Gravitation / Electrophysiology / Humans / Aerospace Medicine / Microgravity / Male / Arm / Electromyography / Medical Physiology / Gravitational force / Bending / Posture / Flight / Middle Aged / Adult / Public health systems and services research / Videotape Recording / Muscle contraction / Aviation and Space History / Male / Arm / Electromyography / Medical Physiology / Gravitational force / Bending / Posture / Flight / Middle Aged / Adult / Public health systems and services research / Videotape Recording / Muscle contraction / Aviation and Space History