'he Effects of Playing Surfaces on Injuries in College Intramural Touch Football

'he Effects of Playing Surfaces on Injuries in College Intramural Touch Football by Michael J. Stevenson, Ph.D. University of Michigan and Bruce D. Anderson, Ph.D., University of Minnesota (*Phokos b y Mari C o r d e s ) There is continuing controversy on the general effects of playing surface on injury occurance rates, especially i n football. (Carry-1970, Lashbrook-1971, Underwood-1971, Chevrette-1977). Major complaints against artificial turf are itsabrasive qualities, heat factors involved with the surfaces and hardness compared t o natural turfs. A review of the literature on the effects of synthetic surfaces on injuries re- veals conflicting results. (Bowers1973, Bowers-1974, Bramwell-1972, Kretzler-1971). An investigation by Adkinson and Garrick, 1974, reported that injuries among football players vary depending on the specific type of artificial turf. They found five injuries per game on natural grass, 16 per game on Astro-Turf, and three per game on Tartan Turf. However, injury rates were lower on both syn- t h e t i c surfaces w h e n wet. The present study describes a comparison of injury rates i n touch football played on synthetic Tartan Turf and natural grass. METHODS AND PROCEDURES Subjects Sixty-four touch football teams (834 individuals) were randomly chosen from a possible 140 teams representing intramural organiza-

tions at the University of Michigan during the 1971 touch football season. Thirty-two of the teams were randomly assigned to play all games (64 games) on Tartan turf while the remaining 32 teams played all games on natural turf. Each team played four games and each player played in an average of 3.4 games. Each of the 834 players received a preseason questionnaire which provided basic.descriptive information. A post-season questionnaire was given to each of the players which provided information concerning injuries during the season, and also included game related items. No protective equipment was worn by the players. Shoe type included regulation football shoes, soccer shoes, ripple-soled track shoes, and common gym or tennis shoes. The field monitors observed no player wearing street shoes. For safety reasons, no player was allowed to participate without shoes. The Fields All touch football games (twofifteen-minute halves with a five-minute intermission) were played on either a Tartan artificial surface field or a natural grass field. The Tartan field (constructed in 1969) is covered with 3M's Tartan Turf and was modified from the 120 X 50 yard tackle football field to the 10UX40yard regulation touch football field. Environmental data (Table 1) recorded for each field when games were played included temperature, wind velocity, and precipitation. Since the fields were in close proximity and games were scheduled at the same time on both fields, these environmental factors did not significantly vary from one surface to the other for the duration of the study. Injury Data Injuries were classified as major or minor according to the Ameriical Association, Stand lature of Athletic lnjur Chicago 1966. Major injuries included fractures, dislocations, concussibns, and serious lacerations. Minor injuries included contusions, sprains, strains, and abrasions. WEATHER AND FIELD CONDITIONS Games -- Games Environmental Tartan Grass Condition Number Percent Number Fercent Weather Conditiz Clear Cloudy Rain Snow Wind Velocity Elild 10 Knots Moderate 10-18 Knots 13 21.0 13 21.0 Very Windy 18 Knots 4 7.2 5 7.2 TOTAL 60 100.0 64 100.0 Field Condition Dry Damp Very Wet TOTAL 60 100.0 64 100.0 Temperature Interval in Degrees Farenhs 60-69 17 28.3 20 31.3 70- + 0 0.0 0 0. 0 TOTALS 60 99.9 64 100.1 Data on injuries were collected and verified from two sources. Each game was assigned an observer trained in advanced first aid who identified injured players byobservation and by questioning apparent victims. Each player who was identified by a game observer as having been injured-completed a followupquestionnaire to provide further medical verification of the injury, particularly the major injuries. This observation and verification strategy identified 75 percent of the recorded injuries. The remaining injuries, 25 percent, were identified by player response to the post-season questionnaire. Each player not previously identified who indicated in the questionnaire that he had been injured was sent the same injury follow-up questionnaire cited earlier in order to provide additional -- medical verification of the injury, particularly the serious injuries. Statistical Techniques Comparisons of selected injuries on Tartan Turf and natural grass were made using chi square anal-

TALLE 7. INJURIES DISTRIBUTED ACCORDING TO INJURY TYPE AND PLAYING SURFACE -- Tartan -- Grass Minor Injuries Major Injuries :.finor Injuries Major Injuries Injury Type Number Percent Number Percent Number Percent Number Percent Fracture 0 0.00 2 11.76 0 0.00 4 33.33 Sprain 17 32.69 0 0.00 12 46.15 0 0.00 Strain 2 3.85 0 0.00 3 11.54 0 0.00 Contusion 15 28.85 0 0.00 5 19.23 0 0.00 Dislocation 0 0.00 2 11.76 0 0.00 2 16.66 Abrasion 14 26.92 0 0.00 /+ 15.38 0 0.00 Concussion 0 0.00 5 29.41 0 0.00 3 25.00 Ldceration 0 0.00 8 47.05 0 0.00 3 25.00 Other 4 7.69 0 0.00 2 7.69 0 0.00 TOTALS ysis. lnjury attack rates were computed by dividing the total number injured in a specific category by the total number in that category. These were computed for each field condition category for both minor and major injuries. lnjury risk ratios were computed bydividing the attack rate of the subcategory with the lowest attack rate within the overall cateogry. RESULTS AND DISCUSSION General lnjury Data There were 107 reported injuries (Table 2) on both fields during the four-week study period. This accounted for an overall attack rate of 12.8 injuries per 100 players. Of the 107injuries,69occurred on Tartan representing an attack rate of 15.9per 100 players. The remaining 38 injuries occurred on the grass field, representing an attack rate of 9.5 per 100 players. These differences are statistically significant [P.05]. The attack rate on the Tartan field was substantially higher than the 8.7 per 100 reported in a similar study on grass field by Kraus in 1969. However, the attack rate on grass (8.7) in the Kraus study is similar to the 9.5 on grass in the current study. Table 2 also illustrates the difference between minor and major injuries. All injury classifications were made according to the American Medical Association,Standard Nomenclature of Athletic Injuries, Chicago 1966. A major injury is designated by the degree of disability. For example, injuries such as fractures, dislocation, head concussions,and severe lacerations (requiring stitches) are defined as major. Differences between minor and major injuries on the Tartan surface were statistically significant [P.05], with roughly three times more minor than major injuries. On the natural turf there were two times more minor than major injuries [P.05]. It is interesting to note that abrasions account for substantially more minor injuries on Tartan than grass surfaces. This may well be attributed to the abrasive nature of the artificial turf and the frequent failure of intramural participants to wear proper protective clothing. Descriptive lnjury Data The injury data was further analyzed as to type, body location, type of play when sustained, nature of players' activities when injured, and condition of the field surface when injured. Type - Sprains (Table 2) were the leading type of minor injury on both Tartan and grass surfaces. This is similar to the findings of Kraus (1969). Contusions and abrasions were the next most frequently reported injuries. Lacerations were the most common major injurieson Tartan while fractures were the most common on grass (Table 2). Concussions accounted for the next highest category on both surfaces. A total of 26 of 107 individuals injured (18 Tartan, eight grass) did not attend class the day following the injury, and 10 of the 26 required hospitalization (Table 3). Body Location - The head was t

the most frequently injured part of TAELE 3. INJURIES DISTRIBUTED ACCORDING TO EXTENT OF PLAYER DISABILITY the body, followed by the knee AND PLAYING SURFACE and ankle, independent of playing surface (Table 4). The head accounted for 70 percent of the major injuries on both Tartan and grass -- Tartan Grass fields. Extent of Player Disability Number percent* Number ~ercenf? Type of Play - Pass plays accounted for 56 percent of all injuries On Not Able to Continue in Game 24 34.8 14 36.8 both fields while running plays 'Jot Able to Attend Class Next accounted for 32percent (Table 5). Day 18 26.1 8 22.1 These figures should be viewed carefully since intramural touch Saw Doctor More Than Two Times 7 20.1 7 18.4 football is primarily a passing game. Hospitalized 5 7.2 5 13.2 Nature of Player Activity - Injuries to offensive and defensive players were similar (Table 6). The block- *Per cent of all Injured by Surface er is the most frequently injured TABLE 4. INJURIES DISTRIBUTED ACCORDING TO SPECIFIC BODY LOCATIONS AND PLAYING SURFACE Tartan - Grass Combined Minor Injuries Major Injuries Minor Injuries _Maj:-ror_- Injuries - All Injuries Body Location Number Percent Number Percent Number Percent Number Percent Number Percent Leg 1 1.92 0 0.00 0 0.00 0 0.00 1 0.93 Ankle 12 23.00 1 5.88 9 34.62 2 16.67 24 22.43 Knee 16 30.77 3 17.64 9 34.62 0 0.00 28 26.17 Foot 0 0.00 0 0.00 1 3.85 0 0.00 1 0.93 Head 15 28.85 12 70.58 6 23.08 7 58.33 40 37.38 Shoulder 6 11.54 1 5.88 1 3.a5 3 25.00 11 10.28 Arm 2 3.85 0 0.00 0 0.00 0 0.00 2 1.87 TOTALS 52 99.93 17 99.98 26 100. 02 12 100.00 107 99.99 TABLE 5. INJURIES DISTRIBUTED ACCORDING TO TYPE OF PLAY AND PLAYING SURFACE Tartan -- Grass Combined Minor Injuries Major. - -- Injuries >!inor Injuries Major Injuries All Injuries Type of Play Number Percent Number Percent Number Percent Number Percent Number Percent Pass 27 51.92 8 47.06 18 69.23 7 58.33 60 56.07 Run 20 38.46 7 41.18 5 19.23 2 16.67 34 31.78 Punt 1 1.92 1 5.88 0 0.00 1 8.33 3 2.80 Kickoff 3 5.77 1 5.88 3 11.54 1 8.33 8 7.48 Extra Point 1 1.92 0 0.00 0 0.00 1 8.33 2 1.87 TOTALS 52 99.99 17 100.00 26 100.00 12 99.99 107 100.00

offensive player, while the line rusher was the most frequently injured defensive player. Field Surface Condition -The surfacecondition of each field was judged as either dry, damp, wet, very wet, or poor (i.e., rough, uneven) (Table 7). Very wet field conditions yielded the highest attack rates for minor injuries on tartan. This iscontrary to the results reported by Adkinson and Garrick, 1974, and may be explained by the fact that players in the Adkinson-Garrick investigation were all varsity athletes provided with cleated football shoes which provide superior traction and mobility on a wet sur- face. Dry field conditions yielded the highest attack rates for minor injuries on grass. Wet field conditions yielded the greatest attack rates for major injuries on Tartan, as well as on grass. A chi square test yielded a significant difference [P.05] between the two fields for major injuries. fable 6. INJURIES DISTRIBUTED ACCORDING TO NATURE OF PLAYER ACTIVITY IN THE GAME AND PLAYING SURFACE Tartan - Grass Combined Minor Injuries _Major I1l.i ur* Yinor Injuries Maiop Injuries All Injuries Name of Activity Number Percent Number Percent Number Percent Number Percent Number Percent Offensive 30 57.69 9 52.94 13 50.01 5 41.67 54 53.27 Run!~er 4 7.69 2 11.76 1 3.85 0 0.00 7 6.54 Kicker 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 Passer 1 1.92 1 5.88 1 3.85 3 25.00 6 5.61 Blocker 15 28.85 5 29.41 5 19.23 1 8.33 26 24.30 Pass Receiver 10 19.23 1 5.88 6 23.08 1 8.33 18 16.82 Defensive 22 42.31 8 47.06 13 50.00 7 58.33 50 46.73 Line Rusher 12 23.08 6 35.29 10 38.46 3 25.00 31 28.97 Pass Defender 9 17.30 1 5.88 3 11.54 4 33.33 17 15.89 Pass Interference 1 1.92 1 5.58 0 0.00 0 0.00 2 1.87 TOTALS 52 100.00 17 99.98 26 100.01 12 100.00 107 100.00 TABLE 7. ATTACK RATES AND RISK RATI0S ACCORDING TO CONDI'rION OF FIELD AND PIAYING SURFACE TARTAN - GRASS Minor Injuries Major-_ Injuries llinor Injuries. Major - Injuries Condi- Total lotal tion of Players Number Attack Risk Number Attack Risk Players Number Attack Risk Number Attack Risk Field Tartan Injured Rate Ratio Injured Rate Ratio Grass Injured Rate Ratio Injured Rate Ratio Dry 38 29,7632 3.8160 9.2368 1.2+30 LG 21.8750 2.6253 3.I250 1.0000 Damp 21 17.SO95 4.0475 4.I905 1.0000 5 2.3333 1.0000 4.6666 5.3328 Wet 5 1.2000 1.0000 4.8000 4.1995 3 2.6666 2.0000 1.3333 2.6664 Very Wet 5 5 1.0000 5.0000 0.OOOO.0000 3 0.OOOO.OOOO 3 1.0000 8.0000 Poor 0 0.OOOO.0000 0.OOOO.0000 2 1.5000 1.5002 1-5000 4.0000 TOTALS 69 52l.7536 3.7680 17'.2464 1.2934 38 26.6842 2.0528 12.3158 2.5264 1 - Chi-Square Analysis of the Number of Minor Injuries on Tartan Versus Grass Playing Surface Results in Statistical Significance; Xt4) = 10.82, PL.05. 2 - Chi-Square Analysis of the Number of Major Injuries on Tartan Versus Grass Playing Surface Results in no Statistical Difference; Xc4) = 8.81, PL.05.

I n summary, it appears that significantly more injuries occur o n Tartan turf than o n natural grass. However, n o significant differences were present comparing major injurieson Tartan or natural surfaces. RECOMMENDATIONS 1. As abrasions account for such a high percentage of minor injuries, particularly o n Tartan turf, it i s recommended that pads for the elbows and the knees be worn. 2. Since head injuries account for a relatively high percentage of major injuries, i t is recommended that foam rubber helmets be made available for all participants. 3. Since there i s a high risk of injury t o blockers and line rushers, it is recommended that a rule change be adopted which would require pass blockers and rushers by reducing the distance and potential velocity between blockers and rushers. 4. Since riskof injury isexcessive for both surfaces when wet o r very wet, it is recommended that game administrators postpone games under such conditions. t h e rugs. Sports lllustrated 23:40-42, September, 1970. Chevette, J., Artificial Turf i s Faster. Athletic Journal 57 (10):22,54, 1977. Garrick, J., Requa, R., and Adkinson, J., Traction, playing characterisitics, and injury rates o n a synthetic turf field i n college football. Medicine and Science i n Sports 4-1:62, Spring, 1972. Kraus, J., An Epidemiologic Investigation of Predictor Variables Associated w i t h I n t r a m u r a l Touch Football Injuries. Unpublished Doctoral Dissertation, University of Minnesota, 1967, 251 pages. Kraus, I., and Gullen, W., An epidemiologic investigation of predictor variables associated with intramural touch football injuries. American Journal o f Public Health 59:2144-56, December, 1969. Kretzler, H., Artificial turf and football injuries. Mimeographed, presented t o National conference o n the Medical Aspects of Sports, New Orleans: American Medical Association, November 28, 1971,15 pages. Lashbrook L., The facts about fake grass.)ournal of Health, Physical Education, a n d Recreation 42:28-29, November-Decem ber, 1971. Underwood J., New slant on the m o d sod. Sports Illustrated, 35:32-24, November 15,1971. REFERENCES Adkinson, J., and Garrick, J. High school football injuries, A comparison of synthetic playing surfaces. Medicine & Science i n Sports 4-1: 62, Spring, 1974. Bowers, K., Ankle and knee injuries at West Virginia University before and after Astro Turf. West Virginia Medical Journal 69-1 :I3, January, 1973. Bowers, K., and Martin, R. Impact absorption, new and old Astro Turf at West Virginia University. Medicine a n d Science in Sports 6-3: 217-221,1974. Bowerse, K., and Martin, R. Turf Toe: A shoe-surface related football injury. Medicine a n d Science in Sports 8-2:81-83,1976. --"Bramwell, S., and Garrick, 1. High school football injuries: Acomparison of playing surfaces. Medicine a n d Science in Sports 41:63, Spring, 1972. Carry, P., A surprise case of bugs i n