Single Muscle Fibers
Conditions
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.
Interventions
None listed
Sponsors
Wake Forest University
Study design
Observational model
CASE_CONTROL
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
65 Years to 75 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Muscle Fiber | Baseline | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Muscle Strength | Baseline | Non-obese older adults will exhibit greater whole muscle strength (absolute and relative to muscle mass and volume) and power than obese, older adults. |
Countries
United States
Outcome results
None listed