Athletic Injury Monitoring System
High School Football – 1997
The following are preliminary observations based on the AIMS national high school football injury data summary from the 1997 season. This prospective epidemiological study used a stratified sample (based on geographic region) of 57 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 4,420 players on the 56 teams in the sample (average squad size = 78.9; 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 1,126 individuals (25.5%) had at least one time-loss injury during the season.
- With 1,499 recorded injuries that kept a player out for one day or more, there were 33.9 injuries/100 players per season.
- There were 296,005 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 259,479 athlete-exposures (87.7%) in practices and 36,526 athlete-exposures (12.3%) in games.
- While injuries in practices accounted for 57.7% of all recorded injuries, and 42.3% of the injuries occurred in games, the injury rate in games (JV and varsity combined) was 5.2 times as high in practices. In other words, an individual participating in a game is 5.2 times as likely to be injured during the game than he is while participating in practice.
- Each injury kept a player out for an average of slightly less than two weeks (11.2 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 72 season-ending injuries recorded, or 4.9% of all injuries. In this case a better statistic to use is the median, which is 4 days per injury.
- As was the case during similar college football injury data collection the investigator did during the 1986-90 seasons, the total injury rate on artificial turf was higher (by nearly 50%) than on natural grass, although the general trend has been a narrowing of this difference over the years. 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 three-fourths the rate on rushing plays (1.34 and 1.76 per 1,000 athlete-exposures, respectively). This is the reverse of what is 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 20.9% of the recorded injuries. Impact from another player’s shoulder pads was a direct cause of a minimum of 11.1% of the recorded injuries. At the collegiate level, the helmet was a direct cause of a minimum of 13.1% 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 55.2% of the recorded injuries, 39.4% were to defensive players, and kickers and special teams accounted for the remaining 5.4% 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 (0.46/1,000 A-E) and running backs (0.39/1,000 A-E). On the defense, backs (0.23) and linebackers (0.22) had nearly the same injury rate, as did down linemen (0.18) and safeties (0.17/1,000 A-E).
- As expected, the body parts most frequently injured were knees and ankles, with sprains and strains the most common types of injuries. Of continuing concern is the fact that cerebral concussions are the fourth most common injury.
- A total of 3.7% of the injuries resulted in surgery.
- As was the case with data collected during the 1986-90 collegiate seasons, 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).)
Eric D. Zemper, Ph.D.
Director of Research