A new British study suggests that women are more susceptible to musculoskeletal disorders (MSDs) at specific times in their menstrual cycle. The findings will contribute to the fund of knowledge about gender differences, an important factor in the ergonomic design of workplaces.
The study suggests the risk is linked to fluctuating hormone levels that affect the muscles and ligaments. According to the BBC, which reported the study, London’s Portland Hospital surveyed 1,000 osteopaths and studied 17 women with a regular menstrual cycle. The researchers found that midway through the cycle the level of the female sex hormone oestrogen, which gives strength to muscles and ligaments, drops dramatically and there is sudden weakness. At the end of the cycle levels of another hormone, relaxin, rise. This is to allow the cervix to open so that menstruation can occur, but it also means the ligaments in general are softened. The researchers say that strains and other injuries were more likely at both these stages.
“I had noted that, whereas men often came to me with injuries due to sport or over-exertion, women often couldn’t explain why simple acts like reaching down to pick something up had caused injury and pain,” lead researcher Dr Stephen Sandler, an osteopath, explained in the BBC article.
He compared hormone levels in the blood with the laxity of the forefinger joint. He found joint laxity increased throughout the hormone cycle, then reverted back to normal once the period began.
The study suggests that women on the combined pill, who do not experience sudden drops in their oestrogen levels, are less likely to experience injury as the result of loosened joints.