Validation and calibration of the Actical accelerometer in preschool children

PURPOSE

Decreased physical activity (PA) is likely a contributor to the rising prevalence of obesity in children. Lack of valid and acceptable measures of PA has been an issue in studies involving young children. The Actical accelerometer is a promising tool for measurement of PA in young children. The purpose of this study was to calibrate and validate the Actical accelerometer for use with 3- to 5-yr-old children.

METHODS

Eighteen preschool children wore an Actical accelerometer and a Cosmed portable metabolic system during a period of rest, while performing three structured activities in a laboratory setting (used for calibration), and during 20 min each of unstructured indoor and outdoor activities at their preschool (used for cross-validation). Expired respiratory gases were collected, and oxygen consumption was measured on a breath-by-breath basis. Accelerometer data were collected in 15-s intervals.

RESULTS

For the accelerometer calibration, the correlation between VO2 and counts was r = 0.89 across all activities. The calibration equation established was VO2 = counts x 15 s(-1) (0.01437) + 9.73 (R2 = 0.96, SEE = 3.02). The cut-point for moderate activity (20 mL x kg(-1) x min(-1)) was 715 counts x 15 s(-1) (sensitivity 97.2%, specificity 91.7%), and the cut-point for vigorous activity (30 mL x kg(-1) x min(-1)) was 1411 counts x 15 s(-1) (sensitivity 98.2%, specificity 61.1%). For the cross-validation, the intraclass correlation coefficient was R = 0.59 and the Spearman correlation coefficient was R = 0.80 (P < 0.001) between measured and predicted VO2. Percentage of agreement, kappa, and modified kappa for moderate activity were 0.73, 0.40, and 0.46, respectively. For vigorous activity, the same measures were 0.85, 0.26, and 0.71, respectively.

CONCLUSION

The Actical accelerometer is a valid tool for measuring PA in young children.

Factorial validity and invariance of the Physical Self-Description Questionnaire among black and white adolescent girls

Meaningful comparison of physical self-concept among racial or ethnic groups requires that the measurement instruments used have equivalent measurement properties. We tested the factorial validity and invariance of the Physical Self-Description Questionnaire (PSDQ) among Black (n = 658) and White (n = 479) adolescent girls in the 12th grade. Construct validity was examined by estimating correlations between PSDQ subscales and external criteria (physical activity, physical fitness, body mass index [BMI], and participation in sports). The hypothesized 11-factor model demonstrated adequate overall fit in both groups. Comparison of nested models supported the between-group invariance of the overall factor structure. Convergent and discriminant evidence for construct validity was supported by the pattern of correlations with the external criteria. The results indicate that a meaningful comparison of PSDQ scores can be made between Black and White girls in the 12th grade and that valid inferences from PSDQ scores can be made about specific aspects of physical self-concept. Despite lower levels of physical activity, sport participation, and fitness and higher BMI, Black girls had similar self-esteem and higher physical self-concept and perceived appearance compared to White girls.

Physical activity correlates in adolescent girls who differ by weight status

OBJECTIVE

This study compared correlates of physical activity (PA) among African-American and white girls of different weight groups to guide future interventions.

RESEARCH METHODS AND PROCEDURES

Participants were 1015 girls (mean age, 14.6 years; 45% African-American) from 12 high schools in South Carolina who served as control subjects for a school-based intervention. Post-intervention measures obtained at the end of ninth grade were used. PA was measured using the Three-Day PA Recall, and a questionnaire measured social-cognitive and environmental variables thought to mediate PA. Height and weight were measured, and BMI was calculated. Girls were stratified by race and categorized into three groups, based on BMI percentiles for girls from CDC growth charts: normal (BMI < 85th percentile), at risk (BMI, 85th to 94th percentile), and overweight (BMI > or = 95th percentile). Girls were further divided into active and low-active groups, based on a vigorous PA standard (average of one or more 30-minute blocks per day per 3-day period). Mixed-model ANOVA was used to compare factors among groups, treating school as a random effect

RESULTS

None of the social-cognitive or environmental variables differed by weight status for African-American or white girls. Perceived behavioral control and sports team participation were significantly higher in girls who were more active, regardless of weight or race group. In general, social-cognitive variables seem to be more related to activity in white girls, whereas environmental factors seem more related to activity in African-American girls.

DISCUSSION

PA interventions should be tailored to the unique needs of girls based on PA levels and race, rather than on weight status alone.

Perceived physical environment and physical activity across one year among adolescent girls: self-efficacy as a possible mediator?

PURPOSE

This study involved an examination of the direct and mediated effects of perceived equipment accessibility and neighborhood safety on physical activity across a one-year period among adolescent girls.

METHODS

Adolescent girls (N = 1,038) completed self-report measures of perceived environment, barriers self-efficacy, and physical activity in the Spring semesters of 1999 (baseline) and 2000 (follow-up) when students were in the 8th and 9th grades.

RESULTS

An initial analysis demonstrated that neighborhood safety did not exhibit cross-sectional or longitudinal direct effects on physical activity, whereas equipment accessibility exhibited a statistically significant cross-sectional, but not longitudinal, direct effect on physical activity. The secondary analysis demonstrated that self-efficacy for overcoming barriers mediated the cross-sectional effect of equipment accessibility on physical activity.

CONCLUSIONS

We conclude that the cross-sectional effect of perceived equipment accessibility on physical activity is mediated by self-efficacy for overcoming barriers among adolescent girls. This is consistent with the reciprocal relationships among the environment, person, and behavior described by social-cognitive theory.

Longitudinal continuity of care is associated with high patient satisfaction with physical therapy

BACKGROUND AND PURPOSE

Recent literature has suggested that longitudinal continuity (ie, the patient is seen by the same practitioner for the entire course of treatment) may be linked to high degrees of patient satisfaction with medical care. The purpose of this study was to provide preliminary information regarding the association between longitudinal continuity and reports of patient satisfaction with physical therapy outpatient care.

SUBJECTS AND METHODS

A sample of 1,502 adult subjects completed the MedRisk Instrument for Measuring Patient Satisfaction With Physical Therapy Care at the time of discharge from outpatient physical therapy. Relationships between satisfaction measures and the presence or absence of longitudinal continuity were assessed by use of binary logistic regression.

RESULTS

Overall, 36.8% of the subjects reported complete satisfaction on the internal subscale (patient-therapist), and 47.9% of the subjects reported complete satisfaction on the external subscale (patient-support staff). Higher percentages of women (40.2% and 51.1% for internal and external subscales, respectively) than of men (31.9% and 43.3% for internal and external subscales, respectively) were completely satisfied with care. Of subjects who reported complete satisfaction on the internal subscale, 71.2% had longitudinal continuity of care, and 28.8% did not. A similar trend was noted for the external subscale (patient-support staff); 66.8% of subjects who reported complete satisfaction had longitudinal continuity, and 33.2% did not. Odds ratios describing the probability of complete satisfaction with care for subjects who had longitudinal continuity and for those who did not were significant and ranged from 2.7 to 3.5.

DISCUSSION AND CONCLUSION

Subjects who received their entire course of outpatient physical therapy from only 1 provider were approximately 3 times more likely to report complete satisfaction with care than those who received care from more than 1 provider. These findings suggest that clinicians and managers should make efforts to preserve longitudinal continuity of care as a means of improving patient satisfaction with care.

Promotion of physical activity among high-school girls: a randomized controlled trial

OBJECTIVES

Many adolescent girls fail to meet national guidelines for physical activity, and the prevalence of obesity is increasing among this group. Our study examined the effects of a comprehensive school-based intervention on physical activity among high-school girls.

METHODS

A group-randomized controlled field trial was conducted at 24 high schools. A school-based sample of 2744 girls (48.7% African American, 46.7% White) participated in a measurement protocol when they were in eighth and then ninth grade. A comprehensive physical activity intervention was designed to change the instructional program and the school environment to increase support for physical activity among girls.

RESULTS

At follow-up, 45% of girls in the intervention schools and 36% of girls in the control schools reported vigorous physical activity during an average of 1 or more 30-minute time blocks per day over a 3-day period.

CONCLUSIONS

A comprehensive school-based intervention can increase regular participation in vigorous physical activity among high-school girls.

Scale development for perceived school climate for girls' physical activity

OBJECTIVES

To test an original scale assessing perceived school climate for girls' physical activity in middle school girls.

METHODS

Confirmatory factor analysis (CFA) and structural equation modeling (SEM).

RESULTS

CFA retained 5 of 14 original items. A model with 2 correlated factors, perceptions about teachers' and boys' behaviors, respectively, fit the data well in both sixth and eighth graders. SEM detected a positive, significant direct association of the teacher factor, but not the boy factor, with girls' self-reported physical activity.

CONCLUSIONS

School climate for girls' physical activity is a measurable construct, and preliminary evidence suggests a relationship with physical activity.

Evaluating the sustainability of SPARK physical education: a case study of translating research into practice

Dissemination and sustainability of evidence-based physical education programs (PE) has been studied rarely. The sustainability of a health-related PE program (SPARK) was independently evaluated in 111 elementary schools in 7 states. Surveys were mailed to schools that had received SPARK curriculum books, training and follow-up (response rate = 47%). Up to 80% of schools that adopted SPARK PE reported sustained use up to 4 years later. Schools using SPARK had more frequent PE classes. Sustained use was related to support from the principal, not previously having a standard PE program, having adequate equipment, and teachers being physically active. Program sustainability was similar in advantaged and disadvantaged schools. Evidence-based PE programs can be sustained up to 4 years.

Enjoyment Mediates Effects of a School-Based Physical-Activity Intervention

PURPOSE

The study evaluated whether targeted changes in factors influencing enjoyment of physical education (PE), physical activity enjoyment, and self-efficacy beliefs about participating in physical activity mediated the effect of the Lifestyle Education for Activity Program (LEAP) intervention on participation in physical activity.

METHODS

High schools (N=24) paired on enrollment size, racial composition, urban or rural location, and class structure were randomized into control (N=12) or experimental (N=12) groups. Of the 4044 girls enrolled and eligible, 2087 (51.6%) participated in the measurement component of the study. There were 1038 girls in the control group and 1049 girls in the experimental group.

INTERVENTION

LEAP was a comprehensive school-based intervention emphasizing changes in instruction and school environment designed to increase physical activity among black and white adolescent girls. It was organized according to the Coordinated School Health Program and included a PE component with core objectives of promoting enjoyment of PE, physical activity enjoyment, and self-efficacy.

RESULTS

Latent variable structural equation modeling indicated that: 1) the intervention had direct, positive effects on physical activity and factors influencing enjoyment of PE, which subsequently explained the effects of increased physical activity enjoyment and self-efficacy on increased physical activity; and 2) an additional, indirect effect of physical activity enjoyment on physical activity operated by an influence on self-efficacy.

CONCLUSIONS

Increases in enjoyment partially mediated the positive effect of the LEAP intervention. To our knowledge, we have provided the first experimental evidence from a randomized controlled trial linking increased enjoyment with increased physical activity among black and white adolescent girls.

Promoting physical activity in girls: a case study of one school's success

This case study profiles one of 24 high schools that participated in a school-based, NIH-funded study to increase physical activity among high school girls. The case study school was one of 12 randomly assigned to the intervention group. The study intervention was based on the premise that a successful intervention is developed and tailored by teachers and staff to fit the context of their school. Intervention guidelines (Essential Elements) and the Coordinated School Health Program (CSHP) model were used to direct intervention activities for physical education, health education, school environment, school health services,faculty/staff health promotion, andfamily/community involvement. All girls at the case study school received the intervention. A team of school employees provided leadership to develop and implement the intervention in collaboration with a university project staff. Data collected over a two-year period were used to describe changes that occurred in each CSHP area. Key changes were made in the school environment, curricula, policies, and practices. Qualitative measures showed girls more involved in physical activity. Quantitative measures taken in eighth grade, and repeated with the same set of girls in ninth grade, showed increases in both moderate-to-vigorous physical activity (p = < .01) and vigorous physical activity (p = .04). Other schools can use this case to modify components of the CSHP model to increase physical activity among high school girls.

Comparison of Barriers Self-Efficacy and Perceived Behavioral Control for Explaining Physical Activity Across 1 Year Among Adolescent Girls

The absence of longitudinal data about correlates of physical activity during adolescence has hindered the identification of key mediator variables that can be targeted by interventions. Building on the authors' previous report of a cross-sectional analysis, this study compared barriers self-efficacy and perceived behavioral control as predictors of change in 2 levels of physical activity across a 1-year period among a sample of Black and White adolescent girls (N=1,038). Self-efficacy did not predict change in either moderate or vigorous physical activity. In contrast, perceived behavioral control exhibited a longitudinal, independent relationship with change in vigorous physical activity. The authors concluded that perceived behavioral control is an independent predictor of change in vigorous physical activity levels across a 1-year period among a sample of Black and White adolescent girls and warrants study as a potential mediator variable in interventions designed to increase or maintain physical activity.

The MedRisk Instrument for Measuring Patient Satisfaction With Physical Therapy Care: a psychometric analysis

STUDY DESIGN

Psychometric evaluation of a cross-sectional survey.

OBJECTIVES

To determine the validity of measures obtained from the MedRisk Instrument for Measuring Patient Satisfaction With Physical Therapy Care (MRPS) to differentiate between patient satisfaction with internal and external factors.

BACKGROUND

Self-report measures that sample a variety of items provide clinicians with an array of information that may assist in assessing patient satisfaction. An important measurement characteristic of these instruments is the ability to discriminate between different factors that may influence patient reports of satisfaction with care, ie, discriminant validity. In previous work, exploratory factor analysis suggested that the MRPS questionnaire has a 2-factor structure: "internal," relating to the patient-therapist interaction, and "external," describing nontherapist issues such as admissions and clinic environment.

METHODS AND MEASURES

One thousand four hundred forty-nine adult patients completed the MRPS questionnaire upon finishing their course of outpatient physical therapy treatment. Discriminant validity of the 2-factor model was assessed using confirmatory factor analysis. The measures from the 2 factors were then evaluated for reliability by calculating the standard error of measurement (SEM), and for concurrent validity by correlating the mean score of the factors and individual items to global measures of satisfaction.

RESULTS

Confirmatory factor analysis supported a good to excellent model fit for the internal factor (7 items) and external factor (3 items). The SEM for the 2 factors was 0.19 and 0.24, indicating a low degree of measurement error. Both factors had high significant correlation with global measures of satisfaction (internal, r = 0.83 and 0.80; external, r = 0.71 and 0.71). All individual items within the 2 factors had significant correlations with global measures ranging from r = 0.33 to 0.80.

CONCLUSIONS

Our findings provide evidence of discriminant and concurrent validity of the 2-factor solution for the MRPS questionnaire for the sample that was tested. This 2-factor solution yields measures that are relatively free of error and may discriminate between internal and external factors influencing patient satisfaction. Patients who complete their course of physical therapy report that the professional interaction between the therapist and patient, especially the meaningful exchange of relevant information, is critical for patient satisfaction with care. The generalizability of our data to patients who do not complete their physical therapy care or who are receiving care in other health care environments is unknown.

Physical activities and sedentary pursuits in African American and Caucasian girls

The purposes of this study were to describe and compare the specific physical activity choices and sedentary pursuits of African American and Caucasian American girls. Participants were 1,124 African American and 1,068 Caucasian American eighth-grade students from 31 middle schools. The 3-Day Physical Activity Recall (3DPAR) was used to measure participation in physical activities and sedentary pursuits. The most frequently reported physical activities were walking, basketball, jogging or running, bicycling, and social dancing. Differences between groups were found in 11 physical activities and 3 sedentary pursuits. Participation rates were higher in African American girls (p < or = .001) for social dancing, basketball, watching television, and church attendance but lower in calisthenics, ballet and other dance, jogging or running, rollerblading, soccer, softball or baseball, using an exercise machine, swimming, and homework. Cultural differences of groups should be considered when planning interventions to promote physical activity.

Physical activity among children attending preschools

OBJECTIVES

Obesity rates are increasing among children of all ages, and reduced physical activity is a likely contributor to this trend. Little is known about the physical activity behavior of preschool-aged children or about the influence of preschool attendance on physical activity. The purpose of this study was to describe the physical activity levels of children while they attend preschools, to identify the demographic factors that might be associated with physical activity among those children, and to determine the extent to which children's physical activity varies among preschools.

METHODS

A total of 281 children from 9 preschools wore an Actigraph (Fort Walton Beach, FL) accelerometer for an average of 4.4 hours per day for an average of 6.6 days. Each child's height and weight were measured, and parents of participating children provided demographic and education data.

RESULTS

The preschool that a child attended was a significant predictor of vigorous physical activity (VPA) and moderate-to-vigorous physical activity (MVPA). Boys participated in significantly more MVPA and VPA than did girls, and black children participated in more VPA than did white children. Age was not a significant predictor of MVPA or VPA.

CONCLUSIONS

Children's physical activity levels were highly variable among preschools, which suggests that preschool policies and practices have an important influence on the overall activity levels of the children the preschools serve.

Differentiating sensory and affective-sensory pain descriptions in patients undergoing magnetic resonance imaging for persistent low back pain

The study design is a cross-sectional survey with psychometric analysis. The objective is to determine the validity of a modified version of the Short-Form McGill Pain Questionnaire (SF-MPQ). The SF-MPQ has been widely used to differentiate between reports of sensory and affective pain. The validity of this instrument to reflect independence between these constructs remains unclear. The SF-MPQ, the Roland-Morris Questionnaire (RM) and a measure of current pain intensity were completed by 373 patients undergoing lumbar magnetic resonance imaging (MRI). Four hypothesized factor structures for the SF-MPQ (three 2-factor and one 1-factor solution) were tested using confirmatory factor analysis. A modified 2-factor solution (MSF-MPQ) containing 3 items labeled sensory and 5 items labeled affective-sensory had the best degree of fit. Correlations between factors were substantially lower for the modified 2-factor solution (0.48) than for previously described 2-factor solutions (0.88 and 0.92) indicating a higher degree of independence between these factors. Correlations with measures of pain intensity and the RM were significant, but slightly lower, for the subscales of the modified 2-factor solution (0.26-0.40) than for the subscales of the previously described 2-factor solutions (0.34-0.45). The MSF-MPQ can be used as a brief tool to differentiate the language used to describe pain in patients who are undergoing lumbar MRI. The evidence indicates that this clinical tool can be used to categorize how these patients describe their pain and potentially may be very valuable in determining the optimal course of treatment.

Factorial validity and invariance of a self-report measure of physical activity among adolescent girls

We examined the factorial validity and factorial invariance of the 3-day physical activity recall (3DPAR) using confirmatory factor analysis. Adolescent girls from two cohorts (N = 955, N = 1,797) completed the 3DPAR in the eighth grade; participants in Cohort 2 (N = 1,658) completed the 3DPAR again 1 year later in the ninth grade. The 3DPAR was best represented by two uncorrelated factors in Cohort 1. The two-factor, uncorrelated measurement model exhibited evidence of cross-validity between Cohorts 1 and 2. This model also exhibited configural and partial metric invariance between race and across time. Hence, the 3DPAR consisted of two uncorrelated factors underlying three indicators of both moderate and vigorous physical activity in this sample of Black and White girls across a 1-year period. The 3DPAR can be used in cross-sectional, prospective cohort and intervention studies that examine mediators and moderators of physical activity among Black and White adolescent girls.

Comparison of social variables for understanding physical activity in adolescent girls

OBJECTIVE

To evaluate social support and theory of planned behavior (TPB) constructs in explaining physical activity in adolescent girls.

METHODS

One thousand seven hundred ninety-seven 8th-grade girls completed a survey measuring social provisions, family support, TPB constructs, moderate-to-vigorous physical activity (MVPA), and team sport involvement (TSI).

RESULTS

Structural equation modeling (SEM) indicated statistically significant direct effects from TPB constructs and social provisions to intention; social provisions, family support, and intention to MVPA; and social provisions and family support to TSI.

CONCLUSIONS

Social variables play a greater role in explaining TSI than in explaining MVPA in this sample.

Influences of Preschool Policies and Practices on Children's Physical Activity

The objective of this study was to determine if moderate to vigorous physical activity (MVPA) of 3-5 year old preschool children varied with differences in policies/practices, and overall quality of preschools. A total of 266 children (47% males, 60% African American) from 9 preschools were observed for 1 hour on 3 different days. PA of children was observed twice per minute and scored as 1-5, with 1 for stationary/motionless and 5 for fast movement. Summary MVPA was calculated over the 3 days as percent of times observed at levels of 4 or 5, and percent of time at levels 1 or 2 as sedentary activity. A structured interview about PA policies was conducted with an administrator at each preschool and overall quality of the preschool was assessed using Early Childhood Environment Rating Scale-Revised Edition (ECERS-R). Preschools were divided into groups according to whether a specific policy/practice that would be logically hypothesized to promote PA was in place at the school. MVPA differences between groups of children was assessed using mixed ANOVA controlling for preschool. When preschools offered more field trips, and more college educated teachers, the children participated in more MVPA. Children who attended preschools with lower quality spent more time in sedentary activity. In conclusion, children in preschools which may have more resources and better quality appear to show both more sedentary behavior and more MVPA.

Self-efficacy partially mediates the effect of a school-based physical-activity intervention among adolescent girls

BACKGROUND

This study evaluated the effects of the Lifestyle Education for Activity Program (LEAP), a comprehensive school-based intervention emphasizing changes in instruction and school environment, on variables derived from social-cognitive theory (SCT) as mediators of change in physical activity among black and white adolescent girls.

METHODS

Twenty-four high schools paired on enrollment size, racial composition, urban, suburban, or rural location, and class structure were randomized into control (n = 12) or experimental (n = 12) groups. There were 1038 girls in the control group and 1049 girls in the experimental group. The multicomponent intervention emphasized the enhancement of self-efficacy and development of behavioral skills by using curricular activities within physical education classes and health education instruction. The primary outcomes were self-efficacy, outcome-expectancy value, goal setting, satisfaction, and physical activity.

RESULTS

Latent variable structural equation modeling indicated that: (1) self-efficacy and satisfaction exhibited synchronous, cross-sectional relationships with physical activity; (2) the intervention had direct effects on self-efficacy, goal setting, and physical activity; and (3) self-efficacy partially mediated the effect of intervention on physical activity.

CONCLUSIONS

To our knowledge, this study provides the first evidence from a randomized controlled trial that manipulation of self-efficacy results in increased physical activity among black and white adolescent girls. The results encourage the use of self-efficacy as a targeted, mediator variable in interventions designed to increase physical activity among girls.

Evaluating a model of parental influence on youth physical activity

OBJECTIVE

To test a conceptual model linking parental physical activity orientations, parental support for physical activity, and children's self-efficacy perceptions with physical activity participation.

PARTICIPANTS AND SETTING

The sample consisted of 380 students in grades 7 through 12 (mean age, 14.0+/-1.6 years) and their parents. Data collection took place during the fall of 1996.

MAIN OUTCOME MEASURES

Parents completed a questionnaire assessing their physical activity habits, enjoyment of physical activity, beliefs regarding the importance of physical activity, and supportive behaviors for their child's physical activity. Students completed a 46-item inventory assessing physical activity during the previous 7 days and a 5-item physical activity self-efficacy scale. The model was tested via observed variable path analysis using structural equation modeling techniques (AMOS 4.0).

RESULTS

An initial model, in which parent physical activity orientations predicted child physical activity via parental support and child self-efficacy, did not provide an acceptable fit to the data. Inclusion of a direct path from parental support to child physical activity and deletion of a nonsignificant path from parental physical activity to child physical activity significantly improved model fit. Standardized path coefficients for the revised model ranged from 0.17 to 0.24, and all were significant at the p<0.0001 level.

CONCLUSIONS

Parental support was an important correlate of youth physical activity, acting directly or indirectly through its influence on self-efficacy. Physical activity interventions targeted at youth should include and evaluate the efficacy of individual-level and community-level strategies to increase parents' capacity to provide instrumental and motivational support for their children's physical activity.

Correlates of physical activity among U.S. young adults, 18 to 30 years of age, from NHANES III

Young adults are often in periods of transition, and lifestyle changes such as a decline in physical activity can occur during this period. The purpose of this study was to determine the relationships between demographic, biologic, lifestyle, social support index, environmental factors, and physical activity in young adults. The participants were 4,152 young adults from 18 to 30 years of age enrolled in the Third National Health and Nutrition Examination Survey (NHANES III). A moderate to vigorous physical activity (MVPA) score was calculated from responses to nine activities and up to four activities not previously listed. Multiple regression analyses were used to assess the relationship between MVPA and independent variables separately for men and women. Non-Hispanic Blacks were more active than non-Hispanic White or Mexican American men, whereas, among women, non-Hispanic Whites were more active. Education, social support index, and trying to lose weight were positively associated with MVPA, whereas being married was inversely related in both men and women. Among women, those who were unemployed, in better health, had smaller families, had lower body mass indexes (BMIs), and were not from the South had higher MVPA. Men who were in school during the past 12 months were more active than those who were not in school. The results from this study suggest that demographic and social factors are important determinants of physical activity in young adults and should be considered when planning interventions.

Physical activity in overweight and nonoverweight preschool children

OBJECTIVE

To compare the physical activity levels of overweight and non overweight 3- to 5-y-old children while attending preschool. A secondary aim was to evaluate weight-related differences in hypothesized parental determinants of child physical activity behavior.

DESIGN

Cross-sectional study.

SUBJECTS

A total of 245, 3- to 5-y-olds (127 girls, 118 boys) and their parent(s) (242 mothers, 173 fathers) recruited from nine preschools. Overweight status determined using the age- and sex-specific 85th percentile for body mass index (BMI) from CDC Growth Charts.

MEASUREMENTS

Physical activity during the preschool day was assessed on multiple days via two independent objective measures-direct observation using the observation system for recording activity in preschools (OSRAP) and real-time accelerometry using the MTI/CSA 7164 accelerometer. Parents completed a take-home survey assessing sociodemographic information, parental height and weight, modeling of physical activity, support for physical activity, active toys and sporting equipment at home, child's television watching, frequency of park visitation, and perceptions of child competence.

RESULTS

Overweight boys were significantly less active than their nonoverweight peers during the preschool day. No significant differences were observed in girls. Despite a strong association between childhood overweight status and parental obesity, no significant differences were observed for the hypothesized parental influences on physical activity behavior.

CONCLUSIONS

Our results suggest that a significant proportion of overweight children may be at increased risk for further gains in adiposity because of low levels of physical activity during the preschool day.

Evaluation of a community-based intervention to promote physical activity in youth: lessons from Active Winners

PURPOSE

To test the effects of a community-based physical activity intervention designed to increase physical activity and to conduct an extensive process evaluation of the intervention.

DESIGN

Quasi-experimental.

SETTING

Two rural communities in South Carolina. One community received the intervention, and the other served as the comparison.

SUBJECTS

Public school students who were in fifth grade at the start of the study (558 at baseline) were eligible to participate. A total of 436 students participated over the course of the study.

INTERVENTION

The intervention included after-school and summer physical activity programs and home, school, and community components designed to increase physical activity in youth. The intervention took place over an 18-month period.

MEASURES

Students reported after-school physical activity at three data collection points (prior to, during, and following the intervention) using the Previous Day Physical Activity Recall (PDPAR). They also completed a questionnaire designed to measure hypothesized psychosocial and environmental determinants of physical activity behavior. The process evaluation used meeting records, documentation of program activities, interviews, focus groups, and heart rate monitoring to evaluate the planning and implementation of the intervention.

RESULTS

There were no significant differences in the physical activity variables and few significant differences in the psychosocial variables between the intervention and comparison groups. The process evaluation indicated that the after-school and summer physical activity component of the intervention was implemented as planned, but because of resource and time limitations, the home, school, and community components were not implemented as planned.

CONCLUSIONS

The intervention did not have a significant effect on physical activity in the target population of children in the intervention community. This outcome is similar to that reported in other studies of community-based physical activity intervention.

Examining social-cognitive determinants of intention and physical activity among black and white adolescent girls using structural equation modeling

Structural equation modeling was used to evaluate components within the theories of reasoned action (TRA), planned behavior (TPB), and self-efficacy (SET) for understanding moderate and vigorous physical activity among 1,797 Black and White adolescent girls. Modest to strong support was provided for components of TPB and SET; weak support was provided for components of TRA. Perceived behavioral control was related to vigorous physical activity. Self-efficacy was related to moderate and vigorous physical activity, and it accounted for the effect of intention on physical activity. The observed relationships were similar between Black and White girls. Self-efficacy and perceived behavioral control are independent influences on physical activity among Black and White adolescent girls and warrant study as potential mediators in physical activity interventions.

Psychosocial correlates of physical activity in white and African-American girls

PURPOSE

To evaluate the relative utility of the Theory of Reasoned Action (TRA) and the Theory of Planned Behavior (TPB) in explaining intentions and physical activity behavior in white and African-American eighth-grade girls.

METHODS

One-thousand-thirty white and 1.114 African-American eighth-grade girls (mean age 13.6 +/- 0.7 years) from 31 middle schools in South Carolina completed a 3-day physical activity recall and a questionnaire assessing attitudes, subjective norms, perceived behavioral control, self-efficacy, and intentions related to regular participation in moderate-to-vigorous physical activity (MVPA).

RESULTS

Among Whites, 17% of the variance in intentions was contributed by subjective norms and attitude, with intentions accounting for 8% of the variance in MVPA. The addition of perceived behavioral control and self-efficacy to the TRA significantly improved the prediction of intentions and MVPA accounting for 40% and 10% of the variance, respectively. Among African-Americans, subjective norms and attitude accounted for 13% of the variance in intentions, with intentions accounting for only 3% of the variance in MVPA. The addition of perceived behavioral control and self-efficacy to the TRA significantly improved the prediction of intentions and MVPA accounting for 28% and 5% of the variance, respectively.

CONCLUSIONS

The results provided limited empirical support for the TPB among white adolescent girls; however, our findings suggest that the planned behavior framework has limited utility among African-American adolescent girls. The relatively weak link between intentions and MVPA observed in both population groups suggest that constructs external to the TPB may be more important mediators of physical activity behavior in adolescent girls.

Differences in physical activity between black and white girls living in rural and urban areas

This study examined the relationship of race and rural/urban setting to physical, behavioral, psychosocial, and environmental factors associated with physical activity. Subjects included 1,668 eighth-grade girls from 31 middle schools: 933 from urban settings, and 735 from rural settings. Forty-six percent of urban girls and 59% of rural girls were Black. One-way and two-way ANOVAs with school as a covariate were used to analyze the data. Results indicated that most differences were associated with race rather than setting. Black girls were less active than White girls, reporting significantly fewer 30-minute blocks of both vigorous and moderate-to-vigorous physical activity. Black girls also spent more time watching television, and had higher BMIs and greater prevalence of overweight than White girls. However, enjoyment of physical education and family involvement in physical activity were greater among Black girls than White girls. Rural White girls and urban Black girls had more favorable attitudes toward physical activity. Access to sports equipment, perceived safety of neighborhood, and physical activity self-efficacy were higher in White girls than Black girls.

Compliance with physical activity guidelines: prevalence in a population of children and youth

PURPOSE

To use objective monitoring of physical activity to determine the percentages of children and youth in a population that met physical activity guidelines.

METHODS

A total of 375 students in grades 1-12 wore an accelerometer (CSA 7164) for seven consecutive days. Bouts of continuous activity and accumulation of minutes spent in physical activity at various intensities were calculated to determine how many students met three physical activity guidelines.

RESULTS

Over 90% of students met Healthy People 2010, Objective 22.6 and nearly 70% met the United Kingdom Expert Consensus Group guideline, both of which recommend daily accumulation of moderate physical activity. Less than 3% met Healthy People 2010, Objective 22.7, which calls for bouts of continuous vigorous physical activity. For the United Kingdom Expert Consensus Group guideline, compliance decreased markedly with age, but gender differences were not statistically significant.

CONCLUSIONS

Prevalence estimates for compliance with national physical activity guidelines varied markedly for the three guidelines examined. Objective monitoring of physical activity in youth appears to be feasible and may provide more accurate prevalence rates than self-report measures.

Age and gender differences in objectively measured physical activity in youth

PURPOSE

The purpose of this study was to evaluate age and gender differences in objectively measured physical activity (PA) in a population-based sample of students in grades 1-12.

METHODS

Participants (185 male, 190 female) wore a CSA 7164 accelerometer for 7 consecutive days. To examine age-related trends, students were grouped as follows: grades 1-3 (N = 90), grades 4-6 (N = 91), grades 7-9 (N = 96), and grades 10-12 (N = 92). Bouts of PA and minutes spent in moderate-to-vigorous PA (MVPA) and vigorous PA (VPA) were examined.

RESULTS

Daily MVPA and VPA exhibited a significant inverse relationship with grade level, with the largest differences occurring between grades 1-3 and 4-6. Boys were more active than girls; however, for overall PA, the magnitudes of the gender differences were modest. Participation in continuous 20-min bouts of PA was low to nonexistent.

CONCLUSION

Our results support the notion that PA declines rapidly during childhood and adolescence and that accelerometers are feasible alternatives to self-report methods in moderately sized population-level surveillance studies.

Factorial invariance and latent mean structure of questionnaires measuring social-cognitive determinants of physical activity among black and white adolescent girls

BACKGROUND

We previously developed questionnaires based on contemporary theories to measure physical activity determinants among youth [Motl et al., Prev Med 2000; 31:584-94]. The present study examined the factorial invariance and latent mean structure of unidimensional models fit to the questionnaires measuring attitude, subjective norm, perceived behavioral control, and self-efficacy about physical activity among black and white adolescent girls.

METHODS

Black (n = 896) and white (n = 823) girls in the 8th grade completed the questionnaires measuring attitude, subjective norm, perceived behavioral control, and self-efficacy about physical activity. The responses were subjected to analyses of factorial invariance and latent mean structure using confirmatory factor analysis with full-information maximum likelihood estimation in AMOS 4.0.

RESULTS

The unidimensional models of the four questionnaires generally demonstrated invariance of the factor structure, factor loadings, and factor variance across race but not invariance of the variance-covariance matrices or item uniquenesses. The analyses of latent mean structure demonstrated that white girls had higher latent mean scores on the measures of attitude and self-efficacy than black girls; there were similar, but smaller, differences between white and black girls on the measures of subjective norm and perceived behavioral control.

CONCLUSIONS

The questionnaires can be employed in interventions to test the mediating influences of attitude, subjective norm, perceived behavioral control, and self-efficacy on participation in physical activity by black and white adolescent girls.

Measuring enjoyment of physical activity in adolescent girls

BACKGROUND

Enjoyment has been implicated as a determinant of physical activity among youth, but advances in understanding its importance have been limited by the use of measures that were not adequately validated. The present study examined: (1) the factorial validity of the Physical Activity Enjoyment Scale (PACES), and (2) the construct validity of PACES scores.

METHODS

Adolescent girls (N=1797), who were randomly assigned to calibration (n=899) and cross-validation (n=898) samples, completed the PACES and measures of factors influencing enjoyment of physical education, physical activity, and sport involvement. The factorial validity of the PACES and the measure of factors influencing enjoyment of physical education was tested using exploratory and confirmatory factor analysis. The hypothesized relationships among the measures were tested using structural equation modeling.

RESULTS

Unidimensional models fit the PACES and the measure of factors influencing enjoyment of physical education in the calibration and cross-validation samples. The hypothesized relationships between the PACES and the measures of factors influencing enjoyment of physical education, physical activity, and sport involvement were supported in the entire sample, were similar in African-American and Caucasian girls, and were independent of physical fitness.

CONCLUSIONS

Evidence of factorial validity and convergent evidence for construct validity indicate that the PACES is a valid measure of physical activity enjoyment among adolescent girls, suitable for use as a mediator variable in interventions designed to increase physical activity.

Environmental influences, physical activity, and weight status in 8- to 16-year-olds

OBJECTIVE

To assess the association between vigorous physical activity, participation on sport teams and in exercise programs, television watching, family environment, and weight status in youth.

DESIGN

Cross-sectional data from the Third National Health and Nutrition Examination Survey.

PARTICIPANTS

A group of 2791 youth between the ages of 8 and 16 years who were enrolled in the Third National Health and Nutrition Examination Survey.

MAIN OUTCOME MEASURES

Overweight was defined using age- and sex-specific 85th percentile of body mass index using Center for Disease Control and Prevention growth charts.

RESULTS

Both males and females who had an overweight mother and or father were more likely to be overweight compared with youth who did not have an overweight parent. Females who watched 4 or more hours of television were more likely to be overweight than those who watched less than 4 hours. Males and 14- to 16-year-old females who participated in sport team and exercise programs were less likely to be overweight than their counterparts who did not participate. Also, females with larger families and males from families with higher family incomes were less likely to be overweight.

CONCLUSIONS

These results suggest that family environment is associated with overweight in youth and that sport and exercise program participants are less like to be overweight and that, for females, increased television watching is related to overweight.

Factorial validity and invariance of questionnaires measuring social-cognitive determinants of physical activity among adolescent girls

BACKGROUND

There are few theoretically derived questionnaires of physical activity determinants among youth, and the existing questionnaires have not been subjected to tests of factorial validity and invariance. The present study employed confirmatory factor analysis (CFA) to test the factorial validity and invariance of questionnaires designed to be unidimensional measures of attitudes, subjective norms, perceived behavioral control, and self-efficacy about physical activity.

METHODS

Adolescent girls in eighth grade from two cohorts (N = 955 and 1,797) completed the questionnaires at baseline; participants from cohort 1 (N = 845) also completed the questionnaires in ninth grade (i.e., 1-year follow-up). Factorial validity and invariance were tested using CFA with full-information maximum likelihood estimation in AMOS 4.0. Initially, baseline data from cohort 1 were employed to test the fit and, when necessary, to modify the unidimensional models. The models were cross-validated using a multigroup analysis of factorial invariance on baseline data from cohorts 1 and 2. The models then were subjected to a longitudinal analysis of factorial invariance using baseline and follow-up data from cohort 1.

RESULTS

The CFAs supported the fit of unidimensional models to the four questionnaires, and the models were cross-validated, as indicated by evidence of multigroup factorial invariance. The models also possessed evidence of longitudinal factorial invariance.

CONCLUSIONS

Evidence was provided for the factorial validity and the invariance of the questionnaires designed to be unidimensional measures of attitudes, subjective norms, perceived behavioral control, and self-efficacy about physical activity among adolescent girls.

Sports participation and health-related behaviors among US youth

OBJECTIVE

To examine the relationship between sports participation and health-related behaviors among high school students.

DESIGN

Cross-sectional design using data from the 1997 Centers for Disease Control and Prevention Youth Risk Behavior Survey.

PARTICIPANTS

A nationally representative sample of 14,221 US high school students.

MAIN OUTCOME MEASURES

Prevalence of sports participation among males and females from 3 ethnic groups and its associations with other health behaviors, including diet, tobacco use, alcohol and illegal drug use, sexual activity, violence, and weight loss practices.

RESULTS

Approximately 70% of male students and 53% of female students reported participating on 1 or more sports teams in school and/or nonschool settings; rates varied substantially by age, sex, and ethnicity. Male sports participants were more likely than male nonparticipants to report fruit and vegetable consumption on the previous day and less likely to report cigarette smoking, cocaine and other illegal drug use, and trying to lose weight. Compared with female nonparticipants, female sports participants were more likely to report consumption of vegetables on the previous day and less likely to report having sexual intercourse in the past 3 months. Among white males and females, several other beneficial health behaviors were associated with sports participation. A few associations with negative health behaviors were observed in African American and Hispanic subgroups.

CONCLUSION

Sports participation is highly prevalent among US high school students, and is associated with numerous positive health behaviors and few negative health behaviors.

Tracking of avoidance of alcohol use and smoking behavior in a fifth grade cohort over three years

This study examined the maintenance of positive health behavior (avoidance of alcohol use and cigarette smoking) and factors associated with the maintenance of these behaviors from fifth through seventh grade by a cohort of rural students (N = 232). African American and White students showed similar patterns of high avoidance of alcohol until seventh grade. Although more girls avoided use than boys, avoidance decreased in both groups with progression in grade. Mothers', fathers', and best friends' drinking behaviors influenced avoidance behavior; drinking was less likely to occur among those whose parents and friends did not drink. Friends' drinking behavior influenced alcohol use as early as fifth grade. Smoking avoidance was maintained by 74% of the students over the 3 years. Although there were no racial differences in smoking, African Americans started smoking about 1 year earlier than Whites. During seventh grade, an increase in smoking occurred among boys and girls, but was particularly striking among girls. Avoidance of smoking was influenced by mothers' behavior but not fathers'. Best friends' smoking behavior exerted a major influence on avoidance between grades 6 and 7. In grades 5 and 6, those who avoided smoking were more physically active than smokers, but by seventh grade their physical activity declined to a similar level as smokers. Rural adolescent boys seemed to be at early risk for alcohol use and smoking, while rural girls delayed involvement by 1 to 2 years. Communities, schools, and families can help adolescents avoid alcohol use and smoking through early prevention efforts.

Health risk behaviors of rural sixth graders

The purposes of this study were to examine the frequency and risk factors (correlates) of single and concurrent health risk behaviors (HRBs) including obesity, physical inactivity, smoking, and alcohol use in a sample of 352 rural, predominately African-American sixth graders. This study was guided by Jessor's (1992) adolescent risk behavior conceptual framework. Data were collected using physical measures and a self-report questionnaire. Thirty-two percent of the sample had no HRB, 44% had one HRB, and 24% had two or more HRBs. Obesity and physical inactivity were more prevalent in this sample than in the general population. Gender differences in risk factors were evident. Our findings suggest the testing of interventions that focus on the social needs of girls and that influence behavioral modeling for boys to reduce single and concurrent health risk behaviors.