Risk Factors for Stress Fractures in Track and Field Athletes

Abstract

The aim of this 12-month prospective study was to investigate risk factors for stress fractures in a cohort of 53 female and 58 male track and field athletes, aged 17 to 26 years. Total bone mineral content, regional bone density, and soft tissue composition were measured using dual-energy x-ray absorptiometry and anthropometric techniques. Menstrual characteristics, current dietary intake, and training were assessed using questionnaires. A clinical biomechanical assessment was performed by a physical therapist. The incidence of stress fractures during the study was 21.1% with most injuries located in the tibia. Of the risk factors evaluated, none was able to predict the occurrence of stress fractures in men. However, in female athletes, significant risk factors included lower bone density, a history of menstrual disturbance, less lean mass in the lower limb, a discrepancy in leg length, and a lower fat diet. Multiple logistic regression revealed that age of menarche and calf girth were the best independent predictors of stress fractures in women. This bivariate model correctly assigned 80% of the female athletes into their respective stress fracture or nonstress fracture groups. These results suggest that it may be possible to identify female athletes most at risk for this overuse bone injury.

Bone Geometry According to Menstrual Function in Female Endurance Athletes

“…Previous studies have reported lower lumbar spine BMD in amenorrheic than eumenorrheic athletes (13,(34)(35)(36).…”

“…Exercise has previously been shown to enhance the bone's accrual on the periosteal (outer) bone surface, thus conferring greater resistance to bending, whereas estrogen may inhibit periosteal apposition (12). In eumenorrheic women, exercise may be a potential preventive measure for osteoporotic fractures, as the increased high impact loads can lead to increases in BMD relative to sedentary women (13,14). However in amenorrheic athletes, estrogen deficiency is related to bone loss, raising concerns about increased risk of future osteoporosis (11,12).…”

Stress fractures in the foot and ankle of athletes

“…Basketball athletes have a prominence of the medial malleolus, navicular bone and metatarsal stress fractures, while for footballers lesser metatarsal fractures are more common. 6,7,8 From a biomechanical point of view, fatigue fractures are the result of specific, cyclical and repetitive muscle action until exhaustion, with load transfer to the bone exceeding its adaptation capacity. 8,10 The shear and compression forces stimulate bone transformation according to Wolff's law, that is, the compression forces promote osteoblast activity and bone deposition leading to a strengthening of bone structures, adapting to the applied load, while shear forces lead to the reverse process of bone resorption by stimulating osteoclast activity.…”

“…22 The same occurs with age: older individuals present a higher incidence of such fractures (B). 7 Stress fractures are less common in children than adolescents and adults (D). 23 In relation to sex, some studies have shown that military women have an incidence 5 to 10 times higher than men (B).…”

“…23 In relation to sex, some studies have shown that military women have an incidence 5 to 10 times higher than men (B). 7 With regard to genetic factors, studies on identical twin military recruits submitted to the same treatment in quantity, duration and intensity reveal fatigue fractures in the metatarsal bones in both (B). 7 In relation to biomechanical factors, a high longitudinal arch of the foot, difference in the length of the lower limbs and a marked varus foot associated with multiple stress fractures have been observed (B) 15,21 (C).…”