Moderate-to-vigorous Physical Activity In Youth Research Articles

Convergent Validity Between Epoch-Based activPAL and ActiGraph Methods for Measuring Moderate to Vigorous Physical Activity in Youth and Adults

Purpose: We investigated convergent validity of commonly used ActiGraph scoring methods with various activPAL scoring methods in youth and adults. Methods: Youth and adults wore an ActiGraph and activPAL simultaneously for 1–3 days. We compared moderate to vigorous physical activity (MVPA) estimates from the ActiGraph Evenson 15-s (youth) and Freedson 60-s (adult) cut-point scoring methods and four activPAL scoring methods based on metabolic equivalents (METs), step counts, vertical axis counts, and vector magnitude counts. All activPAL methods were applied to 15-s epochs for youth and 60-s epochs for adults, and the METs method was also applied to 1-s epochs. Epoch-level agreement was examined with classification tests (sensitivity, positive predictive value, and F1) using the ActiGraph methods as the referent. Day-level agreement was examined using tests of mean error, mean absolute error, and Spearman correlations. Results: Relative to ActiGraph methods, which indicated a mean MVPA of 41 min/day for youth and 24 min/day for adults, the activPAL METs method applied to 15-s epochs in youth and 60-s epochs in adults yielded the most comparable estimates of MVPA. Daily MVPA estimated from all other activPAL scoring methods generally had poor agreement with ActiGraph methods in youth and adults. Conclusion: When using the same epoch lengths between monitors, MVPA estimation via the activPAL METs scoring method appears to have good comparability to ActiGraph cut points at the group-level and moderate comparability at the individual-level in youth and adults. When using this scoring method, the activPAL appears to be appropriate for measuring daily minutes of MVPA in youth and adults.

Correlation and Wear-Time Compliance of the Wrist-Worn SQORD Activity Monitor Compared to the Actigraph 3TGX in Measuring Free-Living Physical Activity in Low SES Elementary Youth

Background and Purpose: Activity trackers have grown increasingly popular, yet research grade accelerometers, like Actigraph, are still very expensive and must be worn on the waist. This study correlated the low-cost wrist-worn SQORD band to the Actigraph accelerometer to assess physical activity (PA) in youth from a low-income area. Methods: Forty-one participants (22:19 male:female; mean age= 10.7 years) in an after-school program participated. Participants wore a waist-worn Actigraph accelerometer and a wrist-worn SQORD for seven days. Abdominal, upper and lower body strength and endurance, and aerobic capacity were assessed through FITNESSGRAM tests. Bivariate correlations were used to analyze the relationship between moderate-to-vigorous PA (MVPA) via the Actigraph and SQORD and to examine relationships between physical fitness and MVPA. Results: At 8- and 10-hour wear-time, compliance with wearing the devices was higher with the SQORD than the Actigraph. A correlation was found between MVPA via SQORD and Actigraph (r=0.651). Neither the SQORD or Actigraph was associated with any fitness measures (r = -0.061; – 0.817). Conclusion: The SQORD appears to be successful in tracking MVPA in youth and was worn more than the Actigraph. Wrist-worn, consumer-grade devices may be a cost-effective alternative to traditional accelerometers for physical education programs and research in low-income populations.

Does physical activity differ between youth with and without intellectual disabilities?

BackgroundChildren and youth with intellectual disabilities (ID) are known to face obstacles to physical activity participation, yet the activity patterns of this population are not well characterized.Objective/Hypothesis: In this study, time spent in moderate to vigorous physical activity (MVPA), type, and frequency of participation in physical activities were assessed in youth with ID and in a comparison group of typically developing (TD) youth. MethodsWeekly participation in MVPA in 38 youth with ID and 60 TD youth was assessed via accelerometry. Participants were also administered an interview about the frequency and type of physical activities they engaged in over the past year. ResultsAfter adjusting for age and sex, youth with ID spent significantly less time in MVPA (33.5 vs. 46.5 min/day, p = 0.03) and were less likely to meet the US Physical Activity Guidelines than TD youth (6% vs. 29%, p = 0.01). Although time in MVPA was lower in youth with ID, females with ID participated in physical activities more frequently than TD females (47.1 vs. 28.2 times/month, p = 0.008) and also reported engaging in a greater variety of physical activities (7.8 vs. 5.2 activities/year, p = 0.01). No differences between males in the frequency of physical activity participation or the number of activities performed were observed. Both groups reported walking/hiking and active video as top activities. ConclusionsFindings emphasize the need for targeted efforts to increase MVPA in youth with ID.

Three-Year Tracking of Moderate-to-Vigorous Physical Activity During Structured and Unstructured Play In Youth

Tracking is the maintenance of a relative position within a group over time. Previous studies indicate that habitual, moderate-to-vigorous physical activity (MVPA) tracks at low to moderate levels in youth, but there is limited research on specific contexts of MVPA, such as during structured and unstructured play. PURPOSE: To characterize tracking of MVPA in youth across four time points during a three-year period for both structured and unstructured play. METHODS: Youth (N=108), 58.3% female, 6-15 years old, visited the laboratory four times over three years. During each visit, participants engaged in 30 minutes each of structured and unstructured play. Youth wore a uniaxial accelerometer on an elastic belt over their right hip (data collected in 1-second epochs). MVPA minutes were determined using Evenson cut-points (≥574 counts/15-sec). Tracking of MVPA minutes was evaluated using tracking coefficients (Pearson’s r) between each pair of time points [classified as low (r<0.30), moderate (r=0.30-0.60), or moderately high (r>0.60)] and intra-class correlations (ICC) via ANOVA. ICCs provided an overall correlation across the four time points [classified as poor (ICC<0.50), moderate (ICC=0.50- 0.75), good (ICC=0.75-0.90), or excellent (ICC>0.90)]. Participants were classified into quartiles of MVPA for each visit, and percent agreement and weighted kappa [classified as poor (κ≤0.20), fair (κ=0.21–0.40), moderate (κ=0.41–0.60), good (κ=0.61–0.80), or very good (κ=0.81–1.0)] were calculated. RESULTS: Tracking coefficients were non-significant to moderate for structured play (r=-0.20-0.30) and moderate to moderately high for unstructured play (r=0.38-0.66, p’s<0.05). The ICC was classified as poor (0.42) for structured play and excellent (0.80) for unstructured play (p<0.05). Percent agreement ranged from 24.0-36.6% for structured play and 30.1-44.3% for unstructured. Weighted kappa for structured play ranged from non-significant to poor (-0.09-0.19), but was fair to moderate (0.24-0.49, p’s<0.05) for unstructured. CONCLUSION: We found evidence of low to moderate tracking for participation in MVPA during structured and unstructured play. Results suggest that MVPA during structured and unstructured play tracks similarly to habitual physical activity in youth. Funded by NICHD R01 55400.

The influence of friends and psychosocial factors on physical activity and screen time behavior in adolescents: a mixed-methods analysis.

(1) Determine the association between adolescent moderate-to-vigorous physical activity (MVPA) and screen time with their nominated friends' behaviors and (2) explore potential mechanisms of friends' social influences on MVPA and screen time. Participants consisted of 152 adolescents (mean age: 14.5years, 53% female, 50% high school, 80% Caucasian). MVPA was measured with an Actigraph GT3X+ accelerometer. Demographic and psychosocial variables were assessed via questionnaires. Participants nominated up to 5 friends who completed MVPA and screen time questionnaires. A subset of adolescents (n=108) participated in focus groups that examined potential mechanism of friends' influence on MVPA and screen time. Multiple regression analysis examined the association of demographic, psychological, and nominated friend variables with participants' MVPA and screen time. NVivo 10.0 was used to analyze qualitative data. Greater levels of friends' MVPA was associated with greater levels of MVPA in both males (p<.0001) and females (p<.0001). Greater levels of friends' screen time was associated with greater levels of screen time in males (p=.04) while psychosocial variables, such as increased screen time enjoyment, were associated with increased screen time in females (p=.01). School level was not associated with either MVPA or screen time. Focus group data indicated that friends positively influenced participants' MVPA through engaging in activity with participants, verbal encouragement, and modeling of MVPA. All participants preferred to be active with friends rather than alone, however, females preferred activity with a close friend while males preferred to be active with a group. Enjoyment of MVPA was the most cited reason for engaging in MVPA with friends. The majority of participants reported friends not having an influence on screen time. Adolescents with active friends are more likely to be physically active and spend less time engaging in screen-based behaviors. Interventions to increase MVPA in youth could be designed to include the recruitment of friends to increase enjoyment of MVPA.

Correlates of subjectively and objectively measured physical activity in young adolescents

BackgroundMany studies examining individual-level correlates in youth utilize self-report rather than objective measures of physical activity (PA). This utilization of self-report may result in associations that are not present when examining objectively measured PA. The present study investigates the relationship between hypothesized correlates of PA with objectively and subjectively measured PA. MethodsParticipating children (n = 232, 101 males, mean age = 12.3 years) provided a minimum of four monitored days of PA (via accelerometer) and completed a survey assessing moderate-to-vigorous physical activity (MVPA), sport competence, appearance, enjoyment, and self-efficacy. Height and weight were measured and body mass index (BMI) was calculated. ResultsHierarchical regression models controlling for sex, race, and BMI Z-score showed that only sex and BMI Z-score were significant correlates of objective MVPA while only sex was a significant correlate of objective total PA. However, in a separate model examining the relationship with subjective MVPA, enjoyment of PA and self-efficacy for PA were the only significant correlates of self-reported PA. ConclusionMeasuring MVPA via self-report versus accelerometry produces considerably different results in a sample of young adolescents. Future studies should use caution when selecting outcome measures if the intent is to identify modifiable correlates of MVPA in youth.

Active transportation and adolescents' health: the Canadian Health Measures Survey.

Active transportation (AT; e.g., walking and cycling) is increasingly promoted to increase youth physical activity (PA). Most previous research focused solely on school trips, and associations among AT and cardiovascular risk factors have seldom been examined in adolescents. To address these important research gaps using data from the nationally representative 2007-2009 Canadian Health Measures Survey. A total of 1,016 adolescents aged 12-19 years reported their weekly time spent utilitarian walking and cycling, and wore an Actical accelerometer for 7 days. They underwent a series of physical tests (measures of fitness, body composition, blood pressure, and blood sampling) following standardized protocols. In 2013, differences in PA and health-related outcomes across levels of walking and cycling were assessed with ANCOVA analyses adjusted for age, gender, parental education, and usual daily PA. Greater walking and cycling time was associated with higher moderate-to-vigorous PA (MVPA). Compared to adolescents reporting walking 1-5 hours/week, those reporting <1 hour/week had lower waist circumference and total cholesterol/high-density lipoprotein (HDL) ratio and higher glycohemoglobin; those reporting >5 hours/week had better grip strength, lower total cholesterol, and total cholesterol/HDL ratio. Compared to adolescents reporting no cycling, those reporting ≥1 hour/week accumulated more light PA, had greater aerobic fitness, and lower BMI, waist circumference, and total cholesterol/HDL ratio; those who reported cycling <1 hour/week had lower total cholesterol. Utilitarian walking and cycling were associated with higher daily MVPA in youth. Cycling was associated with a more consistent pattern of health benefits than walking.

Comparison of Objectively Measured Physical Activity Levels of Rural, Suburban, and Urban Youth

Nationally, youth are generally not achieving 60 minutes of daily moderate-to-vigorous physical activity (MVPA). Studies suggest that rural adults are less active than their urban counterparts, although studies of children are equivocal. To compare objectively measured physical activity across the rural-urban continuum in a sample of fourth- to eighth-grade youth. In fall 2010, youth from 20 North Carolina counties wore an accelerometer a minimum of 4 monitored days (n=804, 54% female, 25% African American, 54% urban). In spring 2013, two random-effects regression models were estimated separately for boys and girls. Comparisons among minutes of MVPA/day continuous and binary (≥60 minutes vs <60 minutes MVPA/day) among rural, suburban, and urban children were made, controlling for race, monitor wear time, and grade. For boys, there were no differences in MVPA/day among urbanicity categories. However, a 4.2 minutes/day decrease in MVPA occurred with each increase in grade. For girls, rural girls accumulated 9.3 minutes MVPA/day and 8.0 minutes MVPA/day more than suburban and urban girls, respectively. A 3 minutes/day decrease in MVPA occurred with each increase in grade. Rural girls were 4.6 times and 2.8 times more likely to accumulate ≥60 minutes MVPA/day compared to suburban and urban girls, respectively. No interactions across all models were significant for boys or girls. The relationship between urbanicity and MVPA in youth appears to be more complex than previously envisioned. Rural residence appears to be supportive of MVPA in girls but not boys. Future research should consider urbanicity when investigating correlates/determinants of MVPA in youth.