Acceptability of Two Perturbation-based Balance Training Paradigms: Perturbation Treadmill vs Dynamic Stability Training in the Presence of Perturbations.

INTRODUCTION: Perturbation-based balance training is promising for fall prevention in older adults mimicking real-life fall situations at a person's stability thresholds to improve reactive balance. Hence, it can be associated with anxiety, but knowledge about the acceptability of perturbation-based balance training is scarce. METHOD: This is a secondary analysis of a randomized controlled trial comparing effects of two different perturbation-based balance training paradigms that aims to evaluate and compare the acceptability of those training paradigms in fall-prone older adults. Participants (74.9±5.7 years) who completed the training (6 weeks, 3x/week) on either a perturbation treadmill (PBTtreadmill: n=22) or unstable surfaces in the presence of perturbations (PBTstability: n=27) were surveyed on the acceptability of perturbation-based balance training using a 21-items questionnaire addressing seven domains (perceived effectiveness, tailoring, demand, safety, burden, devices, affective attitude), based on the Theoretical Framework of Acceptability and context-specific factors. Relative scores (% of absolute maximum) for single items and domains were calculated. RESULTS: Median domain scores of perceived effectiveness, tailoring, safety, devices, and affective attitude were all ≥70% for both paradigms. The highest scores were obtained for tailoring (both paradigms=100% [interquartile range 80-100%]). Domain scores of demand and burden were in the medium range (40-45%) for both paradigms. No significant differences between paradigms were found for any domain score. Two single items of safety differed significantly, with PBTtreadmill perceived as needing less support (p=.015) and leading less often to balance loss (p=.026) than PBTstability. CONCLUSION: Perturbation-based balance training conducted on a perturbation treadmill or on unstable surfaces is well accepted in this fall-prone older sample, even though it is conducted at individual stability thresholds. Tailoring may play a key role in achieving high levels of perceived effectiveness, appropriate levels of demand and burden, and high sense of safety. Perturbation-based balance training delivered on treadmills might be more appropriate for more anxious persons.

Feasibility, effectiveness and acceptability of two perturbation-based treadmill training protocols to improve reactive balance in fall-prone older adults (FEATURE): protocol for a pilot randomised controlled trial.

INTRODUCTION: Perturbation-based balance training (PBT) targets the mechanism of falls (eg, slipping, tripping) to specifically train the recovery actions needed to avoid a fall. This task-specific training has shown great promise as an effective and efficient intervention for fall prevention in older adults. However, knowledge about the dose-response relationship of PBT, as well as its feasibility and acceptability in older adults with increased risk of falling is still limited. Thus, the aim of this study is to compare the effectiveness of two different treadmill PBT protocols for improving reactive balance control in fall-prone older adults, and to evaluate the feasibility and acceptability of these protocols. METHODS AND ANALYSIS: The study is designed as a pilot randomised controlled trial with a 6-week intervention and 6-week follow-up period. Thirty-six community-dwelling, fall-prone (Timed Up and Go >12 s, habitual gait speed <1.0 m/s and/or fall history) older adults will be randomised (1:1) to receive six (weeks 1-6) or two treadmill PBT sessions (weeks 1+6) plus four conventional treadmill training sessions (weeks 2-5). Training sessions are conducted 1×/week for 30 min. Each PBT will include 40 perturbations in anterior-posterior and mediolateral directions. Reactive balance after perturbations in standing (Stepping Threshold Test (STT)) and walking (Dynamic Stepping Threshold Test (DSTT)) will be assessed as the primary outcome for effectiveness. Secondary outcomes are spatiotemporal and kinematic parameters collected during STT, DSTT and PBT, maximum perturbation magnitude for each PBT session, static and dynamic balance, physical capacity, physical activity, concerns with falling and executive functions. Feasibility will be assessed via training adherence, drop-out rate, perturbations actually performed and adverse events; and acceptability via self-designed questionnaire and focus groups. ETHICS AND DISSEMINATION: The study has been approved by the Ethics Committee of the Medical Faculty Heidelberg (S-602/2022). Findings will be disseminated through publications in peer-reviewed journals and conference presentations. TRIAL REGISTRATION NUMBER: DRKS00030805.

Validity and reliability of the Apple Health app on iPhone for measuring gait parameters in children, adults, and seniors.

This study assessed the concurrent validity and test-retest-reliability of the Apple Health app on iPhone for measuring gait parameters in different age groups. Twenty-seven children, 28 adults and 28 seniors equipped with an iPhone completed a 6-min walk test (6MWT). Gait speed (GS), step length (SL), and double support time (DST) were extracted from the gait recordings of the Health app. Gait parameters were simultaneously collected with an inertial sensors system (APDM Mobility Lab) to assess concurrent validity. Test-retest reliability was assessed via a second iPhone-instrumented 6MWT 1 week later. Agreement of the Health App with the APDM Mobility Lab was good for GS in all age groups and for SL in adults/seniors, but poor to moderate for DST in all age groups and for SL in children. Consistency between repeated measurements was good to excellent for all gait parameters in adults/seniors, and moderate to good for GS and DST but poor for SL in children. The Health app on iPhone is reliable and valid for measuring GS and SL in adults and seniors. Careful interpretation is required when using the Health app in children and when measuring DST in general, as both have shown limited validity and/or reliability.

Comparing the Effects of Two Perturbation-Based Balance Training Paradigms in Fall-Prone Older Adults: A Randomized Controlled Trial.

INTRODUCTION: There is increasing evidence that perturbation-based balance training (PBT) is highly effective in preventing falls at older age. Different PBT paradigms have been presented so far, yet a systematic comparison of PBT approaches with respect to feasibility and effectiveness is missing. Two different paradigms of PBT seem to be promising for clinical implementation: (1) technology-supported training on a perturbation treadmill (PBTtreadmill); (2) training of dynamic stability mechanisms in the presence of perturbations induced by unstable surfaces (PBTstability). This study aimed to compare both program's feasibility and effectiveness in fall-prone older adults. METHODS: In this three-armed randomized controlled trial, seventy-one older adults (74.9 ± 6.0 years) with a verified fall risk were randomly assigned into three groups: PBTtreadmill on a motorized treadmill, PBTstability using unstable conditions such as balance pads, and a passive control group (CG). In both intervention groups, participants conducted a 6-week intervention with 3 sessions per week. Effects were assessed in fall risk (Brief-BEST), balance ability (Stepping Threshold Test, center of pressure, limits of stability), leg strength capacity, functional performance (Timed Up and Go Test, Chair-Stand), gait (preferred walking speed), and fear of falling (Short FES-I). RESULTS: Fifty-one participants completed the study. Training adherence was 91% for PBTtreadmill and 87% for PBTstability, while no severe adverse events occurred. An analysis of covariance with an intention-to-treat approach revealed statistically significant group effects in favor of PBTstability in the Brief-BEST (p = 0.009, η2 = 0.131) and the limits of stability (p = 0.020, η2 = 0.110) and in favor of PBTtreadmill in the Stepping Threshold Test (p < 0.001, η2 = 0.395). The other outcomes demonstrated no significant group effects. CONCLUSION: Both training paradigms demonstrated high feasibility and were effective in improving specific motor performances in the fall-prone population and these effects were task specific. PBTtreadmill showed higher improvements in reactive balance, which might have been promoted by the unpredictable nature of the included perturbations and the similarity to the tested surface perturbation paradigm. PBTstability showed more wide-ranging effects on balance ability. Consequently, both paradigms improved fall risk-associated measures. The advantages of both formats should be evaluated in light of individual needs and preferences. Larger studies are needed to investigate the effects of these paradigms on real-life fall rates.