Measurement and correlates of physical activity behavior among older minority women

Research has shown that physical activity serves a preventive function against the development of several major chronic diseases. However, studying physical activity and its health benefits is difficult due to the complexity of measuring physical activity. The overall aim of this research is to contribute to the knowledge of both correlates and measurement of physical activity. Data from the Women On The Move study were used for this study (n = 260), and the results are presented in three papers. The first paper focuses on the measurement of physical activity and compares an alternate coding method with the standard coding method for calculating energy expenditure from a 7-day activity diary. Results indicate that the alternative coding scheme could produce similar results to the standard coding in terms of total activity expenditure. Even though agreement could not be achieved by dimension, the study lays the groundwork for a coding system that saves considerable amount of time in coding activity and has the ability to estimate expenditure more accurately for activities that can be performed at varying intensity levels. The second paper investigates intra-day variability in physical activity by estimating the variation in energy expenditure for workers and non-workers and identifying the number of days of diary self-report necessary to reliably estimate activity. The results indicate that 8 days of activity are needed to reliably estimate total activity for individuals who don't work and 12 days of activity are needed to reliably estimate total activity for those who work. Days of diary self-report required by dimension for those who don't work range from 6 to 16 and for those who work from 6 to 113. The final paper presents findings on the relationship between daily living activity and Type A behavior pattern. Significant findings are observed for total activity and leisure activity with the Temperament Scale summary score. Significant findings are also observed for total activity, household chores, work, leisure activity, exercise, and inactivity with one or more of the individual items on the Temperament Scale. However, even though some significant findings were observed, the overall models did not reveal meaningful associations. ^

A cross-sectional analysis of physical activity and obesity in inner city Houston Texas Mexican American youth

Obesity prevalence among children and adolescents is rising. It is one of the most attributable causes of hospitalization and death. Overweight and obese children are more likely to suffer from associated conditions such as hypertension, dyslipidemia, chronic inflammation, increased blood clotting tendency, endothelial dysfunction, hyperinsulinemia, and asthma. These children and adolescents are also more likely to be overweight and obese in adulthood. Interestingly, rates of obesity and overweight are not evenly distributed across racial and ethnic groups. Mexican American youth have higher rates of obesity and are at higher risk of becoming obese than non-Hispanic black and non-Hispanic white children. ^ Methods. This cross-sectional study describes the association between rates of obesity and physical activity in a sample of 1313 inner-city Mexican American children and adolescents (5-19 years of age) in Houston, Texas. This study is important because it will contribute to our understanding of childhood and adolescent obesity in this at-risk population. ^ Data from the Mexican American Feasibility Cohort using the Mano a Mano questionnaire are used to describe this population's status of obesity and physical activity. An initial sample taken from 5000 households in inner city Houston Texas was used as the baseline for this prospective cohort. The questionnaire was given in person to the participants to complete (or to parents for younger children) at a home visit by two specially trained bilingual interviewers. Analysis comprised prevalence estimates of obesity represented as percentile rank (<85%= normal weight, >85%= at risk, >95%= obese) by age and gender. The association between light, moderate, strenuous activity, and obesity was also examined using linear regression. ^ Results. Overall, 46% of this Mexican American Feasibility cohort is overweight or obese. The prevalence for children in the 6-11 age range (53.2%) was significantly greater than that reported from NHANES, 1999–2002 data (39.4%). Although the percentage of overweight and obese among the 12-19 year olds was greater than that reported in NHANES (38.5% versus 38.6%) this difference was not statistically significant. ^ A significant association between BMI and sit time and moderate physical activity (both p < 0.05) found in this sample. For males, this association was significant for moderate physical activity (p < 0.01). For the females, this association was significant for BMI and sit time (p < 0.05). These results need to be interpreted in the light of design and measurement limitations. ^ Conclusion. This study supports observations that the inner city Houston Texas Mexican American child and adolescent population is more overweight and obese than nationally reported figures, and that there are positive relationships between BMI, activity levels, and sit time in this population. This study supports the need for public health initiatives within the Houston Hispanic community. ^

Ambulatory blood pressure and physical activity in heart failure

Background. Ambulatory blood pressure (ABP) measurement is a means of monitoring cardiac function in a noninvasive way, but little is known about ABP in heart failure (HF) patients. Blood pressure (BP) declines during sleep as protection from consistent BP load, a phenomenon termed "dipping." The aims of this study were (1) to compare BP dipping and physical activity between two groups of HF patients with different functional statuses and (2) to determine whether the strength of the association between ambulatory BP and PA is different between these two different functional statuses of HF. ^ Methods. This observational study used repeated measures of ABP and PA over a 24-hour period to investigate the profiles of BP and PA in community-based individuals with HF. ABP was measured every 30 minutes by using a SpaceLabs 90207, and a Basic Motionlogger actigraph was used to measure PA minute by minute. Fifty-six participants completed both BP and physical activity for a 24-hour monitoring period. Functional status was based on New York Heart Association (NYHA) ratings. There were 27 patients with no limitation of PA (NYHA class I HF) and 29 with some limitation of PA but no discomfort at rest (NYHA class II or III HF). The sample consisted of 26 men and 30 women, aged 45 to 91 years (66.96 ± 12.35). ^ Results. Patients with NYHA class I HF had significantly greater dipping percent than those with NYHA class II/III HF after controlling their left ventricular ejection fraction (LVEF). In a mixed model analysis (PROC MIXED, SAS Institute, v 9.1), PA was significantly related to ambulatory systolic and diastolic BP and mean arterial pressure. The strength of the association between PA and ABP readings was not significantly different for the two groups of patients. ^ Conclusions. These preliminary findings demonstrate differences between NYHA class I and class II/III of HF in BP dipping status and ABP but not PA. Longitudinal research is recommended to improve understanding of the influence of disease progression on changes in 24-hour physical activity and BP profiles of this patient population. ^ Key Words. Ambulatory Blood Pressure; Blood Pressure Dipping; Heart Failure; Physical Activity. ^

The association between classroom characteristics and student physical activity in physical education classrooms

Background. With the rapid rise in childhood obesity, physical activity participation among young children has become the subject of much recent attention. Physical education classes have been specifically targeted as a method of providing opportunities for all children to be active. Unfortunately, student participation in moderate-to-vigorous physical activity during these classes still falls far below the current recommendations. While some research to date has reported the levels of activity among elementary-aged children, research is limited on the relationship between these activity levels and the environmental characteristics that exist within the PE classroom. ^ Purpose. The purpose of this study is to examine the association between specific classroom characteristics and contextual characteristics (lesson context, class size, class location, teacher gender, and teacher encouragement for PA) with elementary aged children's moderate-to-vigorous activity during PE class. ^ Methods. A secondary analysis of 211 3rd, 4th and 5th grade physical education classes amongst 39 elementary schools in Harris County, TX and 35 elementary schools in Travis County, TX was conducted using cross-sectional data from the evaluation of a school-based health program. Lesson context and student activity levels were measured using a direct observation measurement tool. Additionally, these variables were further analyzed against a number of classroom characteristics to determine any significant associations. ^ Results. Overall, elementary PE classes are still participating in low levels of moderate-to-vigorous physical activity averaging only 38% of class time. Additionally, close to 25% of class time is spent in classroom management. Male directed classes spent significantly more time in game activities and female directed classes spent more time in fitness, knowledge, and skill activities. Classes that took place outdoors were more active and spent more time in games than those that took place indoors. Significant correlations were demonstrated between class size and time spent in management context. Time spent in management context was also correlated with time spent sitting and standing. Additionally, positive correlations were demonstrated between time very active and teachers that praised students and encouraged physical activity among their classes.^

Validity and reliability of using MVP 4 Function Walk4Life digital pedometers to assess physical activity levels among preschool-aged Head Start children

The Surgeon General recommends preschoolers 3-5 years old accumulate 60 minutes of moderate-to-vigorous physical activity (MVPA) per day. However, there is limited data measuring physical activity (PA) and MVPA amongst this population. The purpose of this cross-sectional study is to determine the validity, reliability, and feasibility of using MVP 4 Function Walk4Life digital pedometers (MVP-4) in measuring MVPA among preschoolers using the newly modified direct observational technique, System for Observing Fitness Instruction Time-Preschool Version (SOFIT-P) as the gold standard. An ethnically diverse population of 3-5 year old underserved children were recruited from two Harris County Department of Education (HCDE) Head Start centers. For 2 days at baseline and 2 days at post-test, 75 children enrolled wore MVP-4 pedometers for approximately 6-hours per observation day and were observed using SOFIT-P during predominantly active times. Statistical analyses used Pearson "r" correlation coefficients to determine mean minutes of PA and MVPA, convergent and criterion validity, and reliability. Significance was set at p = <0.05. Feasibility was determined through process evaluation information collected during this study via observations from data collectors and teacher input. Results show mean minutes of PA and MVPA ranged between 30-42 and 11-14 minutes, respectively. Convergent validity comparing BMI percentiles with MVP-4 PA outcomes show no significance at pre-test; however, each measurement at post-test showed significance for MVPA (p = 0.0247, p = 0.0056), respectively. Criterion validity comparing percent MVPA time between SOFIT-P and MVP-4 pedometers was determined; however, results deemed insufficient due to inconsistency in observation times while using the newly developed SOFIT-P. Reliability measures show no significance at pre-test, yet show significant results for all PA outcomes at post-test (p = 0.001, p = 0.001, p = 0.0010, p = 0.003), respectively. Finally, MVP-4 pedometers lacked feasibility due to logistical barriers in design. Researchers feel the significant results at post-test are secondary to increased familiarity and more accurate placement of pedometers across time. Researchers suggest manufacturers of MVP-4 pedometers further modify the instrument for ease of use with this population, following which future studies ought to determine validity using objective measures or all-day direct observation techniques.^