Effects of a Resistance Physical Exercise Program in Multiple Myeloma Patients

Health related quality of life

The primary outcome measure will be health related quality of life. Quality of life will be assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ). Specifically, the EORTC QLQ-C30 will be used, which is widely used to assess quality of life in cancer patients \[X\]. This instrument consists of 30 items, 24 of which are grouped into five functional domains: physical, role, emotional, cognitive, and social. It also includes three symptom scales-fatigue, pain, and nausea/vomiting-and an overall health status scale. Six other items assess additional symptoms such as dyspnoea, loss of appetite, insomnia, constipation, diarrhoea, and financial difficulties. Responses are recorded on a four-point scale ('none,' 'a little,' 'quite a bit,' 'a lot'), except for the general health and quality of life scales, which use a seven-point format. On the functional and overall health scales, higher scores indicate better health, while on the

Frailty

Frailty will be assessed using the Short Physical Performance Battery (SPPB) scale \[X\], which comprises three components: a balance test, a gait speed test, and a chair rise test. The maximum possible score is 12 points, with higher scores reflecting a better level of physical function.

Anxiety and depression

The presence of anxiety and depression will be assessed using the Hospital Anxiety and Depression Scale (HADS), a validated questionnaire widely used in different populations \[X\]. The scale consists of 14 items: seven corresponding to the anxiety subscale (HADS-A) and seven to the depression subscale (HADS-D). Each item is scored from 0 to 3, with separate scores obtained for both emotional dimensions.

Fatigue

Fatigue will be measured using the Functional Assessment of Cancer Therapy-Fatigue (FACT-F) subscale \[X\], a self-reported instrument designed to assess the severity of fatigue in cancer patients \[X,X\]. This widely used tool combines the 27 items of the FACT-General with 13 additional fatigue-specific items, generating a total score range between 0 and 160. Higher scores indicate lower perceived fatigue levels.

Sleep quality

Sleep quality will be assessed using the Athens Insomnia Scale (AIS), an eight-item self-administered scale developed by Soldatos \[X\] and validated for use in the Spanish population \[X\]. The first five items assess sleep disturbances-sleep onset, night-time awakenings, early awakening, total sleep duration, and overall quality-corresponding to criterion 'A' for the diagnosis of insomnia according to the ICD-10 classification. The remaining three items assess daytime consequences (well-being, physical and mental functioning, and daytime sleepiness), aligned with criterion 'C' of the same classification. Each item is scored on a Likert scale from 0 ('no problem') to 3 ('significant problem'), yielding a total range of 0 to 24. Higher scores indicate greater sleep disturbance, and values equal to or greater than 6 are considered indicative of clinically relevant insomnia \[X\].