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  • Author: Marijka Batterham x
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Sze Yen Tan, Marijka Batterham and Linda Tapsell

Background:

Knowing the total energy expenditure (TEE) of overweight adults is important for prescribing weight loss interventions. However, objective measurements of TEE may not always be readily available and can be expensive. This study aimed to investigate the validity of RT3 accelerometers in predicting the TEE of sedentary overweight adults, and to identify any sensitivity to anthropometric changes.

Methods:

The analysis used data from a 12-week weight loss study. At baseline and 12-week, TEE was predicted using RT3 accelerometers during whole room calorimeter stays. Bias between 2 methods was compared at and between the baseline and 12-week measurement points. Multiple regression analyses of TEE data were conducted.

Results:

Predicted and measured values for TEE were not different at baseline (P = .677) but were significantly different after weight loss (P = .007). However, the mean bias between methods was small (<100 kcal/d) and was not significantly different between 2 time-points. RT3 activity counts explained an additional 2% of the variation in TEE at 12-week but not at baseline.

Conclusion:

RT3 accelerometers are not sensitive to body composition changes and do not explain variation in TEE of overweight and obese individuals in a sedentary environment.

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Alexander Allan Wetten, Marijka Batterham, Sze Yen Tan and Linda Tapsell

Background:

With physical inactivity inextricably linked to the increasing prevalence of obesity, there is a need for validated methods that measure free-living energy expenditure (EE) within sedentary environments. While accelerometers enable these measurements, few studies have compared device accuracy in such settings. The aim of this study was to investigate the relative validity of the Actigraph, RT3 and SenseWear Armband (SWA).

Methods:

Twenty-three (11 male, 12 female) participants (age: 25.3 ± 6.3 yr; BMI: 22.6 ± 2.7) wore 3 accelerometers at designated sites during a 4-hour stay in the Whole Room Calorimeter (WRC). Participants performed 2 10-minute bouts of light-intensity exercise (stepping and stationary cycling) and engaged in unstructured sedentary activities. EE estimated by accelerometers was compared with WRC EE derived from measurements of gaseous exchange.

Results:

The Actigraph and SWA both accurately estimated EE during the stepping exercise. EE estimated by the RT3 during stepping was significantly lower than the WRC value (31.2% ± 15.6%, P < .001). All accelerometers underestimated cycling and unstructured activity EE over the trial period (P < .001).

Conclusions:

The Actigraph and SWA are both valid tools for quantifying EE during light-intensity stepping. These results provide further valuable information on how accelerometer devices may be appropriately used.

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Rachel A. Jones, Annaleise Riethmuller, Kylie Hesketh, Jillian Trezise, Marijka Batterham and Anthony D. Okely

The aim of this study was to assess the feasibility, acceptability and potential efficacy of a physical activity program for preschool children. A 20-week, 2-arm parallel cluster randomized controlled pilot trial was conducted. The intervention comprised structured activities for children and professional development for staff. The control group participated in usual care activities, which included designated inside and outside playtime. Primary outcomes were movement skill development and objectively measured physical activity. At follow-up, compared with children in the control group, children in the intervention group showed greater improvements in movement skill proficiency, with this improvement statically significant for overall movement skill development (adjust diff. = 2.08, 95% CI 0.76, 3.40; Cohen’s d = 0.47) and significantly greater increases in objectively measured physical activity (counts per minute) during the preschool day (adjust diff. = 110.5, 95% CI 33.6, 187.3; Cohen’s d = 0.46). This study demonstrates that a physical activity program implemented by staff within a preschool setting is feasible, acceptable and potentially efficacious.

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Rachel A. Jones, Jacque Kelly, Dylan P. Cliff, Marijka Batterham and Anthony D. Okely

Objectives:

Single sex after-school physical activity programs show potential to prevent unhealthy weight gain. The aim of this study was to assess the acceptability and potential efficacy of single-sex after-school physical activity programs for overweight and at-risk children from low-income communities.

Design:

7-month, 2-arm parallel-group, RCT, conducted at an elementary school in a disadvantaged area in Wollongong, Australia (March-November 2010).

Methods:

20 boys and 17 girls were randomized to intervention (PA) or active comparison groups (HL). Primary outcomes included implementation, acceptability, percentage body fat and BMI z-score.

Results:

The PA programs were acceptable with high implementation and enjoyment rates. At 7 months postintervention girls in the PA group displayed greater changes in percentage body fat (adjust diff. = -1.70, [95% CI -3.25, -0.14]; d = -0.83) and BMI z-score (-0.19 [-0.36, -0.03]; d= -1.00). At 7 months boys in the PA group showed greater changes in waist circumference (-3.87 cm [-7.80, 0.15]; d= -0.90) and waist circumference z-score (-0.33 [-0.64, -0.03]; d= -0.98). For both boys’ and girls’ PA groups, changes in adiposity were not maintained at 12-month follow-up.

Conclusions:

Single-sex after-school physical activity programs are acceptable and potentially efficacious in preventing unhealthy weight gain among overweight and at-risk children. However improvements are hard to sustain once programs finish operating.

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Xanne Janssen, Dylan P. Cliff, John J. Reilly, Trina Hinkley, Rachel A. Jones, Marijka Batterham, Ulf Ekelund, Soren Brage and Anthony D. Okely

This study examined the classification accuracy of the activPAL, including total time spent sedentary and total number of breaks in sedentary behavior (SB) in 4- to 6-year-old children. Forty children aged 4–6 years (5.3 ± 1.0 years) completed a ~150-min laboratory protocol involving sedentary, light, and moderate- to vigorous-intensity activities. Posture was coded as sit/lie, stand, walk, or other using direct observation. Posture was classified using the activPAL software. Classification accuracy was evaluated using sensitivity, specificity and area under the receiver operating characteristic curve (ROC-AUC). Time spent in each posture and total number of breaks in SB were compared using paired sample t-tests. The activPAL showed good classification accuracy for sitting (ROC-AUC = 0.84) and fair classification accuracy for standing and walking (0.76 and 0.73, respectively). Time spent in sit/lie and stand was overestimated by 5.9% (95% CI = 0.6−11.1%) and 14.8% (11.6−17.9%), respectively; walking was underestimated by 10.0% (−12.9−7.0%). Total number of breaks in SB were significantly overestimated (55 ± 27 over the course of the protocol; p < .01). The activPAL performed well when classifying postures in young children. However, the activPAL has difficulty classifying other postures, such as kneeling. In addition, when predicting time spent in different postures and total number of breaks in SB the activPAL appeared not to be accurate.

Open access

Christiana M.T. van Loo, Anthony D. Okely, Marijka Batterham, Tina Hinkley, Ulf Ekelund, Soren Brage, John J. Reilly, Gregory E. Peoples, Rachel Jones, Xanne Janssen and Dylan P. Cliff

Background:

To validate the activPAL3 algorithm for predicting metabolic equivalents (TAMETs) and classifying MVPA in 5- to 12-year-old children.

Methods:

Fifty-seven children (9.2 ± 2.3y, 49.1% boys) completed 14 activities including sedentary behaviors (SB), light (LPA) and moderate-to-vigorous physical activities (MVPA). Indirect calorimetry (IC) was used as the criterion measure. Analyses included equivalence testing, Bland-Altman procedures and area under the receiver operating curve (ROC-AUC).

Results:

At the group level, TAMETs were significantly equivalent to IC for handheld e-game, writing/coloring, and standing class activity (P < .05). Overall, TAMETs were overestimated for SB (7.9 ± 6.7%) and LPA (1.9 ± 20.2%) and underestimated for MVPA (27.7 ± 26.6%); however, classification accuracy of MVPA was good (ROC-AUC = 0.86). Limits of agreement were wide for all activities, indicating large individual error (SB: −27.6% to 44.7%; LPA: −47.1% to 51.0%; MVPA: −88.8% to 33.9%).

Conclusions:

TAMETs were accurate for some SB and standing, but were overestimated for overall SB and LPA, and underestimated for MVPA. Accuracy for classifying MVPA was, however, acceptable.