Medial tibial stress syndrome or shin splints is a common injury that affects athletes that engage in running sports or basic activities such as cross country, soccer, or hiking. MTSS injuries affect the connective muscle tissue surrounding the tibia (bone located near the lower leg). This injury is brought on by one of the following: exerting too much pressure on the lower leg muscles or excessive impact on the muscle. Consequences of severe MTSS can result in, at worst, broken bones.