Female runners with a body mass index below 19 may have a higher risk of developing stress fractures than women with a BMI of 19 or above. They may also take longer to recover from them, according to researchers.

“We found that over time, we were able to identify the factors that put female runners at an increased risk of developing a stress fracture,” says Timothy Miller, MD, assistant professor of clinical orthopaedic surgery and sports medicine at The Ohio State University, and an author of the study, published in Current Orthopaedic Practice.

“One of the most important factors we identified was low body weight, or low body mass index,” he adds.

Miller notes in a media release from the university that runners endure repetitive pounding on hard surfaces and, without enough lean muscle mass for dissipation of impact forces, the bones of the legs are vulnerable.

“When body mass index is very low and muscle mass is depleted, there is nowhere for the shock of running to be absorbed other than directly into the bones. Until some muscle mass is developed and BMI is optimized, runners remain at increased risk of developing a stress fracture,” Miller explains.

The team also suggests that among female runners with severe stress fractures, those with a BMI of 19 or higher took about 13 weeks to recover from their injuries and return to running. However, runners with a BMI lower than 19 took more than 17 weeks to recover.

“It’s imperative that women know their BMI and work to maintain a healthy level. They should also include resistance training in their training regimen to strengthen the lower leg to prevent injury, even if that means adding weight from additional muscle mass,” Miller states.

[Source(s): Ohio State University, Science Daily]