Overuse injuries are injuries of the musculoskeletal and nervous systems that may be caused by repetitive tasks, forceful exertions,vibrations,mechanical compression,or sustained or awkward positions.It is also known as Repetitive Strain Injury or Cumulative Trauma Disorders. These are most commonly used to refer to patients in whom there is no discrete,objective,pathophysiology that corresponds with the pain complaints.Physical activity is a great way for kids to build bone strength, prevent obesity and stay healthy,when paired with safety and prevention practices. With youth sports injuries rising at alarming rates,overuse injuries such as sore bones and muscles, and swollen or injured joints need prompt attention in child athletes to prevent chronic musculoskeletal problems later in life. Understanding overuse injuries can guide you to designing your training to reduce the risk of injury and help you to recognize and treat them as they inevitably occur.Overuse injuries can be defined as the product of "too much,too fast,too soon." The topics discussed in these chapters are conditions commonly seen by the author in his long stint as an orthopedic and sports medicine consultant.