The present clinical trial will consider 2 groups of older women between 60 and 79 years old: normal weight (BMI=18.5 to 24.9 kg/m 2 and % fat \<25.9) and obese (BMI =30 to 39.9 Kg/m 2 and fat % \>32). Participants will perform 12 weeks of training with resistance exercises 3 times a week. Before and after training, intramuscular infiltration of adipose tissue (echogenicity) will be measured by ultrasound, followed by aspects of muscle architecture (muscle thickness, penile angle and fascicle length) and functional parameters of muscle quality (maximum strength determined by 1 repetition maximum-1RM, maximum voluntary isometric strength of knee extensors through a lower limb force and power transducer). Finally, fasting blood samples will be obtained (immune response) and physical performance, body composition, physical activity level, and quality of life will be evaluated. conditions: Aging conditions: Obesity studyType: INTERVENTIONAL phases: NA allocation: NON_RANDOMIZED interventionModel: PARALLEL primaryPurpose: SCREENING masking: SINGLE whoMasked: OUTCOMES_ASSESSOR count: 32 type: ESTIMATED name: Prolonged resistance exercise training measure: Change in intermuscular adipose tissue (measured via ultrasonography) after prolonged resistance-type exercise training measure: Change in muscle thickness (measured via ultrasonography) after prolonged resistance-type exercise training measure: Change in pennation angle (measured via ultrasonography) after prolonged resistance-type exercise training measure: Change in fascicle length (measured via ultrasonography) after prolonged resistance-type exercise training measure: Change in physical performance (measured via Short physical performance battery (SPPB)) after prolonged resistance-type exercise training measure: Change in arms and legs strength (measured via 1-Repetition Maximum (1RM) testing) after prolonged resistance-type exercise training measure: Change in hand grip strength (measured via JAMAR(R) handheld dynamometer) after prolonged resistance-type exercise training measure: Change in maximum voluntary isometric strength (measured via Force transducer) after prolonged resistance-type exercise training. measure: Change in muscle power of the lower limbs (measured via Five Times Sit to Stand test) after prolonged resistance-type exercise training. measure: Change in Immune response in blood (measured via flow cytometry) after prolonged resistance-type exercise training. measure: Change in NETosis in blood (measured via IncuCyte) after prolonged resistance-type exercise training. measure: Change in Whole body lean mass (measured via Bioimpedance) after prolonged resistance-type exercise training. measure: Change in Whole body fat mass (measured via Bioimpedance) after prolonged resistance-type exercise training. measure: Change in Physical activity level (measured via IPAQ short version) after prolonged resistance-type exercise training. measure: Change in Quality of Life level (measured via SF-36) after prolonged resistance-type exercise training. sex: FEMALE minimumAge: 60 Years maximumAge: 79 Years stdAges: ADULT stdAges: OLDER_ADULT facility: Universidad de La Frontera city: Temuco state: IX Región De La Araucanía zip: 4780000 country: Chile name: Nicolás Vidal-Seguel, MSc role: CONTACT phone: 998595445 email: nicolasenrique.vidal@ufrontera.cl name: GABRIEL MARZUCA, MSc, PhD role: CONTACT phone: 996343630 email: gabriel.marzuca@ufrontera.cl lat: -38.73965 lon: -72.59842 hasResults: False