Moderate-to Vigorous-intensity Activity Research Articles

Impact of ActiGraph Sampling Rate and Intermonitor Comparability on Measures of Physical Activity in Adults

Background: ActiGraph is a commonly used, research-grade accelerometer brand, but there is little information regarding intermonitor comparability of newer models. In addition, while sampling rate has been shown to influence accelerometer metrics, its influence on measures of free-living physical activity has not been directly studied. Purpose: To examine differences in physical activity metrics due to intermonitor variability and chosen sampling rate. Methods: Adults (n = 20) wore two hip-worn ActiGraph wGT3X-BT monitors for 1 week, with one accelerometer sampling at 30 Hz and the other at 100 Hz, which was downsampled to 30 Hz. Activity intensity was classified using vector magnitude, Euclidean Norm Minus One (ENMO), and mean amplitude deviation (MAD) cut points. Equivalence testing compared outcomes. Results: There was a lack of intermonitor equivalence for ENMO, time in sedentary/light- or moderate-intensity activity according to ENMO cut points, and time in moderate-intensity activity according to MAD cut points. Between sampling rates, differences existed for time in moderate-intensity activity according to vector magnitude, ENMO, and MAD cut points, and time in sedentary/light-intensity activity according to ENMO cut points. While mean differences were small (0.1–1.7 percentage points), this would equate to differences in moderate-to vigorous-intensity activity over a 10-hr wear day of 3.6 (MAD) to 10.8 (ENMO) min/day for intermonitor comparisons or 3.6 (vector magnitude) to 5.4 (ENMO) min/day for sampling rate. Conclusions: Epoch-level intermonitor differences were larger than differences due to sampling rate, but both may impact outcomes such as time spent in each activity intensity. ENMO was the least comparable metric between monitors or sampling rates.

Comparison of Inhibitory Control After Acute Bouts of Exergaming Between Children with Obesity and Their Normal-Weight Peers.

Objective: The benefits of exergaming on executive function in children have been increasingly reported; however, weight-dependent effects of exergames on executive function, and inhibitory control in particular, remain poorly understood. We examined performance on an inhibitory control task at baseline and following acute bouts of exergaming in children who varied in weight status. Materials and Methods: Forty 8-12-year-old children with obesity (n = 20) and normal weight (n = 20) performed neutral, congruent, and incongruent conditions of a Victoria Stroop Test (VST) before and after exergames through an Xbox One in an elementary classroom. We measured time spent in moderate-to vigorous-intensity activity through ActiGraph accelerometers and recorded gameplay time. Results: At baseline, children with obesity relative to their normal-weight peers had significantly longer reaction times (P = 0.011), resulting in significantly longer completion time (P = 0.005) during incongruent trials requiring greater inhibitory control, and therefore had higher interference scores (P = 0.024). However, following acute bouts of exergames, children with obesity compared with their normal-weight counterparts significantly decreased completion time (P = 0.013), made fewer errors (P = 0.012) during incongruent trials, and subsequently had reduced interference effects (P = 0.037). Children with obesity and normal-weight children spent similar time (minutes) (7.8 vs. 8.6, P = 0.725) in moderate-to vigorous-intensity activity during similar gameplay time (8.7 vs. 10.5, P = 0.819). Conclusion: Our results suggest that greater, acute cognitive gains occur in children with obesity relative to normal-weight children following similar intensity and duration of exergames, which may be due to reduced inhibitory control capacity at baseline in childhood obesity.