Objectively measured physical activity in sixth-grade girls

OBJECTIVES

To describe the objectively measured physical activity characteristics of a diverse sample of sixth-grade girls, to examine influences on physical activity, and to report compliance with physical activity guidelines.

DESIGN

Cross-sectional study.

SETTING

Six locations across the United States.

PARTICIPANTS

A total of 1578 sixth-grade girls. Accelerometers were worn for 7 days, and data for 6 days were included in the analyses. Main Exposures Race/ethnicity, free or reduced-price lunch, and geographic region.

MAIN OUTCOME MEASURES

Six operational definitions of adequate activity (60 or 30 minutes of daily moderate to vigorous physical activity at or above 4.6, 3.8, or 3.0 metabolic equivalents) were used to examine whether girls met physical activity guidelines.

RESULTS

Average times spent in sedentary, light, moderate, and vigorous activities were 460, 342, 18, and 6 min/d, respectively. White girls were more active than girls in other race/ethnic groups, and girls who did not receive free or reduced-price lunch were more active than girls who did. Girls in western states were most active. Percentages of girls in compliance with the 6 thresholds for adequate activity varied widely and ranged from 0.6% to 100.0%.

CONCLUSIONS

When physical activity is measured objectively and a 4.6-metabolic equivalents cut point for moderate to vigorous physical activity is used, most sixth-grade girls do not meet guidelines for adequate physical activity. One notable finding was the effect of different accelerometer scoring protocols on estimates of compliance. Conceptual and empirical work is needed to define appropriate physical activity for youth using objective physical activity measures.

Policies and opportunities for physical activity in middle school environments

BACKGROUND

This study examined physical activity opportunities and barriers at 36 geographically diverse middle schools participating in the Trial of Activity for Adolescent Girls.

METHODS

Principals, physical education and health education department heads, and program leaders were interviewed to assess policies and instructional practices that support physical activity.

RESULTS

Schools provided approximately 110 hours per year in physical education instruction. Approximately 20% of students walked or bicycled to school. Eighty-three percent of schools offered interscholastic sports and 69% offered intramural sports. Most schools offered programs for girls, but on average, only 24 girls ( approximately 5%) in the schools attended any programs. Only 25% of schools allowed after school free play. An overall score created to assess school environmental support for physical activity indicated that, on average, schools met 6.7 items of 10 items. Free/reduced lunch program participation versus not (p = .04), perceived priority of physical education instruction over coaching (p = .02), and safety for walking/bicycling to school (p = .02) predicted environmental support score.

CONCLUSIONS

Schools have policies and practices that support physical activity, although unfavorable practices exist. Schools must work with community partners and officials to provide environments that optimally support physical activity, especially schools that serve low-income students.

Accelerometry-measured activity or sedentary time and overweight in rural boys and girls

OBJECTIVE

The aim of this study was to examine the association between overweight and physical activity or sedentary time measured by accelerometry in rural boys and girls 7 to 19 years old.

RESEARCH METHODS AND PROCEDURES

A cross-sectional study was conducted involving 130 girls and 99 boys in elementary, middle, and high school in rural Maryland. After weight, height, and body composition were measured, children wore an Actiwatch accelerometer for 6 days. Comparisons for activity counts were made between normal and overweight or at risk for overweight (at-risk/overweight) participants (>or=85th percentile of BMI). The associations between body composition and accelerometry-defined activity levels (sedentary, light, moderate, and vigorous) were analyzed by age group for boys and girls.

RESULTS

Differences in total activity in counts per day or counts per minute were not observed between normal and at-risk/overweight boys or girls in all age groups. No associations between measures of body composition and time spent in an activity level were seen in boys. Fat mass and percentage fat were positively correlated to time spent in sedentary activity (range r = 0.42 to 0.54, all p < 0.01) for girls. In contrast, fat mass and percentage fat were negatively related to time spent in light activity (range, r = -0.40 to -0.51, p < 0.05) for girls.

DISCUSSION

In girls, but not boys, greater body fat is associated with greater time spent being inactive, and lower levels of body fat are associated with more time spent in light activity. Physical activity interventions targeting inactive children in rural communities are warranted.

Physical activity, cardiorespiratory fitness, and their relationship to cardiovascular risk factors in African Americans and non-African Americans with above-optimal blood pressure

This report describes cross-sectional associations among physical activity, cardiorespiratory fitness, dietary habits, and cardiovascular disease (CVD) risk factors in a large sample (n = 810) of African Americans (n = 279) and non-African Americans (n = 531) with above-optimal blood pressure. Participants in PREMIER, a clinical trial for blood pressure control through lifestyle approaches, underwent baseline assessments to determine physical activity level, cardiorespiratory fitness category, dietary intake, and CVD risk factors. Mean levels of body mass index (BMI), total cholesterol, LDL cholesterol, HDL cholesterol, daily percent calories from fat and saturated fat, daily servings of fruits and vegetables, and daily fiber intake were examined across three physical activity levels and two fitness categories. Hypertension status was also assessed. Data were stratified by sex and ethnicity. For all participants, those in the low fitness category had higher BMI levels. Total cholesterol was lower in African American women in the high fitness category. Mean values of more than five daily servings of fruits and vegetables were reported by non-African American women and African American men in the high activity category. Higher intake of dietary fiber was found for non-African American women at the high activity level, with a similar trend observed for African American women. Future work examining these associations prospectively should include sufficient minority representation to enhance generalizability to all population groups and determine the beneficial effects from increased physical activity and improved cardiorespiratory fitness.

Validity and reliability of the Fels physical activity questionnaire for children

PURPOSE

The aim was to evaluate the reliability and validity of the Fels physical activity questionnaire (PAQ) for children 7-19 yr of age.

METHODS

A cross-sectional study was conducted among 130 girls and 99 boys in elementary (N=70), middle (N=81), and high (N=78) schools in rural Maryland. Weight and height were measured on the initial school visit. All the children then wore an Actiwatch accelerometer for 6 d. The Fels PAQ for children was given on two separate occasions to evaluate reliability and was compared with accelerometry data to evaluate validity.

RESULTS

The reliability of the Fels PAQ for the girls, boys, and the elementary, middle, and high school age groups range was r=0.48-0.76. For the elementary school children, the correlation coefficient examining validity between the Fels PAQ total score and Actiwatch (counts per minute) was 0.34 (P=0.004). The correlation coefficients were lower in middle school (r=0.11, P=0.31) and high school (r=0.21, P=0.006) adolescents. The sport index of the Fels PAQ for children had the highest validity in the high school participants (r=0.34, P=0.002).

CONCLUSION

The Fels PAQ for children is moderately reliable for all age groups of children. Validity of the Fels PAQ for children is acceptable for elementary and high school students when the total activity score or the sport index is used. The sport index was similar to the total score for elementary students but was a better measure of physical activity among high school students.

Design of the Trial of Activity in Adolescent Girls (TAAG)

The primary aim of the Trial of Activity in Adolescent Girls (TAAG) is to test an intervention to reduce by half the age-related decline in moderate to vigorous physical activity (MVPA) in middle school girls. The intervention will be evaluated using a group-randomized trial involving 36 middle schools. The primary endpoint is the mean difference in intensity-weighted minutes (i.e., MET-minutes) of MVPA between intervention and comparison schools assessed using accelerometry. The TAAG study design calls for two cross-sectional samples, one drawn from 6th graders at the beginning of the study and the second drawn from 8th graders at the end of the study following the 2-year implementation of the intervention. An important strength of this design over a cohort design is the consistency with the goals of TAAG, which focus on environmental-level rather than individual-level interventions to produce change. The study design specifies a recruitment rate of 80% and a smaller sample of girls at baseline (n=48 per school) than at follow-up (n=96 per school). A two-stage model will be used to test the primary hypothesis. In the first stage, MET-weighted minutes of MVPA will be regressed on school, time (baseline or follow-up), their interaction, ethnicity and week of data collection. The second stage analysis will be conducted on the 72 adjusted means from the first stage. In the main-effects model, we will regress the follow-up school mean MET-weighted minutes of MVPA on study condition, adjusting for the baseline school mean. The TAAG study addresses an important health behavior, and also advances the field of group-randomized trials through the use of a study design and analysis plan tailored to serve the main study hypothesis.

Physical activity attitudes of African American and white adolescent girls

BACKGROUND

Understanding the attitudes of African American adolescent girls toward physical activity may help identify strategies to enable these adolescents to adopt a more physically active lifestyle that could track into adulthood.

OBJECTIVE

To identify and compare attitudes of African American adolescent girls toward physical activity with the attitudes of white adolescent girls.

METHODS

Six focus groups (N = 49) were conducted with 9th- through 12th-grade African American and white adolescent girls. Participants were recruited from community and medical settings in an urban city. Groups were audiotaped, coded, and analyzed for themes.

RESULTS

African American participants were more accepting of their body image than were the white participants as individuals, as a community, and in the media. Themes common among African American and white participants included appearance and hygiene, value of physical activity, and issues of masculinity. Physically active adolescents reported on the significance of social support in motivating their physical activity participation.

CONCLUSION

Future research on these attitudes could help inform the design of effective and culturally appropriate interventions to promote physical activity in African American and white adolescent girls.

Efficacy of fipronil/(S)-methoprene combination spot-on for dogs against shed eggs, emerging and existing adult cat fleas (Ctenocephalides felis, Bouché)

The inhibitory activities of fipronil (10% (w/v) solution), (S)-methoprene (9% (w/v) solution), and fipronil/(S)-methoprene (10 and 9% (w/v) solution, respectively) combination against eggs and emerging adult cat fleas (Ctenocephalides felis) and adulticidal activity were tested on experimentally infested dogs. Thirty-two Beagle dogs were selected for this study and eight replicates of four animals were formed based on body weight within sex. One dog in each replicate was randomly allocated to treatment with: (1) untreated control; (2) fipronil 10% (w/v) solution, (3) (S)-methoprene 9% (w/v) solution, and (4) fipronil 10% (w/v) and (S)-methoprene 9% (w/v) combination solution. Treatments were applied once topically on Day 0 at the rate of 0.067 ml/kg. On Days -12, -1, 21, and weekly to Day 84 each dog was infested with approximately 200 fleas and comb counted approximately 24h later, or 2 days (our 48 h) after in the case of Day -1 infestation. On Days -11, 1, 22, and weekly to Day 85 each dog was again infested with approximately 200 fleas. Flea eggs were collected over approximately 24 h beginning 3 days after infestation. Fleas were combed off of the dogs and counted at the end of the egg collection period (approximately 96 h count). One aliquot of up to about 100 eggs, if available, from each animal at each infestation time was incubated for approximately 72 h to determine larval hatch and the other for 35 days to determine the number of adults that developed. The 10% (w/v) fipronil spot-on provided excellent control (>95%) of adult fleas on dogs for 5 weeks. Similarly, the combination spot-on of 10% (w/v) fipronil and 9% (w/v) (S)-methoprene provided excellent control of adult fleas, i.e., >95% for 5 weeks. From week 6 post-treatment onward, the relatively low inhibition of adult flea emergence substantiated the lack of significant ovicidal/larvicidal activity in the fipronil (10%, w/v) treatment group. However, the combination product provided excellent (>90%) ovicidal activity for 8 weeks and high (91.4%) inhibition of adult flea emergence for 12 weeks. In addition, a synergistic effect of the two compounds in combination was demonstrated with fipronil enhancing the ovicidal and inhibition of adult flea emergence activity of (S)-methoprene against cat flea eggs. When all stages of the life cycle of the cat flea are considered, the combination spot-on product provided a high level of total flea control yielding a curative effect against adult fleas and inhibition of flea development stages with little to no potential reinfestation pressure on the animal or in the environment for 12 weeks.

Effects of comprehensive lifestyle modification on blood pressure control: main results of the PREMIER clinical trial

CONTEXT

Weight loss, sodium reduction, increased physical activity, and limited alcohol intake are established recommendations that reduce blood pressure (BP). The Dietary Approaches to Stop Hypertension (DASH) diet also lowers BP. To date, no trial has evaluated the effects of simultaneously implementing these lifestyle recommendations.

OBJECTIVE

To determine the effect on BP of 2 multicomponent, behavioral interventions.

DESIGN, SETTING, AND PARTICIPANTS

Randomized trial with enrollment at 4 clinical centers (January 2000-June 2001) among 810 adults (mean [SD] age, 50 [8.9] years; 62% women; 34% African American) with above-optimal BP, including stage 1 hypertension (120-159 mm Hg systolic and 80-95 mm Hg diastolic), and who were not taking antihypertensive medications.

INTERVENTION

Participants were randomized to one of 3 intervention groups: (1) "established," a behavioral intervention that implemented established recommendations (n = 268); (2) "established plus DASH,"which also implemented the DASH diet (n = 269); and (3) an "advice only" comparison group (n = 273).

MAIN OUTCOME MEASURES

Blood pressure measurement and hypertension status at 6 months.

RESULTS

Both behavioral interventions significantly reduced weight, improved fitness, and lowered sodium intake. The established plus DASH intervention also increased fruit, vegetable, and dairy intake. Across the groups, gradients in BP and hypertensive status were evident. After subtracting change in advice only, the mean net reduction in systolic BP was 3.7 mm Hg (P<.001) in the established group and 4.3 mm Hg (P<.001) in the established plus DASH group; the systolic BP difference between the established and established plus DASH groups was 0.6 mm Hg (P =.43). Compared with the baseline hypertension prevalence of 38%, the prevalence at 6 months was 26% in the advice only group, 17% in the established group (P =.01 compared with the advice only group), and 12% in the established plus DASH group (P<.001 compared with the advice only group; P =.12 compared with the established group). The prevalence of optimal BP (<120 mm Hg systolic and <80 mm Hg diastolic) was 19% in the advice only group, 30% in the established group (P =.005 compared with the advice only group), and 35% in the established plus DASH group (P<.001 compared with the advice only group; P =.24 compared with the established group).

CONCLUSION

Individuals with above-optimal BP, including stage 1 hypertension, can make multiple lifestyle changes that lower BP and reduce their cardiovascular disease risk.

Results of the Diet, Exercise, and Weight Loss Intervention Trial (DEW-IT)

National guidelines for the prevention and treatment of hypertension recommend sodium reduction, weight loss, the Dietary Approach to Stop Hypertension (DASH) diet, and regular aerobic exercise. However, no trial has assessed the efficacy of simultaneously implementing all of these recommendations. The objective of this study was to determine the effects on blood pressure and other cardiovascular disease risk factors of a comprehensive lifestyle intervention. We conducted a randomized controlled trial of 44 hypertensive, overweight adults on a single blood pressure medication. Participants were randomized to a lifestyle or control group. For 9 weeks, the lifestyle group was fed a hypocaloric version of the DASH diet that provided 100 mmol/d of sodium. This group also participated in a supervised, moderate-intensity exercise program 3 times per week. The control group received no intervention. Outcomes were ambulatory blood pressure, serum lipids, weight, and fitness. At the end of the intervention, mean weight loss in the lifestyle group, net of control, was 4.9 kilograms. In the lifestyle group mean net reductions in 24-hour ambulatory systolic and diastolic blood pressures were 9.5 mm Hg (P<0.001) and 5.3 mm Hg (P<0.002), respectively. Corresponding changes in daytime systolic and diastolic blood pressures were 12.1 mm Hg (P<0.001) and 6.6 mm Hg (P<0.001). The lifestyle group experienced mean reductions in total cholesterol (-25 mg/dL, P<0.001), low-density lipoprotein cholesterol (-18 mg/dL, P=0.005), high-density lipoprotein cholesterol (-5 mg/dL, P<0.001), net of control. In conclusion, among hypertensive overweight adults already on antihypertensive medication, a comprehensive lifestyle intervention can substantially lower blood pressure and improve blood pressure control.

Motivations for exercise and weight loss among African-American women: focus group results and their contribution towards program development

OBJECTIVE

African-American women are more likely to be sedentary and maintain higher body weights compared with Caucasian women, although some are physically active and able to maintain weight loss. To develop effective intervention strategies, we need to understand why some women are successful.

DESIGN

We conducted focus groups on four distinct groups of African-American women (currently physically active; currently sedentary; successful weight loss for > or = 1 year; unsuccessful weight loss) to explore motivations and intervention strategies. Open-ended questions, probes, and visual aids were used to stimulate discussions. Transcripts of sessions were read to highlight themes and concepts.

RESULTS

Results indicated that motivators for the exercisers to start exercising were health concerns, weight control, stress reduction, and the influence of others. Motivators to continue exercising were feeling good and having energy. In contrast, the sedentary women reported that social support and enjoyment would be motivating. Both groups reported that physically active women conveyed the image of high energy and self-esteem. The successful weight loss women employed strategies that allowed them to eat a variety of foods and were less likely to 'diet'. The unsuccessful women referred to 'going on a diet' and were more likely to label foods as 'good' or 'bad'. They reported feeling tired and thought that losing weight would give them more energy.

CONCLUSION

This information was used to develop two culturally appropriate interventions for African-American women, which is presented. Conducting formative research in study design protocols can provide an important role in intervention development.