This subproject is one of many research subprojects utilizing theresources provided by a Center grant funded by NIH/NCRR. The subproject andinvestigator (PI) may have received primary funding from another NIH source,and thus could be represented in other CRISP entries. The institution listed isfor the Center, which is not necessarily the institution for the investigator.Background: Nutritional intake and weight lifting exercise can both stimulate muscle growth. However, nutritional intake (such as regular meal) does not promote as much muscle growth in senior citizens as compared to younger individuals.Hypothesis: We hypothesize that an aquatic exercise training (combining both aerobic and weight lifting exercise) will maximize the muscle growth when combined with regular meal intake.
Specific Aims and Procedures (summary): 1) To determine which molecular markers involved in muscle growth are stimulated with nutritional intake in young and older volunteers. 2) To determine if a 12-week aquatic exercise training program (utilizing both aerobic and weight lifting exercises) will improve the muscle growth in response to a nutritional intake.Experimental Design (summary): Volulnteers will come to the GCRC the afternoon before the study. The nurses will measure their weight, height, blood pressure, and the nurses will draw blood to check again blood count, clotting, and some other blood tests including electrolytes (salts) and liver function. Should these tests result abnormal, volunteers will not be allowed to participate to the study. A DEXA scan will also be performed.Stable isotopes. After the catheters are placed, volunteers will be given stable isotopes (infusion) through one of the arm catheters. This infusion will go on until the end of the study, about 7 hours. In general, stable isotopes are of a material very similar to the regular material our body is made of, except that they are heavier (but not radioactive). Stable isotopes are natural compounds also present in very small quantities in your body. The isotopes are tested in order to assure their sterility (absence of microorganisms, such as bacteria, that may give infections and fever). We will then be able, using highly sophisticated analytical instruments, to measure the small changes in the concentration of these substances in your blood, breath, and muscle.Muscle biopsies. During the study we will take 4 muscles biopsies from the same leg in which we placed the catheters. This procedure involves the taking of a small piece of muscle from your leg. The skin is cleaned and made sterile, and the skin and tissue below are injected with local anesthetic (numbing medicine) to eliminate pain After the last biopsy the incision will be closed with one stitch or a special skin glue (Dermabond). Blood draws. The total amount of blood drawn during the study will be approximately 150 ml (approximately 5 ounces or 10 tablespoons).Nutritional Supplement. During the study you will drink a nutritional supplement that contains sugar and protein (amino acids) one hour prior to exercising or one hour after completing the weight lifting exercise. (3) Aquatic Exercise Training (senior volunteers)24-Hour food record. You will be asked to record your daily food intake in the form provided by us for three days during the same week (two week days and one weekend day) at the start of the training (1st week), during 4th, 8th, and last (12th) week of training. Dr. Inniss (research dietitian) will give you an instruction how to fill out the form.Aquatic Exercise Training. You will perform aquatic exercise (combination of aerobic and resistance exercise in the water) at the TideWay Aquatic Therapy Center (6444 Central City Blvd, Galveston TX 77551) instructed by certified trainers. You will be asked to attend three scheduled classes each week for 12 weeks consecutively. Each exercise session will be performed entirely in the water which lasts approximately for 45 minutes.(4) Infusion Study (Post-training) (senior volunteers)At least 48 hours after the last exercise session, you will be admitted at GCRC and whole body DEXA scan will be performed. After an overnight fast, you will perform another infusion study as described above in (2) Infusion Protocol.Significance (summary): These studies will provide regarding the mechanisms that regulate human muscle growth, and will be utilized as a basis from which to develop interventions for improving muscle growth in aging population.
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