Related Experiment Video
Updated: Jan 16, 2026
Physical Activity Measurement in Children Accepting Table Tennis Training
Published on: July 27, 2022
Impact of cut-point methods on classification of physical activity and sedentary behaviour of toddlers
Jill Marie Ferry1,2, Joaquin Escribano3,4, Mariona Gispert-LLauradó3
1Department of Paediatrics, Dr. von Hauner Children's Hospital, LMU University Hospital, Munich, Germany.
Insights
Choosing the right accelerometer cut-point method significantly impacts physical activity (PA) and sedentary behavior (SB) classifications in toddlers. Different methods alter adherence to PA guidelines, highlighting the need for standardized data processing.
Area of Science:
- Pediatric Exercise Science
- Biomedical Data Analysis
- Public Health Research
Background:
- Accelerometer-based physical activity (PA) classification relies on specific cut-point methods.
- Variations in cut-point selection can influence estimates of time spent in sedentary behavior (SB) and different PA intensities.
- Understanding these variations is crucial for accurately assessing PA levels and guideline adherence in young children.
Purpose of the Study:
- To investigate the impact of three validated accelerometer cut-point methods on classifying PA and SB in toddlers.
- To determine how different cut-point methods affect the estimated adherence to physical activity guidelines in this age group.
Main Methods:
- Utilized ActiGraph wGT3X-BT accelerometers to measure PA in 653 two-year-old children.
- Employed three distinct cut-point methods (Trost VA, Costa VA, Costa VM) with varying epoch lengths (15s and 5s) to estimate time in SB and PA.
- Compared SB and PA estimates across methods using repeated measures ANOVA, standardizing data to individual mean wear-time.
Main Results:
- Significant differences were observed in time spent in PA and SB based on the cut-point method used.
- The Costa VM method classified significantly more time as SB and less as light PA (LPA) compared to Trost VA.
- Differences in moderate-to-vigorous PA (MVPA) were smaller, but adherence to WHO PA guidelines varied notably (86% vs. 97%).
Conclusions:
- The choice of accelerometer cut-point method substantially influences the classification of PA intensities and SB in toddlers.
- Methodological variations can lead to substantial discrepancies in estimated LPA and SB, and affect the proportion of children meeting PA recommendations.
- Standardization of data processing methods is essential for improving the comparability of findings across studies on toddlers' physical activity.
Background:
Classification of physical activity (PA) depends on the cut-point method used to allocate PA counts from accelerometer measurements. This study investigates how three validated cut-point methods affect the time spent in various levels of PA and sedentary behaviour (SB), and how they impact toddlers estimated adherence to PA guidelines.
Methods:
PA was assessed using an ActiGraph wGT3X-BT accelerometer in a cohort of 653 two-year-old children participating in the Toddler Milk Intervention study. Children wearing the ActiGraph for at least four days, with a minimum of six hours wear-time per day, were included. Time spent in SB and different activity levels were estimated according to three cut-point methods and were standardized to individual mean wear-time. We used one cut-point method based on the vertical axis (VA) (Trost VA), with an epoch length of 15 s and two cut-point methods based on either the VA (Costa VA) or on the vector magnitude (VM) (Costa VM) with an epoch length of five seconds. Estimates of SB and PA for each method were compared with repeated measures ANOVA.
Results:
The time toddlers spent in PA was significantly different depending on the cut-point methods. Costa VM classified on average 62 min (95% CI 61, 64] more per day as SB and 57 min (95% CI -58, -56] less per day as LPA compared to Trost VA (both p < 0.0001). For MVPA, the mean difference between Costa VA and Trost VA was 6.8 min (95% CI -7, -6; p < 0.0001). Concurrently, the proportion of children meeting the WHO recommendation of 180 min of total PA differed between cut-point methods, with 86% according to Costa VM and 97% according to Trost VA.
Conclusions:
The time toddlers engage in different intensities of PA is significantly determined by the selection of cut-point method. Notably, the use of a different cut-point method leads up to a 10% difference in the estimated time spent in LPA and SB, but only a 1% difference of moderate-vigorous PA. These differences change the estimated adherence to recommendations. Future research is needed to standardize the data processing methods for better comparability between studies analysing toddlers' PA.
Registry:
ClinicalTrials.gov, TRN: NCT02907502, Registration Date: 31 August 2016.
