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INCIDENCE RATE OF INJURIES DURING SPORT ACTIVITY AND PHYSICAL EXERCISE IN CRAIOVA: INCIDENCE RATES IN 8 SPORTS
Lect.univ.dr. Jean FIRICA
Lect.univ.dr. Camelia FIRICA
Asist. mr. Christian Manuel FIRICA
University Center - Craiova
Keywords: sports injuries, prevention, incidence rate, risk calculation
Abstract
A prospective study of acute injuries from sports and physical exercise was carried out during 1 year in a total population of a municipality with 320.000 inhabitants. Data on exposure were collected: the number of participant in each sport, the hours of participation, and number of weeks in the season per year. The number of injuries was used as numerator and the exposure data as denominator in a formula modified from Chambers for the calculation of population at risk in sports. A total of 585 injuries occurred in 8 different sports: 22% of the injured were males. The majority of the injuries were from soccer. 50% of the males and 29% of the females. Incidence rates in 8 sports are presented. The ranking order differs, when calculating not only the number, but also the exposure. Volleyball and handball were then found to have the highest risk followed by soccer. Team and contact sports on the whole had the highest rates in both genders. As a group, intercom any players had the highest rate, especially in soccer. The lowest rates were found in individual sports. Gymnastics, except in school physical education, had no injuries at all. Sprains and strains were diagnosed in nearly half of the cases and the foot and ankle were the most frequent sites. Preventive measures are proposed.
Introduction
The benefits of a physically active life for prevention of disease have been described. There are, nevertheless, adverse effects, especially the risks of acute injuries from sports and physical exercise. In a review of the current status of data on mortality and morbidity from sports-related injuries. Injuries related to sports participation are declared a major public health problem. The development of comprehensive surveillance systems arc desired to counteract the deficits in data on morbidity and mortality. Further demands are:
1. Enlargement of the International Classification of Diseases for identification of sports-related injuries.
2. Generation of accurate data on populations at risk.
3. Description of the economic costs and physical disabilities associated with long-term chronic sports injuries.
A prospective study which meets these requirements was carried out in a total population of a municipality in Romania. Variables were studied such as the amount of sports and exercise practiced, the exposure to risk, the number of injuries, severity and mechanisms of acute injuries as well as their consequences for the injured and for society. The study also compared injuries due to sports and exercise relative to all other injuries in a total population.
The purpose of this article is to report the number of injuries per year and the incidence rate, i.e., the population at risk for acute injuries in sports and physical exercise in a defined area. It is intended to provide recommendations for preventive measures to reduce the number of acute injuries, especially in sports associated with a high rate of injury per person-hours of participation.
Subject - Methods- Material
The population comprised all inhabitants of the municipality of Craiova, an area in the southwest of Romania. The area has one urban population center. In 2004, the year of the investigation, the population of the municipality was 320.000 inhabitants. The study included all persons who were attended to by a physician and registered for an acute injury sustained in sports activity or physical exercise. The Public Health Care of Dolj County has a system for registration of every acute visit to the clinics in the municipality of Craiova. The system is designed for accident and injury research. There are five different Public Health Clinics: Three Health Centers, one General Casualty Care Center, and the Casualty Department of the Municipal Hospital, the latter including both outpatient and inpatient clinics. The only private physician specialized in sports medicine also registered the visits relevant to this study. The patients thus registered for an acute injury from sports activity or physical exercise were all interviewed on the telephone and the interviews were later completed with the case histories. The no coverage in the registration system has been assessed at 5,5% in 2003.
The exposure to risk, the incidence rate, was calculated with a formula modified from Chambers:
Table 1
Inpatient and outpatient injuries in Craiova 2004 by environment
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n of injuries in sport during year x 104
(n of participants) x (average hours of participation/week) x (weeks of season/year)
Data were collected on the amount of sports and physical exercise practiced in the population from three different sources:
1. A questionnaire developed by authors were sent to a random sample of 7% of the population in the age range of 16 to 60 years. It concerns activities in sports during leisure time and inquires about frequency, intensity, duration, and type of activity. The results were used in the denominator of the sports presented, namely, in soccer, running, handball, volleyball. They have also been used in one team sport: Volley-ball. The no response was 22.9%.
2. Data on team and contact sports came from the sports clubs of the region. They reported the number of all teams and participants, their age and sex, and the amount of practice and number and duration of matches or competitions.
3. The number of pupils and the amount of lessons in physical education in the schools in the municipality were obtained from the Romanian National Board of Education and National Sports Agency. This allowed the calculation of the exposure to obligatory sport at school to be made.
The severity of the injuries was classified with two different measures, the first being the abbreviated injury scale (AIS), which grades the injuries from 1 to 6, where 6 is the severity code for maximum injury, virtually unsurvivable, and the second, a measure often used in sports injury epidemiology: Absence from sports activity due to injury.
It has three grades:
Mino = absence of less than I week
Moderate = more than I week, but less than I month
Major = more than I month.
These three grading have their greatest utility in the AIS codes 1,2, and 3.
Statistical Method
Confidence intervals have been calculated in team and contact sports estimating the variance of the number of injuries as the number of injuries and assuming a Poisson distribution. In individual sports the incidence rate is a ratio of two stochastic variables. The logarithm of the ratio gives a difference of two logarithmic functions. Confidence intervals of the logarithmic transformation of the ratio has been calculated using a formula:
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Table 2
Number of sport injuries per year (males, aged 5-65 years)
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Table 3
Number of sports injuries per year (females, aged 5-70 years)
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The tabled confidence intervals are antilogarithms of the I and upper bounds of the interval in the logarithmic scale, I the asymmetry around the point estimate.
Results
Distribution of Sex and Age
Of all acute visits to the clinics due to accidents during the 1 period, 18% were from sports or physical exercise (Table 1). These 18%, or 549 injuries, occurred in 8 different sports of the injured were males. Their mean age was 23.0 years with a median age of 21 years. The female mean age was 19.5 with a median of 15 years. Seventy-five percent of the injuries were within the age groups of 10 to 29 years. Sixty-two were injured more than once, 39 of the reinjured were males (62%).
Number of Injuries/ Year
Data on the number of injuries in different sports are in Tables 2 and 3. The majority of the injuries were at soccer, 50% of the injured males and 29% of the females. Nearly half or 48% of all injuries in male during a match or competition, whereas in females o their injuries were from a match or competition.
Incidence Rates
When the exposure is taken into account, the ranking differs. Tables 4 and 5 indicate how the incidence rate were devised for males and females according to each sport category.
Table 4
Incidence rates (males, aged 16-60 years)
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Twenty-nine of the of the injuries in handball and soccer occurred in intercom any games. The average incidence rate for these two categories was:
Total: 810 0.70 22.5 29 22.5 13.5 28.1
Table 5
Incidence rates (males, aged 16-60 years)
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As Soccer accounted for 44% of all injuries and showed a high incidence rate, risk calculations have been made for all soccer a players, also for the ages from 8 - 14 (Tables 6 - 7).
Diagnoses and Sites of Injury
Sprains and strains were diagnosed in nearly half of the cases. The diagnoses were very similar for males and females.
Table 6
Incidence rates in soccer (males, aged 8-60 years)
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**Mainly time involved in match: 0.67h (2x20min) is the estimated time spent warming up before match.
Of the 155 soccer injuries 119(77%) occurred during matches. The average incidence rate for time at match was consequently higher:
Total 1845 1.60 26.0 119 17.1 13.4, 19.4
Table 7
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Of the 36 soccer injuries 26 (72%) occurred during matches. The average incidence rate for time at match in females was:
Total: 451 1.68 24.7 26 14.8 9.2, 20.4
Table 8 shows the most frequent diagnoses. There may be more than one injury per person.
Table 8
Diagnoses of injures by sex
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Sites and Diagnoses of Injury in Soccer
Fifty-nine percent of ail foot and ankle injuries in males were sustained in soccer. Injuries to the knee accounted for 58% and to the wrist 72%. The male soccer players had fewer fractures, 29% of all fractures in males, but they had 59% of the sprains and strains. In female injuries there were no striking differences in the patterns of site of in jury or diagnoses when comparing the injuries sustained in soccer with those sustained in other sports.
Injury Severity
Abbreviated injure scale. Close to 50% were minor injuries. Of the 148 moderate male injuries, 98 were foot or ankle ligament injuries (26% of the 270) and of the 42 serious male injuries, there were 37 knee ligament injuries (1o% of 270). Corresponding numbers for females were 45 foot and ankle ligament (21 % of 200) and 18 knee ligament injuries (8 % of 200). Brain injuries /concussions vary in this material from AIS 1 to AIS 3, depending on the neurological deficit. There juries with the severity degrees from AIS 4 to AIS 6.
Table 9
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Absence from sports activity. Absence from sports activity due to the sustained injury was the second measure used to estimate the severity of the injuries (Table 10).
Table 10
Absence from sports activity due to injury
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Discussion
Reports on acute sports injuries are often made wrought analysis of the exposure to participation sports. There is also little conformity in the methods of risk calculation. The modified formula from Chambers used this paper has a denominator that considers number of participants in a sport, but also the duration of training and match or competition as well as the length of season. The absence from training and match or has not been accounted for though; the rates then be slightly underestimated. Another possible source underestimated rates is the population-based questionnaire the specialists point at the likelihood that certain individuals might exaggerate the report on the amount of physical act life. Concerning the accuracy of risk calculation on data from the Romanian National Board of Education and National Sports Agency, these data also contain a hidden underestimation: The absence from or the non-occurrence of lessons in physical education have not been considered. Team and contact spoils accounted for the majority of the injuries in both genders and the highest risks were found in handball and soccer. Soccer was the most popular of the team sports and had the highest number of injuries per year. Even after considering the exposure time in 8 different sports, it remained a high-risk sport. As a consequence, it will be subject to further discussion. The incidence rate was especially high for male junior soccer players. The result is not surprising; this is a very active age. The inter-company soccer players, however, had the highest rate of all. Their exposure time during the match was very short and so was their warming up. Many of them did not warm up at all, as was reported by the questionnaire and the interviews. These players seldom attended training, the activity was mostly organized only with short matches, and all the injuries occurred at matches. Furthermore, intercom any players were often older. Their mean age of 31.5 should be compared with the senior league players whose mean age was 24.0. In females soccer injuries were just above one-quarter of all injuries, but the incidence rate was high. I n the age group of 15-16 years, the rate was three times as high as for senior female players. In the lower ages the injuries were very few; calculations with such low numerators call for special carefulness by the interpretation. A high risk for males was found in horseback riding, but the calculation of risk for male riders was based on only four injured, which does not allow any general comment to be made. In females this sport category had the second-highest number of injuries per year, but the incidence rate could only be calculated for the age of the respondents of the questionnaire, which was from 15 to 59 years. The other individual sports in which an incidence rate was calculated had rates below 1.5: running and swimming. Gymnastics, finally, had no injuries registered at all. School physical education had a higher incidence rate for females than for males in the ages from 15 and upward. The approach to the question of the risks in school physical education is different, due to the fact that it is a compulsory activity. The material was classified according to the last revision of the AIS system which was done in 1994. The codes for distortions and ruptures of the ligaments of the foot and ankle were then change from AIS l to AIS2 and from AIS2 to AIS3 for the distortions or rupture of a knee ligament. This makes a big difference in a study of sports trauma, where more than one-third of the injuries range into these two categories. It gives bias to any comparison with earlier classifications.
Preventive Measures - Recommendations
One of the purposes of this study was to propose preventive measures for the sports with high incidence rates and a high number of injuries per year.
Team and contact sports. Soccer then becomes a main concern for prevention. Authors have demonstrated a reduction of as much as 74% of the injuries in soccer (including overuse injuries) by a prophylactic program made up of seven different parts. The program has been recommended to the soccer teams in Romania and the ideas are becoming known to coaches and players. The work on consolidating these prophylactic methods of coaching and practicing should therefore be supported. Methods for preventive measures in cooperation with organizations have been developed within the Craiova project, but have not yet been tested on sports injuries. The organization of the inter-company sports is very different from other team sports. The lack of training possibilities, the schedules of the sports arenas with no time for warming up, and the absence of supervising by coaches and persons with medical or paramedical education are all factors that might have an effect on the injury incidence. More knowledge and information about the etiology of injuries and the effects of warming up need to be spread to participants of inter-company sports. The preseason medical test developed by the authors for soccer teams could be made a routine before obtaining a player's licence in all team sports. Besides regular physical examination, history of injuries and persistent symptoms, it includes screening for functional instabilities of ankle and knee joints and measurements of range of movement in the lower extremities. Players with instability in these joints or muscular tightness have an increased risk for injury. The specialists demonstrated the improvement of functional instability and the preventive effects by ankle disk training. Foot and ankle injuries were found to be the most common in this material, as well as in a great number of other studies on acute sports injuries. Some foreign specialist declared ankle injuries as being one of the most significant problems of the sports world. One preventive measure to suggest would thus be the use of ankle disks for coordination training of the ankle joints as a routine exercise after the warming up program and before starting the actual training or match. This can be recommended in many different sports. In team sports such as soccer, handball, volleyball, basketball, and in pure contact sports such as aikido sports the main injury mechanism was by strong contact or collision with another player (75%). As a consequence the most serious injuries (AIS 3) occurred in these sports, especially tears or ruptures of knee ligaments: 45 of 59 knee ligament injuries, and exactly half of these as a result of tackling, contact, or collision with another player. This fact elucidates the importance of observing existing rules. It is possible that there is a tolerating attitude toward violence, as only one person of the seriously injured mentioned noncompliance to rules as a possible cause. Of all 549 injured only 38 (8%) considered violation of rules to be the cause of the accident. In competitive sports there is often a desire to extend the performance to the limits of capacity. By increasing professionalization and commercialization of sports, the will or the feeling necessity to extend to these limits for economic reasons might arise. Aggressive behavior can also result and the forming of an unofficial normative rule system with higher tolerance for violence than the official rules. To counteract any aberrant aggressive behavior therefore becomes a concern in sports injury prevention. It is necessary that rules and regulations observed continuously by players, coaches, referees, and officials.
Individual sports. The individual sports show on the whole lower incidence rates than team or contact sports. Yet, the rate soccer is high. All but one of these accidents occurred in school physical education. The interaction of uneven ground requires skill, strength, and endurance. This can only be acquired by training, but it would be recommendable that the training be supervised and systematically directed to skill training as accident prevention, especially for beginners. Nearly half of these accidents happened during private training. Further, observance of safety regulations is of importance. Skill training and supervision are also important these sports together with learning to anticipate the reaction. It is important to continue to spread information at good safety equipment. For runners and racket sport players, ankle disk coordination training, as described earlier, can be recommended: 69 % of the injuries in these sports were to the foot and ankle. The choice adequate footwear should also be stressed.
Conclusions
The generation of denominator data on populations at risk demanded in sports injury epidemiology, but there is little conformity in the methods of risk calculation. A modified formula from Chambers offers an accurate basis for the calculation of risk in different sports. Most of the injuries were from team and contact sports especially soccer, which accounted for 50% of all injuries males and 29 in females. The highest risks were found in handball and soccer. However, as a group, the intercom any soccer players had an even higher risk. Low risks were found in individual sports such as running and swimming. Gymnastics, except during physical education in school, had no injuries at all. Sprains and strains were diagnosed in nearly half of the cases. The foot and ankle was the most frequent site of injury, foil' by wrist/hand and knee. The classification of severity according to the abbreviated injury scale showed no injuries above AIS 3.
The following preventive measures are proposed:
1. A prophylactic program developed by specialists, with a demonstrated reduction of 75% of all injuries in soccer (including overuse injures), is further recommended to coaches and players. These methods can be used in most team sports.
2. A preseason medical test as described for soccer teams by specialists could be made a routine before obtaining a player's license in team sports.
3. The use of ankle disks for coordination training as a routine exercise after the warming up program in many sports. The prophylactic effect of disk training on ankle sprains has been demonstrated.
4. The necessity of the observance of rules and regulations must be stressed. To counteract aberrant and aggressive behavior and a tolerance for violence is a major concern in injury prevention. Rules and regulation should be observed continuously by players, coaches, referee and officials.
5. For intercom any sports, the schedules of the sports arenas should be reorganized with time for warming up and training possibilities. More supervising by coaches and persons with medical or paramedical education and information about the etiology of sports injuries are further recommendation.
6. In individual sports riding the observation of safety regulation, the control of safety equipment and supervised and directed skill training are measures to decrease the number of injuries.
Reference
ARMITAGE, P., Statistical Methods in Medical Research (1984), Oxford, BLACKWELL, p.85
CHAMBERS, R.B. (1981), Orthopedic injuries in athletes (ages 6 to 17), Comparison of injuries occurring in six sports. In: Am J Sports Med. 7: p. 92-95
Statistics Department of the Public Health Clinics Craiova
