fitbit One, and wrist-worn Fitbit Flex, Nike Fuelband, and Jawbone UP. A range of activities (some constant among all participants, some randomly assigned) were then used to accumulate steps including walking on a hard surface for 400m, treadmill walking/running at 2mph, 3mph, and ≥5mph, walking up five flights of stairs, and walking down five flights of stairs. To validate the accuracy of each device, steps were also counted by direct observation. Results showed high concordance with directly observed steps for all devices (intraclass correlation coefficient range: 0.86 to 0.99), with hip-worn devices more accurate than wrist-worn devices. Absolute percent error values were lower among hip-worn devices and at faster walking/running speeds. Nike Fuelband consistently was the worst performing of all test devices. These results are important because as pedometers become more complex, it is important that they remain accurate throughout a variety of activities. Future directions for this research are to explore the validity of these devices in free-living settings and among younger and older populations.

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Created

Date Created
  • 2014-05

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Vitamin C supplementation and physical activity levels in young men

Description

Among its many roles in the body, ascorbic acid functions as a cofactor in carnitine and catecholamine synthesis, metabolites involved in fat oxidation and mood regulation, respectively. Given that

Among its many roles in the body, ascorbic acid functions as a cofactor in carnitine and catecholamine synthesis, metabolites involved in fat oxidation and mood regulation, respectively. Given that fat oxidation and mood affect one's feelings of vigor, I hypothesized that those with lower levels of plasma ascorbic acid would be less likely to exercise at high levels than individuals with adequate or high levels of vitamin C. To test this, I conducted a double-blind, placebo-controlled intervention. A group of healthy, non-smoking males between the ages of 18 and 40 were put on a vitamin C-restricted diet for two weeks and then randomized to a control group that received placebo capsules for six weeks or an intervention group that received 500 mg of vitamin C daily for six weeks. The men were restricted from eating foods high in vitamin C, instructed to wear a pedometer daily and to record their step counts, and to take a pill daily (either the placebo or vitamin C supplement). Unexpectedly, the subjects receiving the intervention had lower step counts than the control group; the control group, rather than the vitamin C group, significantly (p=0.017) increased their steps at week 8 compared to week 2. However, I also estimated daily Metabolic Equivalent Tasks (METs), and subjects receiving the placebo had lower MET outputs than subjects receiving vitamin C at the end of the trial, in spite of having higher step counts. This means the intensity of their activity was higher, based on METs expenditure. Additionally, depression scores (POMS-D) as measured by the Profile of Mood States (POMS) questionnaire were significantly higher (p=0.041) among subjects receiving the placebo at the end of the study. These latter results are consistent with my expectations that subjects with higher levels of plasma vitamin C would have improved mood and higher energy output than subjects with low levels of vitamin C.

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Created

Date Created
  • 2011

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Maintaining hózhó: perceptions of physical activity, physical education and healthy living among Navajo high school students

Description

ABSTRACT

Native American populations have higher obesity and diabetes rates overall in the U.S. Percentages of obesity among Native American children were 11-25% higher than the national average. Among Navajo, cultural

ABSTRACT

Native American populations have higher obesity and diabetes rates overall in the U.S. Percentages of obesity among Native American children were 11-25% higher than the national average. Among Navajo, cultural lifestyles changes have led to less physical activity and obesity problems with youth more disassociated from traditional Navajo living, culture, beliefs, language and religion. They were at highest risk for Type II diabetes among ethnic groups due to less physically activity, increased weight gain and obesity.

This study had dual purposes: Part one of this study was to examined the perceptions of physical activity, physical education and living healthy lifestyles of Navajo adolescents, physical educators, a Navajo culture teacher, a Diné studies teacher and a community member. Part two of this study examined the physical activity patterns of Navajo adolescent students. To gain their perspectives, eight Navajo students (9-12 grades), two physical educators, two classroom teachers and one community member were recruited and interviewed individually for 60-minutes. Secondly, pedometers were used to assess the students’ physical activity levels during the school day and 24-hour increments.

Results of the part one study indicated important aspects of physical activity by Navajo adolescents, physical education teachers, classroom teachers and a community member were cultural identity, family involvement, and structure of family/extended family. Navajo respondents participated in traditional form of running in the morning, a practice performed by parents and/or extended family. Physical activity was described as active involvement of the body, movement, physical fitness, and sport related interests. Stakeholders described physical activity and healthy living as culturally driven beliefs and learning based on Navajo way of life.

Findings of part two study indicated that boys were significantly more physically active on weekday than girls t(32)=2.04, p=<.05. Weekday step counts for boys indicated (M=11,078, SD= 4,399) and for girls (M=7,567, SD=5,613). Girls were significantly more active on weekend t(27)=2.30,p=.03. Weekend step counts indicated boys and girls accumulated (M=6493, SD=5650) and (M=7589, SD=5614) steps. Physical education step counts showed minimal differences between boys (M=2203, SD=918) and girls (M=1939, SD=889) step counts. Overall results indicate that Navajo adolescents did not meet daily physical activity recommendations.

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Created

Date Created
  • 2015

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Application of methods in physical activity measurement

Description

It is broadly accepted that physical activity provides substantial health benefits. Despite strong evidence, approximately 60% to 95% of US adults are insufficiently active to obtain these health benefits. This

It is broadly accepted that physical activity provides substantial health benefits. Despite strong evidence, approximately 60% to 95% of US adults are insufficiently active to obtain these health benefits. This dissertation explored five projects that examined the measurement properties and methodology for a variety of physical activity assessment methods. Project one identified validity evidence for the new MyWellness Key accelerometer in sixteen adults. The MyWellness Key demonstrated acceptable validity evidence when compared to a criterion accelerometer during graded treadmill walking and in free-living settings. This supports the use of the MyWellness Key accelerometer to measure physical activity. Project two evaluated validity (study 1) and test-retest reliability evidence (study 2) of the Global Physical Activity Questionnaire (GPAQ) in a two part study. The GPAQ was compared to direct and indirect criterion measures including object and subjective physical activity instruments. These data provided preliminary validity and reliability evidence for the GPAQ that support its use to assess physical activity. Project three investigated the optimal h.d-1 of accelerometer wear time needed to assess daily physical activity. Using a semi-simulation approach, data from 124 participants were used to compare 10-13 h.d-1 to the criterion 14 h.d-1. This study suggested that a minimum accelerometer wear time of 13 h.d-1 is needed to provide a valid measure of daily physical activity. Project four evaluated validity and reliability evidence of a novel method (Movement and Activity in Physical Space [MAPS] score) that combines accelerometer and GPS data to assess person-environment interactions. Seventy-five healthy adults wore an accelerometer and GPS receiver for three days to provide MAPS scores. This study provided evidence for use of a MAPS score for future research and clinical use. Project five used accelerometer data from 1,000 participants from the 2005-2006 National Health and Nutrition Examination Study. A semi-simulation approach was used to assess the effect of accelerometer wear time (10-14 h.d-1) on physical activity data. These data showed wearing for 12 h.d-1 or less may underestimate time spent in various intensities of physical activity.

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Created

Date Created
  • 2011