The most common reason of medical evacuation for non-combat related injuries appears to be related to the musculoskeletal system. This is reported during both military deployments as well as during basic combat training. The most common cause of non-combat musculoskeletal injuries appear to occur from overuse, generally as a result of physical training. Overuse injuries are considered an outcome of the overtraining syndrome, which is considered a continuum of negative adaptations to training. Symptoms appear when the training stimulus has reached the point where the intensity and or volume of training have become too excessive, coupled with inadequate rest and recovery. These are issues that are quite common within the military during both training and deployment. During periods of deployment additional physiological stresses such as the environment (altitude, cold and heat), and nutritional and sleep deprivation may pose significant challenges on the health and performance of the soldier. This is often manifested during sustained combat operations, in which the ability to provide rest and recovery become secondary to the mission’s objectives. This chapter will focus on the frequency, mechanism and risks associated with overuse injuries reported during both military training and deployment.