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

Playing Surface and Sport Contact Status Modulate Time to Lower Extremity Musculoskeletal Injury at a Greater Level than Concussion History Among Collegiate Student-Athletes

OBJECTIVES

While previous investigations have demonstrated a positive correlation between previous concussion and risk of subsequent lower extremity musculoskeletal injury (LEMSKI), the effect of sport- and patient-specific factors on time to injury has not been thoroughly described. This study's main objective was to evaluate the relationship between prior concussion and time to LEMSKI among a population of collegiate student-athletes. Secondary objectives were to evaluate the relationship between playing surface, sport contact status, and biologic sex on time to LEMSKI. We hypothesized that those with previous concussion, those competing on synthetic surfaces, and those competing in collision sports would experience decreased latency to LEMSKI overall.

METHODS

A retrospective observational analysis of National Collegiate Athletic Association (NCAA) Division I student-athletes was conducted utilizing a mixed linear model analysis with contrasts. Inclusion criteria included participation in the Pac-12 Health Analytics Program with a documented LEMSKI between 2017 and 2020. Exclusion criteria included concurrent concussion and LEMSKI, injury resulting in serious morbidity or mortality, and incomplete medical record. Participants were classified by whether they sustained a concussion prior to LEMSKI in each athletic season.

RESULTS

Of 1179 athletes included, 1140 had no previous concussion and 37 had a previous concussion. There was no observed effect of previous concussion (F=0.038; p=0.846) on time to LEMSKI overall. Student-athletes competing on constructed surfaces sustained a subsequent LEMSKI 14.5 days sooner (SE=5.255; p=0.045), and those competing on organic surfaces sustained a subsequent LEMSKI 23.5 days sooner (SE=4.018; p<0.001) in the season than those competing on synthetic surfaces. Contact sport student-athletes sustained a subsequent LEMSKI 52.1 days sooner than collision sport student-athletes (SE=5.248; p<0.001), and limited contact sport student-athletes sustained a subsequent LEMSKI 42.29 days sooner than collision sport student-athletes (SE=4.463; p<0.001). There was no observed effect of biologic sex (F=0.602; p=0.438) on time to LEMSKI overall.

CONCLUSION

There was no observed impact of concussion on time to LEMSKI overall in this collegiate athletic population. Contact sports were associated with decreased time to LEMSK, while synthetic surfaces were associated with increased time to LEMSKI in this population. There was no observed impact of biologic sex on time to LEMSKI.

LEVEL OF EVIDENCE

Case-control, level of evidence III.

Injury-Inciting Activities in Male and Female Football Players: A Systematic Review

BACKGROUND

A comprehensive examination of the sport-specific activities performed around the time of injury is important to hypothesise injury mechanisms, develop prevention strategies, improve management, and inform future investigations. The aim of this systematic review is to summarise the current literature describing the activities performed around the time of injury in football (soccer).

METHODS

A systematic search was carried out in PubMed, Web of Science, SPORTDiscus, and OpenGrey. Studies were included if participants were football players aged > 13 years old and the activities performed at the time of injury were reported together with the total number of injuries. Risk of bias was assessed using an adapted version of checklists developed for prevalence studies. The activities reported by the studies were grouped to account for inconsistent reporting, and the proportion of each injury activity was calculated. Data were not meta-analysed due to high heterogeneity of methods and classification criteria.

RESULTS

We included 64 studies reporting on 56,740 injuries in total. ACL injures were analysed by 12 studies, ankle/foot and knee injuries were analysed by five studies, thigh injuries were analysed by four studies, hip/groin injuries were analysed by three studies, and hamstring injuries were analysed by two studies. Five studies analysed more than one type of injury and 38 studies did not specify the type of injuries analysed. Running and kicking were the predominant activities leading to thigh and hamstring injuries. Changing direction and kicking were the predominant activities leading to hip and groin injuries and duels were the predominant activities leading to ankle injuries. Duels and pressing seem the predominant activities leading to ACL injuries, while results for other knee and general injuries were inconsistent.

CONCLUSIONS

A qualitative summary of the activities performed at the time of injury has been reported. The results need to be interpreted carefully due to the risk of bias observed in the included studies. If we are to meaningfully progress our knowledge in this area, it is paramount that future research uses consistent methods to record and classify injuries and activities leading up to and performed at the time of injury.

REGISTRATION

The protocol of this systematic review was registered at the Open Science Framework ( https://doi.org/10.17605/OSF.IO/U96KV ).

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.

Player Sex and Playing Surface Are Individual Predictors of Injuries in Professional Soccer Players

Background: The factors contributing to soccer injuries and their influence on the occurrence of injury are controversial and inconclusive. This study aimed to determine the association between player characteristics and playing factors with injuries in professional soccer players. Methods: One hundred and fifty-two professional soccer players completed a self-administered questionnaire that asked about demographic information and injury profile, the type of playing surface on which they sustained their injury, medical treatment, and the time lost due to soccer injury at the end of the soccer season. Results: The injury rate was 44.74% (n = 68; males: 61.50% (n = 56), females: 19.70% (n = 12)). Players’ age (OR: 1.15, 95%CI: 1.05−1.25, p < 0.002) and BMI (OR: 1.21, 95%CI: 1.06−1.38, p < 0.003) were significantly associated with soccer injuries. After adjusting for age and BMI, players’ sex (OR: 5.39, 95%CI: 2.11−13.75, p < 0.001), previous soccer injury (OR: 3.308, 95%CI: 2.307−29.920, p < 0.001), and playing surfaces (OR: 11.07, 95%CI: 4.53−27.03, p < 0.001) were the significant predictors of soccer injuries. Conclusion: Players’ age, BMI, sex, previous soccer injury, and playing surface were associated with injuries among professional soccer players. Old male athletes with high BMI, previous soccer injuries, and playing on natural grass were more likely to sustain soccer injuries than young female players with low BMI who had no previous injuries and played on synthetic surfaces.

Increased Risk of ACL Injury for Female but Not Male Soccer Players on Artificial Turf Versus Natural Grass: A Systematic Review and Meta-Analysis

Background:

Both natural grass (NG) and artificial turf (AT) are popular playing surfaces for soccer. Biomechanical studies have found increased frictional forces on AT that may lead to anterior cruciate ligament (ACL) injury. The increased risk of ACL injury during soccer in female participants may amplify this effect.

Purpose:

To systematically review the literature for studies comparing ACL injury risk in soccer players on AT versus NG and to specifically determine whether there were differences in injury risk in male versus female players when considering the playing surface.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Three databases were searched for studies with evidence level 1 to 3 that compared the incidence of ACL injuries on AT versus NG in soccer players. Data recorded included study characteristics, sex, competition level, exposure setting (games or practices), turf type, and ACL injury information. Study methodological quality was analyzed using the methodological index for non-randomized studies (MINORS) score, and incidence rate ratios (IRRs) were calculated.

Results:

Included were 7 articles (3 studying professional soccer, 3 collegiate soccer, 1 youth-level soccer; 4 male cohorts, 2 female cohorts, and 1 male and female cohort; mean MINORS score, 20 ± 0.8). Pooled ACL injury IRRs demonstrated no significant differences in overall ACL injury risk when playing soccer on AT compared with NG (IRR = 0.57 [95% CI, 0.21-1.53]; P = .31). A significantly increased risk of ACL injury in games played on AT compared with NG was detected for female (IRR = 1.18 [95% CI, 1.05-1.31]; P = .004) but not for male players (IRR = 1.18 [95% CI, 0.97-1.42]; P = .09). Subgroup analyses showed no significant differences in injury risk for games (IRR = 1.07 [95% CI, 0.97-1.18]; P = .20) or practices (IRR = 0.21 [95% CI, 0.04-1.23]; P = .09).

Conclusion:

Findings indicated that female soccer players had a significantly higher risk of ACL injury when playing games on AT versus NG, whereas no significant difference was seen in male players. No differences were found for the combined male/female cohort or for soccer games or training sessions played on AT compared with NG.

Lower Extremity Injury Rates on Artificial Turf Versus Natural Grass Playing Surfaces: A Systematic Review

BACKGROUND

No study has provided a comprehensive systematic review of sports injuries on artificial turf versus natural grass.

PURPOSE

To comprehensively examine the risk of overall injuries and multiple types of lower extremity injuries across all sports, all levels of competition, and on both old-generation and new-generation artificial turf.

STUDY DESIGN

Systematic review; Level of evidence, 3.

METHODS

A systematic review of the English-language literature was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. All included articles compared overall injury rates or lower extremity (hip, knee, or foot and ankle) injury rates on artificial turf and natural grass. All sports, levels of competition, and turf types were included. Studies were excluded if they did not include overall injury rates or lower extremity injury rates. Because of the heterogeneity of the included studies, no attempt was made to aggregate risk ratios to conduct a quantitative meta-analysis.

RESULTS

A total of 53 articles published between 1972 and 2020 were identified for study inclusion. Most studies on new-generation turf (13/18 articles) found similar overall injury rates between playing surfaces. When individual anatomic injury locations were analyzed, the greatest proportion of articles reported a higher foot and ankle injury rate on artificial turf compared with natural grass, both with old-generation (3/4 articles) and new-generation (9/19 articles) turf. Similar knee and hip injury rates were reported between playing surfaces for soccer athletes on new-generation turf, but football players, particularly those at high levels of competition, were more likely to sustain a knee injury on artificial turf than on natural grass.

CONCLUSION

The available body of literature suggests a higher rate of foot and ankle injuries on artificial turf, both old-generation and new-generation turf, compared with natural grass. High-quality studies also suggest that the rates of knee injuries and hip injuries are similar between playing surfaces, although elite-level football athletes may be more predisposed to knee injuries on artificial turf compared with natural grass. Only a few articles in the literature reported a higher overall injury rate on natural grass compared with artificial turf, and all of these studies received financial support from the artificial turf industry.

Epidemiological Comparison of ACL Injuries on Different Playing Surfaces in High School Football and Soccer

Background:

Anterior cruciate ligament (ACL) injuries are among the most common serious injuries to athletes in the United States. Among high school sports, the highest rates of ACL injury occur in soccer and football.

Purpose:

To compare ACL injuries on artificial turf and natural grass using a nationally representative sample of high school athletes participating in football and boys’ and girls’ soccer.

Study Design:

Descriptive epidemiology study.

Methods:

ACL injuries among high school athletes participating in football and soccer were obtained from the High School Reporting Information Online surveillance system during the 2007-08 through 2018-19 school years. National estimates and injury proportion ratios (IPRs) with 95% CIs were calculated for ACL injuries that occurred on artificial turf versus natural grass.

Results:

A total of 1039 ACL injuries were reported, which represented an estimated 389,320 (95% CI, 358,010-420,630) injuries nationally. There were 74,620 estimated football-related ACL injuries on artificial turf and 122,654 on natural grass. Likewise, 71,877 of the estimated soccer-related ACL injuries occurred on artificial turf and 104,028 on natural grass. A contact-injury mechanism accounted for 50.2% of football-related ACL injuries on artificial turf and 60.8% on natural grass. For soccer-related ACL injuries, a noncontact mechanism predominated on artificial turf (61.5%) and natural grass (66.4%). Among all injuries, ACL injuries were more likely to occur on artificial turf than natural grass in both football (IPR, 1.23 [95% CI, 1.03-1.47]) and girls’ soccer (IPR, 1.53 [95% CI, 1.08-2.16]); however, no significant association was found in boys’ soccer (IPR, 1.65 [95% CI, 0.99-2.75]). Among lower extremity injuries, ACL injuries were more likely to occur on artificial turf than natural grass in both boys’ soccer (IPR, 1.72 [95% CI, 1.03-2.85]) and girls’ soccer (IPR, 1.61 [95% CI, 1.14-2.26]); however, the association was not significant in football (IPR, 1.17 [95% CI, 0.98-1.39]).

Conclusion:

ACL injuries were more likely to occur (ie, had larger IPRs) on artificial turf than natural grass; however, this relationship was not statistically significant for all sports.

Investigating Turf Burn-Related Videos on TikTok: Cross-sectional Study

BACKGROUND

Due to the increased use of artificial turf, turf burn has become a common sports injury. Turf burn is caused by exposed skin sliding on artificial turf. Health complications, such as methicillin-resistant Staphylococcus aureus outbreaks, sepsis, and pneumonia, have been linked to untreated turf burns, and many athletes have been turning to social media for advice and companionship regarding their sports injuries.

OBJECTIVE

The goal of this study is to categorize and quantitatively assess the percentage of turf burn-related posts on TikTok based on creator type, content, athletes' experiences, and treatment and prevention methods. With these data, we not only investigate if there is room for health care professionals to assist in the distribution of evidence-based health education to athletes to counteract misinformation but also investigate if there is a potential audience of athletes on TikTok who have the potential to develop problematic responses to injuries.

METHODS

By using the Discover page on TikTok, we searched for the term turf burn on October 17, 2021. In total, 100 videos were analyzed. Videos were categorized and analyzed based on creator type, content, experiences of the athletes, and treatment and prevention methods. The number of likes and comments was recorded.

RESULTS

Most videos (98/100, 98%) were created by athletes. A small number of videos (2/100, 2%) were created by health care professionals. In terms of content, most videos (67/100, 67%) displayed turf burns. A small amount of videos (15/100, 15%) showed the incidents when turf burns were acquired, while around one-quarter of the videos (23/100, 23%) demonstrated the treatment and prevention of turf burns. Of the 23 treatment and prevention videos, a minority (4/23, 17%) showed the preferred treatment of turf burns, while most videos (19/23, 83%) showed nonpreferred treatments. The smallest amount of videos (2/100, 2%) were about turf burn education. Most of the videos created by athletes (56/98, 57%) depicted the negative experiences that patients had with turf burns. Some videos (37/98, 38%) depicted neutral experiences, while the smallest amount of videos (5/98, 5%) depicted positive experiences.

CONCLUSIONS

Our study suggests that there is a potential audience of athletes on TikTok who could develop problematic responses to sports injuries, such as turf burns, as most of the people who post videos are athletes, and many of the posts demonstrate negative experiences associated with turf burns. TikTok is a growing social media platform that should be studied to determine if it can be used to create a social support group for injured athletes to prevent the progression of negative emotional responses into problematic responses. Physicians should also have a role in establishing their social media presence on TikTok and offering evidence-based advice to athletes while disproving misinformation on TikTok.

Endoscopic Flexor Hallucis Longus Transfer for the Management of Acute Achilles Tendon Ruptures in Professional Soccer Players

BACKGROUND

Acute Achilles tendon ruptures (AATRs) that occur in athletes can be a career-ending injury. The aim of this study was to describe return to play and clinical outcomes of isolated endoscopic flexor hallucis longus (FHL) transfer in active soccer players with AATR.

METHODS

Twenty-seven active male soccer players who underwent endoscopically assisted FHL tendon transfer for acute Achilles tendon ruptures were included in this study. Follow up was 46.2 (±10.9) months after surgery. Return to play criteria and clinical outcome measures were evaluated.

RESULTS

All players returned to playing professional competitive soccer games. Return to active team training was at a mean of 5.8 (±1.1) months postoperatively. However, return to active competitive match play occurred at a mean of 8.3 (±1.4) months. Twenty-two players (82%) were able to return to their preinjury levels and performances and resumed their professional careers at the same soccer club as their preinjury state. One player (3.7%) shifted his career to professional indoor soccer. At 26 months postoperatively, the mean Tegner activity scale score was 9.7 (±0.4), the mean Achilles tendon total rupture score was 99 (±2), and the mean American Orthopaedic Foot & Ankle Society ankle-hindfoot score was 99 (±3). No patients reported any great toe complaints or symptomatic deficits of flexion strength.

CONCLUSION

The current study demonstrated satisfactory and comparable return to play criteria and clinical results with minimal complications when using an advanced endoscopically assisted technique involving FHL tendon transfer to treat acute Achilles tendon ruptures in this specific subset of patient cohort.

LEVEL OF EVIDENCE

Level II, prospective cohort case series study.

Physical exercises for preventing injuries among adult male football players: A systematic review

BACKGROUND

Football is the most practised sport in the world and is associated with the risk of injuries in the players. Some studies have been published that identify injury prevention programs, but there is no review of the full body of evidence on injury prevention programs for use by football coaches. The aim of this article was to carry out a systematic review of published studies on injury prevention programs for adult male footballers, identify points of common understanding and establish recommendations that should be considered in the design of injury prevention strategies.

METHODS

PubMed and EMBASE databases were used to identify relevant published articles using the following keywords: "soccer" AND "injury" AND "prevention".

RESULTS

A total of 2512 studies were identified initially, but only 11 studies met the inclusion criteria, and their outcomes are presented. Results revealed that injury prevention programs in football have focused on strength training, proprioceptive training, multicomponent programs (balance, core stability, and functional strength and mobility), and warm-up programs.

CONCLUSION

Based on results from the studies analyzed, football players can lower the incidence of match and training injuries by participating in dynamic warm-up programs that include preventive exercises before games or during training sessions, and by adding strength, balance, and mobility training to the training sessions.

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.

Athletic Play Surfaces and Injury Risk

ABSTRACT

Advancements in technology and the economic desires to maximize use of athletic playing surfaces have led to the development of various playing surfaces across the spectrum of sports. Each of these surfaces possesses specific safety profiles which are sport and population specific. Despite the growing medical literature on outdoor playing surfaces, inconsistent data exist on both orthopedic injuries and general medical concerns, such as surface component exposure toxicity and infection risk. Unfortunately, there is a paucity of data regarding various indoor playing surfaces and their effects on injury risk; this is an area ripe for further medical investigation. Understanding the differences in various play surfaces and their associated injury and health concerns is crucial for all medical staff providing care to athletes across the spectrum of skill and competition.

Epidemiology of Anterior Cruciate Ligament Injury on Natural Grass Versus Artificial Turf in Soccer: 10-Year Data From the National Collegiate Athletic Association Injury Surveillance System

Background:

Anterior cruciate ligament (ACL) injury is prevalent among National Collegiate Athletic Association (NCAA) soccer players. Controversy remains regarding the effect of the surface type on the rate of ACL injury in soccer players, considering differences in sex, type of athletic exposure, and level of competition.

Hypothesis:

Natural grass surfaces would be associated with decreased ACL injury rate in NCAA soccer players. Sex, type of athletic exposure (match vs practice), and level of competition (Division I-III) would affect the relationship between playing surface and ACL injury rates.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Using the NCAA Injury Surveillance System (ISS) database, we calculated the incidence rate of ACL injury in men and women from 2004-2005 through 2013-2014 seasons. The incidence was normalized against athletic exposure (AE). Additional data collected were sex, athletic activity at time of injury (match vs practice), and level of competition (NCAA division) to stratify the analysis. Statistical comparisons were made by calculating incidence rate ratios (IRR). Statistical significance was set at an alpha of .05.

Results:

There were 30,831,779 weighted AEs during the study period. The overall injury rate was 1.12 ACL injuries per 10,000 AEs (95% CI, 1.08-1.16). Women comprised 57% of the match data (10,261 games) and 55% of practice data (26,664 practices). The overall injury rate was significantly higher on natural grass (1.16/10,000 AEs; 95% CI, 1.12-1.20) compared with artificial turf (0.92/10,000 AEs [95% CI, 0.84-1.01]; IRR, 1.26 [95% CI, 1.14-1.38]) (P < .0001). This relationship was demonstrated consistently across all subanalyses, including stratification by NCAA division and sex. The injury rate on natural grass (0.52/10,000 AEs; 95% CI, 1.11-1.26) was significantly greater than the injury incidence during practice on artificial turf (0.06/10,000 AEs; 95% CI, 0.043-0.096). Players were 8.67 times more likely to sustain an ACL injury during practice on natural grass compared with practice on artificial turf (95% CI, 5.43-12.13; P < .0001). No significant difference was found in injury rates between matches played on grass versus turf (IRR, 0.93; 95% CI, 0.84-1.03; P = .15).

Conclusion:

NCAA soccer players who practice on natural grass have increased risk of ACL injury compared with the risk of those practicing on an artificial surface, regardless of sex or NCAA division of play. No difference in risk of ACL injury between playing surfaces was detected during matches. Further research is necessary to examine the effect of multiple factors when evaluating the effect of the surface type on the risk of ACL injury in soccer players.

Association of artificial turf and concussion in competitive contact sports: a systematic review and meta-analysis

Objective

To determine the incidence of head injuries and concussion in contact sports, comparing natural grass with artificial turf surfaces.

Design

Systematic review and meta-analysis via the RevMan V.5.3 software.

Eligibility criteria for selecting studies

All studies describing competitive contact sports played on both natural grass and artificial turf. The primary outcome measured was occurrence of head injury and concussion.

Data sources

The databases include PubMed, Embase, Cochrane, Medline and Sport Discus. The last search took place on 23 May 2019. The Newcastle-Ottawa Quality Assessment Scale evaluated the methodological quality of the selected studies with a funnel plot designed to determine publication bias. Study screening and data extraction were performed by two independent reviewers.

Results

Initial screening generated 42 publications, with 12 meeting criteria for inclusion. Eight studies described concussion only. The rate ratio (RR) of head injury and concussion was less on artificial turf compared with natural grass (RR=0.89, 95% CI 0.77 to 1.04) as was the rate ratio of concussion only (RR=0.72, 95% CI 0.58 to 0.89).

Conclusion

Analysis of published data demonstrates a decreased incidence of head injury and concussion when contact sports are played on artificial turf. This difference was most marked for sports such as rugby and American football. However, artificial turf has no association with the incidence of head injury or concussion while playing soccer.

Movement Technique During Jump-Landing Differs Between Sex Among Athletic Playing Surfaces

Pryor, JL, Burbulys, ER, Root, HJ, and Pryor, RR. Movement technique during jump-landing differs between sex among athletic playing surfaces. J Strength Cond Res XX(X): 000-000, 2020-Whether athletic surface type affects movement technique, a causal factor for lower extremity injury, is unclear. This study evaluated the influence of 4 common athletic surfaces on movement technique using the Landing Error Scoring System (LESS). Secondarily, we aimed to evaluate differences in movement technique between men and women among surfaces. Recreationally active men and women (n = 38) completed jump-landing tests on 4 common athletic surfaces in a quasi-randomized crossover fashion. Vertical jump height, perceptual fatigue, and muscle soreness were evaluated before jump-landing movement analyses and were similar across testing sessions (p > 0.05). Men achieved higher LESS scores on hardwood and artificial pellet turf compared with women (p ≤ 0.037). Women exhibited lower LESS scores on grass and artificial turf vs. concrete (p ≤ 0.048). Data indicate differential lower extremity movement technique and therefore injury risk across athletic surface types and sex, challenging the generalizability of the LESS construct. Athletic playing surface should be considered during movement technique assessment and implementation of injury prevention programs.

The cumulative and residual fatigue response associated with soccer-specific activity performed on different playing surfaces

This study aimed to assess the effect of playing surface (Natural [NT] and Artificial [AT] Turf) on the fatigue response to a soccer-specific exercise protocol (SSEP). Eighteen male soccer players completed the SSEP on NT and AT with pre-, post-, and 48 h post-assessments of eccentric knee flexor (eccKF) and concentric knee extensor peak torque (PT), peak countermovement (CMJ) and squat jump (SJ) height, and Nordic hamstring break angle. No significant main effects for surface or any surface and time interactions were observed for any of the outcome measures, except for eccKF PT recorded at 3.14 rad·s^-1, which was significantly lower 48 h post-trial in the AT condition (AT = 146.3 ± 20.4 Nm; NT = 158.8 ± 24.7 Nm). Main effects for time were observed between pre- and post-trial measures for eccKF PT at all angular velocities, Nordic break angle, CMJ and SJ height. Nordic break angle, and both CMJ and SJ height were significantly impaired 48 h post-trial when compared to pre-trial. The findings of the current study suggest surface dependent changes in eccKF PT which may have implications for recovery and subsequent performance after competition on AT.

Descriptive Epidemiology of Injuries in Professional Ultimate Frisbee Athletes

CONTEXT

Injuries in professional ultimate Frisbee (ultimate) athletes have never been described.

OBJECTIVE

To determine injury rates, profiles, and associated factors using the first injury-surveillance program for professional ultimate.

DESIGN

Descriptive epidemiology study.

SETTING

American Ultimate Disc League professional ultimate teams during the 2017 season.

PATIENTS OR OTHER PARTICIPANTS

Sixteen all-male teams.

MAIN OUTCOME MEASURE(S)

Injury incidence rates (IRs) were calculated as injuries per 1000 athlete-exposures (AEs). Incidence rate ratios were determined to compare IRs with 95% confidence intervals, which were used to calculate differences.

RESULTS

We observed 299 injuries over 8963 AEs for a total IR of 33.36 per 1000 AEs. Most injuries affected the lower extremity (72%). The most common injuries were thigh-muscle strains (12.7%) and ankle-ligament sprains (11.4%). Running was the most frequent injury mechanism (32%). Twenty-nine percent of injuries involved collisions; however, the concussion rate was low (IR = 0.22 per 1000 AEs). Injuries were more likely to occur during competition and in the second half of games. An artificial turf playing surface did not affect overall injury rates (Mantel-Haenszel incidence rate ratio = 1.28; 95% confidence interval = 0.99, 1.67).

CONCLUSIONS

To our knowledge, this is the first epidemiologic study of professional ultimate injuries. Injury rates were comparable with those of similar collegiate- and professional-level sports.

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.

UEFA model in identification of types, severity and mechanism of injuries among footballers in the Nigerian Women's Premier League

Objective

To prospectively investigate the injury profile and the incidence rate per 1000 hours exposure during training and actual league matches in the Nigerian Women’s Premier League (NWPL) and to develop an adequate information pool, using the UEFA injury study model in order to develop appropriate injury prevention strategies.

Methods

241 women footballers from the eight football clubs that participated in the 2015/2016 Nigerian Women Premier league (NWPL) season were selected for the study and prospectively followed for a period of 6 months. The UEFA injury report forms and Competitive Aggressiveness and Anger Scale were sent to the various clubs, and the forms administered on them as at when due. The forms were analysed using descriptive statistics.

Results

There was a high incidence rate per 1000 hours of exposure during training sessions (10.98 injuries/1000 hours) and matches (55.56 injuries/1000 hours); the predominant injury type was muscle rupture/strain injuries (35.49%), while moderate severity injuries were the most frequent. The predominant injury mechanism was traumatic injuries caused by contact with other players as a result of a tackle by other players (14.5%). No statistical association was established between the level of aggression and the prevalent types of injury (p=0.63).

Conclusions

The organisers of the league and indeed the referees should ensure that the rules of the game are upheld, and foul or overly aggressive play is penalised. Medical staff and coaches should consider evidence-based injury prevention strategies to reduce the risk of the common injuries sustained in the NWPL.

Higher Rates of Lower Extremity Injury on Synthetic Turf Compared With Natural Turf Among National Football League Athletes: Epidemiologic Confirmation of a Biomechanical Hypothesis

BACKGROUND

Biomechanical studies have shown that synthetic turf surfaces do not release cleats as readily as natural turf, and it has been hypothesized that concomitant increased loading on the foot contributes to the incidence of lower body injuries. This study evaluates this hypothesis from an epidemiologic perspective, examining whether the lower extremity injury rate in National Football League (NFL) games is greater on contemporary synthetic turfs as compared with natural surfaces.

HYPOTHESIS

Incidence of lower body injury is higher on synthetic turf than on natural turf among elite NFL athletes playing on modern-generation surfaces.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Lower extremity injuries reported during 2012-2016 regular season games were included, with all 32 NFL teams reporting injuries under mandated, consistent data collection guidelines. Poisson models were used to construct crude and adjusted incidence rate ratios (IRRs) to estimate the influence of surface type on lower body injury groupings (all lower extremity, knee, ankle/foot) for any injury reported as causing a player to miss football participation as well as injuries resulting in ≥8 days missed. A secondary analysis was performed on noncontact/surface contact injuries.

RESULTS

Play on synthetic turf resulted in a 16% increase in lower extremity injuries per play than that on natural turf (IRR, 1.16; 95% CI, 1.10-1.23). This association between synthetic turf and injury remained when injuries were restricted to those that resulted in ≥8 days missed, as well as when categorizations were narrowed to focus on distal injuries anatomically closer to the playing surface (knee, ankle/foot). The higher rate of injury on synthetic turf was notably stronger when injuries were restricted to noncontact/surface contact injuries (IRRs, 1.20-2.03; all statistically significant).

CONCLUSION

These results support the biomechanical mechanism hypothesized and add confidence to the conclusion that synthetic turf surfaces have a causal impact on lower extremity injury.

Professional Soccer Players' Return to Play and Performance After Operative Repair of Achilles Tendon Rupture

Background:

The majority of Achilles tendon ruptures are sports related; however, no investigation has examined the impact of surgical repair for complete ruptures on professional soccer players.

Purpose:

To examine the return to play, playing time, and performance of professional soccer players following Achilles tendon repair.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Union of European Football Associations (UEFA) and Major League Soccer (MLS) athletes who sustained a primary complete Achilles tendon rupture and were treated surgically between 1988 and 2014 were identified via public injury reports. Demographic information and performance-related statistics for the identified athletes were recorded for the season before surgery and 2 seasons after surgery and were compared with information for matched controls. Statistical analyses were used to assess differences in recorded metrics.

Results:

A total of 24 athletes with Achilles ruptures met inclusion criteria, 17 (70.8%) of whom were able to return to play. On average, players had 8.3 years of professional-level experience prior to sustaining an Achilles rupture. Among athletes who returned to play, no differences were found in the number of games played or started, minutes played, or goals scored 1 year postoperatively compared with the year prior to injury. However, 2 years postoperatively, these athletes played 28.3% (P = .028) fewer minutes compared with their preoperative season, despite starting and playing in an equivalent number of games. Matched controls had baseline playing time and performance statistics similar to those of players. However, controls played and started in significantly more games and played more minutes at 1 and 2 years compared with players (P < .05). No differences were found in goals scored at any time point.

Conclusion:

This is the first investigation examining the effect of an Achilles repair on the career of professional soccer players. This is a difficult injury that most commonly occurs in veteran players and prevents 29.2% of players from returning to play despite surgical management. Additionally, athletes able to return to play were found to play fewer minutes 2 years postoperatively compared with their baseline as well as playing less at 1 and 2 years postoperatively compared with uninjured matched controls. The reduction in playing time following an Achilles repair has significant implications for professional players and teams.

Physiological responses, fatigue and perception of female soccer players in small-sided games with different pitch size and sport surfaces

The aim of this research was to evaluate the influence of game surface and pitch size on the physiological responses, jump performance and perceptions of sub-elite female soccer players playing four-a-side games. Sixteen sub-elite female soccer players were divided into four groups of four players each. Three small-sided games (SSGs; pitch size: 400 m², 600 m² and 800 m²) were played on three surfaces (dirt [DT], artificial turf [AT] and natural grass [NG]). Players' heart rate (HR) was monitored during each game. Before and after each SSG, participants performed two counter-movement jumps (CMJs) and answered a questionnaire based on visual analogue scales (VASs) to indicate their perception of the effort required on each surface. DT obtained lower outputs for most variables. In the SSG 600 mean HR was higher on NG than AT (+3.31 %HR_max; p = 0.029), but players' overall satisfaction with both surfaces was similar (p>0.05). The SSG 400 received the lowest ratings for most variables, whereas the SSG 600 resulted in higher mean HR than SSG 800 [NG (+9.14 b.p.m.; p = 0.001); AT (+7.32 b.p.m.; p = 0.014)]. No surface differences in CMJ performance were found. In conclusion, a higher internal load can be achieved on NG, whereas DT is not recommended for playing soccer. Moreover, the internal load on players in SSGs can be controlled by manipulating pitch size, but over-large pitches may entail a reduction in the physiological profile of female soccer players.

Switching between pitch surfaces: practical applications and future perspectives for soccer training

INTRODUCTION

Soccer training and completion is conventionally practiced on natural grass (NG) or artificial turf (AT). Recently, AT pitches for training/competition, and of unstable surfaces for injury prevention training has increased. Therefore, soccer players are frequently exposed to variations in pitch surface during either training or competition. These ground changes may impact physical and physiological responses, adaptations as well as the injury. The aim of this review was to summarize the acute physical and physiological responses, chronic adaptations, and injury risk associated with exercising on different pitch surfaces in soccer.

EVIDENCE ACQUISITION

Eligible studies were published in English, had pitch surface as an independent variable, and had physical, physiological or epidemiological information as outcome variables. Specific data extracted from the articles included the training response, training adaptations or injury outcomes according to different pitch surfaces. A total of 224 studies were retrieved from a literature search.

EVIDENCE SYNTHESIS

Twenty articles met the inclusion criteria: 9 for acute physical and physiological responses, 2 for training adaptations and 9 for injury assessment. The literature lacks consistent evidence regarding the effects of pitch surface on performance and health outcomes in soccer players. However, it seems that occasionally switching training surfaces seems a valuable strategy for focusing on specific musculoskeletal queries and enhancing players' fitness. For instance, sand training may be occasionally proposed as complementary training strategy, given the recruitment of additional musculature probably not involved on firmer surfaces, but the possible training-induced adaptations of non-conventional soccer surfaces (e.g., sand) might potentially result into a negative transfer on AT or NG.

CONCLUSIONS

Since the specific physical demands of soccer can differ between surfaces, coaches should resort to the use of non-traditional surfaces with parsimony, emphasizing the specific surface-related motor tasks, normally observed on natural grass or artificial turf. Further studies are required to better understand the physiological effects induced by systematic surface-specific training, or switching between pitch surfaces.

Neuromuscular responses and physiological patterns during a soccer simulation protocol. Artificial turf versus natural grass

BACKGROUND

Latest studies suggest similar performance of soccer players either on artificial turf (AT) or natural grass (NG). However, it is not clear if their muscular and physiological responses are also similar on both surfaces. This research aims to assess the influence of game surface on physiological patterns and neuromuscular responses of soccer players during a soccer simulation protocol (SSP) that incorporates repeated sprints and nonlinear actions at maximum speed.

METHODS

Sixteen amateur soccer players completed three bouts of the SSP on both AT and NG. The mechanical behaviour of both surfaces was recorded and the order was randomly established for each player. The physiological responses were measured during the SSP. A contra-movement jump and a tensiomyography analysis of the rectus femoris (RF) and biceps femoris (BF) were assessed right before and right after the SSP.

RESULTS

Both surfaces presented different mechanical properties. No differences among either surfaces or bouts were found for heart rate (HR) peak and HR mean (P>0.05). While the half-relaxation time of the RF on NG decreased after the SSP (right-leg: -44.430 ms; P=0.049; left-leg: -52.131 ms; P=0.008), the sustain time of the BF decreased after the SSP on AT (right-leg: +64.868 ms; P=0.007; left-leg: +87.564 ms; P<0.001). No differences between surfaces were found for the contra-movement jump.

CONCLUSIONS

The mechanical behaviour of both surfaces does not differ enough to cause different physiological and neuromuscular responses. Playing on AT should cause similar neuromuscular responses to NG.