Lean Muscle Function

Study Overview
=================
Brief Summary
-----------------
This pilot study is designed to determine the relationship between intra-myocellular lipids and muscle contractility in fibers from obese and non-obese older adults. Obese participants are being recruited for an on-going weight loss intervention study and this application seeks approval to recruit and enroll a lean comparison group of non-obese older adults. The primary goal of this study is to characterize the contractile properties of single muscle fibers and whole muscle in healthy, non-obese individuals under the same recording conditions the investigators used for the obese population to begin to determine whether fat infiltration accounts for diminished force.

Official Title
-----------------
Obesity and Muscle Function Pilot Study

Conditions
-----------------
Single Muscle Fibers

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age=65-75 years BMI=18-24 kg/m2 No resistance training for past 6 months Normal cognitive function (MMSE >24) No contraindications for participation in weight loss or weight lifting exercise including severe arthritis or musculoskeletal disorders, knee or hip replacement or spinal surgery in past year Able to provide own transportation to study visits Not involved in any other research study involving strength training or undergoing physical therapy Not dependent on a cane or walker Willing to provide informed consent Exclusion Criteria: Weight loss or gain (±5%) in past 6 months Body mass >136 kg (DXA limit) Current smoker (No nicotine within past year) or evidence of alcohol or drug abuse Insulin dependent or uncontrolled diabetes (FBG >140 mg/dL) Uncontrolled hypertension (BP>180/100 mmHg) Abnormal kidney function or liver blood tests Serious conduction disorder (e.g., 3rd degree heart block), uncontrolled arrhythmia, or new Q waves or ST-segment depressions (>2 mm) on ECG Past or current cardiovascular disease, including uncontrolled angina or dysrhythmia, hypertrophic cardiomyopathy, congestive heart failure, PAD, stroke, history of myocardial infarction, use of defibrillator or major heart surgery, or deep vein thrombosis or pulmonary embolus. These will be reviewed on a case by case basis. Past or current respiratory disease (requiring steroid treatment or supplemental oxygen) Past or current clinical diagnoses of neurological or hematological disease Use of any medications that could influence study variables (growth/steroid hormones, prescription anti-inflammatory medications, or beta blockers, Coumadin or any other blood thinner, including Plavix, Ticid, and Aggrenox) Cancer requiring treatment in past 2 years, except non-melanoma skin cancers Clinically evident edema or anemia

Ages Eligible for Study
-----------------
Minimum Age: 65 Years
Maximum Age: 75 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Lean<br>Comparison data from this lean cohort will be compared to the obese older adults are already being collected in an R01-funded study (Improving Muscle for Functional Independence Trial; IRB00009098; NCT01049698) | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Muscle Fiber | Primary Aim: To measure single muscle fiber contractile properties, including specific force, unloaded shortening velocity, and maximum power. We will also measure whole muscle strength and size and fiber fat infiltration. These results will establish a reference database against which data recorded in older obese individuals can be compared. Primary hypothesis: Single muscle fibers will exhibit more force and power in healthy non-obese than obese older adults due to greater intra-myocellular fat infiltration. | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Muscle Strength | Non-obese older adults will exhibit greater whole muscle strength (absolute and relative to muscle mass and volume) and power than obese, older adults. | Baseline |