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1.
Objective: Our objective was to determine the association between physical activity and BMI among racially diverse low‐income preschoolers. Research Methods and Procedures: This was a cross‐sectional study of 2‐ to 5‐year‐olds (n = 56) enrolled in Massachusetts Special Supplemental Nutrition Program for Women, Infants & Children (WIC). Physical activity was measured for 7 consecutive days with an accelerometer. Height and weight were obtained from WIC records, and BMI‐for‐age percentiles were calculated based on the Centers for Disease Control and Prevention's (CDC) 2000 Growth Charts. At‐risk‐for‐overweight (BMI‐for‐age of ≥85th to <95th percentile) and overweight (BMI‐for‐age ≥95th percentile) groups were combined and referred to as overweight. Final analysis inclusion criteria were: completion of 4.5 days of activity assessment and anthropometric data obtained within 90 and 120 days of the activity assessment for children ages 24 to 35.99 and 36 to 59.99 months, respectively. Results: Overweight children had significantly lower mean daily very vigorous minutes (VVM) (2.6 mins vs. 4.6 mins, p < 0.05) and lower very active minutes (VAM) [i.e., sum of vigorous minutes (VM) and VVM] per day (22.9 mins vs. 32.1 mins, p < 0.05) than children who were not overweight. Daily VVM [odds ratio (OR) = 0.68; 95% confidence interval (CI), 0.49 to 0.96], VM (OR = 0.94; CI, 0.88 to 1.00), and VAM (OR = 0.94; 95% CI, 0.89 to 1.00) were all associated with significantly lower odds of being overweight. Discussion: This study suggests that, in a diverse group of preschoolers, vigorous and very vigorous activity are associated with lower odds of overweight. However, these findings require corroboration in a diverse sample of preschoolers using a longitudinal design.  相似文献   

2.
Objective: The impact of activity and inactivity on relative weight and fatness change are best evaluated longitudinally. We examined the longitudinal relationship of physical activity, inactivity, and screen time with relative weight status and percentage body fat (%BF) and explored how it differed by parental overweight status. Research Methods and Procedures: Non‐obese pre‐menarcheal girls (173), 8 to 12 years old, were followed until 4 years post‐menarche. %BF, BMI z‐score, and time spent sleeping, sitting, standing, walking, and in vigorous activity were assessed annually. We developed a physical activity index to reflect time and intensity of activity. Inactivity was defined as the sum of time spent sleeping, sitting, and standing. Screen time was defined as time spent viewing television, videotapes, or playing video games. Parental overweight was defined as at least one parent with BMI > 25. Results: In separate linear mixed effects models, activity, inactivity, and screen time were unrelated to BMI z‐score longitudinally, with and without accounting for parental overweight. After controlling for parental overweight, activity was inversely related (p < 0.001), and inactivity was directly related (p < 0.035) to increased %BF longitudinally. Screen time was unrelated to %BF change. With stratification for parental overweight, effects of activity and inactivity on %BF were observed only among girls with at least one overweight parent. Discussion: In this cohort of initially non‐overweight girls, activity and inactivity were related to accrual of BF over adolescence, particularly among children with at least one overweight parent. These results suggest that girls with a family history of overweight represent a target population of high priority for interventions around physical activity and inactivity.  相似文献   

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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 ≥ 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.  相似文献   

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The pattern of locomotor (walking) activity was studied in adult males and females of short‐winged (brachypterous) and long‐winged (macropterous) morph of the flightless bug Pyrrhocoris apterus (Linnaeus) (Heteroptera: Pyrrhocoridae) under constant laboratory conditions. Walking activity was measured with a computerized video system and analysed with respect to sex, physiological status (reproduction, diapause and reproductive arrest of non‐diapause type) and wing dimorphism of the bugs. The largest duration was observed in the macropterous females with reproductive arrest of non‐diapause type (average 6 h per day) and the shortest duration in diapausing brachypterous females and males (average less than 2 h per day). This was reflected also in the overall time spent by walking during the first 14 days after imaginal ecdysis. The time spent by walking significantly increased in the macropterous morph as the bugs aged, whereas in diapausing brachypters the time spent by walking decreased with age. No linear relationship between walking activity and age was found in reproductive brachypterous morph. The bugs of all experimental groups moved mostly during the photophase and were almost inactive during the scotophase. Thus, walking activity in P. apterus is diurnal, irrespective of the wing morph, physiological status, sex and age. Contrary to the macropterous morph, where the locomotor activity of females during photophase was significantly higher than in males, no significant differences were found between the locomotor activities of brachypterous males and females. The observed differences in locomotor activity are discussed in relation to different roles of two wing morphs in the life history of this heteropteran.  相似文献   

7.
A potential association between socioeconomic status (SES) and self‐reported use of mobile phones has been investigated in a few studies. If measured exposure to mobile phone networks differs by SES in children, it has not yet been studied. Interview data of 1,481 children and 1,505 adolescents on participants' mobile phone use, socio‐demographic characteristics and potential confounders were taken from the German MobilEe‐study. Sociodemographic data was used to stratify participants into three “status groups” (low, middle, high). Using a personal dosimeter, we obtained an exposure profile over 24 h for each of the participants. Exposure levels during waking hours were expressed as mean percentage of the reference level. Children with a low SES were more likely to own a mobile phone (OR 2.1; 95% CI: 1.1–3.9) and also reported to use their mobile phone longer per day (OR 2.4; 95% CI: 1.1–5.4) than children with a high SES. For adolescents, self‐reported duration of mobile phone use per day was also higher with a low SES (OR: 3.4; 95% CI: 1.4–8.4) compared with a high SES. No association between SES and measured exposure to mobile telecommunication networks was seen for children or adolescents. Mobile phone use may differ between status groups with higher use among disadvantaged groups. However, this does not result in higher overall exposure to mobile telecommunication networks. Whether short duration of own mobile phone use or the small numbers of participants with a low SES are causal, have to be investigated in further studies. Bioelectromagnetics 31:20–27, 2010. © 2009 Wiley‐Liss, Inc.  相似文献   

8.
Objective: Levels of estrogen, androgen, and prolactin have been related to risk of postmenopausal breast cancer. However, the determinants of these hormone concentrations are not established. The purpose of this study was to examine correlates of endogenous sex hormones. Research Methods and Procedures: Associations among adiposity, physical activity, and diet and concentrations of estradiol, free estradiol, estrone, testosterone, free testosterone, sex hormone‐binding globulin (SHBG), androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and prolactin were evaluated in 267 postmenopausal women randomly selected from the Women's Health Initiative Dietary Modification Trial. Results: In multiple regression analyses on log‐transformed hormones, BMI was positively associated with estrone (β = 0.031, p < 0.001), estradiol (β = 0.048, p < 0.001), free estradiol (β = 0.062, p < 0.001), free testosterone (β = 0.017, p = 0.02), and prolactin (β = 0.012, p = 0.02) and negatively associated with SHBG (β = ?0.02, p = 0.001). Total physical activity (metabolic equivalent tasks per week) was negatively associated with concentrations of estrone, estradiol, and androstenedione (β = ?0.006, ?0.007, and ?0.005, respectively, all p ≤ 0.05). Using a composite variable of BMI and physical activity dichotomized by median values, women with high BMI/low physical activity had a mean estrone concentration of 28.8 pg/mL, compared with 24.1, 19.9, and 18.4 pg/mL for women with high BMI/high physical activity, low BMI/low physical activity, and low BMI/high physical activity, respectively (p trend < 0.001). Similar trends were observed for estradiol and free estradiol and, in inverse, for SHBG. Discussion: These associations may, in part, explain the positive associations between overweight/obesity and a sedentary lifestyle on breast cancer risk.  相似文献   

9.
We examined the hypothesis that elementary school-age children will be more physically active while attending school in a novel, activity-permissive school environment compared to their traditional school environment. Twenty-four children were monitored with a single-triaxial accelerometer worn on the thigh. The students attended school in three different environments: traditional school with chairs and desks, an activity-permissive environment, and finally their traditional school with desks which encouraged standing. Data from the school children were compared with another group of age-matched children (n = 16) whose physical activity was monitored during summer vacation. When children attended school in their traditional environment, they moved an average (mean +/- s.d.) of 71 +/- 0.4 m/s(2). When the children attended school in the activity-permissive environment, they moved an average of 115 +/- 3 m/s(2). The children moved 71 +/- 0.7 m/s(2) while attending the traditional school with standing desks. Children moved significantly more while attending school in the activity-permissive environment compared to the amount that they moved in either of the traditional school environments (P < 0.0001 for both). Comparing children's activity while they were on summer vacation (113 +/- 8 m/s(2)) to school-bound children in their traditional environment showed significantly more activity for the children on summer vacation (P < 0.0001). The school children in the activity-permissive environment were as active as children on summer vacation. Children will move more in an activity-permissive environment. Strategies to increase the activity of school children may involve re-designing the school itself.  相似文献   

10.

[Purpose]

Little is known about the potential role of lifestyle factors in sex differences in insulin resistance in late elementary school children.

[Methods]

In this cross-sectional study, we compared sex differences in Tanner scales, body fat, physical activity (PA) and fitness, and insulin resistance markers in elementary school children (boys, n = 69 and girls, n = 81) aged 12-13 years. Body composition was assessed with a standardized protocol. Cardiorespiratory fitness was measured as oxygen consumption during an incremental treadmill exercise. Fasting blood samples were collected for blood chemistry assays including lipids, glucose, insulin and homeostasis model assessment for insulin resistance (HOMA-IR), leptin, and adiponectin. Daily PA was measured with an accelerometer for 7 consecutive days, and they were classified as low-, moderate-, and vigorous-PA. Independent t-tests were used to compare mean differences in the measured variables between boys and girls. There were significant sex differences in Tanner scales, body mass index, percent body fat, and waist circumference (WC).

[Results]

Girls had significantly higher values in Tanner scales (p < 0.001) and percent body fat (p < 0.001) than boys. Boys had significantly higher values in body mass index (p = 0.019) and waist circumference (p < 0.001) than girls. Boys also had significantly higher values in VO2max (p < 0.001) and low (p < 0.001), moderate (p < 0.001), and vigorous (p < 0.001) PAs. With respect to metabolic risk factors, girls had significantly higher serum levels of triglycerides (p = 0.005), insulin (p < 0.001), and HOMA-IR (p < 0.001) and significantly lower high-density lipoprotein cholesterol (p = 0.015) than boys.

[Conclusion]

In summary, the current findings of the study showed that the increased risk for insulin resistance in girls over boys is associated with higher Tanner scale and percent body fat in conjunction with poor cardiorespiratory fitness and physical inactivity, suggesting that exercise intervention to promote physical activity and fitness is imperative for general health promotion of school children, with a special focus on girls.  相似文献   

11.
This study examined self‐reported physical activity (PA) barriers, and their effects on PA behavior change at 3 and 12 months among 280 previously inactive women enrolled in a PA promotion trial. Effect modification of baseline barriers by baseline weight status on PA behavior change was also examined. At baseline and month 12, obese women reported significantly greater PA barriers compared with normal and overweight women (P < 0.05). Individual barriers that were more likely to be elevated for obese vs. normal and overweight participants at baseline were feeling too overweight, feeling self‐conscious, reporting minor aches and pains, and lack of self‐discipline. Also, weight status moderated the effect of PA barriers on PA behavior change from baseline to month 3 (P < 0.05), but not to month 12 (P = 0.637), with obese participants reporting high barriers achieving 70 min/week fewer than those with low barriers (P < 0.05). Finally, the interaction between barriers (high vs. low) and weight status (obese vs. normal), shows PA barriers had a detrimental PA effect among obese participants that was 122.5 min/week (95% confidence interval (CI) = 15.7, 229.4; P < 0.05) lower than their effect on normal‐weight participants. These results suggest that for obese women, PA barriers have quantifiable effects on PA behavior change. This study has implications for the design of future weight loss and PA interventions, suggesting that a comprehensive assessment of PA barriers is a prerequisite for appropriate tailoring of behavioral PA interventions.  相似文献   

12.
Objective: Our aim was to examine whether secular trends in childhood overweight and obesity during five decades could be explained by economic growth. Research Methods and Procedures: Annual measurements of height and weight were available for all children born between 1930 and 1983 attending primary school in the Copenhagen Municipality: 165,389 boys and 163,609 girls from the age of 7 through 13 years. After computerization, we calculated BMI (kg/m2) and estimated the prevalence of overweight and obesity, according to international age‐ and gender‐specific criteria, by year of birth and of measurement, and separately by each age group and gender. Economic growth was indicated by the Gross National Product and the overall consumption per capita, adjusted for inflation. Results: The prevalence of overweight occurred in phases: an increase from 1930 until the 1950s, followed by a plateau period between the 1950s and the 1960s and a steep increase thereafter. This pattern was apparent across all age groups and in both genders. Obesity trends showed a similar phase pattern; the prevalence remained relatively stable from 1930 until the 1940s, increased until the mid‐1950s, followed by a plateau until 1965, and thereafter a second steep increase. Obesity trends were similar among boys across all age groups, although only among girls from 11 to 13 years of age. In both genders, increments were most pronounced in the upper BMI percentiles. After stagnation until 1947, the economic growth indicators showed a steady increase; i.e., after the first increase started in overweight and obesity, whether analyzed by year of birth or year of measurement, there were no indications of phases in the rise thereafter. Discussion: Prevalence of overweight and obesity among Danish children rose in phases, which were not paralleled by trends in economic growth. The macroeconomic growth indicators seem inappropriate as proxies for the environmental exposures that have elicited the obesity epidemic.  相似文献   

13.
Objective: To investigate the associations among parenting style, gender, Chinese culture, and overweight children's attraction to physical activity. Research Methods and Procedures: A total of 104 parents with overweight children were recruited from six primary schools in Hong Kong, China. Only overweight children in grades 3 through 6 (8 to 12 years of age) were invited to participate. Overweight children were defined and identified using the international cut‐off points stratified by sex and age. Questionnaires were used to assess Children's Attraction to Physical Activity (CAPA), perceived competence, and parental socialization influences. Results: Parental influence, especially father's role modeling, was significantly related to attraction to physical activity in overweight Chinese children. Perceived physical competence was also an important correlate of an overweight child's attraction to physical activity. Gender differences in CAPA were not significant among the Chinese overweight children. However, gender differences were observed in the relationship between parent physical activity orientation and CAPA. Discussion: In addition to a child's perceived competence, father's role modeling can provide additional and significant influence with regard to overweight children's attraction to physical activity. Differences in cultural orientation toward body weight should be considered when explaining overweight children's physical activity.  相似文献   

14.

Background

Latinos in the United States have a higher prevalence of type 2 diabetes than non-Latino whites, even after controlling for adiposity. Decreased adiponectin is associated with insulin resistance and predicts T2DM, and therefore may mediate this ethnic difference. We compared total and high-molecular-weight (HMW) adiponectin in Latino versus white individuals, identified factors associated with adiponectin in each ethnic group, and measured the contribution of adiponectin to ethnic differences in insulin resistance.

Methods

We utilized cross-sectional data from subjects in the Latinos Using Cardio Health Actions to reduce Risk study. Participants were Latino (n = 119) and non-Latino white (n = 60) men and women with hypertension and at least one other risk factor for CVD (age 61 ± 10 yrs, 49% with T2DM), seen at an integrated community health and hospital system in Denver, Colorado. Total and HMW adiponectin was measured by RIA and ELISA respectively. Fasting glucose and insulin were used to calculate the homeostasis model insulin resistance index (HOMA-IR). Variables independently associated with adiponectin levels were identified by linear regression analyses. Adiponectin's contribution to ethnic differences in insulin resistance was assessed in multivariate linear regression models of Latino ethnicity, with logHOMA-IR as a dependent variable, adjusting for possible confounders including age, gender, adiposity, and renal function.

Results

Mean adiponectin levels were lower in Latino than white patients (beta estimates: -4.5 (-6.4, -2.5), p < 0.001 and -1.6 (-2.7, -0.5), p < 0.005 for total and HMW adiponectin), independent of age, gender, BMI/waist circumference, thiazolidinedione use, diabetes status, and renal function. An expected negative association between adiponectin and waist circumference was seen among women and non-Latino white men, but no relationship between these two variables was observed among Latino men. Ethnic differences in logHOMA-IR were no longer observed after controlling for adiponectin levels.

Conclusions

Among patients with CVD risk, total and HMW adiponectin is lower in Latinos, independent of adiposity and other known regulators of adiponectin. Ethnic differences in adiponectin regulation may exist and future research in this area is warranted. Adiponectin levels accounted for the observed variability in insulin resistance, suggesting a contribution of decreased adiponectin to insulin resistance in Latino populations.  相似文献   

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Objective: To determine whether interpersonal stress reduces youths’ motivation to exercise in a laboratory setting. Research Methods and Procedures: Physical activity and sedentary behavior were measured in boys and girls across a control day, after reading children's magazines, and on a stress day, after giving a videotaped speech. For one analysis, children were divided into low (n = 12) and high (n = 13) heart‐rate reactivity groups based on changes in heart rate to stress. In a second analysis, children were divided into low and high perceived level of stress based on changes in perceived stress. To determine differences in choice of exercise or sedentary behavior across the control and stress conditions, subjects chose either to exercise for progressively longer periods to earn a monetary reinforcer or to engage in a high‐rated sedentary behavior. Results: The choice to exercise was influenced by stress reactivity differently in the stress and control conditions. Low heart‐rate reactive children participated in similar (p > 0.50) amounts of exercise on the stress and control days, but high heart‐rate reactive children participated in less (p < 0.01) exercise (22.0 ± 2.5 vs. 26.3 ± 2.2 minutes) on the stress than control days. When grouped by change in perceived stress, there were no group differences, but subjects exercised longer (p < 0.01) on the control day than the stress day. Discussion: Interpersonal stress decreased exercise in children susceptible to interpersonal stress. Stress‐induced alterations in health behaviors may lead to weight gain in children.  相似文献   

17.
Soil-transmitted helminths (STHs) remain a major threat to the health of children throughout the world, mostly in developing nations. The aim of the present study was to determine any relationship between STHs and hemoglobin status in school children of Kashmir Valley (India). Stool and blood samples were collected from 382 male and female school children in the age group of 5-15 yr from all 6 school districts of the Kashmir Valley. Finger-prick blood samples were used to collect the hemoglobin, which was then measured on-site by Sahli's acid hematin method; stool samples were processed using both simple smear and zinc sulphate concentration methods. Of the 382 children surveyed, 299 (78.27%) were infected with Ascaris lumbricoides, Trichuris trichiura, or both. Children infected by STHs were found to have lower mean values of hemoglobin than uninfected children. The present study reveals that STHs are abundant among school children of Kashmir Valley, creating a negative effect on the hemoglobin values and indicating the necessity of implementing control measures.  相似文献   

18.
Objective: Prior randomized and non‐randomized training studies have failed to establish a dose‐response relationship between vigorous exercise and weight loss; this failure may be due, in part, to their short durations and small sample sizes. The objectives of this study were to determine whether exercise reduces body weight and to examine the dose‐response relationships between changes in exercise and changes in total and regional adiposity. Research Methods and Procedures: This was a large prospective study of 3973 men and 1444 women who quit running (detraining), 270 men and 146 women who started running (training), and 420 men and 153 women who remained sedentary during 7.4 years of follow‐up. The outcomes measured were weekly running distance, body weight, BMI, body circumferences, and bra cup size. Results: There were significant inverse relationships between the changes in the amount of vigorous exercise (km/wk run) and the changes in weight and BMI in men (slope ± standard error: ?0.039 ± 0.005 kg/km per week and ?0.012 ± 0.002 kg/m2 per km/wk, respectively) and in older women (?0.060 ± 0.018 kg/km per week and ?0.022 ± 0.007 kg/m2 per km/wk) who quit running, and in initially sedentary men (?0.098 ± 0.017 kg/km per week and ?0.032 ± 0.005 kg/m2 per km/wk) and women (?0.062 ± 0.023 kg/km per week and ?0.021 ± 0.008 kg/m2 per km/wk) who started running. Changes in waist circumference, an indicator of intra‐abdominal fat, were also inversely related to changes in running distance in men who quit (?0.026 ± 0.005 cm/km per week) or started running (?0.078 ± 0.017 cm/km per week). Discussion: The initiation of vigorous exercise and its cessation decrease and increase, respectively, body weight and intra‐abdominal fat, and these changes are proportional to the change in exercise dose.  相似文献   

19.
Objective: The goal was to identify correlates of adherence to a structured physical activity (PA) program. Research Methods and Procedures: Subjects were 136 8‐ to 12‐year‐old African‐American girls. Potential correlates at baseline were: 1) fitness index (FI: % body fat from DXA and cardiovascular fitness from treadmill test), and 2) self‐esteem, anxiety, attitude to school and teachers, relationship with parents, and interpersonal relations (Behavioral Assessment System for Children). The 10‐month PA program included 80 minutes of PA offered 5 days/wk. Regression tree classification was used to model attendance. Results: Six splits occurred (34% total variance explained). Less anxious subjects attended more often than highly anxious subjects (3 days/wk vs. 1.5 days/wk) did. Subjects with a healthier FI attended more often than those with a less healthy FI (3 days/wk vs. 0.5 days/wk) did. Younger subjects attended more often than older ones (3 days/wk vs. 2.5 days/wk) did. The next two splits were again with anxiety (3.5 days/wk vs. 3 days/wk) and FI (3 days/wk vs. 2.5 days/wk). Finally, subjects with higher levels of self‐esteem attended more often than those with lower levels (3.5 days/wk vs. 2 days/wk) did. Discussion: Subjects who were self‐confident, younger, fitter, and less anxious were more likely to participate regularly. This suggests that children who may be more likely to benefit from a PA program are less likely to participate. To enhance participation in PA programs, especially in older African‐American girls: 1) psychological concerns should be identified and addressed before enrollment, and 2) programs should be designed to be appealing to children of all fitness levels.  相似文献   

20.
Objective:This study examined differences in (1) psychosocial correlates of physical activity and in (2) physical activity within different contexts and sedentary behaviors between normal weight and overweight adolescents. It further explored whether the prediction of physical activity by the psychosocial correlates is different in normal weight and overweight adolescents. Research Methods and Procedure: A community sample of 6078 11 to 19 year olds from 38 secondary schools, which were randomly selected throughout the country, completed a validated computerized questionnaire about physical activity, sedentary behaviors, and psychosocial correlates. Differences in mean scores on the psychosocial correlates and on the self‐rated physical activity were analyzed between the normal weight (n = 5563) and the overweight (n = 515, 8.5%) group. Results: This study showed that overweight adolescents do less intense physical activities (p < 0.001) and have less favorable psychosocial correlates related to physical activity (p < 0.001) than their normal weight counterparts. However, the strength of the associations between psychosocial variables and total physical activity were comparable in overweight and normal weight adolescents. More support from family and friends, more fun in physical activity, higher self‐efficacy, the perception of more competition benefits, and the perception of less lack of interest were all associated with higher total levels of physical activity. The results suggest that no specific tailoring on psychosocial correlates of physical activity is necessary for overweight adolescents compared with normal weight ones. Discussion: Both overweight and normal weight adolescents can be approached by interventions focusing on the same psychosocial variables to increase physical activity.  相似文献   

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