Variance In Moderate-to-vigorous Physical Activity Research Articles

Using wearables to promote physical activity in old age : Feasibility, benefits, and user friendliness.

BackgroundWearables provide new opportunities to promote physical activity also among older adults but data on effectiveness and user friendliness are rare.ObjectiveThe effects of a comprehensive self-regulative intervention on moderate to vigorous physical activity (MVPA) and number of steps were examined using commercially available activity trackers. Acceptance regarding the devices was analysed in various domains.MethodsIn this study 80 older adults (mean = 67.03 years, standard deviation = 3.97 years; 59% women) wore a Fitbit Charge HR for 21 days including a baseline, a postintervention and a follow-up week. The intervention comprised feedback, goal setting and planning and 50% of the participants were additionally randomized to a role model component. Social cognitive predictors based on the health action process approach (HAPA) and user experience were assessed via questionnaires.ResultsThe MVPA increased by an average of 19 min per week and steps by 1317 per day. An additional benefit of the role model component could be observed for MVPA. In the follow-up, the intervention effect was still significant for the number of steps, while MVPA dropped back to baseline. Multilevel models including HAPA variables explained small but significant amounts of variance in MVPA (8% within-person, 26% between-person) and steps (11% within-person, 12% between-person). User experience was rated as very high.ConclusionProviding an intervention based on established behavior change techniques and self-monitoring via wearables seems to be effective for increasing physical activity among older adults. The HAPA variables seem to play a limited role to explain activity levels. Acceptance of wearables can be expected to be high.Supplementary InformationThe online version of this article (10.1007/s00391-022-02083-x) contains supplementary material, which is available to authorized users.

Gender Differences in Physical Activity Engagement Among Adolescents With Congenital Heart Disease.

The current study aimed to (a) describe moderate-to-vigorous physical activity (MVPA), sedentary behavior (SB), and cardiorespiratory fitness (VO2Peak) via objective assessment among adolescents with congenital heart disease (CHD), (b) examine gender differences on MVPA, SB, VO2Peak, and the Theory of Planned Behavior elements, and (c) identify whether gender moderates the relationships between the Theory of Planned Behavior elements and MVPA, SB, and VO2Peak. Adolescent CHD survivors (N = 86; ages 15-18 years) wore an accelerometer to assess MVPA and SB, underwent an exercise stress test to assess VO2Peak, and completed a survey of the Theory of Planned Behavior elements as measured by perceived benefits (attitudes), family/friend support and perceived norms (social norms), and self-efficacy and barriers (perceived behavioral control) to engaging in physical activity. On average, CHD survivors engaged in 22.3 min (SD = 15.3) of MVPA/day and 9 hr of SB/day (M = 565.8, SD = 102.5 min). Females engaged in less MVPA but not more SB had a lower mean VO2Peak, reported lower self-efficacy, and perceived greater barriers than males. In a regression model, barriers explained unique variance in MVPA and VO2Peak, but the relationship between barriers and MVPA/VO2Peak did not vary by gender. Self-efficacy did not explain unique variance in MVPA and VO2Peak when included in a model with gender and barriers. Family/friend support for physical activity engagement may be an important consideration when developing physical activity interventions for adolescent CHD survivors. The role of gender differences in self-efficacy and perceived barriers on physical activity engagement warrants further investigation.

The Associations between Physical Activity and Body-Esteem in 15-Year-Old Adolescents: A Cross-Sectional Study from Finland

<strong>Purpose:</strong> Physical activity promotes a positive physical self-image, but less is known about whether the positive effect covers the general self-evaluation of adolescent appearance. This study aimed to further explore the associations between physical activity and body-esteem in Finnish adolescents, via a country-representative cross-sectional study design. <strong>Methods:</strong> The data for the study were drawn from the Finnish component of the Health Behaviour in School-aged Children (HBSC) study (2014), using surveys from 15-year-old adolescents (n=1956, mean age 15.8 years) from 122 schools. Self-evaluations of body or appearance were measured by the Body-Esteem Scale for Adolescents and Adults (BESAA). A mixed effects linear regression analysis for body-esteem was conducted separately for boys and girls. The explanatory variables were (i) self-reported moderate-to-vigorous physical activity (MVPA), (ii) weight status, (iii) self-esteem, and (iv) socioeconomic status. The covariates used in the models were maturation state and ethnic background. <strong>Results:</strong> The body-esteem score was highest among adolescents who reported engagement in MVPA corresponding to the international recommendation for adolescents’ physical activity. The positive association between MVPA and body-esteem was found even when it was considered in conjunction with other body image-related factors, but only among boys. The variance in MVPA explained 5.0% of the body-esteem variance in the model for boys (Model R² = 26.3%). <strong>Conclusions:</strong> The physical activity of young people should be further promoted for a variety of health reasons, including its positive association with higher body-esteem. However, consideration should be given to gender differences and other factors related in this complex association.

Relationship Between Fundamental Motor Skill Competence, Perceived Physical Competence and Free-Play Physical Activity in Children

ABSTRACTPurpose: This study examined the extent to which fundamental motor skill competence (FMSC; locomotor and object control skill competence) and perceived physical competence (PPC) predicted physical activity levels and sedentary behaviors during free-play time at preschool. Method: A total of 72 children (girls n = 33, boys n = 39; Mage = 4.38, SD = .85 years) were recruited from two preschools. Fundamental motor skill competence was measured using the Test of Gross Motor Development − 2nd edition, and PPC was assessed using the physical competence subscale of the Pictorial Scale of Perceived Competence and Social Acceptance. Physical activity was measured using accelerometers. Results: Children engaged in light physical activity 19.66%, and moderate to vigorous physical activity (MVPA) 36.41%, and sedentary behaviors 43.94% of their free-play time. Since no correlation was observed in light physical activity with any variables, a hierarchical multiple linear regression was run for MVPA and sedentary behaviors. The results illustrated 38.9% of the variance in MVPA during free-play time was predicted by FMSC and PPC, after controlling for age and sex, with locomotor skill competence as a significant predictor (t= 2.98, p < .05). For sedentary behaviors, the 32.9% of the variance during free-play time was predicted by FMSC and PPC, after controlling age and sex, with locomotor skill competence as a significant predictor (t = 2.72, p < .05). Conclusion: The findings highlight the importance of developing FMSC and positive PPC during early childhood to enhance physical activity engagement during free-play.

Is sport enough? Contribution of sport to overall moderate- to vigorous-intensity physical activity among adolescents

ObjectivesThis study examined the contribution of sports participation to overall moderate-to-vigorous physical activity (MVPA) among adolescents, and explored potential moderators. DesignCross-sectional observational study using survey and accelerometry data drawn from the NEighbourhood Activity in Youth (NEArbY) study. MethodsAdolescents (n=358) were recruited from secondary schools in Melbourne, Australia. Average min/day in MVPA was assessed using accelerometry. Participants self-reported sports participation (number of teams, type, frequency, and months of participation). Regression models determined the percent variance in MVPA explained by the sport variables, adjusted for wear time, age and sex, and accounting for clustering at the school level. Additional analyses tested if age, sex, body mass index (BMI), and socioeconomic status (SES) moderated relationships between sport variables and MVPA. ResultsParticipants (mean 15.3 years, 59% female) spent a mean (SD) of 68.6 (27.4) min/day in MVPA and 50% reported participating in any sport. Those who participated in sport did so 3.4 times/week on average and accumulated 7min/day of MVPA more than those who did no sport. For each additional sport participated in, on average, there were approximately 5 additional min/day of MVPA. The number and frequency of sports participation explained 3.2% and 3.8% of the variance in MVPA respectively. Participation in field hockey and gymnastics explained 2.2% and 3.6% of the variance in MVPA, respectively. There were no moderating effects. ConclusionsSport appears to make a very small contribution to adolescents’ average daily physical activity. Effectiveness of approaches to increasing youth population levels of physical activity via sports participation needs to be tested.

Predicting physical activity among urban adolescent girls: A test of the health promotion model.

The purpose of this study was to test hypothesized relationships of the health promotion model (HPM) as a means of predicting moderate-to-vigorous physical activity (MVPA) among urban, adolescent girls. A secondary analysis of baseline data from a group randomized controlled trial was conducted. The study involved eight urban schools in the Midwestern United States. The sample included girls (N = 517) in the 5th-8th grades. Data were collected on age, body mass index, pubertal status, enjoyment, self-efficacy, social support, options for physical activity (PA), and commitment to PA. MVPA was measured via accelerometers worn by the girls for 7 days. Structural equation modeling was used to analyze study aims. Mean age of the sample was 11.8 years (standard deviation [SD] = 1.0). Girls attained an average of 3.0 (SD = 1.2) minutes per hour of MVPA. Self-efficacy had a positive direct (β = .337; p < .001) and total effect (β = .310; p < .001) on MVPA. Social support and options for PA were not significant predictors of commitment to PA or MVPA. Commitment to PA had a negative but nonsignificant effect (β = -.056; p = .357) on MVPA. The model predicted 10.1% of the variance in MVPA with 9.6% of the variance predicted by self-efficacy. Limitations include lack of longitudinal analysis and inability to generalize the results to other populations such as boys. PA self-efficacy continues to emerge as a significant predictor of MVPA in the HPM. Continued theory testing is needed to better understand the correlates and determinants of PA among adolescent girls before designing theory-based interventions to promote PA.

Factors Associated With Moderate to Vigorous Physical Activity in Adolescents Born Preterm.

Little is known about the physical activity of adolescents born prematurely. This study aimed to: 1) describe relationships between moderate to vigorous physical activity (MVPA) in adolescents born prematurely and various factors and, 2) compare their MVPA level to guidelines. A secondary analysis was performed using data from 64 adolescents (16.1 ± 2.5 years old, born £29 weeks gestation; 57.8% girls). Time spent in MVPA was based on accelerometry data. Sociodemographic, prematurity and comorbidity variables were based on questionnaire data or, for movement difficulty, from the results of the Movement Assessment Battery for Children-Second Edition. Multiple regression analysis showed that participants who were older (b = -4.52, p < .001), female (b = 14.18, p = .014), with movement difficulty (b = 18.64, p = .014), with health problems (b = 11.78, p = .036) and without hyperactive behavior (trend, b = 2.04, p = .099) spent less time in MVPA. Together these variables explained 44.4% of the variance in MVPA. Most participants (79.7%) did not meet Canadian MVPA guidelines. Study results suggest that physical activity interventions should especially target adolescents born prematurely who are older, female, with health problems, and with marked movement difficulties.

Parental influence on the physical activity of Chinese children

This study aimed to examine the association among parental moderate-to-vigorous physical activity (MVPA), parental support, and the MVPA of children by gender. Participants comprised of 172 boys and 151 girls aged seven to 11 years old from three primary schools in Shanghai. Their parents were also included as research respondents. Accelerometers were utilized to measure MVPA duration among the children. Questionnaires that focused on parental support and MVPA were completed by the parents. Results indicated that only 4% of the children met the recommended MVPA duration of 60 minutes per day based on objective data. Parental support consisted of two constructs: logistic support and explicit modelling. Boys engaged in more MVPA than girls although no gender differences were noted in terms of the logistic support and explicit modelling of parents and their MVPA. A regression analysis revealed that 23.3% of the variance in MVPA for boys was explained by explicit modelling and MVPA of fathers. Moreover, 10.5% of the variance for girls was explained by the explicit modelling of mothers. Thus, parents should be highly encouraged to support the MVPA of their children by acting as role models. They can also enhance the MVPA of their children using different methods based on gender.

A Test of Social Cognitive Theory to Explain Men's Physical Activity During a Gender-Tailored Weight Loss Program.

Physical inactivity is a leading contributor to the burden of disease in men. Social-cognitive theories may improve physical activity (PA) interventions by identifying which variables to target to maximize intervention impact. This study tested the utility of Bandura's social cognitive theory (SCT) to explain men's PA during a 3-month weight loss program. Participants were 204 overweight/obese men (M [SD] age = 46.6 [11.3] years; body mass index = 33.1 [3.5] kg/m2). A longitudinal, latent variable structural equation model tested the associations between SCT constructs (i.e., self-efficacy, outcome expectations, intention, and social support) and self-reported moderate-to-vigorous PA (MVPA) and examined the total PA variance explained by SCT. After controlling for Time 1 cognitions and behavior, the model fit the data well (χ2 = 73.9, degrees of freedom = 39, p < .001; normed χ2 = 1.9; comparative fit index = 0.96; standardized root mean residual = 0.059) and explained 65% of the variance in MVPA at Time 2. At Time 2, self-efficacy demonstrated the largest direct and total effects on MVPA (βdirect = .45, p < .001; βtotal = .67, p = .002). A small-to-medium effect was observed from intention to MVPA, but not from outcome expectations or social support. This study provides some evidence supporting the tenets of SCT when examining PA behavior in overweight and obese men. Future PA and weight loss interventions for men may benefit by targeting self-efficacy and intention, but the utility of targeting social support and outcome expectations requires further examination.

An extended version of the theory of planned behaviour: the role of self-efficacy and past behaviour in predicting the physical activity of Chinese adolescents

This study aimed to use an extended theory of planned behaviour (TPB), which incorporated additional self-efficacy and past behaviour, to predict the intention to engage in moderate-to-vigorous physical activity (MVPA) and the MVPA level of Chinese adolescents. Questionnaires that focused on MVPA, attitude, subjective norm, perceived behavioural control (PBC), self-efficacy and past behaviour related to the MVPA engagement were administered to a sample of 488 young people. Multiple regression analyses provided moderate support for TPB. Three TPB constructs predicted 28.7% of the variance in intentions to engage in MVPA, and that PBC, but not intention, explained 3.4% of the variance in MVPA. Self-efficacy significantly affected intention and behaviour over and above the influence of TPB. Past behaviour had a small but significant improvement in the prediction of intention, but no improvement in the prediction of MVPA. Based on the results, interventions should target adolescent self-efficacy and PBC in physical activity participation.

Using Theory of Planned Behavior to Predict the Physical Activity of Children: Probing Gender Differences.

Objectives. The primary objective of this study was to use the theory of planned behavior (TPB) to examine the association between TPB variables and the moderate-to-vigorous physical activity (MVPA) of children in Shanghai, China. Gender differences were also explored. Methods. The participants were 353 children (180 boys and 173 girls) aged 9 to 13 years from three primary schools in Shanghai. Accelerometers were used to measure the MVPA duration of the children. Questionnaires that focused on attitude, subjective norms, and perceived behavioral control (PBC) related to MVPA engagement were completed by the participants. Results. Regression analyses revealed that intention, and not PBC, accounted for 9% of the variance in MVPA. Meanwhile, attitude and PBC explained 33% of the variance in intentions to engage in MVPA. In terms of gender differences, TPB performed better in the physical activity (PA) domain for boys than for girls. Furthermore, attitude and PBC were significantly associated with intention among boys, whereas only PBC was significantly related to intention among girls. Conclusion. Practitioners should consider tailoring intervention to address gender differences to increase leisure-time PA participation of children.

Objectively measured physical activity and sedentary time in south Asian women: a cross-sectional study.

BackgroundSouth Asian (SA) women in the United Kingdom (UK) are known to be at high risk for developing chronic diseases, and to have low levels of physical activity (PA). Increasing levels of PA and reducing sedentary time (ST) are recognized as factors to target in an effort to curb chronic disease morbidity and mortality. There is limited evidence documenting objectively measured PA/ST and their correlates in SA women. Therefore the purpose of this cross-sectional study was to objectively measure and report patterns of PA/ST among SA women in the UK and examine potential socio-demographic correlates of PA/ST.Methods140 UK SA women (Pakistani and Bangladeshi) wore an accelerometer for 7 consecutive days. Anthropometric measurements and self-reported socio-demographic information were taken.ResultsMean daily moderate-to-vigorous PA (MVPA) was 34.66 ± 21.52 minutes and mean daily ST was 530.20 ± 81.76 minutes, with an inverse correlation (r = -.270, N = 140, p < .001) showing that higher ST was associated with lower MVPA. The same was seen for light intensity PA (LPA) (r = -.610, N = 140, p < .001). MVPA was significantly higher for younger women (18–64.5 yrs), with 64.7% of older women (≥65 yrs) failing to meet PA guidelines (t = 3.101, p < 0.05). Overweight/obese women had lower levels of LPA, MVPA and higher ST (p < .001). Multiple linear regression analyses indicated 14.9% of the variance in MVPA was explained by age and waist circumference (F(2,138) = 6.41, p < 0.002). LPA and ST were significantly higher on weekend days than weekdays (p < .001), and MVPA was significantly higher on weekdays than weekend days.ConclusionsResults indicate higher levels of PA in this sample than previously assumed. High levels of LPA in this sample indicate the need for health promotion interventions to target not only duration, but also intensity of activity in this population to achieve PA recommendations.

Physical activity and sedentary time in persons with obstructive sleep apnea and overweight enrolled in a randomized controlled trial for enhanced physical activity and healthy eating

The aim of the study was to describe the amount of physical activity and sedentary time in patients with obstructive sleep apnea syndrome (OSAS) and overweight and to explore potential disease-related and psychological correlates. A descriptive and correlational study was performed. Prospective data of physical activity and sedentary time were collected through accelerometry, and body mass index (BMI), daytime sleepiness, exercise self-efficacy, fear of movement, and depressive symptoms were measured at one point. Seventy-three participants with overweight (mean BMI, 35kg/m(2) (5 SD)) and moderate/severe OSAS (apnea-hypopnea index ≥15) were consecutively recruited. Multivariate associations were determined through multiple linear regression analysis. The participants took a daily average of 7,734 (3,528 SD) steps, spent an average of 77min (54 SD) in moderate-to-vigorous physical activity (MVPA), and spent 11h and 45min (2h and 8min SD) sedentary. BMI, daytime sleepiness, exercise self-efficacy, fear of movement, and depressive symptoms did not explain variance in MVPA or steps but explained 22.9% of variance in sedentary time. In backward selection analysis, BMI contributed to the explanatory degree of MVPA with 9% whereas, fear of movement explained 6.3% of the variance in steps and 14.3% of the variance in sedentary time. An important implication for future physical activity interventions is that both physical activity and sedentary behaviors should be targeted, and fear of movement may be an important determinant for change in patients with OSAS and overweight.

Students’ Objectively Measured Physical Activity Levels and Engagement as a Function of Between-Class and Between-Student Differences in Motivation Toward Physical Education

Despite evidence for the utility of self-determination theory in physical education, few studies used objective indicators of physical activity and mapped out between-class, relative to between-student, differences in physical activity. This study investigated whether moderate-to-vigorous physical activity (MVPA) and rated collective engagement in physical education were associated with autonomous motivation, controlled motivation, and amotivation at the between-class and between-student levels. Participants were 739 pupils (46.3% boys, Mage = 14.36 ±1.94) from 46 secondary school classes in Flanders (Belgium). Multilevel analyses indicated that 37% and 63% of the variance in MVPA was explained by between-student and between-class differences, respectively. Students' personal autonomous motivation related positively to MVPA. Average autonomous class motivation was positively related to between-class variation in MVPA and collective engagement. Average controlled class motivation and average class amotivation were negatively associated with collective engagement. The findings are discussed in light of self-determination theory's emphasis on quality of motivation.

Self-Presentation and Physical Activity in Breast Cancer Survivors: The Moderating Effect of Social Cognitive Constructs

This study examined (1) the relationships between self-presentation processes (i.e., impression motivation and impression construction) and moderate-to-vigorous physical activity (MVPA) among breast cancer survivors, and (2) whether social cognitive constructs (i.e., self-presentational efficacy expectancy [SPEE]; self-presentational outcome expectancy [SPOE]; self-presentational outcome value [SPOV]) moderate these relationships. Breast cancer survivors (N = 169; Mage = 55.06, SD = 10.67 years) completed self-report measures. Hierarchical regression analysis, controlling for age and body mass index, indicated that impression motivation was a significant correlate of MVPA (β = .25). Furthermore, SPEE (β = .21) and SPOV (β = .27) were moderators of this relationship. The final models accounted for 12-24% of the variance in MVPA. The findings of this study suggest that self-presentation processes (i.e., impression motivation) may indeed relate to breast cancer survivors' MVPA. In addition, social cognitive constructs (i.e., SPEE, SPOV) moderated the relationship between impression motivation and MVPA. It may be effective to target impression motivation, SPEE, and SPOV in interventions aimed at increasing MVPA among breast cancer survivors.

Preschooler's physical activity levels and associations with lesson context, teacher's behavior, and environment during preschool physical education

Abstract Preschools offer two main opportunities, recess and physical education (PE), for preschool children to participate in physical activity (PA) and are considered a suitable institution for PA promotion given the large number of children enrolled. Although PE can have a meaningful effect on preschoolers’ PA levels, preschool PE characteristics associated with increased PA have, to the best of our knowledge, not been identified. Therefore, the purpose of the present study was to examine preschooler's PA levels and the associations with lesson context, teacher behavior, and environment during preschool physical education. A random sample of 573 preschoolers (288 boys; Mage = 5.4 years, SD = 0.4) from 35 preschools was examined during one PE class. Findings indicated that preschoolers accumulated 12 min (33%) of moderate-to-vigorous PA (MVPA), 5 min (13%) of light PA, and 20 min (54%) of sedentary behavior during PE. Forty-seven percent of the variance in pupils’ MVPA may be attributed to differences between PE classes. Less knowledge content, less promotion, less management, less preschoolers per 100 m2, using obstruction material, and not using throwing equipment were significantly associated with higher MVPA levels. These predictors explained 56% of the variance in MVPA at the PE class-level. To conclude, PE in its current format contributes only a small amount to the PA requirements of preschoolers. Preschoolers’ MVPA levels were related to modifiable PE characteristics indicating that preschool PE can be restructured to increase MVPA.

The relative influence of demographic, individual, social, and environmental factors on physical activity among boys and girls.

BackgroundThis study aimed to evaluate the associations of selected demographic, individual, social, and environmental factors with moderate-to-vigorous physical activity (MVPA) in a sample of children and adolescents.MethodsMVPA was assessed among youth (n = 294) 10-17-years-old using the ActiGraph accelerometer. Youth completed measures of demographic and individual variables related to physical activity (PA), perceived social support by parents and peers, and perceived neighborhood characteristics. Parents completed the long-form of the International Physical Activity Questionnaire. The Physical Activity and Media Inventory was used to measure the home environment and Geographical Information Systems software was used to measure the physical neighborhood environment. Bivariate correlations and hierarchical multiple regression were conducted stratified by gender.ResultsBoys participated in significantly more MVPA than girls. In hierarchical analyses, peer support, home PA equipment, and temperature were significantly associated with MVPA among boys whereas distance to the school they attended was associated with MVPA among girls. The final models accounted for 25% and 15% of the variance in MVPA among boys and girls, respectively.ConclusionsImportant differences exist among the individual, social, and environmental factors related to MVPA between boys and girls. Boys' levels of activity appear to be influenced by factors closely linked to unstructured and social types of activities whereas girls' activities relate to internal and external barriers as well as their proximity to their schools. The prospective contribution of these important individual, social, and environmental factors to changes in MVPA among children and adolescents remains to be determined.

Contribution of Athletic Identity to Child and Adolescent Physical Activity

Identity theorists maintain that domain-specific self-concepts help explain the differential investment of people's time and effort in various activities. This study examined the contribution of athletic identity and three key demographic variables to physical activity and sports team participation. Students in Grades 4-5 (n=391, mean age 9.9 years, range 8-13 years, collected in 2003) and Grades 7-8 (n=948, mean age 13.6 years, range 11-15 years, collected in 2002 and 2006) completed the 40-item Athletic Identity Questionnaire, which measures self-perceptions of athletic appearance; competence; importance of physical activity and sports; and encouragement for activity from parents, teachers, and friends. Hierarchic multiple regression analyses in 2008 assessed the effects of athletic identity, race/ethnicity group, gender, and overweight status on 7-day moderate-to-vigorous physical activity (MVPA) and organized sport team participation in each age group. In children and adolescents, the global score of athletic identity was independently, positively related to MVPA (p<0.0001, p<0.0001, respectively) and team participation (p<0.0001, p<0.0001, respectively), after controlling for demographic variables. More variance in MVPA was explained in children (23%) than in adolescents (5%), in contrast to team sports (5% in children, 15% in adolescents). In the subscale analyses, positive relationships for appearance, competence, importance, and parental encouragement persisted independent of demographic factors. Results support the role of athletic self-concept in promoting physical activity and organized sport participation in children and adolescents.

Predicting Physical Activity in Arab American School Children

Theoretically grounded research on the determinants of Arab American children’s physical activity is virtually nonexistent. Thus, the purpose of our investigation was to evaluate the ability of the theory of planned behavior (TPB) and social cognitive theory (SCT) to predict Arab American children’s moderate-to-vigorous physical activity (MVPA). Children (N = 348, ages 10–14) completed questionnaires assessing the TPB and SCT constructs as well as MVPA. Using multiple regression analyses we were able to account for 9% of the variance in MVPA. Based on standardized beta-weights, variance accounted for, and the significance of F change, we concluded that SCT variables were better predictors of MVPA compared with the TPB constructs. In particular, barrier self-efficacy was the most critical variable within SCT and supports the potentially valuable role that efficacy cognitions play in promoting MVPA in Arab American children.

The Theory of Planned Behavior: Predicting Physical Activity in Mexican American Children

Theoretically grounded research on the determinants of Mexican American children's physical activity and related psychosocial variables is scarce. Thus, the purpose of our investigation was to evaluate the ability of the theory of planned behavior (TPB) to predict Mexican American children's self-reported moderate-to-vigorous physical activity (MVPA). Children (N = 475, ages 9-12) completed questionnaires assessing the TPB constructs and MVPA. Multiple regression analyses provided moderate support for the ability of the TPB variables to predict MVPA as we accounted for between 8-9% of the variance in MVPA. Attitude, subjective norm, and perceived behavioral control accounted for 45% of the variance in intention. Descriptive results were encouraging because mean values indicated that most children had positive attitudes, moderately strong intentions, felt in control, and perceived support from significant others (i.e., physical education teachers) for their physical activity engagement.