Comparison of stepping-based metrics from ActiGraph accelerometers worn concurrently on the non-dominant wrist and waist among young adults

Step counts can be estimated from wrist-worn accelerometers through the Verisense Step Count Algorithm. No study has assessed agreement between stepping metrics from ActiGraph accelerometers during free-living. Thirty-four participants (age:22.9±3.4y) provided 24h accelerometer data (non-dominant wrist) and waist. Agreement of two Verisense Algorithms (Verisense 1&2) for estimating daily steps, moderate-to-vigorous physical activity (MVPA), peak 1-min and 30-min accumulated steps, against the waist and ActiLife step-count Algorithm was assessed. Mean bias±95% limits of agreement (LoA) for daily steps was +1255±3780 steps/day (Mean absolute precent error (MAPE):21%) (Verisense 1) and +1357±3434 steps/day (MAPE:20%) (Verisense 2). For peak 1-min accumulated steps, mean bias and 95%LoA was -17±23 steps/min (MAPE:17%) (Verisense 1) and -6±5 steps/min (MAPE: 9%) with Verisense 2. For peak 30-min accumulated steps, mean bias and 95%LoA was -12±45 steps/min (MAPE: 25%) (Verisense 1) and -2±38 steps/min (MAPE:13%) (Verisense 2). For MVPA steps/day, mean bias and 95%LoA was -1450±3194 steps/day (MAPE:420%) (Verisense 1) and -844±2571 steps/day (MAPE:211%) (Verisense 2). For MVPA min/day, mean bias and 95%LoA was -13±27 min/day (MAPE:368%) (Verisense 1) and -8±24 min/day (MAPE:209%) (Verisense 2). The Verisense 2 algorithm enhanced agreement for stepping intensity metrics but further refinement is needed to enhance agreement for MVPA against the waist.