Reciprocal Associations Between Relative or Absolute Physical Activity, Walking Performance, and Autonomy in Outdoor Mobility Among Older Adults: A 4-Year Follow-Up.

Objectives: To examine the reciprocal associations between walking performance, physical activity (PA), and perceived autonomy in outdoor mobility in 322 older adults. Methods: At baseline and four years later, a 6-min walk test assessed walking performance. A thigh-mounted accelerometer monitored relative PA (acceleration exceeding the individual's preferred walking intensity on the walk test) and absolute MVPA (acceleration exceeding 3 METs) in free-living. Autonomy in outdoor mobility was self-reported using the IPA subscale. Cross-lagged panel model was used for analyses. Results: Higher relative PA at baseline predicted better walking performance four years later and vice versa (p < .05). Baseline MVPA did not predict subsequent walking performance, but better initial walking performance predicted higher subsequent MVPA (p < .001). In both models, only walking performance predicted perceived autonomy at follow-up (p < .05). Discussion: Accumulating enough PA of a sufficient relative intensity can maintain good walking performance, which in turn helps to maintain perceived autonomy in mobility.