The Associations of Early Sport Specialization and Training Volume with Injury Rates in NCAA Division I Athletes
Authors: Ahlquist Seth , Cash Brian Michael , Hame Sharon L. 
Published: March 2019

Objectives: Sixty million United States youth ages 6-18 participate in organized athletics, with large increases in both sport participation and specialization in the past two decades. This study seeks to determine whether early specialization in a single sport and high training volume is associated with an increased risk of injury and surgery in NCAA Division I athletes. A secondary aim is to assess whether sport specialization and high training volume is associated with elite athletic status (i.e. being recruited and/or receiving athletic scholarships). Methods: All NCAA Division I athletes at a single institution were sent a voluntary survey by email. Athletes were surveyed regarding demographics, scholarship status, reasons for sport specialization, age of specialization, training volume, and injury/surgical history. A total of 232 out of 652 athletes completed some portion of the survey. 30 surveys were excluded due to incomplete or incorrect survey completion, leaving 202 surveys available for analysis. Injuries were defined as those which precluded sport participation for > 1 week. Early sport specialization was defined as narrowing participation to one primary sport prior to age 14. High training volume was defined as greater than 28 hours per week during pre-high school years. Exclusion criteria included incomplete surveys and individuals less than age 18. Chi-square, Fisher’s Exact, and Mann-Whitney U tests were performed to establish significant differences. Results: Individuals who specialized in their varsity sport prior to age 14 were more likely to report a history of injury (86.9 vs. 74.0%, X = 4.7, p = .03), multiple injuries (64.6 vs. 49.4%, X = 4.2, p = .04), multiple college injuries (17.2 vs. 6.5%, X = 4.5, p = .03), total injuries (2 vs. 1, U = 3035, p = .02), and total time out for injury (15.2 vs. 7.0 weeks, U = 3150, p = .05). Early specializers were more likely to be recruited (92.9 vs. 83.1%, X = 4.1, p = .04) and receive a scholarship in their varsity sport (82.8 vs. 67.5%, X = 5.6, p =.02). Full scholarship athletes were more likely to report multiple surgical injuries (11.7 vs. 3.5%, X = 5.0, p =.03). Those with a scholarships greater than 50% were more likely to report a surgical injury (34.1 vs. 18.3%, X = 6.5, p = .01). Individuals who trained for greater than 28 hours per week in their varsity sport prior to high school were more likely to report multiple injuries (90.0 vs. 56.7%, X = 4.3, p = .04) multiple college injuries (40.0% vs. 14.0%, p = .05), a surgical injury (60.0 vs. 21.7%, p = .01), multiple surgical injuries (30.0 vs. 4.5%, p = .02), and greater total time out for injury (36.5 vs. 11.0 weeks, U = 424, p = .02). Individuals with a pre-high school training volume greater than 28 hours/week in their varsity sport were not more likely to be recruited (90.0 vs. 89.8%, p = 1.0) or receive a scholarship (80.0 vs. 74.5%, p = 1.0). Those in non-contact varsity sports were more likely to report multiple college injuries than those in limited and full contact sports, respectively (20.4 vs. 6.4 vs. 8.8%, X = 7.0, p = .03). Those in individual sports were more likely to report a college injury (55.3 vs. 38.9%, X = 5.1, p = .02) and multiple college injuries (25.0 vs. 7.1%, X = 12.7, p &lt .001). Conclusion: NCAA Division I athletes who specialized in their varsity sport prior to age 14 were more likely to be recruited and receive an athletic scholarship. However, these individuals, as well as those with high training volume prior to high school, had increased rates of injury and injuries requiring surgery.