The OTAGO Exercise Program is a structured, evidence-based intervention developed to improve lower-limb strength and balance and reduce fall risk in older adults. In this study, participants in the control group will complete three non-consecutive, supervised sessions per week for a total duration of 14 weeks. Sessions will be delivered in group settings under the supervision of a licensed physiotherapist. The program includes individualized strength training for the lower extremities, progressive balance exercises, and walking routines. Although originally designed as a home-based program, in this trial it will be implemented in indoor, climate-controlled, non-slip-floor facilities provided by local institutions. The OTAGO protocol does not include recreational, cognitive, or playful components, serving instead as a standard, structured intervention against which the FEXO program will be compared.

Resting heart rate (beats per minute) will be assessed at all three time points using an automated sphygmomanometer, following the European Society of Hypertension guidelines. A reduction or maintenance within normal ranges (60-80 bpm) is considered a favorable outcome, whereas elevated resting heart rate (>80 bpm) or increases across assessments are considered unfavorable.

Frailty status will be assessed using Fried's phenotype, which classifies participants as robust (0 criteria), pre-frail (1-2 criteria), or frail (3-5 criteria) based on five components: unintentional weight loss, exhaustion, low physical activity, slow gait speed, and weak grip strength. Improvement is defined as transition to a lower frailty category (e.g., from frail to pre-frail).

Grip strength will be measured using a JAMAR hand dynamometer, with participants seated, the elbow at 90°, forearm in a neutral position, and wrist slightly extended. The best of three trials is recorded in kilograms. Grip strength is a core indicator of sarcopenia and a strong predictor of functional decline, morbidity, and mortality. Higher values reflect better upper-limb muscle strength.

Participants will perform two walking trials over 10 meters: one at habitual pace and one at maximum pace. The time to walk the central 6-meter portion is recorded and converted into meters per second (m/s). Gait speed is a validated marker of frailty, physical function, and fall risk. Higher walking speeds reflect better functional status.

The MMSE evaluates general cognitive status through domains including orientation, memory, attention, language, and visuospatial skills. It yields a score from 0 to 30, with higher scores indicating better cognitive function. It is widely used for screening and monitoring cognitive impairment in older adults.

The MNA is a validated tool for detecting malnutrition or risk of malnutrition in older adults. It includes 18 items covering anthropometry, general health, dietary intake, and subjective assessment. Total scores range from 0 to 30: scores ≥24 indicate normal nutrition, 17-23.5 suggest risk of malnutrition, and <17 indicate malnutrition. Higher scores reflect better nutritional status.

The Geriatric Depression Scale short form (15 items) will be used to screen for depressive symptoms in participants. Responses are binary (yes/no), and total scores range from 0 to 15. A score of 0 indicates no depressive symptoms (best psychological well-being), while 15 indicates the maximum level of depressive symptoms. Scores >5 may indicate clinical depression.

This 14-item scale assesses balance and postural control in older adults. Each task (e.g., standing, reaching, turning) is scored from 0 (unable) to 4 (independent), with a total score ranging from 0 to 56. Scores below 45 suggest increased fall risk. Higher scores reflect better balance.

The Five-Times Sit-to-Stand test evaluates lower-limb strength and endurance. The time in seconds to complete five sit-to-stand repetitions without arm support is measured. Shorter times reflect better muscle function and physical performance.

The standard Timed Up and Go (TUG) test is a widely used functional assessment that measures basic mobility and dynamic balance. Participants are instructed to stand up from a standard-height chair, walk a distance of 3 meters, turn around, return to the chair, and sit down. The total time required to complete the task is recorded in seconds. Shorter times indicate better functional mobility and lower risk of falls.

This test measures visual attention, processing speed, and cognitive flexibility. Participants are instructed to connect a sequence of numbers as quickly as possible, with total time recorded. Shorter completion times reflect better cognitive performance.

The MoCA is a comprehensive screening tool for mild cognitive impairment, evaluating domains such as executive function, memory, attention, visuospatial ability, and orientation. The score ranges from 0 to 30. Higher scores reflect better overall cognitive function.

The Physical Resilience Instrument for Older Adults (PRIFOR) is a validated 16-item questionnaire designed to assess an individual's capacity to recover and adapt following physical stressors such as illness, injury, or functional decline. It evaluates both internal and external resilience factors across four domains: physical strength and energy, emotional and mental coping ability, perceived control and adaptability, and support from social and healthcare systems. Each item is rated on a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree), producing a total score ranging from 16 to 80. Higher scores reflect greater physical resilience, indicating a stronger ability to maintain or regain function in the face of health challenges.

The TUG-M is a dual-task version of the standard TUG in which participants are asked to perform the same sequence while carrying a cup of water with one hand. This variant assesses functional mobility under motor interference and challenges postural control and attention. Time to complete the task is recorded in seconds. Lower times reflect better motor coordination and dual-task performance, indicating greater safety during daily life activities.

The TUG-C assesses functional mobility under cognitive load. Participants complete the standard TUG task while simultaneously performing a cognitive task, such as counting backwards or solving a simple mental calculation (e.g., subtracting by threes). This version evaluates the impact of divided attention on mobility and fall risk. Faster times suggest better cognitive-motor integration and executive function.

The Cornell Scale for Depression in Dementia (CSDD) will be used to assess depressive symptoms in participants with or without cognitive impairment. The scale consists of 19 items covering mood-related signs, behavioral disturbances, physical signs, cyclic functions, and ideational disturbances. Each item is rated from 0 to 2 (0 = absent, 1 = mild or intermittent, 2 = severe), based on interviews with both the patient and an informant. Total scores range from 0 to 38, with higher scores indicating more severe depressive symptoms. Scores above 10 suggest probable major depression, while scores above 18 are highly indicative of a depressive disorder. Lower scores represent better psychological well-being.

Self-reported vision will be assessed through a single-item question asking participants to rate their visual ability. Responses are scored as follows: 0 = severe difficulty or complete blindness, 0.5 = mild to moderate difficulty, and 1 = no difficulty. Higher scores indicate better sensory function.

Self-reported hearing will be assessed through a single-item question asking participants to rate their hearing ability. Responses are scored as follows: 0 = severe difficulty or complete deafness, 0.5 = mild to moderate difficulty, and 1 = no difficulty. Higher scores indicate better sensory function.