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.
MHSAA 2026-27 School Year Classifications Announced
By
Geoff Kimmerly
MHSAA.com senior editor
April 7, 2026
Classifications for Michigan High School Athletic Association elections and postseason tournaments for the 2026-27 school year have been announced, with enrollment breaks for postseason tournaments posted to each sport’s page on the MHSAA Website.
Classifications for the upcoming school year are based on a second semester count date, which for MHSAA purposes was Feb. 11. The enrollment figure submitted for athletic classification purposes may be different from the count submitted for school aid purposes, as it does not include students ineligible for athletic competition because they reached their 19th birthday prior to Sept. 1 of the current school year and will not include alternative education students if none are allowed athletic eligibility by the local school district.
All sports’ tournaments are conducted with schools assigned to equal or nearly equal divisions, with lines dependent on how many schools participate in those respective sports.
For 2026-27, there are 755 tournament-qualified member schools. Schools recently were notified of their classification, and sport-by-sport divisions were posted to the MHSAA Website today (April 7). MHSAA Executive Director Mark Uyl said a school may not subsequently lower its enrollment figure. However, if a revised enrollment figure is higher and indicates that a school should be playing in a higher division, that school would be moved up.
Five MHSAA Finals champions from fall and winter this school year will change divisions for 2026-27, including a few which have dominated over the first half of this decade.
Whitmore Lake’s girls cross country team will compete in Lower Peninsula Division 3 this upcoming fall coming off three straight Division 4 titles, and Farmington Hills Mercy’s girls swimming & diving team will be moving to Division 3 after winning the last three Division 2 championships. Allen Park’s competitive cheer team, which has won the last three Division 2 championships, will compete in Division 1 next winter. Reigning LPD4 girls golf champion Grand Rapids NorthPointe Christian will move into Division 3 this fall, and Division 3 girls volleyball champion Kingsley will be moving into Division 2.
Among spring sports teams currently competing, Pickford’s boys track & field team won the last three Upper Peninsula Division 2 titles and will move to Division 3 for 2027 after competing in Division 2 again this spring, while Newberry – winners of the last two UP Division 3 titles – will move into Division 2 in 2027 after competing in Division 3 this season. The Pickford and Newberry girls teams, both coming off Finals championships last spring as well, will make the same switches for 2027. Powers North Central boys golf, which won the last two UP Division 3 titles, will compete in Division 3 again this spring but move to Division 2 next year.
Schools also may request to play in a higher classification or division in a sport for a minimum of two years. Requests to opt up in fall sports for 2026-27 must be submitted by May 1, winter sports by Aug. 15 and spring sports by Oct. 15
Visit the respective sport pages at MHSAA.com to review the divisional alignments for all MHSAA-sponsored tournament sports. Click the “SPORTS” menu above to access the page for each sport, then the “Assignments” link on the selected sport page and then “DIVISION LIST” to see the 2026-27 division.
Traditional classes (A, B, C, D) – formerly used to establish tournament classifications – are used only for MHSAA elections. To determine traditional classifications, after all counts are submitted, tournament-qualified member schools are ranked according to enrollment and then split as closely into quarters as possible. For 2026-27, there are 188 member schools in Class A and 189 each in Class B, Class C and Class D.
Effective with the 2026-27 school year, schools with 783 or more students are in Class A. The enrollment limits for Class B are 358-782, Class C is 167-357, and schools with enrollments of 166 and fewer are Class D. The break between Classes A and B decreased five students from 2025-26, the break between Classes B and C decreased 12 students, and the break between Classes C and D decreased four students from the 2025-26 school year.
The new classification breaks will see 20 schools move up in Class for 2026-27 while 18 schools will move down:
Moving Up from Class B to Class A
Battle Creek Harper Creek
Chelsea
Harper Woods
Linden
Parma Western
Pontiac
Wayland
Moving Down from Class A to Class B
Adrian
Bay City John Glenn
Fruitport
Grand Rapids Kenowa Hills
Marysville
Owosso
Stevensville Lakeshore
Moving Up from Class C to Class B
Detroit Communication Media Arts
Detroit The School at Marygrove
Ecorse
Fennville
Lake City
Ovid-Elsie
Moving Down from Class B to Class C
Flint Hamady
Manistee
Napoleon
Taylor Prep
Waterford Oakside Prep
Moving Up from Class D to Class C
Brimley
Coldwater Pansophia Academy
Ishpeming
Jackson Prep
Newberry
Petersburg Summerfield
Vestaburg
Moving Down from Class C to Class D
Fulton
Kalamazoo Phoenix
Mayville
Taylor Trillium Academy
Traverse City Greenspire
Vandercook Lake
New Postseason-Eligible Tournament Schools in 2026-27
Calumet Copper Island
Interlochen New Covenant Christian
West Branch Alternative Education Academy
Jackson da Vinci
Enrollment Breaks by Classes – 2026-27
(Number of schools in parentheses)
Class A: 783 and above (188 schools)
Class B: 358 – 782 (189)
Class C: 167 – 357 (189)
Class D: 166 and below (189)
The MHSAA is a private, not-for-profit corporation of voluntary membership by more than 1,500 public and private senior high schools and junior high/middle schools which exists to develop common rules for athletic eligibility and competition. No government funds or tax dollars support the MHSAA, which was the first such association nationally to not accept membership dues or tournament entry fees from schools. Member schools which enforce these rules are permitted to participate in MHSAA tournaments, which attract more than 1.4 million spectators each year.