Development of a Prediction Model for Stress Fracture During an Intensive Physical Training Program: The Royal Marines Commandos.

Background:Stress fractures (SFs) are one of the more severe overuse injuries in military training, and therefore, knowledge of potential risk factors is needed to assist in developing mitigating strategies.Purpose:To develop a prediction model for risk of SF in Royal Marines (RM) recruits during an arduous military training program.Study Design:Case-control study; Level of evidence, 3.Methods:RM recruits (N = 1082; age range, 16-33 years) who enrolled between September 2009 and July 2010 were prospectively followed through the 32-week RM training program. SF diagnosis was confirmed from a positive radiograph or magnetic resonance imaging scan. Potential risk factors assessed at week 1 included recruit characteristics, anthropometric assessment, dietary supplement use, lifestyle habits, fitness assessment, blood samples, 25(OH)D, bone strength as measured by heel broadband ultrasound attention, history of physical activity, and previous and current food intake. A logistic least absolute shrinkage and sele...