The female South Korean astronaut Yi So-yeon may have been injured in Soyuz TMA-11 on April 19, 2008.
Yi So-yeon was hospitalized after her return to South Korea due to
injuries caused by the rough return voyage in the Soyuz TMA-11
spacecraft. The South Korean Science Ministry stated that the
astronaut had a minor injury to her neck muscles and had bruised her
Due to a malfunction with the Soyuz vehicle, the craft followed a
ballistic re-entry which subjects the crew to severe gravitational
forces up to 10 times the amount experienced on Earth.
Yi was hospitalized after her return to Korea due to severe back
pains. Though many believed these pains were the result of the
rough landing, they were in fact normal and expected. They were the
result of spinal re-compression.
Quotes from Wikipedia articles about Soyuz TMA-11 and Yi So-yeon.
So the back pain may have been caused by either the reentry or by the prior stay in weightlessness.