Study: Single-Sport Athletes Injured More

November 3, 2016

A study conducted by the University of Wisconsin School of Medicine and Public Health and funded by the National Federation of State High School Associations (NFHS) Foundation revealed that high school athletes who specialize in a single sport sustain lower-extremity injuries at significantly higher rates than athletes who do not specialize in one sport. 

The study was conducted throughout the 2015-16 school year at 29 high schools in Wisconsin involving more than 1,500 student-athletes equally divided between male and female participants. The schools involved in the study represented a mixture of rural (14), suburban (12) and urban (3) areas, and enrollments were equally diverse with 10 small schools (less than 500 students), 10 medium schools (501-1,000 students) and nine large schools (more than 1,000 students).

Athletes who specialized in one sport were twice as likely to report previously sustaining a lower-extremity injury while participating in sports (46%) than athletes who did not specialize (24%). In addition, specialized athletes sustained 60 percent more new lower-extremity injuries during the study than athletes who did not specialize. Lower-extremity injuries were defined as any acute, gradual, recurrent or repetitive-use injury to the lower musculoskeletal system.

“While we have long believed that sport specialization by high school athletes leads to an increased risk of overuse injury, this study confirms those beliefs about the potential risks of sport specialization,” said Bob Gardner, NFHS executive director. “Coaches, parents and student-athletes need to be aware of the injury risks involved with an overemphasis in a single sport.”

Among those who reported previously sustaining a lower-extremity injury, the areas of the body injured most often were the ankle (43%) and knee (23%). The most common types of previous injuries were ligament sprains (51%) and muscle/tendon strains (20%).

New injuries during the year-long study occurred most often to the ankle (34%), knee (25%) and upper leg (13%), with the most common injuries being ligament sprains (41%), muscle/tendon strains (25%) and tendonitis (20%).

In addition, specialized athletes were twice as likely to sustain a gradual onset/repetitive-use injury than athletes who did not specialize, and those who specialized were more likely to sustain an injury even when controlling for gender, grade, previous injury status and sport.

Thirty-four (34) percent of the student-athletes involved in the Wisconsin study specialized in one sport, with females (41%) more likely to specialize than males (28%). Soccer had the highest level of specialization for both males (45%) and females (49%). After soccer, the rate of specialization for females was highest for softball (45%), volleyball (43%) and basketball (37%). The top specialization sports for males after soccer were basketball (37%), tennis (33%) and wrestling (29%).

The study, which was directed by Timothy McGuine, Ph.D., ATC, of the University of Wisconsin, also documented the effects of concurrent sport participation (participating in an interscholastic sport while simultaneously participating in an out-of-school club sport), which indicated further risk of athletes sustaining lower-extremity injuries.

Almost 50 percent of the student-athletes involved in the survey indicated they participated on a club team outside the school setting, and 15 percent of those individuals did so while simultaneously competing in a different sport within the school. Seventeen (17) percent of the student-athletes indicated that they took part in 60 or more primary sport competitions (school and club) in a single year. Among those student-athletes in this group who sustained new lower-extremity injuries during the year, 27 percent were athletes who specialized in one sport.

The student-athletes involved in the study were deemed “specialized” if they answered “yes” to at least four of the following six questions: 1) Do you train more than 75 percent of the time in your primary sport?; 2) Do you train to improve skill and miss time with friends as a result?; 3) Have you quit another sport to focus on one sport?; 4) Do you consider your primary sport more important than your other sports?; 5) Do you regularly travel out of state for your primary sport?; 6) Do you train more than eight months a year in your primary sport? 

Although some sports (field hockey, lacrosse) are not offered in Wisconsin and were not included in the study, the study concluded that since specialization increased the risk of lower-extremity injuries in sports involved in the survey it would also likely increase the risk of injuries in sports that were not a part of the study.

2018-19 Concussion Data Reinforces Trends

September 26, 2019

By Geoff Kimmerly
Second Half editor

Data on student-athlete concussions collected by the Michigan High School Athletic Association from member high schools during the 2018-19 school year further reinforced findings from the first three years of reporting, and will contribute significantly as a number of MHSAA-associated groups work during the coming year to reduce the incidence of those injuries.

The 2018-19 concussion report found student-athletes at MHSAA member high schools encountered a total of 3,686 head injuries during the past school year – 3.0 percent more than in 2017-18. But that slight increase barely affected two key ratios. The number of injuries per member school was 4.9, up just a tenth of a percent from 2017-18, and for the second straight year only 1.3 percent of participants in MHSAA sports experienced a head injury, still down from 1.4 in 2016-17 and 1.6 percent the first year of the study. Total participation in MHSAA sports for 2018-19 was 281,992 – with students counted once for each sport they played.

The MHSAA has continued to invite Michigan’s universities, health care systems and the National Federation of State High School Associations (NFHS) to take part in analyzing the data and resulting questions that have arisen during the past three years. The 2018-19 results will be examined by the MHSAA’s newly-formed Sports Medicine Advisory Committee and also undergo analysis by representatives of Michigan State University’s Institute for the Study of Youth Sports. Furthermore, the MHSAA is directing its sport committees to study the data as they consider adjustments that could be made to rules for practice and competition. 

“The 2018-19 concussion survey further reinforced the findings and trends we have seen emerge; not only in specific sports, but across all of our activities – and this latest set of results also raises new questions,” MHSAA Executive Director Mark Uyl said. “We must continue to look at how changes to playing rules and improvements in equipment may be beneficial moving forward, and also how we can further educate administrators, coaches, athletes and parents to identify and provide treatment for these injuries as soon as possible. We also are excited for the opportunity to have more eyes on these results as we continue to explore more ways to make our games safer.”  

As first mandated in 2015-16, member schools are required to report head injuries to the MHSAA identifying the sport that each student-athlete was participating in and whether the injury was sustained during practice or competition. Schools also are required to designate at which level – varsity, junior varsity or freshman – the injury occurred.

The full report of all head injuries experienced during 2018-19 by student-athletes at MHSAA member high schools – including percentages by sport (per 1,000 participants), gender and team level, as well as data tracking when athletes returned to play – is available on the Health & Safety page of the MHSAA Website.

Keeping with the first three years of this survey, the MHSAA continued to receive data from more than 99 percent of its member high schools after the fall, winter and spring seasons. Member junior high and middle schools also were allowed, although not mandated, to report their head injuries; and those findings are not part of the published report.

Boys in 2018-19 experienced 2,404 – or 65 percent – of concussion injuries, just a percent less than during 2017-18, and not surprisingly as boys have a much higher participation in contact sports. More than half of head injuries – 59 percent – were experienced by varsity athletes, a slight increase of three percent from the previous year. A total of 2,441 head injuries – or 66 percent – came in competition as opposed to practice. Just more than half took place during either the middle of practice or middle of competition as opposed to the start or end, and 51 percent of injuries were a result of person-to-person contact. 

The MHSAA also asked schools to report the number of days between the head injury and the athlete’s return to activity – and the two largest groups returned to activity after either 6 to 10 days of rest (24 percent) or 11 to 15 days (23 percent). All of these findings were within 1-3 percent of those discovered from the 2017-18 data. 

Contact sports again revealed the most head injuries. Ranking first was football, 11 and 8-player combined, with 44 head injuries per 1,000 participants – an increase of three per 1,000 from 2017-18 but the same ratio as 2016-17 and still down from 49 head injuries per 1,000 football participants shown by the first study in 2015-16. Ice hockey again revealed the second-most injuries per 1,000, with 35 (also up three from a year ago but still down from 36 injuries per 1,000 from 2016-17 and 38 per 1,000 in 2015-16), and girls soccer was third with 25 head injuries per 1,000 participants for the second year in a row. Wrestling followed with 22 head injuries per 1,000 participants. 

Continuing a noticeable trend of the last few years, the next three sports to show the highest incidences of head injuries were girls sports – girls lacrosse, competitive cheer and basketball also revealed 20 per 1,000 participants, although basketball was down two injuries per 1,000 participants or nearly 10 percent from the previous year. Boys lacrosse (16), boys soccer (14), girls volleyball (11), softball (11) and gymnastics (10) also showed double-digit head injuries per 1,000 participants. 

Females again reported significantly more concussions than males playing the same or similar sports – soccer, basketball and baseball/softball. Female soccer players reported nearly double the concussions per 1,000 participants as male soccer players (25 to 14), while female basketball players reported nearly triple the number of concussions per 1,000 participants (20 to 7). Softball players also reported nearly triple the concussions per 1,000 participants of baseball players (11 to 4). 

Schools report possible concussions online via the MHSAA Website. Reports are then examined by members of the MHSAA staff, who follow up with school administrators as those student-athletes continue to receive care and eventually return to play. Student privacy is protected. 

The reporting of concussions is part of a three-pronged advance by the MHSAA in concussion care begun during the 2015-16 school year. The MHSAA completed in spring 2017 the largest-ever state high school association sideline concussion testing pilot program, with a sample of schools from across the state over two years using one of two screening tests designed to detect concussions. The MHSAA also was the first state association to provide all participants at every member high school and junior high/middle school with insurance intended to pay accident medical expense benefits – covering deductibles and co-pays left unpaid by other policies – resulting from head injuries sustained during school practices or competitions and at no cost to either schools or families. 

Previously, the MHSAA also was among the first state associations to adopt a return-to-play protocol that keeps an athlete out of activity until at least the next day after a suspected concussion, and allows that athlete to return to play only after he or she has been cleared unconditionally for activity by a doctor (M.D. or D.O.), physician’s assistant or nurse practitioner.

In addition, the MHSAA’s Coaches Advancement Program – which includes courses that must be completed by all varsity head coaches hired for the first time at a member school – provides substantial instruction on concussion care. Separately, rules meetings that are required viewing for high school varsity and subvarsity head and assistant coaches at the start of each season include detailed training on caring for athletes with possible head injuries.