Dose-response relationship of treadmill perturbation-based balance training for improving reactive balance in older adults at risk of falling: results of the FEATURE randomized controlled pilot trial

Abstract

Background: The inability to appropriately react to balance perturbations is a common cause of falls. Perturbation-based balance training (PBT) is especially beneficial for improving reactive balance and shows high potential for fall prevention. However, its dose-response relationship, feasibility, and acceptability remain to be determined among older adults at risk of falling. The FEATURE study aimed to compare the efficacy of two treadmill PBT protocols with different session numbers to improve reactive balance, and to evaluate their feasibility and acceptability in this population.

Methods: In this randomized controlled pilot trial, 36 older adults at risk of falling were allocated to receive either six (6PBT) or two treadmill PBT sessions (2PBT). Reactive balance in standing (Stepping Threshold Test [STT]) and walking (Dynamic Stepping Threshold Test [DSTT]) was assessed as primary outcome at baseline (T1), post-intervention (T2), and 6-week follow-up (T3). Secondary outcomes included measures on physical, psychological, and cognitive functioning. Feasibility was assessed via PBT adherence, planned perturbations completed, and adverse events; acceptability via questionnaire. Between-group changes over time were compared using repeated-measures analyses of variance with Bonferroni-corrected post-hoc tests. Data analyses followed the intention-to-treat principle.

Results: A significant time effect was observed for the DSTT (p = 0.008), with both groups significantly improving from T1 to T2 (ps < 0.01). A significant interaction effect (p = 0.027) revealed that only the 6PBT group maintained these improvements (T1 vs. T3: p < 0.001) and scored significantly higher than the 2PBT group at T3 (p = 0.015). No significant interaction effects were found for the STT or any secondary outcome, but improvements over time were observed for dynamic balance, gait capacity, functional mobility, physical activity, concerns about falling, and executive functioning (time effects: ps < 0.05). PBT adherence, planned perturbations completed, and acceptability were high in both groups, with no significant between-group differences. No intervention-related serious adverse events were reported.

Conclusions: Findings suggest that a low number of treadmill PBT sessions can lead to task-specific improvements in reactive balance during walking, with a higher practice dose enhancing sustainability. Treadmill PBT appears feasible and well-accepted among older adults at risk of falling, regardless of sessions received.

Trial registration: DRKS00030805 ; prospectively registered December 14, 2022.

Keywords: Dose–response relationship; Exercise; Falls; Feasibility studies; Frail older adults; Patient acceptance of health care; Postural control.

Fig. 1

Flowchart for enrollment, allocation, intervention, assessment, and data analysis. REGE e.V. = Rehabilitation Sports in Geriatrics, 6PBT = six-session perturbation-based balance training, 2PBT = two-session perturbation-based balance training and four-session conventional treadmill training, ITT = intention-to-treat

Fig. 2

Between-group changes over time in static reactive balance. (a) STT-ACE = Stepping Threshold Test – all-step count evaluation, (b) STT-DSE = Stepping Threshold Test – direction-sensitive evaluation, 2PBT = two-session perturbation-based balance training and four-session conventional treadmill training, 6PBT = six-session perturbation-based balance training, T1 = baseline assessment, T2 = post-intervention assessment, T3 = follow-up assessment. Data given as estimated marginal means and standard errors

Fig. 3

Between-group changes over time in dynamic reactive balance. DSTT = Dynamic Stepping Threshold Test, 2PBT = two-session perturbation-based balance training and four-session conventional treadmill training, 6PBT = six-session perturbation-based balance training, T1 = baseline assessment, T2 = post-intervention assessment, T3 = follow-up assessment. Data given as estimated marginal means and standard errors; *p < 0.05, **p < 0.01, ***p < 0.001 for Bonferroni-corrected post-hoc comparisons