Comparing Two Moderate-to-Vigorous Physical Activity Accelerometer Cut Points in Older Adults With Neck and Back...

Different techniques used to analyze and reduce accelerometer data may impact its interpretation. To determine which variables were impacted by changing analysis parameters, the authors performed a secondary analysis of data gained from a clinical trial conducted on older adults (aged ≥65 years; M = 71.1 and SD = 5.3; n = 100) with neck and back disabilities and compared the effects of two different cut- point sets (Matthews and Freedson sets) commonly used to analyze older adult accelerometry data. The Matthews set was found to assign significantly greater moderate-to-vigorous physical activity per day than the Freedson set in all comparisons. This suggests that, if moderate-to-vigorous physical activity per unit time is a primary outcome measure, the choice of which analysis method is used should be carefully considered. Further results from analyses of dependent variables, time in moderate-to-vigorous physical activity bouts of >10 min/day, mean bout length, and number of bouts per day are discussed.