When working in space, astronauts lose bone and muscle from their legs, hips and lower backs due to reduced load-bearing. To put the bone loss in perspective, postmenopausal women who are untreated for bone loss can lose 1-1.5 percent of bone mass in the hip in one year while an astronaut in microgravity can lose the same amount of hip bone mass in a single month. Loss of musculoskeletal tissue mass and function can cause multiple problems for the crew during long-duration space missions, including reduction in physical performance, increased risk of fall-related injuries and accidents, and potentially, bone fractures.
The Musculoskeletal Alterations Team is studying the mechanisms involved in bone and muscle loss and whether reduced gravity increases the risk of bone breaks and impairs fracture healing. The Team is also researching radiation-induced bone loss. In addition to identifying ways to enhance the benefits of exercise during spaceflight for maintaining muscle and bone function, the Team is also investigating methods to prevent or reduce the loss through nutritional and pharmaceutical interventions to complement exercise.
The Team’s efforts will also have benefits on Earth for people with bone disorders, cancer patients and people who are immobilized due to injury or surgery.
Henry J. Donahue, Ph.D.
Virginia Commonwealth University
Associate Team Leader:
Charles H. Lang, Ph.D.
Pennsylvania State University
The Musculoskeletal Alterations Team is developing countermeasures to the negative effects of spaceflight on muscles and bones. Current in-flight exercise regimens, dietary and vitamin supplements, and pre-flight conditioning have not prevented bone loss during long-duration flights such as those on Russia’s Mir Space Station and the International Space Station.
Also, long-duration exposure to microgravity produces functional deficits in skeletal muscle. These include atrophy in the muscles of the lower extremities and losses in strength and power, a shift in appearance and contractile quality of muscle, and deficits in motor control and movement. All of these changes could lead to injury.
The Team’s anticipated deliverables for spaceflight include:
Maintaining bone health during spaceflight is a major goal for researchers. The efforts of the Musculoskeletal Alterations Team will have benefits for people on Earth with bone disorders or are incompacitated due to injury or illness and for people participating in exercise and training programs. The benefits of the Team’s research for Earth are: