Multimodal training, including physical and cognitive activities, has been associated with a reduction in age-related physical and cognitive decline. Therefore, combining these activities into a home-based computerized training program may represent a powerful approach to foster independent life at home. The StayFitLonger study is a 6-month multi-site randomized controlled, double-blind trial, which tests the efficacy of a home-based computerized intervention that combines physical and cognitive exercises through virtual coaching to enhance motivation.

In Switzerland, Canada and Belgium, a total of 128 older participants will be recruited and randomly assigned to one of two physical and cognitive home-based interventions for 6 months: StayFitLonger or active control training. The StayFitLonger intervention provides physical and cognitive training exercises, feedback and instructions through a virtual coach to optimize motivation. It also offers social and psycho-educational contents. Monthly supervision (home-visits and phone calls) will be provided during this 6-month intervention. Outcomes will be measured at baseline, and after 6 months of training.

This study will demonstrate the feasibility, sustainability and efficacy of a home-based multi-domain intervention program allowing further development and possible commercialization of a scientifically validated training program to slow down cognitive and physical decline.

Finding ways to improve and maintain functional abilities and quality of life in older people has become a worldwide priority. It is well recognized that reduced engagement in physical, cognitive and social activities has negative influence on the health of older adults. This leads to more vulnerabilities both physically and cognitively. Sedentary behaviors can ultimately induce physical frailty, defined as a state of high vulnerability with accumulation of adverse health outcomes. Fear of falling and/or unsteady gait are common factors of physical frailty. Moreover, falls are particularly common in older adults. In addition to mobility limitation and falls, cognitive decline has been identified as a major cause of disability and dependency in older populations.

Through non-pharmacological interventions focusing on alterable lifestyle factors, experts believe in the possibility to protect older people from the deleterious effects of physical and brain aging that can lead to dementia. In other words, keeping a healthy mind in a healthy body might be the gold standard for healthy aging. Several studies have shown that physical activity, through aerobic, gait and strength training, induces many beneficial effects including improvement of general health, cognition and quality of life. In addition, a growing number of cognitive interventions have been conducted in healthy seniors and older adults with mild cognitive impairment (MCI) and results show improved cognition and delayed cognitive decline. As well, cognitive deficits, mainly in executive functions, have been associated with an increase number of falls and abnormal gait among others.

Improvement of these physical functions was observed in response to cognitive interventions. Because aging is complex and different interventions are likely to potentiate their effects, an increasing number of studies have reported on combined interventions targeting two or more modifiable factors. However, accessibility to these interventions remain a major challenge because older adults may not have access to specialized expertise and resources.

The use of a computerized system to deliver lifestyle interventions have several advantages: it can be used to support home-based training, reducing costs and increasing access; training can be self-paced and last over practically a unlimited time; it allows providing immediate feedback; it offers potential for scaling up for wider use if efficacy is proven; it provides an excellent interface for active control interventions. Surprisingly, whereas many studies assessed computerized cognitive training programs, only a few have used home-based interventions which combine cognitive training with physical activity and, to our knowledge, only one study used computerized tasks for both physical and cognitive training in healthy older adults.

The StayFitLonger study was designed to test efficacy of a home-based computerized training program targeted at older adults, which combine physical exercises and cognitive training. The main goal of the program is to improve physical health and prevent frailty through an innovative approach using videos of 50 physical exercises focusing on gait and strength, which could be easily implemented in older adults (Test-and-Exercise home-based program). The program was also designed to enhance cognitive functions through a series of activities in form of serious games. These activities train executive control through dual-task exercises that was found to increase divided attention and frontal lobe function general knowledge learning and problem solving training. Other features of the program that are unique include: 1) Prospective memory exercises embedded in the physical exercises; 2) Social interactions whereby participants can create and share with other participants their learning material and can chat with their peers about topics of interest and find solutions to common real-life problems; 3) Psycho-educational content on cognition, physical health, nutrition and on ways to apply newly learned strategies in real life to empower participants and promoting self-management; 4) A virtual coach aimed to improve adherence by guiding participants, reminding them to use the program regularly, and providing feedback and rewards through a system of virtual credits; 5) Possibility to personalize the application settings to tailor the environment to the participant's tastes and wishes; 6) Wearable motion sensors used during physical exercises for movement detection as a game input and for providing measurements on mobility for a better characterization of the potential benefits of the program.

The StayFitLonger study will test the effect of the training on key outcomes using a double-blind, parallel-group, randomised control trial (RCT) over 6 months. The primary objective is to assess whether the 6-month StayFitLonger programme leads to better performance than those observed following the active control condition on the Timed-Up & Go (TUG), a functional physical task, which is associated with lower-body strength and balance. The efficacy study also includes a few secondary objectives. One is to assess whether the StayFitLonger programme improves other physical capabilities as well as cognitive performances and scores of affective variables (e.g., mood, fear of falling), and psycho-social domains (e.g., quality of life, daily living activities, participant's expectation). In addition, the study will also assess whether a similar gain is found in robust vs pre-frail seniors.

In Switzerland, Canada and Belgium, a total of 128 older participants will be recruited. Following the initial eligibility screening, participants will be randomized to one of two home-based computerized intervention conditions, the StayFitLonger training program (experimental) or the active control training program . Enrolled participants will be evaluated at two time points: at baseline (T0) and after 6 months of training (T1, end of the RCT). The training will take place at home for 6 months. Prior to the start of the training and within a month following T0 assessment, introductory courses in groups of a maximum of 6 people will take place to introduce the features of the program and describe the different physical and cognitive exercises. Participants will be supervised through home visits and monthly phone calls to ensure a good use of the program in both groups.

Inclusion Criteria:

• Fluent french speaker adults
• Retired, living at home and having a wireless Internet connection in their house;
• Independent for all daily activities (optimal score to the 4-IADL);
• Open to the use of new technologies and electronic tablets;
• Interested in exercising to stay fit;
• Able to walk without a walking aid (e.g. wheelchair, sticks, walker, etc.);
• Available to commit themselves for the time period during which the study takes place;
• No vision deficits that would prevent them to read information on a tablet;
• No current neurological or psychiatric diagnosis (e.g. Parkinson's disease).

Exclusion Criteria:

• MoCA score < 26;
• score ≥ 3 on the Fried's frailty index (Fried et al., 2001)

Assessors are blind to the hypotheses and to participants' assignment as they only have access to the testing sessions. Participants are asked not to mention elements of their training program to assessors . Would such circumstance occur, it will be reported but this should have minimal effect on integrity as the assessors are blind to the hypotheses.

Team members responsible of the statistical analyses are blind to the training assignment as they only have access to anonymized data set and have no access to neither participants' assignment nor the randomization list.

At each study site, study coordinators and trainers responsible for the introductory and refresher courses, and supervision of participants during the home-based training are not blind.

Participants are aware that the trial has two different training conditions that are compared to each other and that they are randomly allocated to one of them. However, they are not informed of the study hypotheses.