Athletic Injury Monitoring System

High School Football – 1998

The following are preliminary observations based on the AIMS national high school football injury data summary from the 1998 season. This prospective epidemiological study used a stratified sample (based on geographic region) of 34 high school football teams, comprising a representative proportional sample of football-playing schools within each of four geographic regions. These are preliminary observations based on the accompanying raw data summary.

The following observations can be made based on these data:

• There were 2,930 players on the 534 teams in the sample (average squad size = 86.2; most schools reported for both varsity and JV, while some reported for varsity only). Taking into account recurring injuries from this season and those who were injured more than once, approximately 665 individuals (22.7%) had at least one time-loss injury during the season.

• With 896 recorded injuries that kept a player out for one day or more, there were 30.6 injuries/100 players per season.

• There were 189,626 athlete-exposures recorded (one athlete-exposure is one player taking part in one game or practice where he is exposed to the possibility of being injured), with 166,803 athlete-exposures (88.0%) in practices and 22,823 athlete-exposures (12.0%) in games.

• While injuries in practices accounted for 54.4% of all recorded injuries, and 45.6% of the injuries occurred in games, the injury rate in games (JV and varsity combined) was 6.1 times as high in practices. In other words, an individual participating in a game is 6.1 times more likely to be injured during the game than while participating in practice.

• Each injury kept a player out for an average of slightly less than two weeks (11.8 days). This figure may be somewhat skewed by our practice of recording the number of days for a season-ending injury as a ‘99’ in the computer file. However, if it can be assumed that 14 weeks is a reasonable average for a season-ending injury, then this figure probably is not too far off. There were a total of 54 season-ending injuries recorded, or 6.0% of all injuries. In this case a better statistic to use is the median, which is 4 days per injury.

• As has been the case during previous seasons of football injury data collection by the investigator, the total injury rate on artificial turf was higher (by nearly 90%) than on natural grass. However, the total number of exposures to artificial turf in this high school data is relatively small. Data collected over seven seasons at the collegiate level show a trend over the years toward narrowing the difference between injury rates on artificial turf and on natural grass. This season the overall injury rates on artificial turf and natural grass at the college level were nearly equal, although the injury rates during games remained about 10% higher for artificial turf. Our working hypothesis has been that the age, and possibly the brand, of artificial turf has an impact on injury rates, with the newer generation of turfs having better injury characteristics than older, worn turf. Detailed analyses of injury rates on various brands and ages of artificial turf are continuing.

• The injury rate on passing plays was about two-thirds the rate on rushing plays (1.26 and 1.85 per 1,000 athlete-exposures, respectively). This is the reverse of what is normally seen at the collegiate level (which might be explained if there were a higher proportion of passing plays at the collegiate level).

• As would be expected, most injuries occurred during blocking and tackling.

• Impact from another player’s hard-shell helmet caused a minimum of 22.4% of the recorded injuries. Impact from another player’s shoulder pads was a direct cause of a minimum of 9.7% of the recorded injuries. At the collegiate level, the helmet was a direct cause of a minimum of 13.8% of the recorded injuries. An immediate impression is that this might be an indication that at the high school level the head is still being used too frequently as an initial point of contact.

• Injuries to offensive players accounted for 52.9% of the recorded injuries, 40.0% were to defensive players, and kickers and special teams accounted for the remaining 7.1% of the injuries.

• Taking into account the number of players on the field in the various positions (e.g., two offensive tackles, four defensive down linemen, three linebackers, etc.), the highest injury rates on the offensive side of the line appear to have occurred in flankers/wide receivers (0.37/1,000 A-E) and running backs (0.37/1,000 A-E). On the defense, linebackers (0.24) had the highest injury rate, with halfbacks/cornerbacks (0.17) and down linemen (0.18) at nearly the same rate. Safeties had an injury rate of 0.10/1,000 A-E.

• The body parts most frequently injured were knees, the head, and ankles, with sprains, strains and contusions the most common types of injuries. Of continuing concern is the fact that cerebral concussions are the fourth most common type of injury. Exploring this data further shows that head concussions are the second most frequent injury in high school football, following ankle sprains, but the numbers are nearly equal (113 ankle sprains and 110 head concussions). As mentioned previously, this may be a further indication that the head is still being used too frequently as an initial point of contact in high school football. This issue needs to be addressed with coaches, players and parents.

• A total of 4.8% of the injuries resulted in surgery.

• As has been the case with data collected during seven collegiate seasons now, the number of knee injuries to players wearing preventive knee braces was significantly higher than would be expected. These data do not indicate that the braces are reducing the number of knee injuries, since if that were the case we would expect to see significantly fewer knee injuries in braced players based on the proportion wearing braces. These results hold even when considering only MCL injuries. Analyses of these knee brace data are continuing. (A detailed analysis of this issue, based on previously collected AIMS data, appears in Sports Training, Medicine and Rehabilitation 1:287-296 (1990) and in Safety in American Football E.F. Hoerner (ed.) Philadelphia: American Society for Testing and Materials (in press).)