Lucia Andrea Leone and Dianne S. Ward
Obese women have lower levels of physical activity than nonobese women, but it is unclear what drives these differences.
Mixed methods were used to understand why obese women have lower physical activity levels. Findings from focus groups with obese white women age 50 and older (N = 19) were used to develop psychosocial items for an online survey of white women (N = 195). After examining the relationship between weight group (obese vs. nonobese) and exercise attitudes, associated items (P < .05) were tested for potential mediation of the relationship between weight and physical activity.
Obese women were less likely than nonobese women to report that they enjoy exercise (OR = 0.4, 95% CI 0.2−0.8) and were more likely to agree their weight makes exercise difficult (OR = 10.6, 95% CI 4.2−27.1), and they only exercise when trying to lose weight (OR = 3.8, 95% CI 1.6−8.9). Enjoyment and exercise for weight loss were statistically significant mediators of the relationship between weight and physical activity.
Exercise interventions for obese women may be improved by focusing on exercise enjoyment and the benefits of exercise that are independent of weight loss.
Dianne S. Ward, Julie D. Jackman and Floyd J. Galiano
Seventeen children, ages 8-14 years, were compared to an adult group (n = 19) in their ability to execute prescriptive exercise using the Borg 6-20 rating of perceived exertion (RPE) scale. Subjects cycled at a controlled pace (setting resistance) for 2 minutes or traveled one lap of a 400-meter track at four RPE levels: 7, 10, 13, and 16. Results indicated that for pace-controlled cycling, children were similar to adults, reproducing four incremental intensities. Adults were closer to the laboratory determined criterion than the children were. For the self-paced walk/run tasks, both groups overexerted compared to the criterion. Children could only discriminate RPE 7 from the other levels. Based on these observations, it is recommended that exercise prescriptions for children using self-monitored intensity be preceded by adequate practice or be adjusted to account for different modes of activity.
Dianne S. Ward, Oded Bar-Or, Patti Longmuir and Karen Smith
Seventeen individuals (ages 11–30 years), all wheelchair users, were classified as active or sedentary. Peak mechanical power, heart rate (HR), and rating of perceived exertion (RPE) were determined during continuous, incremental all-out arm ergometry. Subjects were asked to wheel on an oval track at prescribed speeds, and one month later they repeated this task. All subjects could distinguish among prescriptions, as judged from HR and wheeling velocities. However, the active subjects chose higher speeds (by 0.8–1.3 m/s), a wider range of speeds, and could better distinguish among sequential RPE levels than did the sedentary subjects. All subjects chose wheeling velocities higher than expected from their originally established HR-on-RPE regression. One-month retention was high and similar between groups. Individuals who use wheelchairs can discriminate among wheeling intensities as prescribed using the RPE scale and have excellent retention for at least one month.
Stewart G. Trost, Dianne S. Ward, Ben McGraw and Russell R. Pate
This study evaluated the validity of the Previous Day Physical Activity Recall (PDPAR) self-report instrument in quantifying after-school physical activity behavior in fifth-grade children. Thirty-eight fifth-grade students (mean age, 10.8 ± 0.1; 52.6% female; 26.3% African American) from two urban elementary schools completed the PDPAR after wearing a CSA WAM 7164 accelerometer for a day. The mean within-subject correlation between self-reported MET level and total counts for each 30-min block was 0.57 (95% C.I., 0.51–0.62). Self-reported mean MET level during the after-school period and the number of 30-min blocks with activity rated at ≥ 6 METs were significantly correlated with the CSA outcome variables. Validity coefficients for these variables ranged from 0.35 to 0.43 (p < .05). Correlations between the number of 30-min blocks with activity rated at ≥ 3 METs and the CSA variables were positive but failed to reach statistical significance (r = 0.19–0.23). The PDPAR provides moderately valid estimates of relative participation in vigorous activity and mean MET level in fifth-grade children. Caution should be exercised when using the PDPAR to quantify moderate physical activity in preadolescent children.
Kelly R. Evenson, Brian Neelon, Sarah C. Ball, Amber Vaughn and Dianne S. Ward
Despite the growing interest in active (ie, nonmotorized) travel to and from school, few studies have explored the measurement properties to assess active travel. We evaluated the criterion validity and test–retest reliability of a questionnaire with a sample of young schoolchildren to assess travel to and from school, including mode, travel companion, and destination after school.
To assess test–retest reliability, 54 children age 8 to 11 years completed a travel survey on 2 consecutive school days. To assess criterion validity, 28 children age 8 to 10 years and their parents completed a travel survey on 5 consecutive weekdays.
test–retest reliability of all questions indicated substantial agreement. The questions on mode of transport, where you will go after school, and how you will get there also displayed substantial agreement between parental and child reports.
For this population, a questionnaire completed by school-age children to assess travel to and from school, including mode, travel companion, and destination after school, was reliably collected and indicated validity for most items when compared with parental reports.
Russell R. Pate, Marsha Dowda, Jennifer R. O’Neill and Dianne S. Ward
Physical activity levels of girls decline in adolescence, but little is known about changes in participation in specific types of physical activity. This study examined change in participation in specific activities during adolescence in girls.
Girls (N = 398, age 13.6 ± 0.6 y at baseline, 58.5% African American) from 31 middle and 24 high schools in South Carolina completed the 3-Day Physical Activity Recall (3DPAR) in 8th, 9th, and 12th grades. Girls reported their predominant activity and its intensity level in each 30-min time block on the previous 3 d.
Vigorous physical activity declined from 45.4% in 8th grade to 34.1% in 12th grade. The probability of participating in several forms of vigorous physical activity in 12th grade was strongly associated with participation in those activities in 8th grade.
Early-in-life participation in sports and other forms of vigorous physical activity are important to the maintenance of physical activity during adolescence in girls.
Stewart G. Trost, Angela M. Morgan, Ruth Saunders, Gwen Felton, Dianne S. Ward and Russell R. Pate
This study evaluated 4th-grade students’ understanding of the concept of physical activity and assessed the effects of two interventions to enhance the students’ understanding of this concept. Students were randomly assigned to 1 of 3 conditions: the video group (n = 40) watched a 5-min video describing physical activity; the verbal group (n = 42) listened to a generic description of physical activity; the control group received no instruction (n = 45). Students completed a 17-item checklist testing their understanding of the concept of physical activity. Compared to controls, students in the verbal and video group demonstrated significantly higher checklist scores, with the video group scoring significantly higher than the verbal group. Only 35.6% of the controls, compared to 52.4% and 70.0% of the verbal and video groups respectively, could classify ≥ 15 of the checklist items correctly. The results indicate that, without intervention, children have a limited understanding of the concept of physical activity.
Temitope Erinosho, Derek Hales, Amber Vaughn, Stephanie Mazzucca and Dianne S. Ward
This study assessed physical activity and screen time policies in child-care centers and their associations with physical activity and screen time practices and preschool children’s (3–5 years old) physical activity.
Data were from 50 child-care centers in North Carolina. Center directors reported on the presence/absence of written policies. Trained research assistants observed physical activity and screen time practices in at least 1 preschool classroom across 3 to 4 days. Children (N = 544) wore accelerometers to provide an objective measure of physical activity.
Physical activity and screen time policies varied across centers. Observational data showed 82.7 min/d of active play opportunities were provided to children. Screen time provided did not exceed 30 min/d/child at 98% of centers. Accelerometer data showed children spent 38 min/d in moderate-to-vigorous physical activity and 206 min/d in sedentary activity. Policies about staff supervision of media use were negatively associated with screen time (P < .05). Contrary to expectation, policies about physical activity were associated with less time in physical activity.
Clear strategies are needed for translating physical activity policies to practice. Further research is needed to evaluate the quality of physical activity policies, their impact on practice, and ease of operationalization.
Alise E. Ott, Russell R. Pate, Stewart G. Trost, Dianne S. Ward and Ruth Saunders
In order to effectively measure the physical activity of children, objective monitoring devices must be able to quantify the intermittent and nonlinear movement of free play. The purpose of this study was to investigate the validity of the Computer Science and Applications (CSA) uniaxial accelerometer and the TriTrac-R3D triaxial accelerometer with respect to their ability to measure 8 “free-play” activities of different intensity. The activities ranged from light to very vigorous in intensity and included activities such as throwing and catching, hopscotch, and basketball. Twenty-eight children, ages 9 to 11, wore a CSA and a heart rate monitor while performing the activities. Sixteen children also wore a Tritrac. Counts from the CSA, Tritrac, and heart rates corresponding to the last 3 min of the 5 min spent at each activity were averaged and used in correlation analyses. Across all 8 activities, Tritrac counts were significantly correlated with predicted MET level (r = 0.69) and heart rate (r = 0.73). Correlations between CSA output, predicted MET level (0.43), and heart rate (0.64) were also significant but were lower than those observed for the Tritrac. These data indicate that accelerometers are an appropriate methodology for measuring children’s free-play physical activities.