Athlete performance tracking devices are becoming prevalent in team sports, especially at the professional and collegiate levels. An individual device is small (~3 x 1.5 inches) and usually inserted into a specially designed vest that holds it to an athlete’s upper back. A device typically contains an accelerometer, gyroscope, magnetometer, and global positioning system (GPS) that are used to measure several variables regarding athlete performance during competition while on a sports field, such as distance covered, top speeds, sprint counts, accelerations, decelerations, and impacts. The GPS is particularly useful for tracking the athlete’s location and time spent within a field. Data are used by coaches, trainers, and sports scientists to develop programs that better prepare athletes for competition and optimize their on-field performance, but can they also be used for sports field management and research?
Sports field management
GPS athlete performance tracking devices are accompanied with software for viewing measured data. The software is user-friendly and normally accessible online with a login name and password. Within the software, each athlete’s performance data are broken down by individual sessions, such as practices and games. This includes a performance summary of the session that is comprised of averages or counts of the measured variables, as well as maps generated from the GPS data.
Data and maps can be viewed for individual athletes, a specified group of athletes, or the entire team. They can also be viewed within certain timeframes of a session. Additionally, video footage can be added and replayed to retroactively view athletes’ performance as it happened in real time. If a team is already using the devices for their own purpose, this information could be free and readily available to a sports field manager to benefit field management.
There are several ways the information from the devices could be valuable for sports field management. Objective field usage information can provide justification to apply programs that mitigate concentrated areas of wear, like site-specific management or mandatory requirement of field and practice drill rotations. This would probably be most beneficial on practice fields, since only partial field usage information can be gathered on game fields during games (because only the home team information will likely be accessible).
If field usage is then combined with field characteristics (e.g. surface hardness, soil moisture, infill depth) and documented over time, the effectiveness of previous management strategies could be assessed to guide future management decisions. Furthermore, the devices offer an opportunity for sports field managers to work collaboratively with coaches and trainers to possibly manipulate field conditions based on gathered data. An example could be irrigating heavily or drying down a field to alter soil moisture and surface hardness levels to perhaps accommodate a coach’s desire to achieve certain athlete performance thresholds. Given all the scenarios sports field managers are confronted with, there are likely many other potential management applications for the devices we have not mentioned here.
Sports field research
Sports fields are comprised of several measurable characteristics that may influence physical and psychological athlete-surface interactions. Among the physical factors, harder surfaces, for instance, have increased peak vertical reaction forces when an athlete lands/falls or applies a force. Game speeds are also thought to generally increase with harder surfaces and could influence athlete performance and injury occurrence due to higher collision rates, fatigue, or exposure to excessive or prolonged loading.
While there remains limited research investigating psychological contributors to athlete performance and injury occurrence in relation to field characteristics, a recent University of Georgia study did report that the unpredictability of a highly variable natural turfgrass field could influence athletes’ perceptions of the field. As a result, behavioral factors such as aggressiveness or tentativeness were said to be affected, and these likely contribute to overall athlete performance and injury occurrence too. GPS athlete performance tracking devices could be a valuable research tool that can further our understanding about the link between field characteristics and athletes’ performance, perceptions, and injury occurrence.
A preliminary study using the devices began in fall 2018 by a team of turfgrass science and sport and exercise psychology investigators from the University of Minnesota. The study involves a university club sports team (15 total athletes), which practices on artificial turf and plays on natural turfgrass. The devices were worn by the athletes for every practice and game during the fall 2018 season to obtain their performance data. Field characteristics were measured once a month at the practice field (surface hardness and infill depth) and the morning before each game at the game field (soil moisture, soil compaction, surface hardness, turfgrass quality). Methods to evaluate athletes’ perceived susceptibility to injury (pre-season questionnaires) and perceptions of the playing field (pre- and post-season on-field interviews) were incorporated. All injuries were recorded, and athlete position and footwear are being considered as well. Data are being compiled and analyzed to explore a variety of questions, including:
- How do field characteristics (within the field and over time) influence athletes’ performance and injury occurrence?
- How do athletes’ perceived susceptibility to injury and perceptions of the playing field affect actual on-field performance and injury occurrence?
- Do performance and psychological factors overlap, and can this information be used for athlete injury prediction and prevention under certain playing field conditions?
Results from this type of study may benefit sports field managers by suggesting new management strategies to help meet team expectations of field conditions. It may benefit sports psychologists, strength and conditioning coaches, and athletic trainers by assisting in the development of programs to improve athletes’ perceptions and confidence about certain field conditions. All of which may enhance athletes’ overall performance, while reducing their risk for injury. This study is on going with the potential to add other teams in 2019.
GPS athlete performance tracking device’s inception into sports field management and research does come with challenges, the most evident being athlete privacy. For management, this may not be as big of an issue as with research, because the most beneficial information to a sports field manager would be field usage maps. These can be easily shared by coaches or trainers as computer screenshots, for example, which would not contain athlete data. General athlete performance could be an informal discussion between all parties without a sports field manager actually seeing any athlete information. For research, privacy can be a larger issue since data is essential to the investigators. To overcome privacy issues when conducting research involving human participants, several procedures take place that ensure proper ethical guidelines are being followed, such as using IDs instead of names, appropriate data handling and security, etc.; however, even with these guidelines in place it can still be difficult to have athletes or teams agree to participate due to concern of their information being mishandled. Technical and logistical challenges, like measurement accuracy and amount of data, are also issues that will need to be considered. It is for all these reasons that it can be difficult to do large-scale studies involving several teams and fields.
Understanding the multifaceted influences of athletes’ performance, perceptions, and injury occurrence is a highly complex process, which cannot be explained by only a few studies. Nevertheless, research involving new technologies, innovative approaches, and key collaborations can move towards filling knowledge gaps that have not yet been fully explored in order to benefit our cause. Technology now exists in sports field management and research where “athlete safety” and “field playability” do not need to be used as broad terms; rather, they can be quantified, to a certain extent, on an athlete-by-athlete and field-by-field basis. Right now, most sophisticated technologies are likely only relevant to higher-end sports fields. Even if they are not applicable in your specific situation, technologies will only improve and become more widespread moving forward.
Chase Straw is a Postdoctoral Research Associate in the Department of Horticultural Science, Francesca Principe is a MS student in the School of Kinesiology, Diane Wiese-Bjornstal is a Professor and Associate Director in the School of Kinesiology, and Brian Horgan is a Professor and Extension Turfgrass Horticulturalist in the Department of Horticultural Science at the University of Minnesota, Twin Cities campus.
The authors would like thank the Minnesota Park and Sports Turf Managers Association for their support; University of Minnesota Recreation and Wellness for their collaboration and use of facilities; Troy Carson and Josh Friell, The Toro Company, for use of their field sampling devices; and Brian Neff, Emma Sackett, Will Wardrop, and Kristin Wood, University of Minnesota undergraduate or graduate student, for their assistance.