2018 Season Report of AUDL Injury Surveillance Program


The AUDL cares about its players and their safety. Over the last three seasons the league has coordinated its teams to participate in a University of Alabama at Birmingham Orthopedics surveillance study* led by Matthew Hess, MD, a former UGA ultimate player. Participating teams have been logging player injury data on a weekly basis for statistical analysis. Below are the results from the 2018 season report. The 2017 season data will be published in the Journal of Athletic Training.


Data Set

The study has grown each of its three seasons, leading to an increase in data collected. The 2018 season saw a growth in team participation, pre-season data collected, and games recorded. Injury rates have remained stable over that time frame increasing confidence in observed trends. Injury rates in the AUDL are comparable to similar NCAA-level sports


The industry standard unit of measure is the Athlete Exposure, defined as one player participating in one game. This method does not factor in points played per game. The 2019 season study will attempt to connect player data to injury data for the first time ever. We hope to be able to analyze many metrics made available by the AUDL’s ultianalytics data set

An injury is described as a physical harm that causes a player to miss part of a game or practice, ie an injury substitution during a point or a player not being able to play any number of subsequent points in the game.


Injury Descriptions

  • 67% of injuries required attention from an athletic trainer
  • 43% of injuries restricted an athlete’s play for 1 or more days
  • 70% of injuries were first time injuries
  • 15% of injuries needed to be seen by a medical professional offsite
  • 68% of total injuries affected the lower body
  • The most common injuries were:
    • Upper leg muscle strains (72% of leg strains affected the hamstrings)
    • Lower leg cramping
    • Ankle ligament sprains
  • 13 (3.8%) injuries affected the head with 6 reported concussions (4 head injuries and 2 concussions in 2017 season)
  • Running was the most common mechanism of injury
  • 27% of injuries were caused by player collisions
  • 21% of injuries were caused by layouts 

Injury Probabilities

Players are 3.5x more likely to be injured in a game than in practice. This is likely attributed to the differences in intensity of play and the percentage of practice that is scrimmaging versus drills and conditioning. Scrimmaging is by far the most common occurrence of injuries at practice.

Players were more likely to be injured as a game progresses with the majority of injuries occurring in the 3rd quarter.

Offensive players are injured more often than defenders. Cutters are injured more often than handlers

Schedule and Field conditions

There has been no statistical difference in injury rates between double headers and single game per week schedules. There is also no statistical difference in injury rates at home vs away games or grass vs turf fields. Players are 1.5x more likely to be injured on wet surfaces and 2x more likely to be injured on uneven surfaces.

Women’s and Mixed Data

Data from several AUDL- affiliated women’s and mixed teams was tracked in 2018.

  • 3 mixed teams and 4 women’s-only teams volunteered surveillance data. 5 practices and 12 games with a total of 245 athlete exposures were recorded.
  • The women’s data was not large enough for robust data analysis so it was excluded from the above data set. Men’s data from mixed play was included.
  • 6 total injuries recorded for a total injury rate of 30.15 injuries per 1000 athlete exposures
    • 2 knee ligament sprains, 2 ankle ligament sprains, 1 quad strain, 1 heel bruising


Recommendations for Improved Player Safety

One way that a study like this provides value is to inform the league, coaches, players, and medical staff so that the best decisions can be made. Each year of subsequent data collection increases the validity and reliability of trends. The research team has collectively decided on several recommendations to potentially improve athlete safety.


Hamstring muscle strains are the most common injuries and although layouts and collision injuries are high, running is still the most common way athletes are injured

  • Strength training and conditioning programs should focus on lower extremity strength and flexibility throughout both the season and off-season with special emphasis on hamstring mobility and running form
  • All athletes should wear compressive clothing (i.e. compression shorts) for the bilateral thighs in both practices and games


Injuries to the ankle and lower leg are very common with ankle ligament sprains a significant source of athlete playing time loss. Data from other sports indicates that wearing under-the-shoe soft ankle braces can reduce non-contract sprains.  Athletes should consider wearing bilateral ankle braces (or an alternative equivalent, such as Lasso compression sock) in all practices and be strongly encouraged to wear them during competition.


Teams should employ a mandatory, organized team warm-up focusing on the bilateral lower extremities after any halftime. This warm up can be shorter than your pre-game routine.

Late game subbing

When substituting athletes, coaches should be aware of the increased injury rate as you get deeper into the game. It can be attractive to tighten playing rotation as the game nears its end. Be mindful of the increased risk of injury and managing your players health for the entire season.


When planning practice time, coaches should be aware of the increased risk of injury with scrimmaging compared to other forms of practice. At this time and with our dataset, we are unable to recommend an optimal safe amount of scrimmaging. Practice times vary too substantially across AUDL teams, club teams, college and youth. 


Special thanks to our Study Team:

Please contact us at audlisp@gmail.com with any questions or comments

  • Matthew Hess, MD - Orthopedic Surgery resident at UAB, former captain and president of UGA’s college ultimate program. Principal investigator.
  • David Swedler, PhD, MPH - Ultimate player and observer, primary author of 1st ultimate Frisbee injury study in college athletes, injury epidemiologist at the Pacific Institute for Research and Evaluation.
  • Christine Collins - Current 1st year medical student at UAB, former women’s club ultimate athlete at University of Alabama. Researcher and contact person for questions about study design, recommendations for study improvements, questions about complicated data entry, consents, or follow-up from research team.
  • Sean Williamson - Current 1st year medical student at UAB, current and former men's club ultimate athlete at UAB and Old Miss (respectively). Weekly contact person for data input and team representative training.
  • John Boezi - Atlanta Hustle General Manager. Main league representative and coordinator.
  • Brent Ponce, MD - UAB Orthopedic surgeon, shoulder specialist, and clinical researcher. Study advisor.
  • Will Brabston, MD - Former college ultimate player. UAB Orthopedic surgeon and sports medicine specialist. Study advisor and primary UAB faculty contact to the AUDL.