Is there a relationship between ground and climatic conditions and injuries in football?

Soccer and volleyball players do not land differently: implications for anterior cruciate ligament injury risk

BACKGROUND

Non-contact anterior cruciate ligament injuries are common in soccer and volleyball, occurring during changes of direction and landings. This study aimed to investigate kinematic differences between soccer and volleyball players in single-planar and multiplanar landing tasks, simulating sport-specific injury mechanisms. Since the anterior cruciate ligament injury rate in soccer is higher than in volleyball, we hypothesized that volleyball players would adopt safer landing strategies, especially in single-planar landing tasks.

METHODS

Twenty-two soccer and 19 volleyball players performed single-leg drop landing, drop jump in vertical, 45°-medial and 45°-lateral directions. Box height and jump length were adapted to the subject's height and performance level, respectively. A 9-camera motion capture system provided lower limb kinematics. Two mixed multivariate analyses of covariance (sport, task, sex as covariate) were used to compare soccer and volleyball players' initial contact and peak kinematics (α=0.05).

RESULTS

Task had significant effects on lower limb initial contact and peak angles, as expected. Sport and task × sport interaction had no significant effects on kinematics.

CONCLUSIONS

Soccer and volleyball players' landing strategies were thus similar in each task, in opposition to initial hypotheses. We might speculate that the higher anterior cruciate ligament injury rate in soccer may be more related to non-predictable factors than the isolated landing kinematics.

3D Kinematics of Male and Female Soccer Players for a Variety of Game-Specific Skills

Soccer is played by a variety of individuals with varying abilities. The complicated lower limb movements involved within the game often lead to knee and ankle injuries, with anterior cruciate ligament injuries being the most severe with regard to rehabilitation time and ongoing health risks. This research explores the biomechanical kinematics of male and female soccer players on synthetic grass to determine whether trends in lower limb biomechanics over a variety of movements could explain injury risk. Both male and female players (n = 10) aged between 19 and 24 years performed running-based and stationary-start movements. Biomechanical measurements at the hip, knee, and ankle were recorded. Observations showed that specific differences in joint angles were largely dependent on the movements performed; however, for male players, on average, across all movements, 84.6% and 72.6% of the variation in joint angles could be explained by internal/external rotation at the hip and knee, respectively. For female players, internal/external knee rotation, as well as hip abduction and adduction, accounted for 83.6% and 80.2% of the variation in joint angles, respectively, across all the tested movements. This highlights the importance of hip mechanics and knee alignment for players when performing a variety of movements.

Interaction of Surface Type, Temperature, and Week of Season on Concussion Risk in the National Football League: A Bayesian Analysis

BACKGROUND

Artificial turf fields and environmental conditions may influence sports concussion risk, but existing research is limited by uncontrolled confounding factors, limited sample size, and the assumption that risk factors are independent of one another. The purpose of this study was to examine how playing surface, time of season, and game temperature relate to diagnosed concussion risk in the National Football League (NFL).

METHODS

This retrospective cohort study examined data from the 2012 to the 2019 NFL regular season. We fit Bayesian negative binomial regression models to relate how playing surface, game temperature, and week of the season independently related to diagnosed concussion risk and any interactions among these factors.

RESULTS

We identified 1096 diagnosed concussions in 1830 games. There was a >99% probability that concussion risk was reduced on grass surface (median incidence rate ratio [IRR] = 0.78 [95% credible interval: 0.68, 0.89]), >99% probability that concussion risk was lower at higher temperatures (IRR = 0.85 [0.76,0.95] for each 7.9 °C), and >91% probability that concussion risk increased with each week of the season (IRR = 1.02 [1.00,1.04]). There was an >84% probability for a surface × temperature interaction (IRR = 1.01 [0.96, 1.28]) and >75% probability for a surface × week interaction (IRR = 1.02 [0.99, 1.05]).

CONCLUSIONS

Diagnosed concussion risk is increased on artificial turf compared with natural grass, and this is exacerbated in cold weather and, independently, later in the season. The complex interplay between these factors necessitates accounting for multiple factors and their interactions when investigating sports injury risk factors and devising mitigation methods.

Field conditions is a risk factor for traumatic injury in youth football-A joint venture of medicine and hydrology

INTRODUCTION

The risk of traumatic injury in football has been suggested to be affected by field conditions. This study, therefore, aimed to investigate whether near surface water content of the football field, influenced the risk of traumatic injuries during a youth football tournament.

METHODS

At Dana Cup, an annual international youth football tournament in Denmark, all injuries were registered and classified at the on-site emergency department over 7 years. The incidence rate of traumatic injury was computed. Meteorological data and soil characteristics were used to simulate near surface water content of the playing fields. The incidence rate ratio (IRR) between water content and injury incidence rate was analyzed using a multivariate Poisson regression, controlling for tournament stage and demographical parameters.

RESULTS

About 2704 injuries were recorded corresponding to a risk time of 284 905 player hours. An inverse relation between water contents and the incidence rate of traumatic injury was found (IRR = 0.24 95% CI 0.1-0.7, p = 0.01). The incidence rate of traumatic injury increased with advancing tournament stage, that is, for the finals (IRR = 4.30 95% CI 2.8-6.6, p < 0.001). Also we found an interaction between dry fields and the final stage of tournament, further exacerbating this effect.

CONCLUSIONS

Our data suggest that the incidence rate of traumatic injury is increased with drier field conditions and advanced tournament stages.

Magnetic resonance imaging of the ankle: Pathology of the lateral and posterior compartments

Magnetic resonance imaging (MRI) is the gold standard for imaging the tendons and the ligaments of the ankle. MRI combines excellent tissue contrast and accurate anatomic delineation of joint structures. In the first article of this series, we discussed a compartmental approach to the interpretation of ankle pathology focusing on the anterior and medial compartments. This article will complete the MR review of the ankle, with a focus on the lateral and posterior compartments of the ankle.

Does Inspiratory Muscle Training Affect Static Balance in Soccer Players? A Pilot Randomized Controlled Clinical Trial

Inspiratory muscle training (IMT) is effective in improving postural stability and balance in different clinical populations. However, there is no evidence of these effects in soccer players. A single-blind, two-arm (1:1), randomized, placebo-controlled pilot study on 14 soccer players was performed with the main aim of assessing the effect of IMT on static balance, and secondarily, of examining changes in the respiratory muscle function. The experimental group (EG) received an IMT program with progressive intensity, from 20% to 80%, of the maximal inspiratory pressure (MIP). The sham group (SG) performed the same program with a fixed load of 20% of the MIP. Static balance and respiratory muscle function variables were assessed. A two-factor analysis of variance for repeated measures was used to assess differences after training. Statistical significance was set at p < 0.05. Significant increases were observed in the EG on length of sway under eyes open (from 2904.8 ± 640.0 to 3522.4 ± 509.0 mm, p = 0.012) and eyes closed (from 3166.2 ± 641.3 to 4173.3 ± 390.8 mm, p = 0.004). A significant increase in the maximal voluntary ventilation was observed for both groups (EG p = 0.005; SG p = 0.000). No significant differences existed between the groups. IMT did not improve the static balance in a sample of soccer players. Conducting a high-scale study is feasible and could refine the results and conclusions stemming from the current pilot study.

Lisfranc injury: Prevalence and maintaining a high index of suspicion for optimal evaluation

OBJECTIVES

To quantify the long-term prevalence of game-related Lisfranc trauma in college football on artificial turf and natural grass.

METHODS

32 universities were evaluated over 10 competitive seasons across all Football Bowl Subdivision (FBS) conferences. Outcomes of interest included injury severity, injury category, primary type of injury, player and skill position, injury mechanism and situation, elective imaging and surgical procedures, and field conditions. Injury incidence rates (IIR) were calculated using injuries per 10 games = (number of injuries) number of games) × 10.

RESULTS

Of the 1577 games documented, 783 games (49.7%) were played on a 3-layer artificial turf (≥9.0 lbs/ft²) infill system versus 794 games (50.3%) played on natural grass. In sum, 78 Lisfranc cases were documented with 34 (43.6%) occurring on artificial turf, and 44 (56.4%) on natural grass. MANOVAs indicated significant main effects by injury category (F_3,74 = 6.439; P = .001), and injury mechanism (F_5,72 = 3.372; P = .009) observed between surfaces, but not by injury severity (F_2,75 = 0.720; P = .490), primary type of injury (F_4,73 = 0.772; P = .547), overall player (F_2,75 = 0.219; P = .804) and skill positions (F_8,69 = 0.850; P = .563), injury situation (F_10,67 = 1.030; P = .428), elective imaging and surgical procedures (F_3,74 = 0.515; P = .673), or field conditions (F_2,75 = 0.375; P = .688). Post hoc analyses indicated significantly greater incidences (P < .05) of Lisfranc trauma on natural grass attributed to shoe:surface interaction during noncontact play, and during no contact, foot rotation or planting. Ligament tears (n = 8; 57.1%), with minimal cases of subluxation/dislocations (n = 4; 28.6%) and fractures (n = 2; 14.3%) comprised grade 3 cases across both surfaces.

CONCLUSION

In regards to Lisfranc trauma, a 3-layer, heavyweight artificial infill surface is as safe or safer than natural grass. The findings of this study may be generalizable only to this level of football competition.

Assessing climatic, travel, and methodological influences on whole-match and worst-case scenario locomotor demands of international men's rugby sevens match-play

AbstractThis study assessed the influence of environmental factors, air travel, and epoch estimation method on locomotor demands of international men's rugby sevens match-play. Eighteen men's rugby sevens players wore 10 Hz Global Positioning Systems (STATsport) during 52 international matches over nine global tournaments (418 observations). Whole-match average speed was recorded, whilst average speed and relative high-speed distance (>5.0 m·s^-1) were quantified using FIXED and ROLL methods over 60-420 s epochs (60 s increments) to establish worst-case scenario demands. Linear mixed models compared FIXED versus ROLL estimation methods and assessed whether temperature, humidity, travel duration, number of time-zones crossed, and travel direction were associated with locomotor responses. Temperature and humidity were positively associated with overall and worst-case scenario average speed (effect estimates; b: 0.18 to 0.54), whilst worst-case scenario high-speed distance at 300 s was also related to temperature (b: 0.19). Easterly air travel compromised overall and 180 and 300 s worst-case scenario average speed (b: -8.31 to-7.39), alongside high-speed distance over 300 s (b: -4.54). For worst-case scenario average speed and high-speed distance, FIXED underestimated ROLL at all epoch lengths (∼9.9 to 18.4%, p≤0.001). This study indicated that international rugby sevens match-play locomotor responses were greater as air temperature increased but reduced following eastward air travel. Underestimation of demands in FIXED vs ROLL over 60-420 s epochs was confirmed. Such climatic and travel influences warrant the adoption of strategies targeted at maximising performance and safety according to the tournament conditions. Knowing the most demanding periods of match-play facilitates training specificity.

Incidence of Injury for Professional Soccer Players in the United States: A 6-Year Prospective Study of Major League Soccer

Background:

Despite an abundance of injury research focusing on European professional soccer athletes, there are limited injury data on professional soccer players in the United States.

Purpose:

To describe the epidemiology of injury across multiple years in Major League Soccer (MLS) players.

Study Design:

Descriptive epidemiology study.

Methods:

A web-based health management platform was used to prospectively collect injury data from all MLS teams between 2014 and 2019. An injury was defined as an incident that required medical attention and was recorded into the health management platform anytime over the course of the 2014-2019 seasons. Injuries and exposure data were recorded in training and match settings to calculate injury incidence.

Results:

A total of 9713 injuries were recorded between 2014 and 2019. A mean 1.1 injuries per year per player were identified, with midfielders sustaining the largest number of injuries. The most common injuries were hamstring strains (12.3%), ankle sprains (8.5%), and adductor strains (7.6%). The mean time missed per injury was 15.8 days, with 44.2% of injuries resulting in no days missed. Overall injury incidence was 8.7 per 1000 hours of exposure, declining over the course of the investigation, with a 4.1-times greater mean incidence during matches (14.0/1000 h) than training (3.4/1000 h).

Conclusion:

Between 2014 and 2019, the most commonly reported injuries in MLS players were hamstring strains, ankle sprains, and adductor strains. Injury incidence during matches was 4.1 times greater when compared with training, while overall injury incidence was found to decline during the course of the study period.

A Narrative Review for a Machine Learning Application in Sports: An Example Based on Injury Forecasting in Soccer

In the last decade, the number of studies about machine learning algorithms applied to sports, e.g., injury forecasting and athlete performance prediction, have rapidly increased. Due to the number of works and experiments already present in the state-of-the-art regarding machine-learning techniques in sport science, the aim of this narrative review is to provide a guideline describing a correct approach for training, validating, and testing machine learning models to predict events in sports science. The main contribution of this narrative review is to highlight any possible strengths and limitations during all the stages of model development, i.e., training, validation, testing, and interpretation, in order to limit possible errors that could induce misleading results. In particular, this paper shows an example about injury forecaster that provides a description of all the features that could be used to predict injuries, all the possible pre-processing approaches for time series analysis, how to correctly split the dataset to train and test the predictive models, and the importance to explain the decision-making approach of the white and black box models.

Effects of Short-Term Dynamic Balance Training on Postural Stability in School-Aged Football Players and Gymnasts

Static and dynamic balance abilities enable simple and complex movements and are determinants of top athletic performance. Balance abilities and their proficiency differ fundamentally with respect to age, gender, type of balance intervention, and type of sport. With this study, we aim to investigate whether 4weeks of dynamic balance training (DBT) improves static balance performance in school-aged gymnasts and football players. For this purpose, young male gymnasts (n=21) and male football players (n=20) completed an initial static balance assessment consisting of two one-legged stance (left and right foot) and two two-legged stance (eyes open and eyes closed) tasks. Subsequently, all participants underwent a 4-week intervention. DBT consisting of nine individual tasks was performed two times per week. Another static balance assessment followed 1day after the last training session and retention was assessed 2weeks later. Dynamic balance scores and total path length were analyzed via rank-based repeated measures designs using ANOVA-type statistics. The influence of factors GROUP and TIME on the static and dynamic balance performance was examined. Prior to DBT, young gymnasts showed better static balance performance than football players. However, after intervention, both groups improved in both one-legged stance tasks and also had high retention rates in these tasks. No significant improvements were seen in either group in the two-legged balance tests. Both groups improved in the dynamic balance tasks, although no differences in learning rates were evident. Our findings imply an inter-relationship between both static and dynamic balance components. Consequently, training regimes should include both balance components to facilitate early development of balance ability.

Surface-Related High School Football Game Injuries on Pad and No-Pad Fields

BACKGROUND

Artificial turf fields are increasingly being installed with lighter weight infill systems that incorporate a pad underlayer, which is reported to reduce surface shock and decrease injuries. At this time, the effects of a pad underlayer on football trauma are unknown.

HYPOTHESIS

Athletes would not experience differences in surface-related injuries between pad and no-pad fields.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Artificial turf fields were divided into 2 groups based on a pad underlayer or no-pad system, with 58 high schools participating across 3 states over the course of 7 seasons. Outcomes of interest included injury severity, head and knee trauma, injury category, primary type of injury, injury mechanism, anatomic location of trauma, tissue type injured, and elective imaging and surgical procedures. Data underwent multivariate analyses of variance (MANOVA) using general linear model procedures and were expressed as injury incidence rates per 10-game season.

RESULTS

Of 658 varsity games, 260 games were played on fields containing pads, and 398 games were played on no-pad fields, with 795 surface-related injuries reported. MANOVA indicated significant main effects by injury severity (F_3,791 = 11.436; P < .0001), knee trauma (F_9,785 = 2.435; P = .045), injury category (F_3,791 = 3.073; P < .0001), primary type of injury (F_10,785 = 2.660; P < .0001), injury mechanism (F_13,781 = 2.053; P < .001), anatomic location (F_16,778 = 1.592; P < .001), type of tissue injured (F_4,790 = 4.485; P < .0001), and elective imaging and surgical procedures (F_4,790 = 4.248; P < .002). Post hoc analyses indicated significantly greater incidences (P < .05) of substantial and severe injury, player-to-turf trauma, patellofemoral syndrome, neck strain, lower leg strain, and elective imaging and surgical procedures when games were played on padded turf fields. No differences in concussion rate from turf impact between pad and no-pad fields were observed.

CONCLUSION

In contrast to conventional wisdom, the addition of a pad under an artificial turf surface increases injury rates when compared with nonpadded fields across most injury categories. At this time, findings do not support the current trend of installing lightweight padded infill systems at the high school level of play.

Relationship between Respiratory Muscle Function and Postural Stability in Male Soccer Players: A Case-Control Study

The important role of postural stability in exercise performance has been determined by several authors. Despite this, few studies have analyzed the relationship between respiratory muscles’ strength and postural stability in athletes. For this reason, the aim of this study was to investigate the relationship between postural stability and respiratory muscles’ function in male soccer players. A case-control study was conducted over twenty-eight healthy men (18 soccer players; 10 non-athletes). Inspiratory muscle strength (MIP) and respiratory resistance (MVV) were obtained through a digital spirometer. Stability variables were obtained in standing position on a stabilometric platform and in open and closed eyes conditions. The area and length of the center of pressures and displacements in the X and Y range were analyzed. Pearson’s coefficient was used to measure the linear correlation between MIP, MVV and stabilometric variables. In the soccer players’ group, MIP and MIP % predictive were inversely correlated with length (r = −0.535 and r = −0.585; p < 0.05) and X range (r = −0.527 and r = −0.560; p < 0.05), whereas MVV was directly correlated with length (r = 0.606; p < 0.01) and Y range (r = 0.558; p < 0.05). Our results show that the greater the inspiratory muscle strength, the less displacement of the pressure center, while at higher respiratory rates there is greater displacement.

Anterior Cruciate Ligament Injuries in Australian Rules Football: Incidence, Prevention and Return to Play Outcomes

Australian Rules football is the most popular of the various codes of football played in Australia. During the game players perform frequent landing, cutting and pivoting manoeuvres that expose them to substantial risk for anterior cruciate ligament (ACL) injury. Recent years have seen the introduction of a professional women's league that has resulted in an exponential growth in the participation of women and girls in this sport. Unfortunately, there is a corresponding growth in ACL injury rates in female players. This review summarizes the incidence of ACL injury in both men's and women's Australian Rules football and reviews potential causative factors and risk reduction strategies. The final section takes an in depth look at return to sport outcomes after ACL reconstruction surgery in these populations. Whilst an ACL injury does not mean the end of a player's career in Australian football, it certainly presents a significant challenge in terms of return to preinjury levels of form and high rates of secondary and tertiary ACL injury are also a significant concern.

Differences in joint loading during a side-step cutting manoeuvre on different artificial turf infill depths

This study investigated differences in joint loading during a side-step manoeuvre on artificial grass turfs with different infill depths. The kinematics and kinetics of 17 trained male inter-college soccer players performing the manoeuvre were captured using 10 high-speed optical cameras synchronised to a force-platform at sampling frequencies of 250 Hz and 1000 Hz respectively. Significantly larger lateral forces (GRF_xpeak) (p = 0.036), larger anterior/posterior forces (GRF_ypeak) (p = 0.062) and larger vertical forces (GRF_zpeak) (p = 0.390) suggests that turf with greater infill depths may be firmer. This could elicit greater stresses on the lower extremity, thereby increasing the risk of knee ligament injuries. Significant differences were reported only for ankle inversion angle (p = 0.001; ES = 0.74), inversion/eversion ankle moment (p = 0.039; ES = 0.52) and abduction-adduction ankle moment (p = 0.022; ES = 0.79) at GRFz_peak. Lower extremity adaptations to execute the manoeuvre on turf with greater infill depths may have taken place at the ankle rather than the knee. While this change in technique may implicate injuries, greater infill depths can be counter-intuitive where a certain level of hardness in the artificial turf might be necessary which otherwise could affect the athletes' performance and potentially reduce injury risk.

Meniscal Injuries in the Olympic and Elite Athletes

INTRODUCTION

Elite and Olympian athletes are often stretching the upper limits of normal physiology and biomechanics of the musculoskeletal system in their efforts to excel in their sport. For them to get back to their sport at the same level after injury, the management, repair techniques, and rehabilitation protocols should be robust to permit healing of tissues to allow supra-normal loading and performance. The knee and the meniscus are commonly injured in these sports. Yet, the incidence, mechanisms, types of injuries to the meniscus, and their management are not known across different sports in the Olympics.

METHODS

We set out to look into the incidence and the trends of publications on meniscal injuries of the knee in Olympic games. A search of the PubMed and Scopus for these injuries using a search strategy gave 79 and 116 articles, respectively.

RESULTS

There were very few publications giving the incidence of meniscal injuries in the Olympics. Football is the sport with the highest rate of meniscal injuries. Different sports are popular in different countries, and depending on the popularity and the country reporting these injuries, incidences differed. There was data available from India and Brazil for Elite athlete from diverse sports, whereas most data from other countries were for football and soccer. Knee was found to be the second most commonly injured part of the body in both Winter and Summer Olympics as well as the Youth Winter Olympics. Data were not available from the Youth Summer Olympics to make any conclusions. The number of publications on this topic is low. We presented the timeline of publications and citations of articles on this topic. The top country, language, journal, university, and author were USA, English, American Journal of Sports Medicine, Hospital of Special Surgery in New York and Brophy RH, respectively. The data on the risk factors for meniscal injuries were analyzed, discussed, and presented for football, as this was the most extensively studied sport.

CONCLUSIONS

Even though the knee is one of the commonly injured anatomical locations in elite athletes, there is a lack of literature on meniscal injuries in this subset of population. We looked at possible reasons and made recommendations to improve data collection on these injuries.

Injury Surveillance in Major League Soccer: A 4-Year Comparison of Injury on Natural Grass Versus Artificial Turf Field

BACKGROUND

Artificial playing surfaces are becoming more common due to decreased cost of maintenance and increased field usability across different environmental conditions. The Fédération Internationale de Football Association (FIFA) has approved newer generation artificial turf for soccer competition at the elite level, but many elite-level athletes prefer to play on natural grass surfaces due to a perceived increase in injury rate, discomfort, and fatigability on artificial turf.

HYPOTHESIS

Injury rates and rates of individually categorized types of injury experienced on artificial turf are noninferior to rates of injury on the standard comparator, natural grass, in elite-level Major League Soccer athletes.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Over the course of 4 Major League Soccer seasons (2013-2016), athlete injury data were recorded electronically. Injury data recorded in matches between 2 Major League Soccer teams were then analyzed. Playing surface was known for each venue, and all artificial turf surfaces were rated as 2-star according to FIFA criteria. Incidence rate ratios (Artificial Turf ÷ Natural Grass) were calculated with a 95% CI (α = .05) for both overall injury incidence and individual injury subgroups. A noninferiority margin (δ) of 0.15 was used to determine noninferiority of injury incidence rates.

RESULTS

A total of 2174 in-game injuries were recorded during the study period, with 1.54 injuries per game on artificial turf and 1.49 injuries per game on natural grass (incidence rate ratio, 1.033; 95% CI, 0.937-1.139). Within injury subgroups, overall ankle injury, Achilles injury, and ankle fracture were found to have a statistically higher incidence on artificial turf. Artificial turf was found to be noninferior to natural grass for overall foot injury and forefoot injury. No statistically significant differences were found in knee injuries between the 2 surfaces.

CONCLUSION

The overall rate of injury on artificial turf was noninferior to that on natural grass. Within individual injury categories, a higher rate of ankle injury was found on artificial turf. No other injury subgroup demonstrated statistically significant differences between surfaces.

CLINICAL RELEVANCE

FIFA 2-star rated artificial turf is a viable alternative to natural grass in elite-level soccer competition. Innovative research methods for comparing artificial turf versus natural grass may elucidate relative advantages with respect to player safety.

Incidence, Mechanisms, and Severity of Game-Related High School Football Injuries Across Artificial Turf Systems of Various Infill Weights

Background:

Artificial turf surfaces are developed to duplicate playing characteristics of natural grass. With the newer generations of sand and rubber infill systems, the infill is a common component that varies between fields and is a critical factor that could influence the player-surface interaction. Because the influence of infill weight on sport trauma is unknown, this study quantified football trauma in high schools in the United States across artificial turf systems of various infill weights.

Hypothesis:

Athletes would not experience differences in game-related injuries across artificial turf systems of various infill weights.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

Artificial turf systems were divided into 4 sand/rubber infill weight groups by pounds per square foot: ≥9.0, 6.0-8.9, 3.0-5.9, and 0.0-2.9. A total of 57 high schools in 4 states participated over the course of 5 seasons. Outcomes of interest included injury severity, as a function of infill weight, across head, knee, and shoulder traumas; injury category; primary type of injury; tissue type; specific body location of injury; cleat design; environmental factors; and turf age. Data were subject to multivariate analyses of variance (MANOVAs) and Wilks λ criteria through use of general linear model procedures.

Results:

Of 1837 games documented, 528 games were played on infill weights of ≥9.0 lb/ft², 521 on 6.0-8.9 lb/ft², 525 on 3.0-5.9 lb/ft², and 263 on 0.0-2.9 lb/ft², with 4655 total injuries reported. MANOVAs indicated significant infill weight effects across injury severity (F_2,4648 = 5.087; P = .0001), with significant main effects also observed by injury category, tissue injured, lower extremity joint and muscle, cleat design, environmental factors, and turf age. Post hoc analyses indicated significantly lower (P < .05 to .0001) total and substantial traumas, concussions, shoe-surface interaction during contact trauma, surface impacts, muscle-tendon overload, cleat design influence, adverse weather trauma, lower extremity injuries, and turf age effect while athletes were competing on the 6.0 to ≥9.0 lb/ft² infill weight systems compared with the lighter infill weight systems.

Conclusion:

As infill surface weight decreased, football trauma significantly increased across numerous playing conditions. Based on findings, high school football fields should minimally contain 6.0 pounds of infill per square foot.

Return to Play and Player Performance After Anterior Cruciate Ligament Injury in Elite Australian Rules Football Players

Background:

Australian Rules football is a highly aerobic and anaerobic game that at times requires players to perform cutting or pivoting maneuvers, potentially exposing them to anterior cruciate ligament (ACL) injury. At present, there are limited data available addressing the impact of ACL injury on return to play and preinjury form after ACL reconstruction.

Purpose:

To determine the prevalence of ACL injury and the incidence of further ACL injury, and to consider player return to play and return to preinjury form after ACL reconstruction. It was hypothesized that elite-level Australian Football League (AFL) players do not return to preinjury form until, at minimum, 2 years after returning to play.

Study Design:

Case series; Level of evidence, 4.

Methods:

A retrospective analysis was undertaken on a cohort of elite AFL players who injured their ACL between 1990 and 2000. Return to play after ACL reconstruction was determined by the mean number of ball disposals, or release of the ball by the hand or foot, at 1, 2, and 3 years after return to play and compared with preinjury form. Associations between player and injury characteristics, method of reconstruction, and outcomes (return to play, preinjury form, and further ACL injury) were examined.

Results:

During the included seasons, a total of 2723 AFL players were listed. Of these, 131 (4.8%) sustained an ACL injury, with 115 players eligible for inclusion. Of 115 players, 26% did not return to elite competition, while 28% of those who did return experienced further ACL injury. The adjusted mean number of disposals (± standard error of the mean) was significantly lower at 1 year (12.21 ± 0.63; P = .003), 2 years (12.09 ± 0.65; P = .008), and 3 years (11.78 ± 0.77; P = .01) after return to play compared with preinjury (14.23 ± 0.67). On average, players did not return to preinjury form by 3 years (P < .01). Players aged 30 years or older were less likely to return to play compared with younger players (P = .0002), moderate-weight players were more likely to return to play compared with lighter-weight players (P = .007), and there were significantly increased odds of not returning to play if the dominant side was injured (odds ratio, 0.10; 95% CI, 0.03-0.34; P = .0002).

Conclusion:

On average, AFL players do not return to their preinjury form after ACL injury and reconstruction, a common injury in this sporting population. This along with the high occurrence of reinjury highlights the career-threatening nature of ACL injury for elite AFL players.

The influence of playing surface on injury risk in italian elite rugby players

BACKGROUND

There is a growing interest in the use of artificial turf surfaces in rugby. In particular, artificial surfaces may be an useful means of increasing participation in the sport by allowing greater usage of a given pitch, especially in regions where natural turf pitches are difficult to maintain.

METHODS

The incidence of site, nature, cause, and severity of training and match injuries was prospectively recorded in two professional teams (one equipped with World Rugby certified third generation artificial turf and the other with natural grass over the 2014-2015 season).

RESULTS

A total of 23,840 minutes of exposure was displayed for the whole sample, 1,440 minutes during matches and 22,400 during training sessions. We recorded 37 (48%) traumatic injuries and 39 (52%) overuse injuries. For traumatic injuries, we did not find significant differences in the overall risk injury between grass and artificial turf considering match exposure and training sessions. For overuse injuries, there were significant differences in the overall risk injury between grass and artificial turf considering match exposure (p=0.03) and training sessions (p=0.02).

CONCLUSION

In elite Italian rugby players, artificial turf seems to be safe in regards to traumatic injury while it seems to be a risk factor for overuse injuries.

LEVEL OF EVIDENCE

II.

Incidence, Mechanisms, and Severity of Match-Related Collegiate Men's Soccer Injuries on FieldTurf and Natural Grass Surfaces: A 6-Year Prospective Study

BACKGROUND

Numerous injuries have been attributed to playing on artificial turf. More recently, newer generations of artificial turf have been developed to duplicate the playing characteristics of natural grass. Although artificial turf has been deemed safer than natural grass in some studies, few long-term studies have been conducted comparing match-related collegiate soccer injuries between the 2 playing surfaces.

HYPOTHESIS

Collegiate male soccer athletes do not experience any difference in the incidence, mechanisms, or severity of match-related injuries between FieldTurf and natural grass.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Male soccer athletes from 11 universities were evaluated over 6 seasons. Demographic features and predictors included player position, cleat design, player weight, turf age, and environmental factors. Outcomes of interest included injury incidence, injury category, time loss, injury mechanism and situation, type of injury, injury grade and anatomic location, injury severity, head and lower extremity trauma, and elective medical procedures. All match-related injuries were evaluated by the attending head athletic trainer and team physicians on site and subsequently in the physician's office when further follow-up and treatment were deemed necessary. In sum, 765 collegiate games were evaluated for match-related soccer injuries sustained on FieldTurf or natural grass during 6 seasons.

RESULTS

Overall, 380 team games (49.7%) were played on FieldTurf versus 385 team games (50.3%) played on natural grass. A total of 722 injuries were documented, with 268 (37.1%) occurring on FieldTurf and 454 (62.9%) on natural grass. Multivariate analysis per 10 team games indicated a significant playing surface effect: F_2,720 = 7.260, P = .001. A significantly lower total injury incidence rate (IIR) of 7.1 (95% CI, 6.6-7.5) versus 11.8 (95% CI, 11.3-12.2; P < .0001) and lower rate of substantial injuries, 0.7 (95% CI, 0.5-1.0) versus 1.9 (95% CI, 1.5-2.3; P < .03), were documented on FieldTurf versus natural grass, respectively. Analyses also indicated significantly less trauma on FieldTurf when comparing injury category, time loss, player position, injury mechanism and situation, injuries under various environmental conditions, cleat design, turf age, anatomic location, and elective medical procedures. No significant difference (F_11,710 = 0.822, P = .618) between surfaces by knee injury was observed, with the majority of knee injuries involving patellar tendinopathies/syndromes followed by medial collateral ligament injuries on both surfaces.

CONCLUSION

Although similarities existed between FieldTurf and natural grass during competitive match play, FieldTurf is, in many cases, safer than natural grass when comparing injuries in collegiate men's soccer. The findings of this study, however, may not be generalizable to other levels of competition or to other artificial surfaces.

Effects of shock-absorbing insoles during transition from natural grass to artificial turf in young soccer players: a randomized controlled trial

BACKGROUND

Playing soccer on artificial turf can provoke pain in young players. Using shock-absorbing insoles (SAIs) can result in decreased pain perception. We sought to investigate the pain and comfort intensity experienced during the switch from natural grass to third-generation artificial turf and with the use of SAIs on artificial turf during training in young soccer players.

METHODS

In a prospective randomized controlled study, 75 players were included from the youth teams of U15, U17, and U19. Pain intensity and comfort were assessed after training on only grass turf for 3 months. Randomization stratified by team level and age was performed; the intervention group received SAIs, and the control group used their own insoles. Assessments were repeated after 3 weeks on artificial turf (baseline) and 3 more weeks (follow-up) on artificial turf with SAIs/usual insoles.

RESULTS

Pain intensity increased and comfort decreased significantly after 3 weeks of training on artificial grass compared with natural grass (P < .05). The addition of SAIs resulted in significantly reduced pain intensity compared with the usual insoles (P < .05).

CONCLUSIONS

The switch to artificial turf is associated with less comfort and more pain during training in young soccer players. The use of SAIs led to lower pain intensity, highlighting a protective role of the insoles after 6 weeks of training on artificial turf.

The NFL Orthopaedic Surgery Outcomes Database (NO-SOD): The Effect of Common Orthopaedic Procedures on Football Careers

BACKGROUND

Injuries are inherent to the sport of American football and often require operative management. Outcomes have been reported for certain surgical procedures in professional athletes in the National Football League (NFL), but there is little information comparing the career effect of these procedures.

PURPOSE

To catalog the postoperative outcomes of orthopaedic procedures in NFL athletes and to compare respective prognoses and effects on careers.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Athletes in the NFL undergoing procedures for anterior cruciate ligament (ACL) tears, Achilles tendon tears, patellar tendon tears, cervical disc herniation, lumbar disc herniation, sports hernia, knee articular cartilage repair (microfracture technique), forearm fractures, tibial shaft fractures, and ankle fractures were identified through team injury reports or other public records. Game and performance statistics during the regular season were collected before and after surgery. Statistical analysis was performed with significance accepted as P < .05.

RESULTS

A total of 559 NFL athletes were included. Overall, 79.4% of NFL athletes returned to play after an orthopaedic procedure. Forearm open reduction and internal fixation (ORIF), sports hernia repair, and tibia intramedullary nailing (IMN) led to significantly higher return-to-play (RTP) rates (90.2%-96.3%), while patellar tendon repair led to a significantly lower rate (50%) (P < .001). Athletes undergoing ACL reconstruction (ACLR), Achilles tendon repair, patellar tendon repair, and ankle fracture ORIF had significant declines in games played at 1 year and recovered to baseline at 2 to 3 years after surgery. Athletes undergoing ACLR, Achilles tendon repair, patellar tendon repair, and tibia IMN had decreased performance in postoperative season 1. Athletes in the Achilles tendon repair and tibia IMN cohorts recovered to baseline performance, while those in the ACLR and patellar tendon repair cohorts demonstrated sustained decreases in performance.

CONCLUSION

ACLR, Achilles tendon repair, and patellar tendon repair have the greatest effect on NFL careers, with patellar tendon repair faring worst with respect to the RTP rate, career length after surgery, games played, and performance at 1 year and 2 to 3 years after surgery.

A Prospective Analysis of the Injury Incidence of Young Male Professional Football Players on Artificial Turf

Background:

The effects of synthetic surfaces on the risk of injuries is still debated in literature and the majority of published data seems to be contradictory. For such reasons the understanding of injury incidence on such surfaces, especially in youth sport, is fundamental for injury prevention.

Objectives:

The aim of this study was to prospectively report the epidemiology of injuries in young football players, playing on artificial turfs, during a one sports season.

Patients and Methods:

80 young male football players (age 16.1 ± 3.7 years; height 174 ± 6.6 cm; weight 64.2 ± 6.3 kg) were enrolled in a prospective cohort study. The participants were then divided in two groups; the first included players age ranging from 17 to 19 (OP) whereas the second included players age ranging from 13 to 16 (YP). Injury incidence was recorded prospectively, according to the consensus statement for soccer.

Results:

A total of 107 injuries (35 from the OP and 72 from the YP) were recorded during an exposure time of 83.760 hours (incidence 1.28/1000 per player hours); 22 during matches (incidence 2.84/1000 per player hours, 20.5%) and 85 during training (incidence 1.15/1000 per player hours, 79.5%). Thigh and groin were the most common injury locations (33.6% and 21.5%, respectively) while muscle injuries such as contractures and strains were the most common injury typologies (68.23%). No statistical differences between groups were displayed, except for the rate of severe injuries during matches, with the OP displaying slightly higher rates compared to the YP. Severe injuries accounted for 10.28% of the total injuries reported. The average time lost due to injuries was 14 days. Re-injuries accounted for 4.67% of all injuries sustained during the season.

Conclusions:

In professional youth soccer injury rates are reasonably low. Muscle injuries are the most common type of injuries while groin and thigh the most common locations. Artificial turf pitches don’t seem to contribute to injury incidence in young football players.

Prediction of hamstring injury in professional soccer players by isokinetic measurements

OBJECTIVES

previous studies investigating the ability of isokinetic strength ratios to predict hamstring injuries in soccer players have reported conflicting results.

HYPOTHESIS

to determine if isokinetic ratios are able to predict hamstring injury occurring during the season in professional soccer players.

STUDY DESIGN

case-control study;

LEVEL OF EVIDENCE

3.

METHODS

from 2001 to 2011, 350 isokinetic tests were performed in 136 professional soccer players at the beginning of the soccer season. Fifty-seven players suffered hamstring injury during the season that followed the isokinetic tests. These players were compared with the 79 uninjured players. The bilateral concentric ratio (hamstring-to-hamstring), ipsilateral concentric ratio (hamstring-to-quadriceps), and mixed ratio (eccentric/concentric hamstring-to-quadriceps) were studied. The predictive ability of each ratio was established based on the likelihood ratio and post-test probability.

RESULTS

the mixed ratio (30 eccentric/240 concentric hamstring-to-quadriceps) <0.8, ipsilateral ratio (180 concentric hamstring-to-quadriceps) <0.47, and bilateral ratio (60 concentric hamstring-to-hamstring) <0.85 were the most predictive of hamstring injury. The ipsilateral ratio <0.47 allowed prediction of the severity of the hamstring injury, and was also influenced by the length of time since administration of the isokinetic tests.

CONCLUSION

isokinetic ratios are useful for predicting the likelihood of hamstring injury in professional soccer players during the competitive season.

Shoe and Field Surface Risk Factors for Acute Lower Extremity Injuries Among Female Youth Soccer Players

OBJECTIVE

To describe acute lower extremity injuries and evaluate extrinsic risk factors in female youth soccer.

DESIGN

Nested case-control study.

SETTING

Youth soccer clubs in Seattle, WA.

PARTICIPANTS

Female soccer players (n = 351) ages 11 to 15 years randomly selected from 4 soccer clubs from which 83% of their players were enrolled with complete follow-up for 92% of players.

INTERVENTIONS

Injured players were interviewed regarding injury, field surface, shoe type, and position. Uninjured controls, matched on game or practice session, were also interviewed.

MAIN OUTCOME MEASURES

The association between risk factors and acute lower extremity injury using logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

One hundred seventy-three acute lower extremity injuries occurred involving primarily the ankle (39.3%), knee (24.9%), and thigh (11.0%). Over half (52.9%) recovered within 1 week, whereas 30.2% lasted beyond 2 weeks. During practices, those injured were approximately 3-fold (OR, 2.83; 95% CI, 1.49-5.31) more likely to play on grass than artificial turf and 2.4-fold (95% CI, 1.03-5.96) more likely to wear cleats on grass than other shoe and surface combinations. During games, injured players were 89% (95% CI, 1.03-4.17) more likely to play defender compared with forward.

CONCLUSIONS

Half of the acute lower extremity injuries affected the ankle or knee. Grass surface and wearing cleats on grass increased training injuries.

CLINICAL RELEVANCE

The majority, 64%, of female youth soccer players' acute injuries involve the ankle and knee and injury prevention strategies in this age group should target these areas. When considering playing surfaces for training, communities and soccer organizations should consider the third-generation artificial turf a safe alternative to grass.

Influence of Extrinsic Risk Factors on National Football League Injury Rates

Background:

The risk of injury associated with American football is significant, with recent reports indicating that football has one of the highest rates of all-cause injury, including concussion, of all major sports. There are limited studies examining risk factors for injuries in the National Football League (NFL).

Purpose:

To identify risk factors for NFL concussions and musculoskeletal injuries.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

Injury report data were collected prospectively for each week over the 2012-2013 and 2013-2014 regular seasons for all 32 teams. Poisson regression models were used to identify the relationship between predetermined variables and the risk of the 5 most frequent injuries (knee, ankle, hamstring, shoulder, and concussion).

Results:

A total of 480 games or 960 team games (TGs) from the 2012-2013 and 2013-2014 regular seasons were included in this study. A trend to an increasing risk of concussion and TG ankle injury with decreasing mean game-day temperature was observed. The risk of TG concussion (incidence rate ratio [IRR], 2.16; 95% CI, 1.35-3.45; P = .001) and TG ankle injury (IRR, 1.48; 95% CI, 1.10-1.98; P = .01) was significantly greater for TGs played at a mean game-day temperature of ≤9.7°C (≤49.5°F) compared with a mean game-day temperature of ≥21.0°C (≥69.8°F). The risk of TG shoulder injury was significantly increased for TGs played on grass surfaces (IRR, 1.36; 95% CI, 1.02-1.81; P = .038) compared with synthetic surfaces. The risk of TG injury was not associated with time in season, altitude, time zone change prior to game, or distance traveled to a game.

Conclusion:

This study evaluated extrinsic risk factors for injury in the NFL. A hazardous association was identified for risk of concussion and ankle injury with colder game-day temperature. Further research should be conducted to substantiate this relationship and its potential implication for injury prevention initiatives.

Football injuries of the ankle: A review of injury mechanisms, diagnosis and management

Football is the most popular sport worldwide and is associated with a high injury rate, most of which are the result of trauma from player contact. Ankle injuries are among the most commonly diagnosed injuries in the game. The result is reduced physical activity and endurance levels, lost game time, and considerable medical cost. Sports medicine professionals must employ the correct diagnostic tools and effective treatments and rehabilitation protocols to minimize the impact of these injuries on the player. This review examines the diagnosis, treatment, and postoperative rehabilitation for common football injuries of the ankle based on the clinical evidence provided in the current literature.

The novel use of a SenseCam and accelerometer to validate training load and training information in a self-recall training diary

Self-recall training diaries are a frequently used tool to quantify training load and training information. While accelerometers are predominantly used to validate training diaries, they are unable to validate contextual training information. Thus this study aimed to examine the novel use of data fusion from a wearable camera device (SenseCam) and accelerometer to validate a self-recall training diary. Thirty participants filled in a training diary for 1 day while simultaneously wearing a SenseCam and accelerometer. The training diary was validated using Bland-Altman plots, Spearman's rank-order correlation, percentage agreement and κ measure of agreement between the diary and the SenseCam and accelerometer. The results demonstrated overall agreement, and no bias, between the training diary and the accelerometer for training intensity, and the SenseCam for duration of activity and travel time. A positive correlation was found for duration (r = 0.82, P < 0.001) and intensity (r = 0.67, P < 0.001). Hundred per cent agreement was found between the SenseCam and training diary for activity, training surface and footwear (κ = 1, P < 0.0001), with a lower agreement noted for sports played (97.3%, κ = 0.91, P < 0.0001). The self-recall training diary was found to be a valid measure of capturing training load and training information using the combined wearable camera device and accelerometer.

Ground condition as a risk factor in sports injury aetiology studies: the level of concordance between objective and subjective measures

Background

It is well known that the condition and type of sporting ground influences the risk of sports injury. However, the lack of evidence on the relationship between subjective and objective sporting ground condition assessments in sports injury aetiology studies has implications for the development of effective injury prevention strategies. This paper aims to examine concordance between subjectively rated and objective ground hardness and moisture measurements to inform data collection methods for future sports injury aetiology studies.

Methods

Subjective, observational assessments of ground hardness and soil moisture were recorded on 36 occasions during an Australian football season using two four-point scales of ‘very soft’ to ‘very hard’ and ‘very wet’ to ‘very dry’, respectively. Independent, objectively measured hardness and soil moisture were also undertaken at nine locations on the same grounds. The maximum and minimum ground values and the computed average of ground hardness and soil moisture were analysed. Somer’s d statistic was calculated to measure the level of concordance between the subjective and objective measures.

Results

A significant, moderate to substantial level of agreement was found between the subjective ratings and the average objective hardness values (d = 0.467, p <0.001), but there was perfect agreement on just less than half of the occasions. The level of concordance between the subjective and objective moisture ratings was low to moderate or trivial for all moisture measures (0.002 < d <0.264, p >0.05).

Conclusions

Compared to objective measures, the subjective assessments were more accurate for ground hardness than for soil moisture levels and raters were just as likely to underestimate or overestimate the condition under review. This has implications for future sports injury aetiology studies that include ground condition assessments and particularly the use of subjective measures to underpin the development of future injury prevention strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s40621-014-0027-y) contains supplementary material, which is available to authorized users.

Spatial and temporal analysis of surface hardness across a third-generation artificial turf pitch over a year

Despite the potentially negative effects on play performance and safety, little is currently known about the spatial and temporal variability in the properties of artificial turf pitches. The primary purpose of this study was to quantify the spatial and temporal variations in surface hardness across a 5-year-old third-generation artificial turf pitch over full year cycle. The secondary purpose was to investigate the key variables that contributed to these variations in surface hardness using a correlation approach. Surface hardness (2.25 kg Clegg impact hammer, average of drops 2-5), ground temperature and infill depth were measured at 91 locations across the third-generation artificial turf pitch in 13-monthly test sessions from August 2011 to August 2012 inclusive. For each month, rainfall in the 24 h prior to testing and pitch usage statistics were also obtained. Shockpad thickness was obtained from measurements taken when the carpet was replaced in 2007. Spatial and temporal variations were assessed using robust statistical measures while Spearman correlation was used to assess the contributions of the secondary variables to surface hardness variability. The results indicated that spatial variation in surface hardness exceeded temporal variation; the former demonstrated a median absolute deviation of 12 ± 1 G across the pitch in any test session while the median absolute deviation for the latter was only 4 ± 2 G across the 13 test sessions. Spatial variation in surface hardness was moderately correlated with shockpad thickness and weakly correlated with infill depth (both negative). These results reinforce the importance of monitoring spatial and temporal variations in play performance variables for third-generation surfaces as well as providing support for the role of maintenance in minimising the spatial variation.

The perceptions of professional soccer players on the risk of injury from competition and training on natural grass and 3rd generation artificial turf

BACKGROUND

The purpose of this study was to describe professional soccer players' perceptions towards injuries, physical recovery and the effect of surface related factors on injury resulting from soccer participation on 3rd generation artificial turf (FT) compared to natural grass (NG).

METHODS

Information was collected through a questionnaire that was completed by 99 professional soccer players from 6 teams competing in Major League Soccer (MLS) during the 2011 season.

RESULTS

The majority (93% and 95%) of the players reported that playing surface type and quality influenced the risk of sustaining an injury. Players believed that playing and training on FT increased the risk of sustaining a non-contact injury as opposed to a contact injury. The players identified three surface related risk factors on FT, which they related to injuries and greater recovery times: 1) Greater surface stiffness 2) Greater surface friction 3) Larger metabolic cost to playing on artificial grounds. Overall, 94% of the players chose FT as the surface most likely to increase the risk of sustaining an injury.

CONCLUSIONS

Players believe that the risk of injury differs according to surface type, and that FT is associated with an increased risk of non-contact injury. Future studies should be designed prospectively to systematically track the perceptions of groups of professional players training and competing on FT and NG.

Comparison of injury incidences between football teams playing in different climatic regions

Australian Football League (AFL) teams in northern (warmer) areas generally have higher rates of injury than those in southern (cooler) areas. Conversely, in soccer (football) in Europe, teams in northern (cooler) areas have higher rates of injury than those in southern (warmer) areas, with an exception being knee anterior cruciate ligament (ACL) injuries, which are more common in the southern (warmer) parts of Europe. This study examined relative injury incidence in the AFL comparing 9,477 injuries over 229,827 player-weeks from 1999–2012. There was a slightly higher injury incidence for teams from warmer parts of Australia (relative risk [RR] 1.05, 95% confidence interval [CI] 1.01–1.10) with quadriceps strains (RR 1.32, 95% CI 1.10–1.58), knee cartilage injuries (RR 1.42, 95% CI 1.16–1.74), and ankle sprains (RR 1.17, 95% CI 1.00–1.37) all being more likely in warmer region teams. Achilles injuries followed a reverse pattern, tending to be more common in cooler region teams (RR 0.70, 95% CI 0.47–1.03). In conclusion, common findings from the AFL and European soccer are that ankle sprains and ACL injuries are generally more likely in teams playing in warmer climate zones, whereas Achilles tendinopathy may be more likely in teams playing in cooler zones. These injuries may have climate or surface risk factors (possibly related to types and structure of grass and shoe-surface traction) that are universal across different football codes.

Epidemiology of time-loss injuries in English community-level rugby union

OBJECTIVES

Using a prospective cohort study design, to establish the incidence and nature of time-loss injuries in English community rugby and to assess the differences between different playing levels.

SETTING

English community rugby clubs.

PARTICIPANTS

Injury information for 4635 matches was collected during seasons 2009/2010 (46 clubs), 2010/2011(67 clubs) and 2011/2012 (76 clubs). Clubs were subdivided into groups A (semiprofessional), B (amateur) and C (recreational) for analysis.

PRIMARY AND SECONDARY OUTCOME MEASURES

Any injury resulting in 8 days or greater absence from match play was reported by injury management staff at the clubs. The primary outcome measure was injury incidence (per 1000 player match-hours) and the secondary outcome measure was severity (ie, days absence).

RESULTS

Overall match injury incidence was 16.9 injuries per 1000 player match-hours. Incidence was higher for group A (21.7; 95% CI 19.8 to 23.6) compared with group B (16.6; 95% CI 15.2 to 17.9) and C (14.2; 95% CI 13.0 to 15.5, both p<0.001). The mean time-loss was 7.6 weeks absence, with knee and shoulder injuries the most severe with mean absences of 11.6 and 9.3 weeks, respectively. Half of all injuries occurred to the lower limb, with knee and ankle joint/ligament injuries the most common diagnoses. Shoulder joint/ligament injuries were the most common and severe upper limb injuries. Contact events accounted for 80% of all injuries and tackles accounted for 50%. Running was the most common non-contact injury event, of which 56% were hamstring injuries.

CONCLUSIONS

More time-loss injuries occur at higher levels of community rugby. Injury prevention strategies should focus on good technique in the tackle and conditioning exercises for the knee, ankle, hamstrings and shoulder.

Incidence, mechanisms, and severity of match-related collegiate women's soccer injuries on FieldTurf and natural grass surfaces: a 5-year prospective study

BACKGROUND

Numerous injuries have been attributed to playing on artificial turf. Over the past 2 decades, however, newer generations of synthetic turf have been developed to duplicate the playing characteristics of natural grass. Although synthetic turf has been determined to be safer than natural grass in some studies, few long-term studies have been conducted comparing match-related collegiate soccer injuries between the 2 playing surfaces.

HYPOTHESIS

Collegiate female soccer athletes do not experience any difference in the incidence, mechanisms, and severity of match-related injuries on FieldTurf and on natural grass.

STUDY DESIGN

Cohort study: Level of evidence, 2.

METHODS

Female soccer athletes from 13 universities were evaluated over 5 competitive seasons for injury incidence, injury category, time of injury, injury time loss, player position, injury mechanism and situation, primary type of injury, injury grade and anatomic location, field location at the time of injury, injury severity, head and lower extremity trauma, cleat design, turf age, and environmental factors. In sum, 797 collegiate games were evaluated for match-related soccer injuries sustained on FieldTurf or natural grass during 5 seasons.

RESULTS

Overall, 355 team games (44.5%) were played on FieldTurf versus 442 team games (55.5%) on natural grass. A total of 693 injuries were documented, with 272 (39.2%) occurring during play on FieldTurf and 421 (60.8%) on natural grass. Multivariate analysis per 10 team games indicated a significant playing surface effect: F₂,₆₉₀ = 6.435, P = .002, n-β = .904. A significantly lower total injury incidence rate (IIR) of 7.7 (95% confidence interval [CI], 7.2-8.1) versus 9.5 (95% CI, 9.3-9.7) (P = .0001) and lower rate of substantial injuries, 0.7 (95% CI, 0.5-1.0) versus 1.5 (95% CI, 1.2-1.9) (P = .001), were documented on FieldTurf versus natural grass, respectively. Analyses also indicated significantly less trauma on FieldTurf when comparing injury time loss, player position, injury grade, injuries under various field conditions and temperatures, cleat design, and turf age.

CONCLUSION

Although similarities existed between FieldTurf and natural grass during competitive match play, FieldTurf is a practical alternative when comparing injuries in collegiate women's soccer. It must be reiterated that the findings of this study may be generalizable to only collegiate competition and this specific artificial surface.

Preventive exercise in sports

Sports injuries are common and can result in significant problems, such as pain, social isolation, depression, disability (temporary or permanent), loss of income, or loss of scholarship. Further, sports injuries can predispose the athlete to future injury or degenerative disorders, for example, osteoarthritis. Therefore, a preventive approach is paramount, and exercise can be used as an effective tool to prevent sports-related injuries. This article describes the process by which successful injury prevention programs can be developed and implemented by using noncontact anterior cruciate ligament injury programs as an example. The knowledge gained from this information can be used in the future to assist in the creation of new injury prevention programs for other common sports injuries.

The proprioceptive senses: their roles in signaling body shape, body position and movement, and muscle force

This is a review of the proprioceptive senses generated as a result of our own actions. They include the senses of position and movement of our limbs and trunk, the sense of effort, the sense of force, and the sense of heaviness. Receptors involved in proprioception are located in skin, muscles, and joints. Information about limb position and movement is not generated by individual receptors, but by populations of afferents. Afferent signals generated during a movement are processed to code for endpoint position of a limb. The afferent input is referred to a central body map to determine the location of the limbs in space. Experimental phantom limbs, produced by blocking peripheral nerves, have shown that motor areas in the brain are able to generate conscious sensations of limb displacement and movement in the absence of any sensory input. In the normal limb tendon organs and possibly also muscle spindles contribute to the senses of force and heaviness. Exercise can disturb proprioception, and this has implications for musculoskeletal injuries. Proprioceptive senses, particularly of limb position and movement, deteriorate with age and are associated with an increased risk of falls in the elderly. The more recent information available on proprioception has given a better understanding of the mechanisms underlying these senses as well as providing new insight into a range of clinical conditions.

The relationship between ground conditions and injury: what level of evidence do we have?

OBJECTIVES

To identify studies which address the relationship between ground conditions and injury, in a sporting context and to evaluate current practice and provide recommendations for future studies that measure ground conditions and injury risk.

DESIGN

Systematic review.

METHODS

A comprehensive search of electronic databases from the earliest records available until the end of 2011, and supplemental hand searching was conducted to identify relevant studies. A classification scale was used to rate the methodological quality of studies.

RESULTS

79 potentially relevant articles were identified, and 27 met all inclusion criteria. They varied in methodological quality, with analytical observational studies the most common design, although four descriptive observational studies, considered to be of lower quality were also identified. Only five studies objectively measured ground conditions, and of studies that used subjective assessment, only one provided descriptors to explain their classifications. It appears that harder/drier grounds are associated with an increased injury risk but the presence of major limitations necessitates cautious interpretation of many key findings.

CONCLUSIONS

There is limited high quality evidence of the relationship between injury risk and ground conditions. Further research with high quality designs, and measurement of ground conditions are required to draw more definitive conclusions regarding this relationship.