Design:: Exploratory secondary data analysis of a pilot randomized control trial conducted between 2015 and 2017.
Setting:: Outpatient physical therapy clinic in an academic setting.
Participants:: 43 participants were randomized to the intervention or control group. Both groups received standard physical therapy (PT) after total knee replacement (TKR).
Interventions:: Participants in the intervention group received a Fitbit, weekly step goals from their physical therapist, and up to six monthly phone calls after their discharge from PT (DC).
Main Outcome Measures:: The outcome, change in sedentary time (∆SED), was measured using a triaxial accelerometer (Actigraph GT3X) from initial evaluation (IE) to DC (short-term), and IE to 12 months (12M) after DC (long-term). Positive values represent a reduction in SED. We compared the short- and long-term ∆SED between the intervention and control groups using independent t-tests.
Results:: Of the 43 participants [mean(SD) age 67.0 (7.0) years, BMI 31.5 (5.9) kg/m2, 53% female], 36 participants had data at IE and DC (18 intervention, 18 control) and 27 had data at IE and 12M (12 intervention, 15 control). The between group difference in short-term ∆SED was [mean(95%CI)] 32.9 (−14.4, 80.1) minutes/day. The between group difference in long-term ∆SED was 59.2 (8.6, 109.7) minutes/day.
Conclusion:: Our preliminary results indicate that a physical therapist-administered physical activity intervention may reduce SED in adults after TKR. However, a full-clinical trial is needed to establish the effect on SED.
Keywords: intervention; outcomes; physical activity; pilot study; sedentary behaviour.