WEIGH IT UP

You may think light means fast but when body weight is too low, your risk of stress fractures increases. In a three-year study4 of female runners, researchers found that a body mass index (BMI) of 19 or under was associated with a higher prevalence of stress fractures. Their injuries also took a month longer to heal than in women with a BMI above 19. Lead author Dr Timothy Miller suggests female athletes maintain a body mass index of 20-24.