Adults (N = 54, 80.78 ± 6.08 years) who reported falling during the previous 12 months participated in a 12-week wobble board training program with internal focus or external focus (EF) instructions. Verbal manipulation checks were performed after training sessions as a self-report of the attentional foci used. The percentage of sessions in which participants reported using an EF (EF[subscript SR]) was subsequently calculated. Mean velocity and mean power frequency in the anterior-posterior (MVELO[subscript AP] and MPF[subscript AP]) and medial-lateral (MVELO[subscript ML] and MPF[subscript ML]) direction were assessed during a 35-s wobble board task at Weeks 0, 6, 12, 13, 16, and 20, with the latter three as retention tests. Piecewise linear growth models estimated treatment effects on individual growth trajectories of MVELO[subscript AP] and [subscript ML] and MPF[subscript AP] and [subscript ML] during intervention and retention periods. Regardless of condition, MVELOML significantly decreased ([pi] = -0.0019, p = 0.005) and MPF[subscript ML] increased ([pi] = 0.025, p < 0.02) during the intervention period. In analyses including interaction terms, participants in the EF group who reported greater EF[subscript SR] had superior progression of MPF[subscript AP] during the intervention ([pi] = 0.0013, p = 0.025). Verbal manipulation checks suggest a preference for and advantage of EF for facilitating postural control performance and automaticity.