The debate continues over the effectiveness of youth sports specialization for future success.

With the ongoing debate regarding injury risk and the health of athletes who focus on a single sport at a younger age, a new study reports that 45 percent of high school athletes specialize in just one sport, two years earlier than current collegiate and professional athletes say they did.

In the study executed by doctors at the Rothman Institute at Philadelphia’s Thomas Jefferson University, a total of 3,090 athletes participated. Of those, 503 were in high school, 856 collegiate and 1,731 were in the professional ranks. The study was released Tuesday and presented at the American Academy of Orthopaedic Surgeons annual meeting.

Among the findings were that a “significantly higher percentage” of current college athletes specialized to play a single sport during their childhood at 67.7%. The figures were 46.3% for current high school athletes and 45.9% for current pro athlete.

Yet, high school athletes began specializing at an average of age of 12.7 (+/- 2.4 years), with college athletes at 14.8 (+/-2.5) and professionals at 14.1 (+/- 2.8).

Of the professional athletes surveyed, only 22% would like their own children to focus on a single sport while just 61.7% think specialization helps the athlete play their sport at a higher level. This is compared to 79.7% of high school athletes and 80.6% of those in college thinking specialization helps an athlete play at a higher level.

With rates of youth single-sport specialization on the rise, the study states that “the link to higher injury risk, increased psychological burden, and perceived benefit for future elite sport participation is unknown.” The conclusion the doctors reached is this:

“This study provides a foundation for understanding current trends in single sport specialization in all athletic levels. Current high school athletes specialized, on average, two years earlier than current collegiate and professional athletes surveyed. This data challenges the notion that success at an elite level requires athletes to specialize in one sport at a very young age.”

Read here for the complete findings.