Sports specialization, defined as the intense training in a single sport to the exclusion of other types of physical activity, is increasingly common during childhood and early adolescence. Such specialization has been associated with the development of high-risk motion control patterns, an increased risk of injury, and an early termination of sports participation due to physical and emotional burnout. A number of organizations have articulated concerns about early sport specialization (ESS) and overuse conditions in young athletes. Some have even outlined general recommendations for sports participation and young athlete development. However, there is a dearth of quality prospective studies on the benefits versus harms of ESS. Moreover, substantial methodological limitations exist in the available scientific literature regarding the effect of specialization on youth motor control development, musculoskeletal injury risk, and on optimal strategies for youth athlete training and development. This talk will address methodological and study design issues that must be considered and addressed in order to advance knowledge in this area and ultimately improve the health and well-being of youth and adolescent athletes.