The mouth-opening, screaming, and kicking some people experience during sex are sadly not tell-tale signs of a body-shaking and bed-rattling orgasm, but of excruciating back pain. The bouts of this physically debilitating pain may cause their sex life to take a back seat to their health, often forcing couples to remain celibate to prevent months of back agony. Luckily, science has got your back and suggests doggy style and missionary, not spooning, are the best spine-sparing sex positions, according to a study forthcoming in the journal Spine.

Spooning has been the popular go-to sex position for back pain patients who wish to avoid added pressure to the spine. “[S]pooning was often recommended by physicians as the one position that fit all. But as we've discovered, that is not the case," said Natalie Sidorkewicz, lead author of the study, and a Ph.D. candidate at the University of Waterloo, in the press release. "Sex positions that are suitable for one type of back pain aren't appropriate for another kind of pain."

Before this study, physicians and chiropractors recommended spooning as the one sex position to alleviate back pain. However, this had no hard science base, and failed to recognize the other triggers for back pain. While someone may find relief in one position, the other person with back pain may not.

In an effort to document the way the spine moves during sex and discover what and why certain positions are better than others when it comes to back pain, Sidorkewicz and her colleagues recruited 10 heterosexual couples, with an average age of 30, to have sexual intercourse in a controled laboratory setting. The couples were given pictures of five different sex positions, including spooning and variations on missionary and doggy style positions, to perform. The participants were outfitted with infrared and electromagnetic motion capture systems, similar to those used in the creation of video games, to model the spine angles used during the five different sexual positions. The researchers also observed how hard muscles worked during sex, and which muscles were affected by orgasm.

The findings revealed there is a solid science that exists to guide clinicians on their recommendations for patients who suffer from back pain but still want to be sexually active. Since both men and women use a lot of spinal motion during sex, the researchers recommend the individual who’s controling the movement to use more of their hips and knees, rather than their spine. Missionary, and rear entry quadrupled, more commonly known as doggy style, are found to be the ideal spine-sparing positions.

"A great example of both of these recommendations is the missionary (position)," said Sidorkewicz, advising that a woman lying on her back place a cushion or other support under the curvature of her spine, CBC reported. The kneeling behind one’s partner during intercourse can also help alleviate back pain caused by flexion in both partners. Those who are flexion-intolerant, meaning those whose back pain is made worse by touching their toes or sitting for long periods of time, should also replace spooning with doggy style sex.

The findings of this study help provide a resource for a chiropractor, physiotherapist, or a physician, to refer to for lower back patients. Currently, any recommendations that are out there are not based on scientific data. "So we are now providing that to help guide those clinicians to make better recommendations for those patients. So the idea is to improve the quality of life of these couples by helping them maintain more of a healthy sexual relationship,” Sidorkewicz said.

Although this study solely focused on how a man’s spine and muscles move during intercourse and orgasm, the researchers also gathered data on female participants, which is set to publish later this year, or earlier next year, The Independent reported. The researchers plan to expand on this research and also focus on people with existing back and/or hip pain to test the effectiveness of their initial recommendations. This will not only help patients but also get a doctor-patient dialogue going, which “has the potential to improve quality of life — and love-life — for many couples.”

Doctors now have scientific evidence to make recommendations related to back pain for their patients. According to the American Chiropractic Association, 31 million people in the U.S. experience lower back pain. This is the single leading cause of disability worldwide.

Source: Sidorkewicz N. Male Spine Motion during Coitus: Implications for the low back pain patient. Spine. 2014.