Abstract / Summary
Multicomponent exercise is widely recommended to support functional fitness in older adults, but evidence remains heterogeneous regarding the contribution of intervention duration, particularly in real-world community-based settings. This study examined associations between observed 12-week and 24-week participation in community-based multicomponent exercise programs and longitudinal changes in functional fitness among community-dwelling older adults. This pragmatic, non-randomized dynamic cohort study included repeated assessments at baseline (T1), week 12 (T2), week 16 following a planned 4-week no-training interval (T3), and week 28 (T4). Participants aged 65 years and older were recruited from nearby communities. Based on observed program exposure, participants were classified into a 12-week group ( n = 166; Cohort A: T1–T2 only, n = 56; Cohort B: T3–T4 only, n = 110) and a 24-week group ( n = 94, T1-T4). Functional fitness outcomes included static balance (Single-leg stance test with eyes open), dynamic balance (8-foot Up-and-Go test), upper-body strength (Arm Curl), lower-body strength (Chair Stand), upper-body flexibility (Back Scratch), lower-body flexibility (Sit and Reach), and cardiorespiratory endurance (2-Minute Step Test). Linear mixed models (LMM) were used to examine Group differences, Time effects, and Group × Time interactions. A total of 260 older adults were included in the final analytic sample (mean age = 73.68 ± 4.37 years; 82.7% female). Significant time effects were observed for all functional fitness outcomes. Significant Group × Time interactions were found for static balance ( p = 0.023), chair stand ( p = 0.001), dynamic balance ( p = 0.004), and 2-Minute Step Test ( p = 0.024), indicating that temporal change patterns differed between the 12-week and 24-week groups for these outcomes. In contrast, no significant interaction effects were observed for arm curl, back scratch, and sit and reach. Observed participation in both the 12-week and 24-week community-based multicomponent exercise programs was associated with temporal changes in functional fitness. Continued participation across both intervention phases was associated with more favorable temporal patterns in selected lower-limb, balance-related, and endurance outcomes. Not Applicable.