Resistance Exercise Training in the Older Population With Obesity

Background:

Aging leads to an alteration in the immune response, characterized by a chronic inflammatory state, and a progressive decrease in muscle quantity and quality, a situation that increases in women and in the presence of obesity. With respect to muscle quality, intramuscular infiltration of adipose tissue has been considered a relevant parameter, involved in the relationship between aging-obesity-inflammation. As a therapeutic strategy, physical training with resistance exercises (or also known as strength training) has been shown to be effective in increasing skeletal muscle mass in this age group. However, its role on muscle quality in normal-weight versus obese older women has not been fully addressed.

Hypothesis:

A 12-week resistance exercise training program is effective in improving muscle quality, immune response and physical performance in normal weight and obese older women. In addition to the above, the investigators hypothesize that women with obesity will present greater baseline alterations, so the percentage of change will be higher compared to older women with normal weight after the training program.

Goals:

The primary aim of this study is evaluate the effects of a 12-week resistance exercise training on muscle quality (infiltration of intramuscular adipose tissue), immune response and physical performance in older women between 60 and 79 years of age with obesity compared to older women with normal weight of the same age range.

Specific goals:

To evaluate the effects of a 12-week resistance exercise training program in elderly women between 60 and 79 years of age with obesity, in comparison to older people with normal weight of the same age range on parameters of:

* Muscle architecture (muscle thickness, pennation angle and fascicle length) and muscle quality functionalities (power and strength). * Immune response through inflammatory cytokines: Tumor necrosis factor a (TNFa) interleukin-1 (IL-1), IL-6, IL-8 and induction of neutrophil extracellular traps (NETosis). * Physical performance (SPPB), Body composition (BIA) and quality of life (SF-36).

Methodology:

The present clinical trial will consider 2 study 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.

Study parameters/endpoints

* The main study endpoint is the decrease in echointensity as a marker of muscle quality, evaluated through ultrasonography in the quadriceps muscles of the lower limbs of participants subjected to 12 weeks of resistance training. * Secondary endpoints include: Muscle architecture parameter (morphological aspects of muscle quality); muscle thickness, pennation angle and fascicle length; Functional parameters of muscle quality, maximum voluntary isometric strength of knee extensors and lower limb power; Immune response in blood (TNFa, IL-1, IL-6, IL-8 and NETosis); Physical performance (SPPB), evaluation of maximum strength (1RM) and handgrip strength; Body composition (fat mass and total muscle mass and for each lower limb) and anthropometry (waist - hip, thigh and calf circumference, leg length and knee height); And Level of physical activity (IPAQ) and Quality of Life (SF-36). * Other study parameters include: Age, body weight, body height, body mass index (BMI), lipid profile, glucose, insulin, HOMA index, blood pressure, heart rate and perception of effort using the Borg scale.

Expected results:

The effect of resistance exercise training on muscle quality in normal-weight versus obese older women is still unclear. The present research project aims to demonstrate the effectiveness of this training modality in improving muscle quality parameters, as well as measures of immune response and physical performance in older women. However, the investigators believe that the impact will be greater in women with obesity, as they present greater baseline alterations compared to older normal weight women. The possible findings will define the scientific-practical foundations for the prescription of physical training in older women with obesity.

• Change in muscle thickness (measured via ultrasonography) after prolonged resistance-type exercise training [Time frame: Before, and after 12 weeks of training]
• Change in pennation angle (measured via ultrasonography) after prolonged resistance-type exercise training [Time frame: Before, and after 12 weeks of training]
• Change in fascicle length (measured via ultrasonography) after prolonged resistance-type exercise training [Time frame: Before, and after 12 weeks of training]
• Change in physical performance (measured via Short physical performance battery (SPPB)) after prolonged resistance-type exercise training [Time frame: Before, and after 12 weeks of training]
• Change in arms and legs strength (measured via 1-Repetition Maximum (1RM) testing) after prolonged resistance-type exercise training [Time frame: Before, and after 12 weeks of training]
• Change in hand grip strength (measured via JAMAR(R) handheld dynamometer) after prolonged resistance-type exercise training [Time frame: Before, and after 12 weeks of training]
• Change in maximum voluntary isometric strength (measured via Force transducer) after prolonged resistance-type exercise training. [Time frame: Before, and after 12 weeks of training]
• Change in muscle power of the lower limbs (measured via Five Times Sit to Stand test) after prolonged resistance-type exercise training. [Time frame: Before, and after 12 weeks of training]
• Change in Immune response in blood (measured via flow cytometry) after prolonged resistance-type exercise training. [Time frame: Before, and after 12 weeks of training]
• Change in NETosis in blood (measured via IncuCyte) after prolonged resistance-type exercise training. [Time frame: Before, and after 12 weeks of training]
• Change in Whole body lean mass (measured via Bioimpedance) after prolonged resistance-type exercise training. [Time frame: Before, and after 12 weeks of training]
• Change in Whole body fat mass (measured via Bioimpedance) after prolonged resistance-type exercise training. [Time frame: Before, and after 12 weeks of training]