Incidence and Time to Return to Training for Stress Fractures during Military Basic Training

Currently, little is known about the length of time required to rehabilitate patients from stress fractures and their return to preinjury level of physical activity. Previous studies have looked at the return to sport in athletes, in a general population, where rehabilitation is not as controlled as within a captive military population. In this study, a longitudinal prospective epidemiological database was assessed to determine the incidence of stress fractures and the time taken to rehabilitate recruits to preinjury stage of training. Findings demonstrated a background prevalence of 5% stress fractures in Royal Marine training; femoral and tibial stress fractures take 21.1 weeks to return to training with metatarsal stress fractures being the most common injury taking 12.2 weeks. Rehabilitation from stress fractures accounts for 814 weeks of recruit rehabilitation time per annum. Stress fracture incidence is still common in military training; despite this stress fracture recovery times remain constant and represent a significant interruption in training. It takes on average 5 weeks after exercise specific training has restarted to reenter training at a preinjury level, regardless of which bone has a stress fracture. Further research into their prevention, treatment, and rehabilitation is required to help reduce these burdens. 1. Introduction Stress fractures are well recognised in military training and athletes, with the first reported case being identified in 1855 by Breithaupt [1] and the first imaging of a stress fracture recorded by Stechow in 1897 [2]. The incidence of sustained stress fractures in military recruits can be as high as 12% [3], as compared with a rate of 21.1% of elite athletes [4] and 1% of the general population [5]. Trone et al. [6] suggest that recruits who sustain a stress fracture during basic training are over four times more likely to be discharged from training programmes, demonstrating that these injuries can be responsible for a significant portion of attrition in military training with consequent financial implication for military budgets. Furthermore, after initial rehabilitation, recruits who suffered a stress fracture during basic training are at higher risk of sustaining stress fractures during subsequent training (10.6% incidence within one year of injury, versus 1.7% in injury-free recruits) [7], thereby increasing working days lost to injury and the accompanying financial burden. Royal Marine training is conducted at the Commando Training Centre in Lympstone, Devon. Between 55 and 60 recruits join at fortnightly