There are many bodily risks associated with the high-performance environment of military aviation and spaceflight. With the advent of faster jet aircraft and rocket engines, the risk for injury to aircrew from hypoxia, g-loading, vibration and poor posture for extended periods of time has increased. As a result of the microgravity environment of space, there are significant orthopedic changes in humans. Specifically, the excessive osteoclast activity producing bone demineralization, and muscle atrophy in load-bearing regions of the body, are of greatest concern.
Lumbar back pain and skeletal muscle wasting can be decreased, but not completely prevented, with resistive exercise. Cervical pain after flight can be substantially diminished with a specific program of physical therapy. Musculoskeletal pain in the cervical region can be mitigated in aviators and astronauts with specific stretching and resistive exercise that targets the neck and shoulder muscles. Bone loss can be decreased with pharmaceutical and nutritional interventions, as a compliment to resistive exercise. However, neither exercise, nor specific nutrient consumption alone, are sufficient to completely prevent the negative impacts that these extreme environments can bring; but they can work synergistically and thus decrease the amount of loss.