Barriers to Therapeutic Exercise in Breast Cancer Patients Before, During, and After Chemotherapy

It will be evaluated with the Spanish version of the self-reported Piper Fatigue Scale. It presents 22 items and includes four dimensions related to subjective fatigue (behavioral, affective, sensory and cognitive). Scores are between 0 and 10, the higher the total score the greater the disability (0 = no fatigue, 1-3 = mild fatigue, 4-6 = moderate fatigue, 7-10 = severe fatigue).

It will be evaluated by means of a scale (TANITA BC-351, Japan). It uses the different impedances of the conductive and isolated parts of the body, allowing to calculate the weight (Kq). Weight and height will be combined to report BMI in kg/m^2)

The hand grip strength test will be evaluated with a digital dynamometer (Jamar Plus+ digital hand dynamometer (Patterson Medical, Sammons Preston, Bolingbrook, IL, USA)). The patient will be placed in a seated position with the shoulder in adduction and neutral rotation, the elbow flexed at 90º and the forearm and wrist in neutral position. The maximum grip strength will be measured alternately three times on each arm, and the mean of the three measurements will be recorded.

It will be evaluated using the Disability of Arm, Shoulder and Hand (DASH) questionnaire. It is a scale of 30 items, of which 21 refer to the degree of difficulty in performing physical activities, 5 refer to the severity of some pain symptoms and 5 refer to other activities. The score ranges from 0 to 100 points, the higher the score the greater the disability.

It will be assessed by the 6-minute walk test (6MWT) on a treadmill. It determines the maximum distance a person can walk in 6 minutes. It will also include the 30 sec Sit to Stand test, which evaluates how many times the patient is able to stand and sit in a chair, with arms crossed over the chest, for 30 seconds.

This will be recorded by means of the International Physical Activity Questionnaire (IPAQ), which will allow patients to be divided according to their level of physical activity as high, moderate and low or inactive. Information on physical activity will also be collected by means of a physical activity diary, in which each patient will record the last seven days of physical activity, type of activity, intensity, duration and perceived level of fatigue.

The Self-Efficacy for Physical Activity Scale (EAF) will be used, which addresses patients' beliefs about their own abilities to perform physical activities. It allows the identification of barriers and limitations that prevent the patient from engaging in regular physical activity. It presents three domains (programmed physical exercise, physical activity in daily activities and walking), which include 39 items, scored from 0 to 10, with a higher score indicating a greater capacity to perform physical activity.

This will be assessed using the abbreviated version of the Minnesota Leisure Time Physical Activity Questionnaire (VREM). It is composed of 5 items, asking about the period of a typical week in which participants perform routine household activities, as well as activities performed during the last month (e.g. walking, stair climbing, sports, dancing etc.). Gastro-energy in METs/min is calculated and the patient is classified from sedentary to very active.

The Spanish version of the International Fitness Scale (IFIS) will be used, which measures general physical confidence, cardiorespiratory confidence, muscular strength, speed/agility and flexibility in comparison with the fitness level of a friend. It is scored on a Likert scale from very poor to very good.

It will be assessed using the Breast Specific Quality of Life Questionnaire by the European Organisation for Research and Treatment of Breast Cancer (EORT QLQ-BR23). It contains 23 items, rated on a four-point scale ranging from 1 (not at all) to 4 (very much), assessing treatment side effects, arm symptoms, body image symptoms and sexual function. Scores range from 0 to 100 points.

It will be evaluated by means of the Spanish version of the Mood Evaluation Scale (EVEA). This questionnaire evaluates mood through 16 items, scored from 0 to 10 and divided into four categories (sadness-depression, anxiety, danger-hostility and happiness).

It will be evaluated by means of the Spanish validation of the fear avoidance components scale (FACS-Sp). The questionnaire consists of 20 items evaluated on a 6-point Likert scale, where 0 indicates "strongly disagree" and 5 indicates "strongly agree". It has a maximum score of 100 points, with higher scores indicating more entrenched fear avoidance beliefs. Severity levels are classified as follows: subclinical (0-20), mild (21-40), moderate (41-60), severe (61-80) and extreme (81-100).

It will be assessed using the Hospital Anxiety and Depression Scale (HADS). It consists of 14 items with two subscales, seven items assess anxiety and seven assess depression. The score of each subscale ranges from 0 to 21 points and a cut-off point equal to or higher than 11 points has been established to consider anxiety and depression states.

Qualitative variables will be collected through a semi-structured interview based on an interview guide. The interview will include questions that seek to know if the person performs physical exercise in breast cancer patients before, in process or after chemotherapy treatment, and the barriers they perceive to exercise. The interviews will be audio-recorded with the permission of the interviewees.