The primary objective is to evaluate the effectiveness of combining action observation with a therapeutic exercise program to improve balance and prevent falls in adults aged ≥65 with low to moderate fall risk.

Background: Action observation activates brain networks involved in motor learning and has shown benefits in neurological and musculoskeletal populations (improvement of balance, gait, and pain). However, evidence in older adults at risk of falls and the role of the observed model remain underexplored. Objectives: The primary objective is to evaluate the effectiveness of combining action observation with a therapeutic exercise program to improve balance and prevent falls in adults aged ≥65 with low to moderate fall risk. Secondary objectives include comparing efficacy according to the observed model, and analyzing effects on strength, fear of falling, adherence, and fall incidence. Methods: A single-blind, randomized clinical trial of 24 weeks (12 intervention, 12 follow-up) is planned. A total of 93 participants will be allocated to 3 groups: exercise, exercise with action observation of a standard model, and exercise with action observation of a self-selected model. The intervention (therapeutic exercise program and/or action observation of the same program) will be delivered three times per week with biweekly progressions. The primary outcome will be balance (static balance measured by sway area on force platform and dynamic balance assessed by Timed Up and Go test). Secondary outcomes will include handgrip and lower limb strength, fear of falling, adherence, and fall incidence. Assessments will be conducted at weeks 0, 6, 12, and 24. Both ITT and per-protocol analyses will be performed, with intra- and inter-group comparisons (p<0.05). Discussion: If effective, this low-cost, low-technology program could be easily scaled up in primary care and community settings, with potential impact on public health and physiotherapy. Applicability may also extend to neurorehabilitation and secondary prevention in frailty. Anticipated limitations: adherence, partial blinding, and external validity limited to community-dwelling older adults. Implications: development of concise practice guidelines, standardized audiovisual materials, and future research in clinical populations.

Inclusion Criteria:

• Individuals over 65 years of age with low or moderate risk of falls as measured by the Timed Up and Go test, who have voluntarily signed the informed consent form and are willing to follow the protocol proposed by the research team.

Exclusion Criteria:

• Presence of uncorrected visual impairments preventing screen observation; diagnosis of a condition that makes adherence to the protocol impossible (cognitive, oncological, psychiatric, psychological, vestibular, neurological, etc.); presence of a musculoskeletal injury at the time of selection and/or prior participation in studies involving movement representation methods.

Withdrawal criteria: Lack of participant compliance, defined as failure to complete at least 80% of the intervention sessions and assessments.

The study was conducted using a single-blind design. The researchers responsible for recruitment and assessments were unaware of each participant's intervention group, which helped reduce detection bias. Data analysis will be performed by an external researcher. The principal investigator will manage the study documentation, informed consent process, and randomization.

Double blinding was not possible because the intervention involved a physical exercise program, meaning that participants were aware that they were taking part in an intervention. To minimize potential bias, study roles were clearly separated: one researcher delivered the intervention; another conducted the balance assessments; another assessed individual characteristics and strength; and another supported the recording of fall-related incidents. No information was exchanged between researchers in order to prevent data crossover.