Background Youth mountain bike racing is a rapidly growing sport in the United States. An injury surveillance system (ISS) is now implemented through a collaboration between University of Utah researchers and the National Interscholastic Cycling Association (NICA), referred to as NICA-ISS, to better understand injury characteristics in this sport and pursue data-driven injury prevention strategies.

Objective Describe types of and factors associated with injuries sustained by youth mountain bike racers during NICA-sanctioned mountain bike racing and training.

Design NICA-ISS was developed using a web-based system. Data were collected from NICA leagues during the 2018–2020 seasons. Designated reporters on each team were asked to complete weekly incident and exposure report forms.

Setting Nation-wide youth mountain biking leagues in the United States.

Participants Student-athletes on NICA teams in grades 8–12 participating in the 2018–2020 seasons.

Assessment of Risk Factors Variables analyzed included injury characteristics, athlete demographics, trail conditions, incline during crash, weather, crash circumstances (practice, race, passing, trail familiarity), and health factors (dehydration, sleep, illness).

Main Outcome Measurements Proportions/rates of injuries overall, by type and location, and by group of athletes.

Results Injuries were tracked in 66,588 student-athlete-years, resulting in 2,587 injuries in 1,677 student-athlete injury events reported. The most commonly reported injury was concussion (23.3%), followed by injury to the wrist/hand (22.7%), shoulder (16.7%), and knee (14.3%). Over a half (52.1%) of injury events occurred on downhills. Males and females reported similar injury rates (2.43% and 2.86%, respectively), but females sustained significantly more lower limb injuries (p = 0.003). A large portion (72.4%) of injured athletes were unable to complete the ride; 49.3% of crashes resulted in an emergency room visit.

Conclusions Acute traumatic injuries are common in mountain bike racing, including concussions and injuries to the upper extremities. Males and females have similar injury rates but different injury types. To our knowledge, this is the largest mountain bike racing ISS in existence.