Abstract In this study, we evaluated agreement among three generations of ActiGraph™ accelerometers in children and adolescents. Twenty-nine participants (mean age = 14.2 ± 3.0 years) completed two laboratory-based activity sessions, each lasting 60 min. During each session, participants concurrently wore three different models of the ActiGraph™ accelerometers (GT1M, GT3X, GT3X+). Agreement among the three models for vertical axis counts, vector magnitude counts, and time spent in moderate-to-vigorous physical exercise (MVPA) was evaluated by calculating intraclass correlation coefficients and Bland-Altman plots. The intraclass correlation coefficient for total vertical axis counts, total vector magnitude counts, and estimated MVPA was 0.994 (95% CI = 0.989-0.996), 0.981 (95% CI = 0.969-0.989), and 0.996 (95% CI = 0.989-0.998), respectively. Inter-monitor differences for total vertical axis and vector magnitude counts ranged from 0.3% to 1.5%, while inter-monitor differences for estimated MVPA were equal to or close to zero. On the basis of these findings, we conclude that there is strong agreement between the GT1M, GT3X, and GT3X+ activity monitors, thus making it acceptable for researchers and practitioners to use different ActiGraph™ models within a given study.
"Sedentary time was measured using the ActiGraph accelerometer models GT1M, GT3X and GT3X+ (ActiGraph TM, LLC, Pensacola, FL, US). Previous studies have demonstrated that there is strong agreement between measures from GT1M, GT3X and GT3X+ activity monitors (Robusto & Trost, 2012; Vanhelst et al., 2012). For standardisation purposes, the GT1M accelerometers were set at 2-s epoch, whereas the GT3X+ was set at 30 Hz and their data were successively converted into 2-s epoch in the download. "
[Show abstract][Hide abstract] ABSTRACT: Abstract The aim of this study was to identify potential correlates of sedentary time and television (TV) viewing time in youth with Down syndrome (DS). A total of 98 adolescents with DS (63 males) aged 11-20 years old participated in this study. Total sedentary time was measured using accelerometers, while total TV viewing time and potential correlates were measured using proxy-report questionnaire. Analyses of covariance and a stepwise multiple linear regression were performed to examine correlates of total sedentary time and total TV viewing time. Different potential correlates were associated with total sedentary time (mother age, mother TV viewing time, perceived benefits of physical activity, birth order and having nearby shops in the neighbourhood) and total TV viewing time (father TV viewing time, TV viewing time with parents, family dietary habits during watching TV and weekend days time indoor). The identification of correlates associated with sedentary behaviour, principally those considered modifiable such as social and environmental factors, may contribute to development strategies to decrease sedentary behaviour in adolescents with DS and consequently promote a healthier lifestyle.
"). There is a strong agreement between the GT1M, GT3X and GT3X+ accelerometers, which makes it acceptable to use these activity monitors together in one study (Robusto & Trost, 2012). All accelerometers were worn on the right hip, secured by an elastic waistband . "
[Show abstract][Hide abstract] ABSTRACT: Abstract This study aimed at translating the physical activity (PA) guideline (180 min of total PA per day) into a step count target in preschoolers. 535 Flemish preschoolers (mean age: 4.41 ± 0.58) wore an ActiGraph accelerometer (GT1M, GT3X and GT3X+) - with activated step count function - for four consecutive days. The step count target was calculated from the accelerometer output using a regression equation, applying four different cut-points for light-to-vigorous PA: Pate, Evenson, Reilly, and Van Cauwenberghe. The present analysis showed that 180 min of total PA per day is equivalent to the following step count targets: 5,274 steps/day using the Pate cut-point, 4,653 steps/day using the Evenson cut-point, 11,379 steps/day using the Reilly cut-point and 13,326 steps/day using the Van Cauwenberghe cut-point. Future studies should focus on achieving consensus on which cut-points to use in preschoolers before a definite step count target in preschoolers can be proposed. Until then, we propose to use a provisional step count target of 11,500 steps/day as this step count target is attainable, realistic and helpful in promoting preschoolers' PA.
"This accelerometer has been widely validated in laboratory settings and free-living conditions with children and adolescents without disabilities (Freedson, Pober, & Janz, 2005). Recent studies have showed that there is strong agreement among the three models (Robusto & Trost, 2013; Vanhelst et al., 2012). Adolescents were instructed to wear the accelerometer for 7 consecutives days at the lower back fitted with an elastic belt, excepted during sleep hours and water-based activities. "
[Show abstract][Hide abstract] ABSTRACT: The aim of the present study was to examine the associations of objectively measured physical activity (PA) with several markers of fatness and fitness in a relatively large sample of adolescents with Down syndrome (DS). This study comprised a total of 100 adolescents with DS (37 females) aged 11–20 years-old, and a sex-matched sample of 100 adolescents without disabilities, participating in the UP&DOWN study. The ALPHA health-related fitness test battery for adolescents was used to assess fatness and fitness. PA was measured by accelerometry. Adolescents with DS had higher fatness and significantly lower fitness levels in all variables measured than adolescents without DS (all p < 0.05). Moderate-to-large effects were observed in fatness variables (d = 0.65–1.42), but particularly large values were found in fitness variables (d = 2.05–2.43). In addition, PA levels was not associated with fatness variables, whereas total PA and vigorous PA were associated with all fitness variables (p < 0.05), and moderate-vigorous PA (MVPA) was associated with muscular fitness (p < 0.05), after adjusting for potential confounders. Further analysis revealed that there were differences in fitness by tertiles of vigorous PA between the lowest and the highest groups in all fitness variables (all p < 0.05). However, no significant differences were found in fitness by tertiles of MVPA according with PA guidelines (≥60 min in MVPA). Our findings indicate that PA levels are not associated with fatness variables, whereas high PA levels, in particular vigorous PA, are positively associated with high fitness in adolescents with DS.
Research in Developmental Disabilities 11/2014; 36. DOI:10.1016/j.ridd.2014.10.022 · 3.40 Impact Factor
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