Scientists have mapped out the best ways for men suffering back pain to have sex.

Contrary to popular belief 'spooning' is not always the best position for those who suffer back ache, researchers found.

Instead having sex 'doggy-style' may work better for many couples, they said.

Scientists at the University of Waterloo in Ontario, Canada, documented precisely how the spine moves during sex.

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Canadian scientists have found contrary to the popular belief that 'spooning' is the best position for those suffering back pain, 'doggy style' may work better

The researchers analysed information gathered by infrared and electromagnetic motion capture systems which documented how 10 couples moved when attempting five common positions.

They then created a set of guidelines that recommended different positions and 'thrusting techniques' based on what triggered a man's back pain.

The findings, published in the journal Spine, included a recommendation for men who were flexion-intolerant - meaning those whose back pain was made worse by touching their toes or sitting for long periods of time - who should replace spooning with doggy-style sex.

They should also try a 'hip-hinging motion rather than thrusting with their spines', the authors said.

Researchers said back pain could leave some couples to be celibate

Lead author Natalie Sidorkewicz said: 'Before now, spooning was often recommended by physicians as the one position that fit all.

'But as we've discovered, that is not the case.

'Sex positions that are suitable for one type of back pain aren't appropriate for another kind of pain.

'For the first time ever, we now have very solid science to guide clinicians on their recommendations for patients who suffer debilitating back pain, but still want to be intimate.

'This has the potential to improve quality of life - and love-life - for many couples.'

Professor Stuart McGill, of the University's faculty of applied health sciences, added: 'Any family doctor will tell you that couples often ask them how to manage their back pain during and after sex.

'Many couples will remain celibate because one night of love-making can lead to months of back agony.

'Until now, doctors have never had any hard science to base their recommendations upon.'