Clinical Research Directory

Inclusion Criteria: * Women aged 60 to 80 years * User of the Casa Club de la Tercera Edad, DIF Tulancingo, Hidalgo, Mexico * Short Physical Performance Battery (SPPB) score of 7 to 12 points, corresponding to Vivifrail exercise passport C (pre-frailty, 7-9 points) or D (robustness, 10-12 points) * Montreal Cognitive Assessment, Mexican Spanish version (MoCA-E), score of 24 or higher * Women with type 2 diabetes or hypertension may participate only if under treatment and controlled * Signed informed consent Exclusion Criteria: * Osteoarticular disease of the spine or limbs that contraindicates or prevents exercise (e.g., active rheumatoid arthritis) * Heart failure or decompensated heart disease, or any medical contraindication to physical exercise * Renal or hepatic failure * Advanced cancer or cancer under active treatment * Cognitive impairment preventing understanding of instructions, informed consent or test performance (MoCA-E score below 24 points) * Pacemaker or other implanted electronic device (contraindication for bioelectrical impedance) * Clinically visible edema (interferes with bioelectrical impedance) * Use of HMB, leucine, protein powder, creatine or other anabolic or ergogenic supplements in the 6 weeks before study start (washout period) * Use of drugs affecting muscle mass or function (e.g., systemic corticosteroids or androgen therapy) * Known allergy or intolerance to the components of the HMB supplement or the placebo (maltodextrin) * Limb amputation or any condition preventing anthropometric or functional measurements * Uncontrolled type 2 diabetes or hypertension, defined as urgent care or hospitalization for these conditions in the previous 3 months * Current participation in a structured strength (resistance) training program outside the study