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Biomedical subjects

J F Sallis

Publications and source records attributed to J F Sallis.

At least 37 records · Page 2Linked to original sources
PubMed2000

Project GRAD: two-year outcomes of a randomized controlled physical activity intervention among young adults. Graduate Ready for Activity Daily.

INTRODUCTION: Project Graduate Ready for Activity Daily evaluated a program to promote physical activity through the transition of university graduation in a randomized controlled trial. METHODS: Three hundred thirty-eight university seniors participated in either a cognitive-behavioral intervention course or a knowledge-oriented general health course during the semester before graduation. Behaviorally oriented phone and mail follow-up was delivered to the intervention group for 18 months. Physical activity outcomes and mediating variables were assessed at baseline, 1 and 2 years (93% retention rate). RESULTS: There were no significant intervention effects on physical activity outcomes at 2 years for either men or women. Experiential and behavioral processes of change were significantly improved for intervention women over 2 years. CONCLUSIONS: Despite excellent participation in a theoretically based, well-attended intervention, few long-term effects on physical activity or its mediators were found. Additional research is needed to determine optimal interventions for physical activity and to validate or alter current behavior change theory.

Adult↗
PubMed2000

Promoting physical activity in rural communities: walking trail access, use, and effects.

INTRODUCTION: Environmental and policy approaches to promote physical activity, such as walking trail construction and promotion, are being widely recommended, yet sparse data exist on their effectiveness. In conjunction with ongoing community-intervention projects in Missouri, walking trails are being built, promoted, and evaluated. Objectives include determining: (1) patterns and correlates of walking, (2) the availability of places to walk and perform other forms of physical activity, (3) the extent of walking trail use and possible effects on rates of physical activity, and (4) attitudes toward the trails and their uses. METHODS: In 12 rural counties in Missouri we used a cross-s ectional telephone survey to ask a population-based sample of residents aged >18 years (n=1269) some standard and specially developed questions about walking behaviors, knowledge, and attitudes. RESULTS: Only 19.5% of respondents were classified as regular walkers. About one third of respondents (36.5%) reported having access to walking trails in their area, and 50.3% reported having access to indoor facilities for exercise. Among persons with access to walking trails, 38.8% had used the trails. Groups who were more likely to have used the walking trails included women, persons with more education, those making $35,000 or more per year, and regular walkers. Among persons who had used the trails, 55.2% reported they had increased their amount of walking since they began using the trail. Women and persons with a high school education or less were more than twice as likely to have increased the amount of walking since they began using the walking trails. CONCLUSIONS: Walking trails may be beneficial in promoting physical activity among segments of the population at highest risk for inactivity, in particular women and persons in lower socioeconomic groups.

Adolescent↗
PubMed2000

Examination of the factor structure of physical activity behaviors.

Multiple physical activity recommendations exist for behaviors that vary in type and intensity (e.g., vigorous physical activity, strengthening exercises, moderate physical activity). The present study examined underlying dimensions of physical activity behaviors and determined the extent to which factors correspond to national health recommendations. Fifteen variables were drawn from six self-report measures and subjected to factor analysis with quartimax rotation. Participants were 547 university seniors (56% female; 60% Caucasian; mean age = 25 years). TV watching, the only index of sedentary behavior, did not load highly with other items, and was analyzed separately. Three interpretable factors were found: variables related to vigorous physical activity loaded highly on Factor 1; flexibility and strengthening items loaded highly on Factor 2; and moderate and housework activity loaded highly on Factor 3. Factors corresponded closely to national recommendations. Unweighted factor scores and TV watching correlated significantly with physiological indicators of fitness, supporting construct validity.

Adolescent↗
PubMed2000

Personal and environmental factors associated with physical inactivity among different racial-ethnic groups of U.S. middle-aged and older-aged women.

Personal, program-based, and environmental barriers to physical activity were explored among a U.S. population-derived sample of 2,912 women 40 years of age and older. Factors significantly associated with inactivity included American Indian ethnicity, older age, less education, lack of energy, lack of hills in one's neighborhood, absence of enjoyable scenery, and infrequent observation of others exercising in one's neighborhood. For all ethnic subgroups, caregiving duties and lacking energy to exercise ranked among the top 4 most frequently reported barriers. Approximately 62% of respondents rated exercise on one's own with instruction as more appealing than undertaking exercise in an instructor-led group, regardless of ethnicity or current physical activity levels. The results underscore the importance of a multifaceted approach to understanding physical activity determinants in this understudied, high-risk population segment.

Activities of Daily Living↗
PubMed2000

Assessment of physical activity with the Computer Science and Applications, Inc., accelerometer: laboratory versus field validation.

Our purpose was to compare the validity of the Computer Science and Applications, (CSA) Inc., accelerometer in laboratory and field settings and establish CSA count ranges for light, moderate, and vigorous physical activity. Validity was determined in 60 adults during treadmill exercise, using oxygen consumption (VO2) as the criterion measure, while 30 adults walked and jogged outdoors on a 400-m track. The relationship between CSA counts and VO2 was linear (R2 = .89 SEE = 3.72 ml.kg-1.min-1), as was the relationship between velocity and counts in the field (R2 = .89, SEE = 0.89 mi.hr-1). However, significant differences were found (p < .05) between laboratory and field measures of CSA counts for light and vigorous intensity. We conclude that the CSA can be used to quantify walking and jogging outdoors on level ground; however, laboratory equations may not be appropriate for use in field settings, particularly for light and vigorous activity.

Adult↗
PubMed2000

Student activity levels, lesson context, and teacher behavior during middle school physical education.

There is little research on students' engagement in physical activity in middle school physical education (PE). We observed student activity, lesson context, and teacher behavior in 430 PE lessons taught by 126 teachers in 24 schools. Variables were analyzed by mixed-model nested analyses of covariance. Boys were more active than girls overall and during skill drills, game play, and free play. Student activity varied by lesson context, with fitness activities producing the most activity. Class size was negatively associated with student activity. Daily PE contributed a weekly total of 25 min of vigorous activity and 83 min of moderate-to-vigorous activity--much less than national objectives. Results suggest that numerous opportunities exist for increasing student physical activity during middle school PE.

Adolescent↗
PubMed2000

Self-report measures and scoring protocols affect prevalence estimates of meeting physical activity guidelines.

PURPOSE: Prevalence estimates of meeting the guidelines for physical activity based on various self-report measures were compared, and the effects of various scoring protocols on the estimates were evaluated. METHOD: A sample of 575 university students aged 24.5 +/- 1.9 yr (56% women, 54% Euro-American) completed the Seven-Day Physical Activity Recall interview (PAR), Youth Risk Behavior Survey (YRBS), and National Health Interview Survey 1991 (NHIS). To determine the prevalence of meeting the ACSM (1990) fitness and the CDC/ACSM (1995) health-related guidelines, various scoring protocols were employed that closely approximated the recommendations. Protocols varied by whether frequency and duration or duration only were considered. For the health-related guidelines, scoring protocols also varied depending on the intensity of activities considered. RESULTS: Depending on the scoring protocol and instrument used, the proportion meeting the fitness guidelines ranged from 32 to 59%. The NHIS, YRBS, and PAR resulted in significantly different proportions of those meeting the health-related guideline, ranging from 4 to 70%. CONCLUSION: The type of measure as well as the scoring protocol affected prevalence estimates of meeting the physical activity guidelines. This study indicates the difficulty of comparing prevalence rates across studies using different measures.

Adult↗
PubMed2000

Using objective physical activity measures with youth: how many days of monitoring are needed?

PURPOSE: The purpose of this study was to establish the minimal number of days of monitoring required for accelerometers to assess usual physical activity in children. METHODS: A total of 381 students (189 M, 192 F) wore a CSA 7164 uniaxial accelerometer for seven consecutive days. To examine age-related trends students were grouped as follows: Group I: grades 1-3 (N = 92); Group II: grades 4-6 (N = 98); Group III: grades 7-9 (N = 97); Group IV: grades 10-12 (N = 94). Average daily time spent in moderate-to-vigorous physical activity (MVPA) was calculated from minute-by-minute activity counts using the regression equation developed by Freedson et al. (1997). RESULTS: Compared with adolescents in grades 7 to 12, children in grades 1 to 6 exhibited less day-to-day variability in MVPA behavior. Spearman-Brown analyses indicated that between 4 and 5 d of monitoring would be necessary to a achieve a reliability of 0.80 in children, and between 8 and 9 d of monitoring would be necessary to achieve a reliability of 0.80 in adolescents. Within all grade levels, the 7-d monitoring protocol produced acceptable estimates of daily participation in MVPA (R = 0.76 (0.71-0.81) to 0.87 (0.84-0.90)). Compared with weekdays, children exhibited significantly higher levels of MVPA on weekends, whereas adolescents exhibited significantly lower levels of MVPA on weekends. Principal components analysis revealed two distinct time components for MVPA during the day for children (early morning, rest of the day), and three distinct time components for MVPA during the day for adolescents (morning, afternoon, early evening). CONCLUSIONS: These results indicate that a 7-d monitoring protocol provides reliable estimates of usual physical activity behavior in children and adolescents and accounts for potentially important differences in weekend versus weekday activity behavior as well as differences in activity patterns within a given day.

Acceleration↗
PubMed2000

A review of correlates of physical activity of children and adolescents.

BACKGROUND: Understanding the factors that influence physical activity can aid the design of more effective interventions. Previous reviews of correlates of youth physical activity have produced conflicting results. METHODS: A comprehensive review of correlates of physical activity was conducted, and semiquantitative results were summarized separately for children (ages 3-12) and adolescents (ages 13-18). The 108 studies evaluated 40 variables for children and 48 variables for adolescents. RESULTS: About 60% of all reported associations with physical activity were statistically significant. Variables that were consistently associated with children's physical activity were sex (male), parental overweight status, physical activity preferences, intention to be active, perceived barriers (inverse), previous physical activity, healthy diet, program/facility access, and time spent outdoors. Variables that were consistently associated with adolescents' physical activity were sex (male), ethnicity (white), age (inverse), perceived activity competence, intentions, depression (inverse), previous physical activity, community sports, sensation seeking, sedentary after school and on weekends (inverse), parent support, support from others, sibling physical activity, direct help from parents, and opportunities to exercise. CONCLUSION: These consistently related variables should be confirmed in prospective studies, and interventions to improve the modifiable variables should be developed and evaluated.

Adolescent↗
PubMed2000

Age-related decline in physical activity: a synthesis of human and animal studies.

The decline in physical activity with age may be the most consistent finding in physical activity epidemiology. Although this phenomenon is well accepted, it is not well understood. The purposes of this symposium are to determine whether there are critical periods of decline and quantify sex differences in the decline. Data from cross-sectional and prospective studies indicate the decline is steepest between the ages of 13 and 18. The decline is generally greater for male than female subjects, and the decline varies by type and intensity of the activity. A review of animal studies documented the age-related decline in many species. This suggests a biological basis, and a probable mechanism is the dopamine system that regulates motivation for locomotion. The decline in physical activity with age is antithetical to public health goals, so methods of countering the decline need to be developed, based upon an improved understanding of the phenomenon and its causes.

Adolescent↗
PubMed2000

Patterns and correlates of physical activity among US women 40 years and older.

OBJECTIVES: This study describes the patterns of physical activity among minority women by using a variety of definitions and determines sociodemographic and behavioral correlates of physical activity in this population. METHODS: A cross-sectional study was conducted in 1996 and 1997 among US women 40 years and older (n = 2912) of the following racial/ethnic groups: African American, American Indian/Alaskan Native, Hispanic, and White. RESULTS: Physical activity was lowest among African Americans and American Indians/Alaskan Natives (adjusted odds ratios [ORs] for no leisure-time activity were 1.35 [95% confidence interval (CI) = 1.08, 1.68] and 1.65 [95% CI = 1.33, 2.06], respectively). A much higher proportion of women were classified as being physically active when occupational activity rather than more traditional assessments of leisure activity were used to determine level of physical activity. On the basis of a composite definition of physical activity, 72% of respondents reported being physically active. Women living in rural regions (OR = 1.33; 95% CI = 1.12, 1.58) were more likely than urban inhabitants to be completely inactive during leisure time. CONCLUSIONS: Minority women are among the least active subgroups in American society, although not all groups are less active than White women when all domains of physical activity are taken into account.

Adult↗
PubMed1999

Insufficiently active Australian college students: perceived personal, social, and environmental influences.

BACKGROUND: A sustainable pattern of participation in physical activity is important in the maintenance of health and prevention of disease. College students are in transition from an active youth to a more sedentary adult behavior pattern. METHODS: We assessed self-reported physical activity and other characteristics in a sample of 2,729 male and female students (median age was 20 years) recruited from representative courses and year levels at four Australian College campuses. They were categorized as sufficiently or insufficiently active, using estimates of energy expenditure (kcal/week) derived from self-reported physical activity. Personal factors (self-efficacy, job status, enjoyment), social factors (social support from family/friends), and environmental factors (awareness of facilities, gym membership) were also assessed. RESULTS: Forty-seven percent of females and 32% of males were insufficiently active. For females, the significant independent predictors of being insufficiently active were lower social support from family and friends, lower enjoyment of activity, and not working. For males, predictors were lower social support from family and friends, lower enjoyment of activity, and being older. CONCLUSIONS: Factors associated with physical activity participation (particularly social support from family and friends) can inform physical activity strategies directed at young adults in the college setting.

Adolescent↗
PubMed1999

Potential mediators of change in a physical activity promotion course for university students: Project GRAD.

The purpose of the study is to evaluate the performance of theoretically-derived mediators of health behavior change. Participants were university seniors (184 females; 154 males) randomly assigned to an intervention course designed to promote physical activity or to a control course. Five physical activity outcomes and nine psychosocial mediating variables were assessed at baseline and the end of the 16-week course. For women, the intervention had significant effects on five of the mediators, including self-efficacy for making time, self-efficacy for resisting relapse, social support from friends, and experiential and behavioral processes of change. Among men, the intervention improved use of behavioral processes of change but also had the unintended effect of increasing perceived barriers to activity. For women, significant contributors to regressions explaining physical activity change were social support from friends (for total activity) and change in self-efficacy for resisting relapse (for vigorous exercise). For men, significant explanatory variables included change in enjoyment (for total activity), change in self-efficacy for resisting relapse (for strength exercise), and change in benefits (for moderate intensity activity). For both sexes, there were significant findings in the unexpected direction. Across the five physical activity outcomes, hypothesized mediators were inconsistent and weak contributors to the models. Investigating mediators of behavior change has the potential to stimulate improvements in theories and interventions.

Adult↗
PubMed1999

Physical activity social support and middle- and older-aged minority women: results from a US survey.

BACKGROUND: Many American adults remain sedentary despite many known health benefits. Research on the determinants of physical activity have indicated that social support is one of the strongest correlates, but little is known about this relation in important subgroups of middle and older-aged women. OBJECTIVE: The purpose of this study was to assess the association of physical activity-related social support on several measures of physical activity in a national sample of minority women. A unique aspect of these measures is the inclusion of vigorous household tasks and occupational physical activities. METHODS: The US Women's Determinants Study was conducted in 1996-1997. The survey was a modified-random sample, telephone survey of 2912 Black, Hispanic, American Indian/Alaskan Native, and White women age 40 and older. A composite score of physical activity social support (PASS) was analyzed as the independent variable in logistic regression analyses. Four measures of physical activity levels served as the dependent variables. A separate analysis was done to distinguish PASS from friends versus PASS from relatives. The potential confounding effect of race/ethnicity, marital status, age, income and education were evaluated and adjusted in the models. RESULTS: Hispanic women were more likely to have high PASS scores than the other racial/ethnic groups. Odds ratios indicate that subjects with high levels of PASS were significantly less likely to be sedentary than those with low support, even after adjusting for race/ethnicity. While there were significant associations among levels of social support and physical activity, this was not true for the measure of "regular exercise." There was no significant difference between the contribution of "friend" support versus "family" support on all four measures on physical activity. DISCUSSION: Based on our results, enhancing social support may be an important aspect of interventions aimed at increasing physical activity in a population of sedentary women of various racial/ethnic backgrounds. Also, "regular exercisers" in this population appear to be less reliant social support to maintain their behavior.

Adult↗
PubMed1999

Predictors of change in children's physical activity over 20 months. Variations by gender and level of adiposity.

BACKGROUND: Physical activity declines during childhood and determinants of this decline are poorly understood. The purpose of this prospective study was to examine modifiable psychological and social correlates of physical activity change over 20 months. SUBJECTS: 370 girls and 362 boys in public schools, studied through the 4th and 5th grades. MEASURES: A physical activity index was computed from child reports, parent reports, and objective activity monitoring. Predictor variables were assessed by child and parent surveys. RESULTS: In multiple regressions, after adjustments for demographic variables, psychological variables explained 4% of the variance in boys' physical activity change, parent variables explained 8%, and interactions with skinfolds explained 3%, for a total of 15% (unadjusted). Regarding change in girls' physical activity, psychological variables explained 3%, parent variables explained 1.5%, and interactions with skinfold explained 1.5%, for a total of 6% explained variance (unadjusted). There were differences in predictors among children with high and low levels of body fat. CONCLUSIONS: Children's preferences for physical activity and frequency of parents transporting children to activity locations explained significant proportions of variance for girls and boys. The results support a dynamic model of the determinants of children's physical activity, but most of the variance was left unexplained.

California↗
PubMed1999

Correlates of physical activity in a national sample of girls and boys in grades 4 through 12.

Psychological, biological, social, and physical environmental variables were examined for their association with physical activity of young people. A national sample of 1,504 parents and children in Grades 4-12 were interviewed by telephone. Twenty-two potential determinants were assessed along with an 11-item child physical activity index (alpha = .76). Hierarchical multiple regressions were conducted separately for 6 age-sex subgroups. Percentage of variance explained ranged from 18% for boys in Grades 4-6 to 59% for girls in Grades 10-12. Three variables had strong and consistent associations with the child physical activity index that generalized across subgroups: use of afternoon time for sports and physical activity, enjoyment of physical education, and family support for physical activity. These 3 variables should be targeted for change to promote physical activity in all groups of young people.

Adolescent↗