Multiple Days of Monitoring Are Needed to Obtain a Reliable Estimate of Physical Activity in Hip-Fracture Patients.

The aim of the study was to investigate the precision of estimated upright time during one week in community-dwelling older adults after hip fracture when monitoring activity for different numbers of consecutive days. Information about upright time was collected by thigh-worn accelerometers during 7 consecutive days in 31 older adults (mean age 81.8 years ± 5.3) 3 months after hip-fracture surgery. Mean time in upright position, including both standing and walking, was 260.9 (±151.2) min/day. A cutoff value of half an hour was used to provide recommendations about number of recording days. Large variability between participants between days, as well as a nonconstant within-participant variability between days indicates that at least 4 consecutive days of recording should be used to obtain a reliable estimate of upright time for individual persons. However, at a group level, one day of recording is sufficient. [ABSTRACT FROM AUTHOR]