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Astronauts may have no trouble moving heavy objects in the weightlessness of space, but that doesn’t mean that the experience isn’t hard on their backs. Astronauts on long-duration spaceflights routinely report back pain, both during and after the flight. Now doctors think they know what’s causing this.
In a new study, researchers used magnetic resonance imaging (MRI) scans to observe the spines of six NASA astronauts before they landed, at the time of landing and about two months after they had spent upward of seven months on the International Space Station. The researchers found that the prolonged exposure to weightlessness weakened the muscles supporting the astronauts’ spines.
The discovery runs counter to the theory that the astronauts’ back pain is caused by the swelling of their spinal disks, the shock-absorbing cushions between the vertebrae, the researchers said.