Sarcopenia assessment will be performed using the SARC-F questionnaire. The protocol includes five components: strength, assisted gait, rising from a chair, climbing stairs, and falls. The SARC-F items were selected to reflect changes in health status associated with the consequences of sarcopenia. SARC-F scale scores range from 0 to 10 (i.e., 0-2 points for each component; 0 = best to 10 = worst) and were dichotomized to represent symptomatic (4+) versus healthy (0-3) status. Additionally, a modified version of the instrument, the SARC-Calf (SARC-F + CP), which integrates an anthropometric measure into the traditional score, was employed.

The Back Scratch Test is part of the battery of physical fitness tests for older adults and is used to measure the flexibility and range of motion of the shoulder joint (scapular girdle). The test consists of placing one hand on the same shoulder and the other hand underneath, attempting to touch or overlap the middle fingers of both hands on the back. The distance between the fingers is measured, where positive values indicate overlap and negative values indicate the distance remaining for touch. Test scores are classified as: negative (-): If the fingers do not touch (distance between them); zero (0): If the fingers only touch; positive (+): If the fingers overlap.

The Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire is a validated self-administered instrument for assessing symptoms and functional capacity in individuals with musculoskeletal disorders of the upper limbs.

The questionnaire is validated for Brazilian Portuguese and consists of 30 items that assess an individual's ability to perform certain physical activities (21 items), the severity of symptoms such as pain, tingling, and weakness (5 items), and the impact of upper limb function on social life, work, sleep, and self-confidence (4 items). Each item is scored on a scale of 1 to 5. DASH score = ({Sum of responses}/{n} - 1 ) x 25. Where n is the number of questions answered. The score ranges from 0 to 100, where the higher the value, the greater the functional disability.

The instrument used to assess quality of life specifically in cases of breast cancer will be the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC-BR). The questions use a numerical scale from 0 to 100. On the functional scale of the EORTC-BR-23, higher scores indicate better quality of life and lower scores indicate worse quality of life. On the symptom scale of the EORTC-BR-23, higher scores indicate worse quality of life and lower scores indicate better quality of life.

The Barthel Index is a widely used instrument to assess the degree of functional independence of individuals in performing basic activities of daily living. Its score ranges from 0 to 100 points, distributed across ten dimensions that encompass tasks related to self-care and mobility. It is a validated measure for Portuguese, with evidence of reliability and clinical applicability in different contexts of functional assessment.

For flexibility assessment, the Schober test was used, which determines functional flexibility and is more specific to the lumbar region. It is a test with high specificity compared to the gold standard, radiography. However, it is a quick and low-cost test, widely used in clinical practice. The test evaluates lumbar movement restrictions through markings: on the lumbosacral joint (joining the posterior superior iliac spines) and 10 cm above; the distance between these markings is noted in an upright position. Immediately after, the subject performs a maximum trunk flexion (lower limbs extended), and the evaluator measures the new distance between the points with a measuring tape and records the difference between the marks based on the patient's best reach score in relation to the ground.

Measuring handgrip strength using a dynamometer is a simple, objective, practical, and easy-to-use procedure. Recommended by the American Society of Hand Therapists. The instruction is to perform a maximum contraction for 3 seconds in each test. A 30-second rest period is required between each test, and a 2-minute rest period is required between tests for each hand.

The 30-Second Chair Stand Test is widely used to assess lower limb strength and muscle endurance in clinical and elderly populations. The protocol requires the participant to stand from a chair and sit down as many times as possible within 30 seconds, without using their hands. Performance on this test is a strong predictor of functional autonomy and is directly related to screening for sarcopenia risk. Classification varies according to age and conditioning achieved during the test, defined as: Disability Risk: >8 repetitions for women are considered predictors of high risk of falls and loss of autonomy; Cutoff Point for Sarcopenia: >15 repetitions is an indicator of reduced muscle quality.

It will be measured using Bioelectrical Impedance Analysis (BIA), a widely used method that estimates muscle mass by measuring the body's resistance and reactance to the passage of a low-intensity electrical current, and is low-cost, easy to apply, and portable.

To assess self-esteem, the Portuguese version adapted and validated by Hutz of the Rosenberg Self-Esteem Scale will be used. The total score ranges from 10 to 40 points. Higher scores indicate better self-esteem and lower scores indicate worse self-esteem.

Anxiety and depression will be assessed using the Hospital Anxiety and Depression Scale (HADS) questionnaire. The total score ranges from 0 to 21 points. The cut-off points adopted will be: an anxiety score of 8 or higher; and a depression score of 9 or higher.