Self-reported psychological characteristics as risk factors for injuries in female youth football

Identifying and understanding injury risk factors are necessary to target the injury-prone athlete and develop injury prevention measurements. The influence of psychological factors on injuries in football is poorly documented. The purpose of this 8-month prospective cohort study therefore was to examine whether psychological player characteristics assessed by a self-administered questionnaire represent risk factors for injury. At baseline, female football players (14–16 years) were asked to complete a detailed questionnaire covering player history, previous injuries, perception of success and motivational climate, life stress, anxiety and coping strategies. During the 2005 season, a total of 1430 players were followed up to record injuries. A history of a previous injury [odds ratio (OR)=1.9 (1.4; 2.5), P <0.001] increased the risk of a new injury to the same region. There were significant differences in disfavor for previously injured compared with non-injured players for ego orientation ( P =0.007), perception of a performance climate ( P =0.003) and experienced stressful life events ( P <0.001). However, only high life stress ( P =0.001) and perception of a mastery climate ( P =0.03) were significant risk factors for new injuries. In conclusion, a perceived mastery climate and a high level of life stress were significant predictors for new injuries in a cohort of young female football players.     

High school football injuries: identifying the risk factors

This epidemiologic survey of the literature on the factors contributing to the high number of high school football injuries consolidates the current information on the characteristics and risk factors associated with these injuries. To reduce the incidence of knee sprains and strains, the most common injuries to this population, the following preventive recommendations are presented: 1) optimum maintenance of playing fields; 2) use of the soccer-style shoe; 3) noncontact and controlled activities in practice sessions; and 4) increased vigilance over technique during injury-prone preseason practices. The authors conclude that more research into factors such as exposure time and activity at injury will further reduce the risk to the high school football player.     

Anterior cruciate ligament injuries in female athletes: Part 1, mechanisms and risk factors

The mechanism underlying gender disparity in anterior cruciate ligament injury risk is likely multifactorial in nature. Several theories have been proposed to explain the mechanisms underlying the gender difference in anterior cruciate ligament injury rates. These theories include the intrinsic variables of anatomical, hormonal, neuromuscular, and biomechanical differences between genders and extrinsic variables. Identification of both extrinsic and intrinsic risk factors associated with the anterior cruciate ligament injury mechanism may provide direction for targeted prophylactic treatment to high-risk individuals.     

Incidence and player risk factors for injury in youth football.

OBJECTIVE: To estimate the incidence of injuries in youth football and to assess the relationship between player-related risk factors (age, body size, biological maturity status) and the occurrence of injury in youth football. DESIGN: Prospective over two seasons. SETTING: Two communities in central Michigan. PARTICIPANTS: Subjects were 678 youth, 9-14 years of age, who were members of 33 youth football teams in two central Michigan communities in the 2000 and 2001 seasons. METHODS: Certified athletic trainers (ATCs) were on site to record the number of players at all practices and home games (exposures) and injuries as they occurred. A reportable injury (RI) was defined by the criteria used in the National Athletic Trainers' Association (NATA) survey of several high school sports. Estimated injury rates (95% confidence intervals) per athlete exposures (AE) and per number of athletes were calculated for practices and games by grade. Player risk factors included age, height, weight, BMI and estimated maturity status. MAIN OUTCOME MEASURE: Estimated injury rates and relative risks of injury during practices and games by grade; logistic regression to evaluate relationships between player-related risk factors and risk of injury. RESULTS: A total of 259 RIs, 178 in practice and 81 in games, were recorded during the two seasons. Practice injury rates increased with grade level, while game injury rates were similar among fourth through fifth grade and sixth grade players and about twice as high among seventh and eighth grade players. The majority of RIs during the two seasons was minor (64%); the remainder was moderate (18%) and major (13%). Injured fourth through fifth grade players were significantly lighter in weight and had a lower BMI; otherwise, injured and non-injured players within each grade did not differ in age, body size and estimated biological maturity status. Logistic regressions within grade revealed no significant associations between injury and age, height, BMI, and maturity status. CONCLUSION: Game injury rates are higher than practice injury rates, and the incidence of injury tends to increase with grade level. Age, height, BMI and maturity status were not related to the risk of injury in youth football players.     

Nutrition and hydration concerns of the female football player

There is little information on the nutritional habits of female football players at any level of the game. There is also a shortage of information on the nutrition and hydration strategies that players should adopt. In general, differences in nutritional needs between males and females are smaller than differences between individuals, so that principles developed for male players also apply to women. There is a need to address energy balance and body composition: prolonged energy deficits cannot be sustained without harm to health and performance. Published reports show mean carbohydrate intakes for female players of about 5 g/kg/day, and this seems to be too low to sustain consistent intensive training. The timing of protein intake may be as important as the amounts consumed, provided that the total intake is adequate. Dehydration adversely affects skill and stamina in women as it does in men, so an individualised hydration strategy should be developed. The prevalence of iron deficiency in women generally is high, but it seems to be alarmingly high in female players. All players should adopt dietary habits that ensure adequate iron intake. Football training seems to increase bone mass in the weight-bearing limbs, with positive implications for bone health in later life, but some players may be at risk from inadequate calcium dietary intake.     

The female football player, disordered eating, menstrual function and bone health

Most female football players are healthy. However, recent findings from our studies on Norwegian female elite athletes also show that football players are dieting and experiencing eating disorders, menstrual dysfunction and stress fractures. Dieting behaviour and lack of knowledge of the energy needs of the athlete often leads to energy deficit, menstrual dysfunction and increased risk of bone mass loss. Although dieting, eating disorders and menstrual dysfunction are less common than in many other sports, it is important to be aware of the problem as eating disorders in female athletes can easily be missed. Therefore, individuals, including the players themselves, coaches, administrators and family members, who are involved in competitive football, should be educated about the three interrelated components of the female athlete triad (disordered eating, menstrual dysfunction and low bone mass), and strategies should be developed to prevent, recognise and treat the triad components.     

Head and neck injuries in college football: an eight-year analysis

The present study documented head and neck injuries in a study group of 342 college football players at a single institution for a period of 8 years. All freshmen players were screened for evidence of: (1) past history of head and neck injuries, and (2) abnormalities of the cervical spine on physical examination and x-ray film. By recording all head injuries and those neck injuries with time loss, incidence rates and patterns of injury incurred in college competition were determined. A total of 175 head and neck injuries were sustained by 100 players over the 8 year period. Those players with abnormal findings on screening examination were twice as likely to have a head or neck injury at some point in their college careers as those players with a normal screening examination. The greater the degree of abnormality on freshman screening examination, the more severe the neck injury in college was likely to be. Twenty-nine percent of all players in the study group sustained a head or neck injury during their college careers. The probability of a subsequent head or neck injury escalated sharply following a single incident. The overall incidence of injury was found to have been dramatically reduced over the 8 years. Influential factors such as legislative rule changes, medical status of recruits, and general coaching philosophies are discussed with regard to injury reduction and prevention of head and neck injuries in college football.     

Stress fracture risk factors in female football players and their clinical implications

A stress fracture represents the inability of the skeleton to withstand repetitive bouts of mechanical loading, which results in structural fatigue, and resultant signs and symptoms of localised pain and tenderness. Reports of stress fractures in female football players are not prevalent; however, they are probably under-reported and their importance lies in the morbidity that they cause in terms of time lost from participation. By considering risk factors for stress fractures in female football players it may be possible to reduce the impact of these troublesome injuries. Risk factors for stress fractures in female football players include intrinsic risk factors such as gender, endocrine, nutritional, physical fitness and neuromusculoskeletal factors, as well as extrinsic risk factors such as training programme, equipment and environmental factors. This paper discusses these risk factors and their implications in terms of developing prevention and management strategies for stress fractures in female football players.     

Cardiovascular risk factors in football players

Cardiovascular disease is a leading cause of death in the United States. Football players represent a subpopulation that may have a unique risk profile pattern. Studies have suggested that football players may be at increased risk for cardiovascular disease. Paradoxically, there may be a cardioprotective effect associated with activity in general and, specifically, participation at higher levels of football. Our review will attempt to outline the pertinent evidence in regards to cardiovascular risk factors in football players. Specifically, hypertension, hypercholesterolemia, obesity, and sedentary lifestyle will be considered. In addition, we will discuss potential risk factors for investigation including C-reactive protein, homocysteine, insulin resistance, and sleep-disordered breathing. Studies at all levels of competition will be considered, including retired players whose findings may represent lifelong changes that occur as a result of participation in football. Further investigation will be needed to help clarify the relationship between football participation and cardiovascular risk.     

Intrinsic risk factors for acute knee injuries among male football players: a prospective cohort study

This prospective cohort study was conducted to identify the risk factors for acute knee injuries among male football players. A total of 508 players representing 31 amateur teams were tested during the 2004 preseason for potential risk factors for knee injury through a questionnaire on previous injury, Knee Osteoarthritis Outcome Score (KOOS) and a clinical examination. Generalized estimating equations were used in univariate analyses to identify candidate risk factors, and factors with a P-value <0.10 were then examined in a multivariate model. During the football season, 61 acute knee injuries, affecting 57 legs (53 players), were registered. Univariate analyses revealed the KOOS subscores "Pain" and "Function in daily living" (OR for a 10-point difference in score: 1.26, 95% CI 1.03-1.55 and 1.35, 95% CI 0.98-1.85, respectively), any findings at clinical examination (OR: 2.62, 95% CI 1.03-6.68), flexion contraction in range of motion testing (OR: 0.96, 95% CI 0.93-1.00) and varus stress tests in full extension (OR: 8.50, 95% CI 1.85-39.0) and 30° flexion (OR: 5.69, 95% CI 1.73-18.8) as candidate factors. However, in a multivariate analysis, none of these factors were associated with an increased injury risk.     

Risk factors for hamstring injuries in community level Australian football

Objectives: To identify risk factors for hamstring injury at the community level of Australian football.

Methods: A total of 126 community level Australian football players participated in this prospective cohort study. To provide baseline measurements, they completed a questionnaire and had a musculoskeletal screen during the 2000 preseason. All were monitored over the season. Injury surveillance and exposure data were collected for the full season. Survival analysis was used to identify independent predictors of hamstring injury.

Results: A hamstring injury was the first injury of the season in 20 players (16%). After adjustment for exposure, increasing age and decreased quadriceps flexibility were identified as significant independent predictors of the time to sustaining a hamstring injury. Older age (23 years) was associated with an increased risk of hamstring injury (RR 3.8; 95% confidence interval (CI) 1.1 to 14.0; p = 0.044). Players with increased quadriceps flexibility (as measured by the modified Thomas test) were less likely to sustain a hamstring injury (RR 0.3; 95% CI 0.1 to 0.8; p = 0.022).

Conclusions: The findings of this study can be used in the development of hamstring injury prevention strategies and to identify Australian football players at increased risk of hamstring injury.

     

Interchange rotation factors and player characteristics influence physical and technical performance in professional Australian Rules football

Objectives

To examine the effects of match-related and individual player characteristics on activity profile and technical performance during rotations in professional Australian football.

Risk factors for acute knee injury in female youth football

Purpose

To prospectively evaluate risk factors for acute time-loss knee injury, in particular ACL injury, in female youth football players.

Methods

Risk factors were studied in 4556 players aged 12–17 years from a randomised controlled trial during the 2009 season. Covariates were both intrinsic (body mass index, age, relative age effect, onset of menarche, previous acute knee injury or ACL injury, current knee complaints, and familial disposition of ACL injury) and extrinsic (no. of training sessions/week, no. of matches/week, match exposure ratio, match play with other teams, and artificial turf exposure). Hazard ratios (HRs) and 95 % confidence intervals (CIs) were calculated from individual variable and multiple Cox regression analyses.

Results

Ninety-six acute knee injuries were recorded, 21 of them ACL injuries. Multiple Cox regression showed a fourfold higher ACL injury rate for players with familial disposition of ACL injury (HR 3.57; 95 % CI 1.48–8.62). Significant predictor variables for acute knee injury were age >14 years (HR 1.97; 95 % CI 1.30–2.97), knee complaints at the start of the season (HR 1.98; 95 % CI 1.30–3.02), and familial disposition of ACL injury (HR 1.96; 95 % CI 1.22–3.16). No differences in injury rates were seen when playing on artificial turf compared with natural grass.

Conclusion

Female youth football players with a familial disposition of ACL injury had an increased risk of ACL injury and acute knee injury. Older players and those with knee complaints at pre-season were more at risk of acute knee injury. Although the predictive values were low, these factors could be used in athlete screening to target preventive interventions.

Level of evidence

II.

     

Incidence of acute volleyball injuries: a prospective cohort study of injury mechanisms and risk factors

The purpose of the study was to examine the incidence and mechanisms of acute volleyball injuries, with particular reference to possible risk factors for ankle injuries. Coaches and players in the top two divisions of the Norwegian Volleyball Federation were asked to keep records of exposure time and all acute volleyball injuries causing a player to miss at least one playing day during one season. We found 89 injuries among 272 players during 51 588 players hours, 45 837 h of training and 5751 h of match play. The total injury incidence was 1.7 ± 0.2 per 1000 h of play, 1.5 ± 0.2 during training and 3.5 ± 0.8 during match play. The ankle (54%) was the most commonly injured region, followed by the lower back (11%), knee (8%) shoulder (8%) and fingers (7%). Of the ankle injuries, 79% were recurrences, and the relative risk of injury was 3.8 ( P < 0.0001) for previously injured ankles (38 of 232) vs. non-injured ankles (10 of the 234). Moreover, a reinjury was observed in 21 of the 50 ankles that had suffered an ankle ankle sprain within the last 6 months (42.0 ± 7.0%; risk ratio: 9.8 vs. uninjured ankles; P < 0.000001). The data indicate that external supports should be worn for 6–12 months after an ankle sprain and that specific injury prevention programs may be developed for ankle sprains in volleyball.     

Radiocontrast-associated renal dysfunction: incidence and risk factors

Contrast-induced nephropathy is a potentially serious untoward reaction to radiologic contrast media. The incidence of this nephropathy and the predisposing conditions are not well established, possibly because of methodologic differences between studies. We evaluated the incidence of contrast-induced nephropathy after femoral arteriography in 394 patients by using multiple definitions (different increases in serum creatinine or blood urea nitrogen levels at various times). When an increase in the level of serum creatinine of greater than 0.3 mg/dl and greater than 20% on day 1, 2, or 3 and on day 5, 6, or 7 was used to define the disorder, the incidence in our group of patients was 10% for nonazotemic patients vs 30% for azotemic patients (p less than .001); 2% for nondiabetic, nonazotemic patients vs 16% for diabetic, nonazotemic patients (p = .003); and 38% for patients who were both diabetic and azotemic vs 16% for diabetic, nonazotemic patients (p = .022). Baseline renal insufficiency and diabetes mellitus (especially when insulin dependent) were significant predisposing factors. The effects of dehydration and increased volume of contrast medium on the incidence of contrast-induced nephropathy were not clear; the age and sex of the patient were not important risk factors. The incidence of contrast-induced nephropathy depends on the definition used. Although contrast-induced nephropathy may develop in any patient, diabetes, renal insufficiency, and, possibly, dehydration and dose of contrast medium are risk factors.