Inclusion Criteria:  Patients over 69 years of age. Hospitalization for a medical cause in Acute Geriatric Units. Holden's Functional Ambulation Classification Scale at level 1 or higher. Informed consent signed by the patient or legal representative.  Exclusion Criteria:  Terminal condition or life expectancy of less than 6 months. Impossibility or refusal to undergo muscle ultrasound. Refusal for follow-up Severe dementia stage Global Deteriorating Scale: 7 Impossibility in the opinion of the investigators to complete the necessary data for the study.