Effectiveness of a Physical Exercise Prescription Program in Primary Care for Adults Aged 65 and Older: PREFIS-AP

Quality of Life will be measured by the SF-36 questionnaire. The SF-36 questionnaire is a widely used, patient-reported questionnaire measuring health-related quality of life. It uses points to assess health, with responses on Likert scales (e.g., 0 to 100) transformed into scores for 8 health domains: physical functioning, role limitations (physical/emotional), bodily pain, general health, vitality, social functioning, and mental health, where higher scores mean better health, ranging from 0 (maximum disability) to 100 (no disability).

Change in physical activity level as measured by the Global Physical Activity Questionnaire (GPAQ), including time spent in work-related activity, transport-related activity, leisure-time activity, and sedentary behavior. Participants will be classified into WHO categories (high, moderate, or low/inactive) based on standardized scoring procedures.

Change in functional aerobic capacity assessed by the 6-minute walk test (6MWT). The primary variable will be the total distance walked in meters during 6 minutes. Physiological responses (heart rate, oxygen saturation, perceived exertion using Borg scale) will also be recorded.

Change in maximal isometric handgrip strength measured with a JAMAR dynamometer (kg), using the highest value from standardized bilateral measurements. Cut-off values will follow European sarcopenia consensus criteria (<27 kg for men; <16 kg for women).

Change in lower-limb functional strength measured by the 30-second chair stand test. The outcome is the total number of complete sit-to-stand repetitions performed within 30 seconds following standardized protocol.

Change in muscle mass estimated by calf circumference (cm), measured at the widest point of the calf using a flexible tape. A value <31 cm will be considered indicative of potential muscle mass deficit.

Change in quantitative and qualitative muscle parameters assessed by ultrasound of the rectus femoris (muscle thickness, cross-sectional area, and echogenicity), following validated measurement criteria for sarcopenia assessment.

This outcome will assess whether biological sex modifies the effect of the intervention on functional and health-related outcomes. Sex-specific differences will be evaluated using standardized change scores (z-scores).

The standardized composite score will be derived from the following previously defined outcome measures:

Muscle strength (handgrip dynamometry (kg) and the 30-second chair stand test) Aerobic capacity (6-minute walk test) Muscle mass, assessed by calf circumference (cm) and ultrasound measurements of rectus femoris muscle thickness Physical activity level, (Global Physical Activity Questionnaire (GPAQ) Health-related quality of life (SF-36 questionnaire) Each variable will be standardized before aggregation to ensure comparability across different units of measurement. The resulting composite score will be compared between men and women to determine if sex influences the magnitude of response to the exercise prescription program.

This outcome will assess the correlation between baseline medication burden and change in muscle strength in older adults from baseline to 3 months.

Medication burden will be defined as the total number of chronic medications taken at baseline (unit: number of medications).

Muscle strength will be assessed by handgrip strength, measured in kilograms (kg) using a calibrated hand dynamometer. Change in handgrip strength will be calculated as the difference between baseline and 3-month values.

This outcome will assess the correlation between baseline medication burden and change in muscle mass in older adults from baseline to 3 months.

Medication burden will be defined as the total number of chronic medications taken at baseline (unit: number of medications).

Muscle mass will be assessed as appendicular skeletal muscle mass, measured in kilograms (kg) using dual-energy X-ray absorptiometry (DXA). Change in muscle mass will be calculated as the difference between baseline and 3-month values.

This outcome will assess the correlation between baseline medication burden and change in physical performance in older adults from baseline to 3 months.

Medication burden will be defined as the total number of chronic medications taken at baseline (unit: number of medications).

Physical performance will be assessed using the Short Physical Performance Battery (SPPB), reported as a total score (points on a standardized scale). Change in SPPB score will be calculated as the difference between baseline and 3-month values.

This outcome will assess the correlation between baseline medication burden and change in quality of life in older adults from baseline to 3 months.

Medication burden will be defined as the total number of chronic medications taken at baseline (unit: number of medications).

Quality of life will be assessed using the EuroQol-5 Dimension (EQ-5D) questionnaire, reported as a standardized index score. Change in EQ-5D score will be calculated as the difference between baseline and 3-month values.