Group-Based and Individually Delivered LiFE: Content Evaluation and Predictors of Training Response - A Dose-Response Analysis.

Introduction: Lifestyle-integrated Functional Exercise (LiFE) is an effective, individually delivered fall prevention program but comes with substantial resource requirements; hence, a group-format was developed (gLiFE). This study 1) evaluates the program content of two different LiFE formats (group vs individual) and 2) examines the relationship between predictors of training response (dose) and improvements in balance, strength, and physical activity (PA) (response). Material and Methods: The analysis included n = 252 (gLiFE = 126, LiFE = 126) community-dwelling older adults (78.6±5.2 years). LiFE was administered in seven sessions either in a group (gLiFE: 8-12 participants) or individually at home (LiFE). Questionnaire-based, descriptive content evaluation (frequency distributions) included reported frequency of practice (days/week, number of activities), activity preferences, safety, intensity, integrability of activities, and acceptance after 6 months of LiFE practice. Predictors (ie, dose [reported frequency and intensity], safety, and integrability of activities) for improvements in balance, strength, and PA were analyzed using radar charts. Results: In both formats, 11.2 activities were practiced on average. Strength activities were more frequently selected than balance. Content evaluation showed some marginal advantages for the LiFE participants for selected aspects. The effects on balance, strength, and PA were nearly similar in both groups. Participants who performed balance activities more frequently (≥4 days/week) scored better in the balance and PA domain. Those who performed strength activities more frequently (≥4 days/week) performed better in all three outcomes. Higher perceived safety was associated with better performance. Those who reported activities as "not physically exhausting" performed better in all three outcomes. Those who found activities easily integrable into daily routines scored higher in the balance and strength domain. Discussion and Conclusion: Overall, both program formats are comparable with respect to content evaluation and effects. Participants need to perceive the activities as safe, not exhausting, and should practice ≥4 days/week to generate a high benefit from the intervention. Trial Registration: ClinicalTrials.gov, NCT03462654. Registered on 12 March 2018.