Part II: Risk Factors for Stress Fractures in Female Military Recruits

Abstract

Introduction Stress fractures (SFx) represent a significant proportion of injuries in military recruits internationally. Stress fractures disproportionately affect female recruits, a disparity that has similarly been consistently demonstrated in female athletes. Stress fractures result in medical morbidity, financial burden, and medical discharge from military service. This review presents current literature regarding SFx risk factors to identify and/or mitigate in this high-risk population. Methods A literature review was conducted using PubMed to find relevant articles. We utilized keywords stress fracture, military, recruits, female, risk factors, modifiable, non-modifiable, overuse, nutrition, and/or prevention. Articles older than 10 years (published before 2010) were not considered. Review articles were considered, but if a research article was cited by a review, the research was included directly. Articles with primary military data, members of the military as subjects, especially when female recruits were included, were strongly considered for inclusion in this review. Results Modifiable risk factors for SFx include nutritional deficiency, especially of iron, vitamin D, and possibly calcium, poor physical fitness, suboptimal training programming for injury development and recovery, load carriage, and military footwear. Non-modifiable risk factors include female sex, greater height, lower weight and body mass index in females but lower or higher weight and body mass index in males, lower body fat percentage, and lower bone mineral density. In addition, menstrual dysfunction, low energy availability, later age at menarche, and iron deficiency pose unique risks to female recruits. Preventive measures include leadership education, programs with recovery considerations, and risk factor screening. Conclusion This review, Part II of a two-part series, guides multidisciplinary management of military recruits, especially females, who are at risk for developing SFx. Unique nuances of the military recruit require specific knowledge to reduce high incidence rates of injury internationally.

High Physical Exposure During Female Recruits’ Basic Military Training in Sweden—A Descriptive Study

“… 38 Furthermore, footwear and equipment modifications should also be considered as preventive strategies. 18 , 37 , 38 …”

“… 14–16 The literature exploring factors associated with MSD during BMT have come to approximately the same results. Thus, older age, 17 height, 2 low BMI, 6 previous injuries, 2 , 6 low physical activity and fitness (muscular and aerobic) levels prior to BMT, 10 , 17 load carriage, 18 and total distance travelled during BMT 19 are factors related to MSD during BMT.…”

Rib Fractures in Professional Baseball Pitchers: Mechanics, Epidemiology, and Management

“…[111][112][113] Finally, in females, low ferritin and iron levels have been found to correlate with a higher risk of stress fractures, however this association has not yet been demonstrated in males. 114,115 In cases of repeat stress fracture, bone density scans can be helpful in ruling out low or excessively high BMDs, which may benefit from an endocrinology referral and further evaluation of the hormones involved in bone homeostasis. 108 Despite the association of low BMD and stress fracture, prophylactic treatment with bisphosphonates has not been shown to be effective in reducing stress fracture in military recruits.…”

Advancing Exoskeleton Development: Validation of a Robotic Surrogate to Measure Tibial Strain

“…Stress fractures are most common in the tibia and midfoot but have also been observed in the spine, pelvis, and upper extremities depending on the stressful activity [1,2]. Incidence rates vary according to age, gender, ethnicity, fitness level, body mass index, type of physical activity, bone geometry, and biomechanics [3][4][5][6][7][8][9]. Runners have an incidence rate of 15%, with BSIs accounting for 70% of all their injuries [2].…”