Elite Football Players Research Articles

The Effect of Thigh Marker Placement on Knee Valgus Angles in Vertical Drop Jumps and Sidestep Cutting.

Knee valgus angles measured in sidestep cutting and vertical drop jumps are key variables in research on anterior cruciate ligament (ACL) injury causation. These variables are also used to quantify knee neuromuscular control and ACL injury risk. The aims of the current study were to (1) quantify the differences in the calculated knee valgus angles between 6 different thigh marker clusters, (2) investigate the trial ranking based on their knee valgus angles, and (3) investigate the influence of marker clusters on the cross-talk effect. Elite female handball and football players (n = 41) performed sidestep cutting and vertical drop jumping motions. We found systematic differences up to almost 15° of peak valgus between the marker sets in the drop jump test. The Spearman's rank correlation coefficient varied from .505 to .974 among the 6 marker sets. In addition, the cross-talk effect varied considerably between the marker clusters. The results of the current study indicate that the choice of thigh marker cluster can have a substantial impact on the magnitude of knee valgus angle, as well as the trial ranking. A standardized thigh marker cluster, including nonanatomical landmark, is needed to minimize the variation of the measurement.

Vitamin D receptor gene polymorphisms and musculoskeletal injuries in professional football players.

The aim of the present study was to investigate the association between vitamin D receptor (VDR) gene polymorphisms and musculoskeletal injury (MI) in elite football players. In total, 54 male professional football players were recruited from an official Italian professional championship team between 2009 and 2013. The cohort was genotyped for the ApaI, BsmI and FokI polymorphisms and MI data were collected over four football seasons. No significant differences were identified among the genotypes in the incidence rates or severity of MI (P=0.254). In addition, no significant associations were observed between VDR polymorphisms and MI phenotypes (P=0.460). However, the results of the casewise multiple regression analysis indicated that the ApaI genotypes accounted for 18% of injury severity (P=0.002). Therefore, while the BsmI and FokI polymorphisms did not appear to be associated with the severity or incidence of MI, the ApaI genotypes may have influenced the severity of muscle injury in top-level football players.

Epidemiological and clinical outcome comparison of indirect (‘strain’) versus direct (‘contusion’) anterior and posterior thigh muscle injuries in male elite football players: UEFA Elite League study of 2287 thigh injuries (2001–2013)

BackgroundData regarding direct athletic muscle injuries (caused by a direct blunt or sharp external force) compared to indirect ones (without the influence of a direct external trauma) are missing in...

The role of community in the development of elite handball and football players in Denmark

The primary purpose of this study was to investigate the effect of the place of early development in a sample of Danish male elite and youth handball and football players. The sample included 366 handball and football players from the elite Danish league in the season 2011–2012 and a comparison sample of youth players under the age of 12 from 2003, including 147,221 football and 26,290 handball players. Odds ratio analysis showed that both population size and density significantly affected the proportional number of youth players per community and the odds of athletes reaching an elite level in football and handball. The odds for youth player registrations in both handball and football increased in rural in contrast to urban communities. However, elite football players primarily came from communities of high density (>1000 pop./km2), whereas elite handball players primarily came from less densely populated communities (100 to <250 pop./km2). Furthermore, there seems to be a relation between representation of elite and talent clubs in different communities and the probability of becoming an elite player in both sports. The limited number of elite players in both sports from rural communities may be due to national talent development strategies that do not incorporate development support for clubs in rural areas. Additionally, the results of the study clearly suggest the need to include the youth player population to advance research findings in birthplace effect studies.

Kinematic effects of a short-term fatigue protocol on punt-kicking performance

The punt kick is a fundamental skill used in several team sports; however, there has been a lack of research on how fatigue affects its technique. The purpose of this study was to determine the effects of short-term fatigue on punt-kicking performance. Eight elite and sub-elite Australian Football players performed maximal drop punt kicks on their preferred leg prior to, during and after a match-specific fatigue protocol. Optotrak Certus collected kinematic data from kick foot toe-off until ball contact. Repeated-measures analysis of variance showed a significant increase in 20 m sprint times after each short-term protocol, indicating fatigue. Foot speed did not significantly change with fatigue; however, increases in the range of motion at the pelvis and kicking thigh, along with increases in kicking thigh angular velocity, occurred. For the support leg, maximum knee flexion angular velocity increased while there was greater flexion found at the knee and hip, and greater range of motion at the knee. Players are able to make kinematic adaptations in order to maintain foot speed while punting for maximal distance after short-term efforts.

Low back pain in young elite field hockey players, football players and speed skaters: Prevalence and risk factors.

Low back pain (LBP) hampers performance and experiencing an episode of LBP is strongly associated with recurrent episodes. The prevalence of LBP and associated risk factors among young elite athletes in popular sports in the Netherlands were studied. A questionnaire-based cross-sectional study was performed among 236 young elite athletes aged between 14–25 years in field hockey, football and speed skating. One hundred and eighty one (n = 181) athletes responded (response rate 77%). The overall, 12-month prevalence of LBP for the three sports was 60%: field hockey 56%, football 64% and speed skating 60%. Satisfaction with their own performance (OR = 0.5 95%CI:0.3–0.9) and with the coaching staff (OR = 0.5, 95%CI:0.4–0.8) were associated with a lower occurrence of LBP in field hockey. No sport-related risk factors were found in football. In speed skating more training hours (OR = 1.1, 95%CI:1.0–1.2), performance of Pilates (OR = 4.1, 95%CI:1.1–15.7) and more time spent on warming up (OR = 1.1, 95%CI:1.0–1.1) were associated with the occurrence of LBP. Prevalence of LBP among young elite athletes compared to the general age-related population was 3–5 times higher. Sport-related risk factors of LBP were found in field hockey and in speed skating.

The relationship between the frequency of football practice during skeletal growth and the presence of a cam deformity in adult elite football players

Background/aimCam deformity (CD) is likely a bony adaptation in response to high-impact sports practice during skeletal growth. We ascertained whether a dose–response relationship exists between the frequency of football practice...

Prevalencia de anomalías genitales en futbolistas jóvenes

The purpose of genital examination (GE) during the Pre-participation Physical Examination (PPE) is to identify the state of maturity, and rule out any genital pathology. To describe genital anomalies (GA) and estimate the awareness of GE in young football players. A descriptive, cross-sectional study was conducted in 280 elite football players from the results of PPE over two seasons. There was a detection rate of 5.4% GA, with varicocele being 3.2%, and of which only 13% were aware of their condition. Although this study shows a low incidence of genital abnormality in the study population, only 13% were aware of the GE prior to assessment. These findings demonstrate a low incidence of GA in this population. While GE is recommended during PPE, it is not a routine practice performed by family doctors or sports medicine specialists. This article attempts to raise awareness of the importance of GE in PPE as a preventive health strategy.

The Effect of Short-Time Pre-Season Intensive, Neuromuscular Training on Postural Stability on Elite Football Players

Objectives:Adequate neuromuscular training is proven to be of enormous importance in the prevention of injuries. It enhances the ability to use somatosensory information, which improves postural capabilities, reduces injury ratios and improves player’s sport performance. We hypothesized that a short-time (3 week) intensive neuromuscular training would significantly improve postural balance of professional football players. We also hypothesized that the non-dominant leg of football players would show a better level of stability than the dominant leg (kicking leg).Methods:Sixteen professional soccer players participated in the study. They were tested before and after the 3-week training period. The controlled grup consisted of 20 players that were tested twice in 3-week period. The study was performed with a use of stabliographic platform, which is based on the measurement and analysis of center of pressure movement (COP). Players were tested during one leg stance with eyes opened and closed.Results:After a period of neuromuscular training football players show statistically better postural control (p <0.05) for both the dominant and non-dominant leg for the test with eyes open and also comparing to the controlled group. The non-dominant leg did not show a better level of stability than the dominant leg.Conclusion:The postural stability of professional football players was better after the 3-week intensive neuromuscular training. A combination of balance, coordination, agility, core and trunk control appears to be a successful training schedule to improve postural balance and reduce injury in football.

Structured neuromuscular warm-up for injury prevention in young elite football players

ObjectiveTo gather evidence about the outcomes of structured neuromuscular warm-up programs without additional equipment, as prevention of non-contact injuries in young professional soccer players. Materials and methodsA literature search was conducted during March and April 2013 (PubMed, Cochrane Library, The American Journal of Sports Medicine, The British Journal of Sports Medicine and the search engine Trip Database). ResultsAfter applying the inclusion and exclusion criteria, a total of 6 studies were obtained (3 clinical trials, one cohort study and 2 systematic reviews). “FIFA 11+” program showed a reduction of injuries of between 33% and 57%. These included 52% in knee, 22% in ankle, 40% in medial tibial stress syndrome, 50% in posterior thigh, and 21% in the anterior, and 12% in the groin area. “FIFA 11” program showed a 58% reduction in ankle sprains and 27% in anterior cruciate ligament (ACL) injuries. Other specific programs to prevent ACL injuries reduced them by 74% and “Knäkontroll, SISU Idrottsböcker©” by 64%. “HarmoKnee” program reduced knee injuries by 78%. DiscussionSeveral methodological weaknesses were observed, but it seems that there is a trend toward a warm-up that contains basic stretching, strengthening and balance exercises, which could prevent injuries when those were regularly performed for more than three months. Conclusions“FIFA 11+” program might be a good preventive measure of injuries by implementing its program of structured warm-up. In any event new, better designed, studies are needed to assess this evidence.

The predictive ability of the talent development environment on youth elite football players' well-being: A person-centered approach

ObjectiveThe objective of this study was to examine the predictive ability of perceived talent development environment (TDE) on the well-being of youth elite football players. DesignA field-based longitudinal design was employed. MethodThe participants were 195 Swedish youth elite football players between 13 and 16 years of age enrolled at Swedish football academies. The players responded to questionnaires regarding their perceptions of their TDE, perceived stress, and well-being in the beginning of the competitive season 2012 (T1). On two more occasions, six and 12 months later, the players completed the stress and well-being questionnaires. ResultsA latent class analysis, based on the TDEQ sub-scale scores at T1, revealed three classes of players with different perceptions of their TDE (one high quality, one moderate quality, and one poor quality class). A second-order multivariate latent growth curve model (factor-of-curves model) showed that the class of players perceiving the lowest TDE quality, experienced higher initial level of stress and lower initial level of well-being at T1 compared to the other two classes. Moreover, there were no significant differences in slopes for neither stress nor well-being between classes (the initial difference between the three groups, in well-being, remained stable over time). ConclusionThe results indicate that players perceiving their TDE as supporting and focusing on long-term development seem to be less stressed and experience higher well-being than other players. Hence, in addition to facilitate sport-specific development and performance among youth athletes, high quality TDEs may be important for youth elite athletes' general well-being.

A team fares well with a fair coach: Predictors of social loafing in interactive female sport teams.

The present research aimed to develop and test a theoretical model that links players' perceived justice of the coach to a more optimal motivational climate, which in turn increases players' team identification and cohesion, and results in lower levels of social loafing in female sport teams. Belgian elite female basketball, volleyball, and football players (study 1; N = 259; M(age) = 22.6) and Norwegian world-class female handball players (study 2; N = 110; M(age) = 22.8) completed questionnaires assessing players' perceived justice (distributive and procedural), motivational climate, team identification, team cohesion (task and social), and social loafing (perceived and self-reported). In both studies, confirmatory and exploratory path analyses indicated that perceived justice was positively related to a mastery climate (P < 0.05) and negatively to a performance climate (P < 0.05). In turn, a mastery climate was linked to increased levels of team identification (P < 0.05) and task cohesion (P < 0.05). Consequently, players' perceived and self-reported social loafing decreased (P < 0.05). The findings of both independent studies demonstrated the impact of coaches' fairness, and consequently, the motivational climate created by the coach on the optimal functioning of female sport teams.

Repeated monitoring of blood parameters for evaluating strain and overload in elite football players: is it justified?

Repeated monitoring of blood parameters for evaluating strain and overload in elite football players: is it justified?

Return to Play Following Metacarpal Fractures in Football Players

Objectives:Injuries involving fractures of the metacarpals are common among football players of all levels. These injuries are typically treated conservatively with casting or splinting among non-in-season athletes, a method that involves a relatively lengthy recovery time (four weeks). To our knowledge, there are no previous reports documenting return to play in elite football players after operative management of metacarpal fractures. The purpose of this study was to retrospectively review and describe the results of operative treatment of metacarpal shaft fractures in 19 high level football players with respect to return to play. We hypothesized that in-season football players with metacarpal fractures treated surgically would be able to return to play more quickly than the typical recovery time following non-operative treatment.Methods:Surgically treated metacarpal fractures in elite football players were queried over a three-year period (2009-2012) from a database maintained by American Sports Medicine Institute (ASMI) in Birmingham, AL. Over the study period, 19 football players were identified who underwent open reduction internal fixation of metacarpal fractures by one of three attending surgeons. Retrospective chart review and phone interviews with the patient and their athletic trainers were performed to identify player position, level of competition, mechanism of injury, return to play, post-operative bracing, and re-fracture event. Radiographs were used to classify the fractures, and operative reports were reviewed for implant choice. Numerical means were calculated for in-season return to play as well as for brace time.Results:Ten high school players (53%) and nine college players (47%) were injured. The most common injured positions were wide receivers and defensive backs (26% each). Most injuries occurred through player to player contact (63%) at a game (37%) or practice (47%). The long finger (58%) was the most commonly involved metacarpal. Two players (11%) had multiple metacarpal fractures. The most common location was mid-diaphyseal (74%). Twelve patients were stabilized with plates and screws, five of whom underwent lag screw augmentation. Six patients were stabilized with a metacarpal nail and one was stabilized with only lag screws. All athletes were able to return to their pre-injury level of play without recurrence of fracture. Return to play for in-season athletes (N=11) was 6.3 days. The average time to return to play for in-season high school football players (N=6) was 9.2 days and 2.8 days for in-season collegiate football players (N=5). All in-season athletes returned to play with protective equipment in the form of a padded glove, bivalve padded cast, padded club cast, or padded splint. The protective equipment was used for an average of 21 days.Conclusion:This study provides support for the surgical treatment of displaced metacarpal shaft fractures with immediate return to play as tolerated for in-season football players. No re-fractures or complications were identified with the use of a plate, nail, or with lag screws. Elite football players can return to play with or without protective bracing depending on the position played and within a week of operative fixation.

The relationship between the piriformis muscle, low back pain, lower limb injuries and motor control training among elite football players.

Australian Football League (AFL) players have a high incidence of back injuries. Motor control training to increase lumbopelvic neuromuscular control has been effective in reducing low back pain (LBP) and lower limb injuries in elite athletes. Control of pelvic and femoral alignment during functional activity involves the piriformis muscle. This study investigated (a) the effect of motor control training on piriformis muscle size in AFL players, with and without LBP, during the playing season, and (b) whether there is a relationship between lower limb injury and piriformis muscle size. Stepped-wedge intervention. 46 AFL players participated in a motor control training programme consisting of two 30min sessions per week over 7-8 weeks, delivered across the season as a randomised 3 group single-blinded stepped-wedge design. Assessment of piriformis muscle cross-sectional area (CSA) involved magnetic resonance imaging (MRI) at 3 time points during the season. Assessment of LBP consisted of player interview and physical examination. Injury data were obtained from club records. An interaction effect for Time, Intervention Group and LBP group (F=3.7, p=0.03) was found. Piriformis muscle CSA showed significant increases between Times 1 and 2 (F=4.24, p=0.046), and Times 2 and 3 (F=8.59, p=0.006). Players with a smaller increase in piriformis muscle CSA across the season had higher odds of sustaining an injury (OR=1.08). Piriformis muscle size increases across the season in elite AFL players and is affected by the presence of LBP and lower limb injury. Motor control training positively affects piriformis muscle size in players with LBP.

Small Multifidus Muscle Size Predicts Football Injuries

Background:In Australian football, lower limb injuries have had the highest incidence and prevalence rates. Previous studies have shown that football players with relatively more severe preseason and playing season hip, groin, and thigh injuries had a significantly smaller multifidus muscle compared with players with no lower limb injuries. Rehabilitation of the multifidus muscle, with restoration of its size and function, has been associated with decreased recurrence rates of episodic low back pain and decreased numbers of lower limb injuries in football players. Assessment of multifidus muscle size and function could potentially be incorporated into a model that could be used to predict injuries in football players.Purpose:To examine the robustness of multifidus muscle measurements as a predictor of lower limb injuries incurred by professional football players.Study Design:Cohort study; Level of evidence, 2.Methods:Ultrasound examinations were carried out on 259 male elite football players at the start of the preseason and 261 players at the start of the playing season. Injury data were obtained from records collected by the Australian Football League (AFL) club staff during the preseason and the playing season.Results:Decreased size of the multifidus muscle at L5 consistently predicted injury in the preseason and playing season. Asymmetry of the multifidus muscle and low back pain were significantly related to lower limb injuries in the preseason, and having no preferred kicking leg was related to season injuries. Seasonal change in the size of the multifidus muscle indicating a decrease in muscle mass was linked to injury. Sensitivity and specificity of the model were 60.6% and 84.9% for the preseason and 91.8% and 45.8% for the playing season, respectively.Conclusion:A model was developed for prediction of lower limb injuries in football players with potential utility for club medical staff. Of particular note is the finding that changes in muscle size from the preseason to the playing season predicted injury.Clinical Relevance:As size of the multifidus muscle has been shown to be modifiable with training and has been associated with reduced pain and occurrence of injuries, this information could be incorporated in current programs of injury prevention.

Isokinetic Concentric Quadriceps and Hamstring Normative Data for Elite Collegiate American Football Players Participating in the NFL Scouting Combine

Isokinetic concentric quadriceps and hamstring strength data using a Cybex dynamometer are collected for elite collegiate American football players invited to the annual National Football League Scouting Combine. We constructed a normative (reference) database of the Cybex strength data for the purpose of allowing comparison of an individual's values to his peers. Data reduction was performed to construct frequency distributions of hamstring/quadriceps (H/Q) ratios and side-to-side strength differences. For the cohort (n = 1,252 players), a statistically significant but very small (1.9%) mean quadriceps strength preference existed for dominant side vs. nondominant side. Peak torque (Newton meters, best repetition) for quadriceps and hamstrings was significantly correlated to player body mass (weight) (the same relationship was found for other variables using peak torque in the calculation). Peak torque varied by player position, being greatest for offensive linemen and lowest for kickers (p < 0.0001). Adjusting for body weight overcorrected these differences. The H/Q ratios and frequency distributions were similar across positions, with a mean of 0.6837 ± 0.137 for the cohort dominant side vs. 0.6940 ± 0.145 for the nondominant side (p = 0.021, n = 1,252). Considerable variation was seen for dominant-to-nondominant side difference for peak torque. For quadriceps, 47.2% of players had differences between -10% and +10%, 21.0% had a peak torque dominant-side deficit of 10% or greater compared to nondominant side, and for 31.8% of players, dominant-side peak torque was greater than 10% compared to nondominant side. For hamstrings, 57.0% of players had differences between -10% and +10%, 19.6% had a peak torque dominant-side deficit of 10% or greater compared to nondominant side, and 23.4% of players, dominant-side peak torque was greater than 10% compared to nondominant side. We observed that isokinetic absolute strength variables are dependent on body weight and vary across player position. The H/Q ratios vary only within a relatively narrow range. Side-to-side differences in strength variables >10% are common, not the exception.

What is the Effect of Compression Garments on a Novel Kick Accuracy Task?

The purpose of this study was to investigate the effect of wearing long leg compression garments (CGs) on the accuracy of elite football players performing a novel kicking task. A double-blinded, crossover, randomised and controlled laboratory trial was used to examine the contribution of the long leg CGs to kicking accuracy of a drop-punt-kick. The drop-punt-kick is a backward spinning kick often used in Australian Rules. Participants performed 10 drop-punt-kicks towards a target for each garment condition (fitted, over-sized and training shorts) with both their dominant and non-dominant leg. Kicking accuracy data was collected using a high-speed camera. Kicking accuracy between garment conditions was only significantly different when kicking with the dominant leg ( p = 0.002). Kicking accuracy was reduced in the fitted CG condition compared to the oversized CG (mean difference = 20 cm, p = 0.018) and for fitted CGs compared to training shorts (mean difference = 21 cm, p = 0.003) indicating that the fitted CGs had a negative effect on kicking accuracy. As these compression garments are worn regularly during training, further research is required to determine the long-term effect on skill development.

The Long-Term Effects of Sports Concussion on Retired Australian Football Players: A Study Using Transcranial Magnetic Stimulation

This study investigated corticomotor excitability and inhibition, cognitive functioning, and fine motor dexterity in retired elite and amateur Australian football (AF) players who had sustained concussions during their playing careers. Forty male AF players who played at the elite level (n=20; mean age 49.7±5.7 years) or amateur level (n=20; mean age 48.4±6.9 years), and had sustained on average 3.2 concussions 21.9 years previously, were compared with 20 healthy age-matched male controls (mean age 47.56±6.85 years). All participants completed assessments of fine dexterity, visuomotor reaction time, spatial working memory (SWM), and associative learning (AL). Transcranial magnetic stimulation (TMS) was used to measure corticospinal excitability: stimulus-response (SR) curves and motor evoked potential (MEP) 125% of active motor threshold (aMT); and intracortical inhibition: cortical silent period (cSP), short-interval intracortical inhibition (SICI), and long-interval intracortical inhibition (LICI). Healthy participants performed better in dexterity (p=0.003), reaction (p=0.003), and movement time (p=0.037) than did both AF groups. Differences between AF groups were found in AL (p=0.027) and SWM (p=0.024). TMS measures revealed that both AF groups showed reduced cSP duration at 125% aMT (p>0.001) and differences in SR curves (p>0.001) than did healthy controls. Similarly, SICI (p=0.012) and LICI (p=0.009) were reduced in both AF groups compared with controls. Regression analyses revealed a significant contribution to differences in motor outcomes with the three measures of intracortical inhibition. The measures of inhibition differed, however, in terms of which performance measure they had a significant and unique predictive relationship with, reflecting the variety of participant concussion injuries. This study is the first to demonstrate differences in motor control and intracortical inhibition in AF players who had sustained concussions during their playing career two decades previously.

EFFECT OF TRUNK MOTOR CONTROL TRAINING ON HIP MUSCLES IN ELITE FOOTBALL PLAYERS

BackgroundDecreased size and altered function of lumbo-pelvic muscles has been found in elite athletes with low back pain (LBP). Previous research has shown that training trunk neuromotor control in elite...