Electrical Stimulation of Human Myocytes in Microgravity

A biopsy of the Vastus Lateralis muscle will be performed on the left leg using the Bergstrom technique.The skin will be incised (approximately 0.75 cm) with a #11 scalpel, and the Bergstrom needle will be inserted into the Vastus Lateralis. Approximately 150 mg of muscle tissue will be obtained under suction. After the biopsy, pressure will be applied to stop bleeding and the skin will be closed with Steri strips (suture(s) if allergy to steri strips and removal 7-10 days post biopsy). A sterile dressing will be applied. Ace bandage may also be used along with applied pressure and an ice pack for any swelling and pain relief.

Aerobic fitness will be determined by measuring maximal O2 consumption (VO2max) during a stationary bicycle exercise test. Heart rate, blood pressure and ECG will be recorded throughout this test. Subjects will breathe through a low resistance mouthpiece and wear a nose clip. Expired gases will be measured by indirect calorimetry and heart rate monitored by a portable heart rate monitor. Following a standardized warm up, subjects will begin exercising at a moderate intensity with the workload increased every minute until the subject can no longer continue. A leveling-off (plateau) or decline in oxygen uptake should be demonstrated in order to be reasonably sure that a subject has achieved the maximum capacity for aerobic metabolism.