The level and pattern of physical activity among fifth-grade students in Ho Chi Minh City, Vietnam.

OBJECTIVES: Despite the benefits of physical activity (PA), a significant proportion of children do not meet physical activity guidelines (PAGs). However, most studies were among secondary-school-aged youth and relied on PA self-report. In addition, information regarding children's PA behaviors during specific segments of day/week is not usually collected. This study, therefore, investigated the level and pattern of PA among fifth-grade students in Ho Chi Minh City (HCMC), Vietnam. STUDY DESIGN: A complex cross-sectional survey was conducted on a representative sample of 619 fifth-grade students in eight public schools in urban areas of HCMC in 2016. METHODS: Demographic/anthropometric characteristics were measured using standard protocols. PA was measured using pedometers. After-school activities were measured using the Previous Day Physical Activity Recall questionnaire. Survey procedures with sampling weights were used for analyses. RESULTS: Approximately 18% of children met the PAG; 52.7% were overweight (OW)/obese (OB). On average, students recorded about 8800 steps/day. Boys were more active than girls at school and on weekdays. Students were more active at school on physical education (PE) days vs non-PE days and weekdays vs weekends. OW/OB students were more active at school on PE days. After-school PAs differed between boys and girls, whereas sedentary activities were popular among both the genders. CONCLUSIONS: Most fifth-grade students had insufficient PA levels. Patterns of PA are different at various times during the day and week. The finding emphasized an urgent need for interventions to improve children's PA and obesity in this area.

Weighing in on international growth standards: testing the case in Australian preschool children.

Overweight and obesity in preschool-aged children are major health concerns. Accurate and reliable estimates of prevalence are necessary to direct public health and clinical interventions. There are currently three international growth standards used to determine prevalence of overweight and obesity, each using different methodologies: Center for Disease Control (CDC), World Health Organization (WHO) and International Obesity Task Force (IOTF). Adoption and use of each method were examined through a systematic review of Australian population studies (2006-2017). For this period, systematically identified population studies (N = 20) reported prevalence of overweight and obesity ranging between 15 and 38% with most (n = 16) applying the IOTF standards. To demonstrate the differences in prevalence estimates yielded by the IOTF in comparison to the WHO and CDC standards, methods were applied to a sample of N = 1,926 Australian children, aged 3-5 years. As expected, the three standards yielded significantly different estimates when applied to this single population. Prevalence of overweight/obesity was WHO - 9.3%, IOTF - 21.7% and CDC - 33.1%. Judicious selection of growth standards, taking account of their underpinning methodologies and provisions of access to study data sets to allow prevalence comparisons, is recommended.

Patterns and correlates of physical activity in adolescents in Dhaka city, Bangladesh.

OBJECTIVES: Despite the widely acknowledged public health importance of physical activity (PA), few studies have examined levels of PA in Bangladesh. The purpose of this study was to investigate the patterns and correlates of PA in adolescents in Bangladesh. STUDY DESIGN: Cross-sectional survey. METHODS: A total of 798 students, aged 13-17 years; 48% girls, from eight purposively selected secondary schools in Dhaka city, Bangladesh completed a self-administered questionnaire including the 3-Day PA Recall. Parents completed a separate questionnaire to provide household/family-level data. Multilevel generalized linear modelling was used to identify the correlates of PA for boys and girls. RESULTS: Two-thirds (66%) of the adolescents met the recommendations of 60 min/day of moderate to vigorous PA (MVPA) daily, with more boys than girls (76% and 55%, respectively). The most common activities reported were walking for travel (42%), cricket (33%) and household chores (30%). Multivariable modelling showed that girls' PA was positively associated with mother's education level, walking to school, involvement in school sports and having home sports equipment. Boys' PA was positively associated with mother's employment, having home sports equipment, having a playground at school and walking to school. CONCLUSIONS: One third of adolescents in Bangladesh were insufficiently active with girls less active than boys. Walking to school and access to sports facilities including playgrounds and home equipment may be important to promote activity among Bangladeshi adolescents, with special attention to the girls.

Reliability and validity of physical fitness field tests for adults aged 55 to 70 years.

The aim of this study was to examine the reliability and validity of field tests for assessing physical function in mid-aged and young-old people (55-70 y). Tests were selected that required minimal space and equipment and could be implemented in multiple field settings such as a general practitioner's office. Nineteen participants completed 2 field and 1 laboratory testing sessions. Intra-class correlations showed good reliability for the tests of upper body strength (lift and reach, R= .66), lower body strength (sit to stand, R = .80) and functional capacity (Canadian Step Test, R= .92), but not for leg power (single timed chair rise. R = .28). There was also good reliability for the balance test during 3 stances: parallel (94.7% agreement), semi-tandem (73.7%), and tandem (52.6%). Comparison of field test results with objective laboratory measures found good validity for the sit to stand (cf 1RM leg press, Pearson r= .68, p < .05), and for the step test (cf PWC140, r = -.60, p < .001), but not for the lift and reach (cf 1RM bench press, r = .43, p > .05), balance (r = -.13, -.18, .23) and rate of force development tests (r = -.28). It was concluded that the lower body strength and cardiovascular function tests were appropriate for use in field settings with mid-aged and young-old adults.

Promoting physical activity to older adults: a preliminary evaluation of three general practice-based strategies.

The aim of this study was to explore the feasibility of an exercise scientist (ES) working in general practice to promote physical activity (PA) to 55 to 70 year old adults. Participants were randomised into one of three groups: either brief verbal and written advice from a general practitioner (GP) (G1, N=9): or individualised counselling and follow-up telephone calls from an ES, either with (G3, N=8) or without a pedometer (G2, N=11). PA levels were assessed at week 1, after the 12-wk intervention and again at 24 weeks. After the 12-wk intervention, the average increase in PA was 116 (SD=237) min/wk: N=28, p<0.001. Although there were no statistically significant between-group differences, the average increases in PA among G2 and G3 participants were 195 (SD=207) and 138 (SD=315) min/wk respectively, compared with no change (0.36, SD=157) in G1. After 24 weeks, average PA levels remained 56 (SD=129) min/wk higher than in week 1. The small numbers of participants in this feasibility study limit the power to detect significant differences between groups, but it would appear that individualised counselling and follow-up contact from an ES, with or without a pedometer, can result in substantial changes in PA levels. A larger study is now planned to confirm these findings.

Test-retest reliability of four physical activity measures used in population surveys.

Accurate monitoring of prevalence and trends in population levels of physical activity (PA) is a fundamental public health need. Test-retest reliability (repeatability) was assessed in population samples for four self-report PA measures: the Active Australia survey (AA, N=356), the short International Physical Activity Questionnaire (IPAQ, N=104), the physical activity items in the Behavioral Risk Factor Surveillance System (BRFSS, N=127) and in the Australian National Health Survey (NHS, N=122). Percent agreement and Kappa statistics were used to assess reliability of classification of activity status as 'active', 'insufficiently active' or 'sedentary'. Intraclass correlations (ICCs) were used to assess agreement on minutes of activity reported for each item of each survey and for total minutes. Percent agreement scores for activity status were very good on all four instruments, ranging from 60% for the NHS to 79% for the IPAQ. Corresponding Kappa statistics ranged from 0.40 (NHS) to 0.52 (AA). For individual items, ICCs were highest for walking (0.45 to 0.78) and vigorous activity (0.22 to 0.64) and lowest for the moderate questions (0.16 to 0.44). All four measures provide acceptable levels of test-retest reliability for assessing both activity status and sedentariness, and moderate reliability for assessing total minutes of activity.

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.

Plasma lipid and lipoprotein responses during exercise.

The purpose of this study was to examine the effect of prolonged exercise on plasma lipid and lipoprotein concentrations and to identify caloric time-points where changes occurred. Eleven active male subjects ran on a treadmill at 70% of maximal fitness (VO2max) and expended 6278.7 kilojoules (Kj) energy (1500 kcal). Blood samples were obtained at the 4185.8 Kj (1000 kcal) timepoint during exercise and at each additional 418.6 Kj (100 kcal) expenditure until 6278.7 Kj was expended. After correcting for plasma volume changes, decreases in low-density lipoprotein cholesterol (LDL-C) were observed during exercise at time-points corresponding to 4604.4 and 5441.5 Kj (1100 and 1300 kcal) of energy expenditure, and immediately after exercise. Total cholesterol concentrations decreased significantly at exercise kilojoule expenditures of 4604.4, 5441.5 and 5860.1 (1100, 1300 and 1400 kcal). There were also exercise induced increases in high-density lipoprotein cholesterol (HDL-C) and HDL2-C concentrations immediately after exercise. Although acute lipid and lipoprotein changes are typically reported in the days following exercise, the current data indicate that some lipoprotein concentrations change during acute exercise. Our data suggest that a threshold of exercise may be necessary to change lipoproteins during exercise. Future work should identify potential mechanisms (lipoprotein lipase, cholesterol ester transport protein, LDL uptake) that alter lipoprotein concentrations during prolonged exercise.

Effects of short-duration and long-duration exercise on lipoprotein(a).

PURPOSE: Most studies that use either a single exercise session, exercise training, or a cross-sectional design have failed to find a relationship between exercise and plasma lipoprotein(a) [Lp(a)] concentrations. However, a few studies investigating the effects of longer and/or more strenuous exercise have shown elevated Lp(a) concentrations, possibly as an acute-phase reactant to muscle damage. Based on the assumption that greater muscle damage would occur with exercise of longer duration, the purpose of the present study was to determine whether exercise of longer duration would increase Lp(a) concentration and creatine kinase (CK) activity more than exercise of shorter duration. METHODS: Ten endurance-trained men (mean +/- SD: age, 27 +/- 6 yr; maximal oxygen consumption [VO(2max)], 57 +/- 7 mL x kg(-1) x min(-1)) completed two separate exercise sessions at 70% VO(2max). One session required 800 kcal of energy expenditure (60 +/- 6 min), and the other required 1500 kcal (112 +/- 12 min). Fasted blood samples were taken immediately before (0-pre), immediately after (0-post), 1 d after (1-post), and 2 d after (2-post) each exercise session. RESULTS: CK activity increased after both exercise sessions (mean +/- SE; 800 kcal: 0-pre 55 +/- 11, 1-post 168 +/- 64 U x L(-1) x min(-1); 1500 kcal: 0-pre 51 +/- 5, 1-post 187 +/- 30, 2-post 123 +/- 19 U x L(-1) x min(-1); P < 0.05). However, median Lp(a) concentrations were not altered by either exercise session (800 kcal: 0-pre 5.0 mg x dL(-1), 0-post 3.2 mg x dL(-1), 1-post 4.0 mg x dL(-1), 2-post 3.4 mg x dL(-1); 1500 kcal: 0-pre 5.8 mg x dL(-1), 0-post 4.3 mg x dL(-1), 1-post 3.2 mg x dL(-1), 2-post 5.3 mg x dL(-1)). In addition, no relationship existed between exercise-induced changes in CK activity and Lp(a) concentration (800 kcal: r = -0.26; 1500 kcal: r = -0.02). CONCLUSION: These results suggest that plasma Lp(a) concentration will not increase in response to minor exercise-induced muscle damage in endurance-trained runners.

Physical activity and determinants of physical activity in obese and non-obese children.

OBJECTIVE: To compare the physical activity (PA) patterns and the hypothesized psychosocial and environmental determinants of PA in an ethnically diverse sample of obese and non-obese middle school children. DESIGN: Cross-sectional study. SUBJECTS: One-hundred and thirty-three non-obese and 54 obese sixth grade children (mean age of 11.4+/-0.6). Obesity status determined using the age-, race- and gender-specific 95th percentile for BMI from NHANES-1. MEASUREMENTS: Objective measurements were collected of PA over a 7-day period using the CSA 7164 accelerometer: total daily counts; daily moderate (3-5.9 METs) physical activity (MPA); daily vigorous physical activity (> or =6 METs; VPA); and weekly number of 5, 10 and 20 min bouts of moderate-to-vigorous physical activity (> or =3 METs, MVPA). Self-report measures were collected of PA self-efficacy; social influences regarding PA, beliefs about PA outcomes; perceived PA levels of parents and peers, access to sporting and/or fitness equipment at home, involvement in community-based PA organizations; participation in community sports teams; and hours spent watching television or playing video games. RESULTS: Compared to their non-obese counterparts, obese children exhibited significantly lower daily accumulations of total counts, MPA and VPA as well as significantly fewer 5, 10 and 20 min bouts of MVPA. Obese children reported significantly lower levels of PA self-efficacy, were involved in significantly fewer community organizations promoting PA and were significantly less likely to report their father or male guardian as physically active. CONCLUSIONS: The results are consistent with the hypothesis that physical inactivity is an important contributing factor in the maintenance of childhood obesity. Interventions to promote PA in obese children should endeavor to boost self-efficacy perceptions regarding exercise, increase awareness of, and access to, community PA outlets, and increase parental modeling of PA.

Objective measurement of physical activity in youth: current issues, future directions.

Objective measurement of physical activity in youth: current issues, future directions. Exerc. Sport Sci. Rev., Vol. 29, No. 1, pp 32-36, 2001. Second-generation activity monitors have revolutionized the way in which we measure youth physical activity. Use of the monitors avoids the problems associated with self-report methods and allows for the estimation of physical activity patterns over time. This article examines important methodological issues related to the use of activity monitors in children and adolescents.

Measurement of energy expenditure of daily tasks among mothers of young children.

There is currently some debate about whether the energy expenditure of domestic tasks is sufficient to confer health benefits. The aim of this study was therefore to measure the energy cost of five activities commonly undertaken by mothers of young children. Seven women with at least one child younger than five years of age spent 15 minutes in each of the following activities: sitting quietly, vacuum cleaning, washing windows, walking at moderate pace (approx 5km/hour), walking with a stroller and grocery shopping in a supermarket. Each of the six 'trials' was completed on the same day, in random order. A carefully calibrated portable gas analyser was used to measure oxygen uptake during each activity, and data were converted to units of energy expenditure (METS). Vacuum cleaning, washing windows and walking with and without a stroller were found to be 'moderate intensity activities' (3 to 6 METs), but supermarket shopping did not reach this criterion. The MET values for these activities were similar to those reported in the Compendium of Physical Activities (Ainsworth et al., 2000). However, the energy expenditures of walking, both with and without a stroller, were higher than those reported in the Compendium. The findings suggest that some of the tasks associated with domestic caring duties are conducted at an intensity which is sufficient to confer some health benefit. Such benefits will only accrue however if the daily duration of these activities is sufficient to meet current guidelines.

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.

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.

Correlates of objectively measured physical activity in preadolescent youth.

OBJECTIVE: The purpose of this study was to identify the psychosocial and environmental correlates of objectively measured physical activity behavior in a diverse sample of sixth-grade students. DESIGN: Cross-sectional. PARTICIPANTS AND SETTINGS: One hundred ninety-eight sixth-grade students from 4 public middle schools in Columbia, South Carolina. The study group was 52.0% female, 55.1% African-American, with a mean age of 11.4 +/- 0.6 years. MAIN OUTCOME MEASURES: Time spent in moderate physical activity (MPA) and vigorous physical activity (VPA) was assessed using a uniaxial accelerometer (CSA WAM 7164) (Computer Science and Applications Inc., Shalimar, FL). Determinant variables included: age, gender, race/ethnicity (demographic); physical activity self-efficacy, social norms related to physical activity, and beliefs regarding physical activity outcomes (psychosocial); and perceived physical activity habits of parents and peers, involvement in community physical activity organizations, involvement in community-based sports programs, access to fitness/sporting equipment at home, and self-reported hours spent watching television or playing video games (environmental). RESULTS: For boys, physical activity self-efficacy, social norms related to physical activity, and involvement in community physical activity organizations were salient predictors of MPA and VPA. Among girls, only physical activity self-efficacy emerged as a clear predictor of objectively measured physical activity. CONCLUSIONS: These findings are consistent with previous studies using self-reported physical activity and suggest that interventions to increase physical activity in preadolescent youth should endeavor to boost physical activity self-efficacy by offering a wide selection of enjoyable, developmentally-appropriate physical activity options.

Determinants of physical activity in active and low-active, sixth grade African-American youth.

This study compared the determinants of physical activity in active and low-active African-American sixth grade students (N = 108, 57 F, 51 M). Objective assessments of physical activity over a seven-day period were obtained using the CSA 7164 accelerometer. Students were classified as active if they exhibited three or more 20-minute bouts of moderate to vigorous physical activity over the seven-day period. Relative to low-actives, active boys reported significantly higher levels of self-efficacy, greater involvement in community physical activity organizations, and were significantly more likely to perceive their mother as active. Relative to low-actives, active girls reported significantly higher levels of physical activity self-efficacy, greater positive beliefs regarding physical activity outcomes, and were significantly less likely to watch television or play video games for > or = 3 hrs/day. These observations provide preliminary guidance as to the design of physical activity interventions targeted at African-American youth.

Effects of four different single exercise sessions on lipids, lipoproteins, and lipoprotein lipase.

The purpose of this study was to determine the threshold of exercise energy expenditure necessary to change blood lipid and lipoprotein concentrations and lipoprotein lipase activity (LPLA) in healthy, trained men. On different days, 11 men (age, 26.7 +/- 6.1 yr; body fat, 11.0 +/- 1.5%) completed four separate, randomly assigned, submaximal treadmill sessions at 70% maximal O2 consumption. During each session 800, 1,100, 1,300, or 1,500 kcal were expended. Compared with immediately before exercise, high-density lipoprotein cholesterol (HDL-C) concentration was significantly elevated 24 h after exercise (P < 0.05) in the 1,100-, 1,300-, and 1,500-kcal sessions. HDL-C concentration was also elevated (P < 0.05) immediately after and 48 h after exercise in the 1,500-kcal session. Compared with values 24 h before exercise, LPLA was significantly greater (P < 0.05) 24 h after exercise in the 1,100-, 1,300-, and 1,500-kcal sessions and remained elevated 48 h after exercise in the 1,500-kcal session. These data indicate that, in healthy, trained men, 1,100 kcal of energy expenditure are necessary to elicit increased HDL-C concentrations. These HDL-C changes coincided with increased LPLA.

Validity of the computer science and applications (CSA) activity monitor in children.

PURPOSE: The purpose of this study was to evaluate the validity of the CSA activity monitor as a measure of children's physical activity using energy expenditure (EE) as a criterion measure. METHODS: Thirty subjects aged 10 to 14 performed three 5-min treadmill bouts at 3, 4, and 6 mph, respectively. While on the treadmill, subjects wore CSA (WAM 7164) activity monitors on the right and left hips. VO2 was monitored continuously by an automated system. EE was determined by multiplying the average VO2 by the caloric equivalent of the mean respiratory exchange ratio. RESULTS: Repeated measures ANOVA indicated that both CSA monitors were sensitive to changes in treadmill speed. Mean activity counts from each CSA unit were not significantly different and the intraclass reliability coefficient for the two CSA units across all speeds was 0.87. Activity counts from both CSA units were strongly correlated with EE (r = 0.86 and 0.87, P < 0.001). An EE prediction equation was developed from 20 randomly selected subjects and cross-validated on the remaining 10. The equation predicted mean EE within 0.01 kcal.min-1. The correlation between actual and predicted values was 0.93 (P < 0.01) and the SEE was 0.93 kcal.min-1. CONCLUSION: These data indicate that the CSA monitor is a valid and reliable tool for quantifying treadmill walking and running in children.

Correlates of physical activity behavior in rural youth.

The purpose of this study was to identify correlates of physical activity behavior in a sample of rural, predominantly African American youth. Three hundred sixty-one fifth-grade students from two rural counties in South Carolina (69% African American, median age = 11 years) completed a questionnaire designed to measure beliefs and social influences regarding physical activity, physical activity self-efficacy, perceived physical activity habits of family members and friends, and access to exercise and fitness equipment at home. After school physical activity and television watching were assessed using the Previous Day Physical Activity Recall (PDPAR). Students were classified as physically active according to a moderate physical activity standard: two or more 30-min blocks at an intensity of 3 METs (metabolic equivalents) or greater, and a vigorous physical activity standard: one or more 30-min blocks at an intensity of 6 METs or greater. According to the moderate physical activity standard, 34.9% of students were classified as low-active. Multivariate analysis revealed age, gender, television watching, and exercise equipment at home to be significant correlates of low activity status. According to the vigorous physical activity standard, 32.1% of the students were classified as low-active. Multivariate analysis revealed age, gender, television watching, and self-efficacy with respect to seeking support for physical activity to be significant correlates of low activity status. In summary, gender and the amount of television watching were found to be the most important correlates of physical activity in rural, predominantly African American youth.