CONVENTIONAL WISDOM is that the male-female divide in running injuries is all about the “Q angle”–the angle that the upper half of your leg makes with vertical. Women tend to have a bigger Q angle than men thanks to their wider hips, and in theory this places greater stress on the knee and lower leg, leading to more – or at least different – running injuries.
There’s some evidence to support this idea. For example, a 2002 study by Jack Taunton and his colleagues at the University of British Columbia’s Allan McGavin Sports Medicine Centre looked back at more than 2,000 running injuries from 30 years of records at the clinic. They found that men tended to have more injuries to tendon and knee cartilage, whereas women tended to have more instability of the pelvis, stress fractures, and patellofemoral pain syndrome (i.e. runner’s knee). The incidence of stress fractures is a reminder that there are other factors like bone density that may differ between men and women.
Of course, the problem with retrospective analysis is that you don’t really know what factors contribute to the differences. There’s an emerging stream of research looking at things like pacing that suggests that (paraphrasing loosely here) men are more likely to be idiots, so perhaps training patterns explain the injury differences.
To find out, Maha Elashi, a grad student at the UBC Environmental Physiology Lab, is undertaking a prospective study whose preliminary results she presented last month at the annual meeting of the Canadian Academy of Sport and Exercise Medicine. She rounded up 68 men and 86 women preparing to follow a 12-week training program for a 10K race. The runners were carefully monitored weekly to determine their injury status, with injury defined as missing at least three consecutive training sessions due to running-related pain.
The results? No significant difference in injury rate. The women had 3.66 injuries per 1,000 training sessions, while the men had 3.56. Of course, the important follow-up question is: could the study really have detected a small difference? For the stats inclined, women had a relative risk of 1.02 of getting injured during the program compared to men–with a very broad 95 percent confidence interval of 0.40 to 2.59. In other words, we’ll need lots more subjects, and perhaps a longer study period, to pick up (or rule out) a sex-related difference in running injury risk.
That’s exactly what Elashi and her colleagues hope to do, so look for more data in a year or two. This is good science: taking assumptions that we’ve been accepting uncritically, and putting them to the test. It’ll be interesting to see what conclusions they end up with.