Table 2 Study inclusion and exclusion criteria

• U.S. Military Veteran

• Age 60 to 80 years

• Nonsmoker of tobacco products

• Body Mass Index of 18.5 - 29.9 kg/m²

• Unstable angina

• Uncontrolled diabetes mellitus (HbA1C > 10)

• Allergic to lidocaine

• Problems walking or exercising with both legs

• Allergic to vaccination

• Metastatic cancer or undergoing chemotherapy

• Allergic to latex or tape

• Hernia that causes pain during physical activity

• Seizure in past 3 months

• Tetanus or TDAP vaccine in previous two years

• Smokes tobacco products

• Certain steroid or androgen use in past 3 months

• Other physician judgment

• Cerebral aneurysm or intracranial bleed in past year

• Systemic bacterial infection

• Unwilling to halt new use of nutritional supplements

• Active oral or genital herpes

• End-stage congestive heart failure (NYHA Stage IV)

• Bleeding or clotting disorders

• Unstable abdominal or thoracic aortic aneurysm (>4 cm)

• Encephalopathy in past 7 days

• Myocardial infarction or cardiac surgery in past 3 months

• Untreated severe aortic stenosis

• Pains, tightness, pressure in chest during physical activity

• Renal disease requiring dialysis

• Significantly abnormal blood tests (CBC or PT/PTT/INR)

• Uncontrolled asthma or allergies

• Bone fractures in the pelvis, legs, or feet in the last 3 months

• Significant problem with fainting

• Taking prescription anti-coagulants (that is, heparin, warfarin, etcetera)

• Current use of appetite stimulants

• Current treatment for mania or bipolar disorder or taking lithium

• History of peripheral artery disease

• Pulmonary embolism or deep venous thrombosis in past 3 months

• Active suicidality or suicidal ideation

• Taking lactulose, nitrates plus hypertension medications or Viagra

• Significant problems with chronic pain

• Uncontrolled hypertension or hypotension (>160/100, <100 systolic)

• Unwilling to maintain current normal diet

• Acute retinal hemorrhage or ophthalmologic surgery in past 3 months

• Diagnosis of a significant cognitive deficit

• Unwilling to halt concurrent use of amino acid or protein supplements

• Guillain-Barre Syndrome in past 3 months

• Proliferative diabetic retinopathy or severe nonproliferative retinopathy

• Uncontrolled malignant cardiac arrhythmia

• Participated in a weight-lifting program targeting the thighs in last 3 months

• Liver cirrhosis or other severe liver disease

• Currently participating in any other research study involving an intervention