Officeworkers who rarely exercise are at increased risk of back injuries, according to UQ researchers working on a European Space Agency study.

The researchers participated in the Agency's Berlin Bed-Rest Study, monitoring 20 healthy, young men who spent 56 days lying in bed.

Lead researcher Dr Daniel Belavy said prolonged inactivity shrunk the deep muscles that protected the mens' backs.

He said that in some cases it took six months to recover but even then the muscles did not return to their normal size.

Dr Belavy said surface muscles closer to the skin, stomach and back became overactive, a condition which persisted for up to a year after returning to normal activity levels.

“If you sit around too much long-term, such as a desk job with no sport in your spare time, the muscles can slowly change in a bad way, giving you a bigger risk of hurting your back,” Dr Belavy said.

He said short-term inactivity such as sitting at a desk for a couple of hours was not a major risk.

But a long-term habit of driving to work, working a desk job, going home watching TV and then going to bed would increase the chances of back problems.

Targeting inactivity could also be used in intervention and rehabilitation programs to decrease low back pain and future health care costs.

“I make sure my workspace is well set up so that I can sit with good posture and concentrate on sitting well,” he said.

“This with regular attention to posture and regular ‘earth-like' exercise such as walking and jogging can help to keep all the muscles fit and functioning.”