The Impact of Beef on Muscle Fatigue in Older Adults

Inclusion Criteria * Ages 60-85 years * Ability to eat study diet meals for a total of 16 weeks * Ability to perform sit-to-stand chair and 6-minute walking tests based on results from PAR-Q questionnaire * Ability to provide fasted blood samples * Access to transportation * Willing to abstain from alcohol consumption and/or use illicit drug use for each 8-week intervention period * Ability to consent to participating in this study * English-speaking * Body mass index between 18.5 (normal) and 39.9 (obese) kg/m2 * Minimum total body weight of 110 pounds * Non-anemia hemoglobin values: Females - \>12.0 grams/dL; Men - \>13.0 grams/dL * Able to ambulate without assistance * Physician's clearance for study participation (required prior to baseline testing) Exclusion Criteria * Inability or refusal to sign the informed consent * Significant orthopedic limitations or other contraindications to exercise * Inability or refusal to perform muscle fatigue tests * Has dietary restrictions that prevent to consumption of beef, soy and/or wheat * Has liver or kidney complications * Live or work \>25 miles from Bloomington study site or does not have transportation to the study site * Anticipate elective surgery during the study period * Diagnosis of progressive neurological disorders, musculoskeletal disorders, osteoarthritis, rheumatoid arthritis * Fracture or serious injury in the last 6 months * Stroke, revascularization, deep vein thrombosis, or pulmonary embolism in the past 12 months * Severe cardiovascular disease, uncontrolled systemic hypertension, chronic pulmonary disease * Plan to move residence or travel out of the local area during the study period * Current use of anti-coagulants (e.g. Coumadin or Warfarin) * Current use of prescription medications that affect heart rate or blood vessel dilation * Psychological or social characteristics that would interfere with their ability to fully participate in the study