Involvement of Muscle Mitochondrial Dysfunction in Frailty in Older Adults. Role of Exercise

Inclusion Criteria: * Inclusion criteria for young controls * Healthy young adults (18-35 years old) * Without any pathology or treatment * Inclusion criteria for older controls * Healthy older adults (65 years or older) * Not currently enrolled in a resistance training program * Inclusion criteria for cases * Age over 65 years * Diagnosis of frailty or robustness * Diagnosis of type 2 diabetes mellitus * Glycosylated hemoglobin (HbA1c) less than 9% * Treatment with metformin * Not currently enrolled in a resistance training program Exclusion Criteria: * Exclusion criteria for young controls * Pregnancy or suspected pregnancy * Body mass index greater than 35 kg/m2 * Treatment within the last 30 days with oral corticosteroids * Edema or severe fluid regulation disorders that could alter bioimpedance results * Allergy to the local anesthetic mepivacaine * Prostheses, metal implants, or surgical staples lodinated or barium contrast for other imaging tests within the last 7 days * Exclusion criteria for older controls * Decompensated and uncontrolled chronic diagnoses * Body mass index greater than 35 kg/m2 * Treatment within the last 30 days with oral corticosteroids * Systemic diseases, active oncological disease, liver cirrhosis, untreated hypothyroidism, or severe chronic obstructive pulmonary disease (COPD). * Severe edema or fluid regulation disorders that could alter bioimpedance results * Allergy to the local anesthetic mepivacaine * Prostheses, metal implants, or surgical staples Iodinated or barium contrast for other imaging tests in the last 7 days * Exclusion criteria for cases * Diagnosis of pre-frailty * Age over 80 years * Body mass index greater than 35 kg/m2 * Time since onset of diabetes mellitus type 2 less than 10 years * Treatment with insulin * Treatment with allopurinol * Treatment with anticoagulant or antiplatelet drugs * Treatment within the last 30 days with oral corticosteroids * Advanced chronic complications of diabetes mellitus type 2 : Renal failure (clearance \<30 ml/min/m2) Macroalbuminuria greater than 200 mg/g Ischemic vascular diseases (acute myocardial infarction) Myocardial infarction, angina, stroke) Proliferative retinopathy or laser therapy Ulcerated diabetic foot or lower limb amputations, except for digital amputations * Systemic diseases, active oncological disease, liver cirrhosis, untreated hypothyroidism, or severe chronic obstructive pulmonary disease * Physical limitations in the lower limbs (acute or acute-on-chronic inflammatory processes, limited joint range of motion, chronic pain (visual analogue scale for pain \> or = 4, etc.) * Senile dementia * Edema or severe fluid regulation disorders that may alter bioimpedance results * Allergy to the local anesthetic mepivacaine * Pacemaker, metallic prostheses or implants, surgical staples, and radiopaque tubes or catheters Iodinated or barium contrast for other imaging tests within the last 7 days