Wrist‐worn accelerometers: Influence of decisions during data collection and processing: A cross‐sectional study

Abstract

Background and AimsAccelerometers collect data in an objective way, however, a number of decisions must be done during data collection, processing and output‐interpretation. The influence of those decisions is seldom investigated, reported, or discussed. Herein, we examined the influence of different decisions on the outcomes: daily minutes of moderate‐to‐vigorous physical activity (MVPA), inactivity and light physical activity (LPA).MethodsIn total, 156 participants wore an accelerometer (ActiGraph wGT3X‐BT) on their nondominant wrist for 7 days. Data collection was conducted from February 2017 to June 2018. Data was processed using the R‐package GGIR and default settings were compared to by‐the‐literature‐suggested options. The output was examined using paired t‐tests.ResultsWhen comparing two commonly used MVPA‐cut‐points, default and Hildebrand et al. we found a marginal difference (0.4 min, 1.0%, p < 0.001) in MVPA/day. When no bout criteria for MVPA/day was applied, MVPA/day was twice as high as bouted MVPA/day. Further, when we changed the epoch‐length from 5 to 1 s, statistically significant changes were seen for MVPA/day (−6.6 min, 19%, p < 0.001), inactivity/day (−22 min, 3.0%, p < 0.001) and LPA/day (28 min, 81%, p < 0.001).ConclusionDecisions made during data processing of wrist‐worn accelerometers has an influence on the output and thus, may influence the conclusions drawn. However, there may be situations when these settings are changed. If so, we recommend examining if the variables of interest are affected. We encourage researchers to report decisions made during data collection, processing and output‐interpretation, to facilitate comparisons between different studies.

Concurrent Validity of Four Activity Monitors in Older Adults

“…Thus, with the LIPA window being only small and yet exhibiting a similar pattern to MVPA, it is conceivable that misclassifications with MVPA could be made, as seen in a previous study that pertained to compare various methods of quantifying LIPA [38]. In addition, decisions during data processing on cut-offs for MVPA have been shown to affect the outcome [12].…”

“…Consequently, any established activity thresholds or cut-off points for activity intensities are unlikely to be applicable to other populations [2,10,11]. In addition, different decisions for the processing of data obtained from accelerometers do have an impact on the interpretation of PA and SB levels [12].…”

Physical Activity Perceptions and Participation of People With Type II Diabetes Mellitus in the Dominican Republic

“…Best practices regarding minimum bout time to accurately capture moderate-to vigorous-intensity PA (MVPA) have not been established. Since this is a preliminary study that may be used as a reference for future research, we used the two widely used bout lengths: one minute [19] and 10 minutes [20] to maximize the generalizability of the findings.…”