Concurrent Validity of activPAL and activPAL3 Accelerometers in Older Adults.

The aim of this study was to assess concurrent validity between activPAL and activPAL3 accelerometers in a sample of 53 community-dwelling older adults ≥ 65 years. Physical activity (PA) was measured simultaneously with activPAL and activPAL3 while performing scripted activities. The level of agreement between both devices was calculated for sitting/lying, standing, and walking. In addition, PA was measured over one week using activPAL to estimate the expected agreement with activPAL3 in real life. Overall agreement between activPAL and activPAL3 was 97%. Compared with activPAL, the largest disagreement was seen for standing, with 5% categorized as walking by activPAL3. For walking and sitting/lying, the disagreement was 2%, respectively. The expected daily differences between activPAL3 and activPAL were +15.0 min (95% CI: 11.3-18.8) for walking and +29.5 min (95% CI: 6.2-52.7) for standing. ActivPAL and activPAL3 showed good agreement in older adults. However, if using these devices interchangeably, observed differences might still bias results.