Wrists playing up? You're shagging too much
Missionary position fingered for carpal tunnel syndrome
A US researcher has suggested a possible link between dodgy wrists caused by carpal tunnel syndrome and sex, "when the hands become repeatedly extended while under pressure from the weight of the upper body".
The syndrome occurs when "the median nerve, which runs from the forearm into the hand, becomes pressed or squeezed at the wrist", as this handy guide  explains. Symptoms range from "frequent burning, tingling, or itching numbness in the palm of the hand and the fingers" to "decreased grip strength" and the inability to tell hot from cold by touch.
According to the Sun, carpal tunnel syndrome is "among the most prevalent forms of RSI", and affects up to one in 20 people in the UK.
It's previously been suggested that the ailment is caused by "extensive use of vibrating hand tools" or "excessive use of a keyboard or mouse ", but writing in the journal Medical Hypotheses, Dr John Zenian proposes: "Sexual intercourse can explain the increase in the overall incidence of carpal tunnel syndrome seen in recent years, since it is the most widely practised activity that uses both hands at the same time."
Other factors may be contributing, too, including the availabilty of drugs such as Viagra. Zenain explains: "The increase of carpal tunnel syndrome in England that affected the middle-aged and the elderly can be attributed to the introduction of erectile dysfunction therapy in England in the late nineties."
Add to this that people are getting fatter, and therefore putting even more strain on their wrists when they make the beast with two backs, and you have a solid case for missionary position-based wrist damage.
Zenian's abstract  summarises: "The bilaterality of carpal tunnel syndrome can be explained by the fact that both hands are needed to support the upper body during sexual intercourse. A parallel decrease in the frequency of sexual intercourse and the incidence of carpal tunnel syndrome between the sixth and the seventh decades of life suggests a possible cause and effect relationship between sexual intercourse and carpal tunnel syndrome." ®