Turf Surfaces Research Articles

Lower Extremity Injury Rates on Artificial Turf Versus Natural Grass Surfaces in the National Football League During the 2021 and 2022 Seasons.

It has been argued that the use of artificial turf football fields in the National Football League (NFL) increases player injury risk compared with natural grass surfaces. The purpose of this study was to quantify the rate of lower extremity injuries occurring in NFL players on artificial turf compared with natural grass surfaces and characterize the time missed due to injury and proportion of injuries requiring surgery. It was hypothesized that lower extremity injuries requiring surgical intervention would occur at a higher rate on artificial turf than on natural grass. Descriptive epidemiology study. Lower extremity injury data for the 2021 and 2022 NFL seasons were obtained using publicly available records. Data collected included injury type, player position, player age, playing surface, weeks missed due to injury, and whether the patient underwent season-ending or minor surgery. Multivariable logistic regression was performed to determine the risk of season-ending surgery according to playing surface. When combining injuries for the 2021 and 2022 seasons (N = 718 injuries), the incidence rate of lower extremity injury was 1.22 injuries/game for natural grass and 1.42 injuries/game for artificial turf. The odds of a season-ending surgery were found to be significantly higher on artificial turf compared with natural grass (odds ratio = 1.60; 95% CI, 1.28-1.99; P < .05), while additional variables, including weather, age, position, week of injury occurrence, and history of prior injury, did not influence the odds of season-ending surgery. The 2021 and 2022 NFL seasons of our analysis demonstrated a higher incidence rate of injuries on artificial turf surfaces compared with natural grass surfaces. In addition, the odds of injury requiring season-ending surgery were found to be significantly higher on artificial turf compared with natural grass.

Examining the Prevalence of Anterior Cruciate Ligament Injuries on Artificial Turf Surfaces Compared to Natural Grass Surfaces in Athletes: A Scoping Review.

The anterior cruciate ligament (ACL) is commonly injured in sports such as American football and soccer. It is currently unknown if ACL injuries are more prevalent on natural grass or artificial turf fields. The purpose of this scoping review is to analyze research studies evaluating the effect of the playing surface on the prevalence of ACL injuries. We hypothesize that athletes face a greater risk of suffering ACL injuries while playing on artificial turfcompared to natural grass.Our team conducted a comprehensive literature review by screening three databases (PubMed, Embase, and Cochrane) that comprised a wide range of peer-reviewed articles on ACL injuries suffered on natural grass and artificial turf surfaces. Inclusion criteria consisted of epidemiological and cohort studies published after 1990 that were written in English and focused on athletes ranging in skill level from youth to professional. Exclusion criteria consisted of biomechanical studies, review articles, and papers that focused on injuries of structures other than the ACL. Bias was assessed with the MINORS criteria. Results were presented by injury rates, calculated ratios, and confidence intervals.The final analysis included nine papers published in peer-reviewed journals. Three of nine papers found that ACL injuries are more likely to occur on artificial turf than on natural grass. Three papers found that there is no difference in the prevalence of ACL injuries between surfaces and one paper stated that ACL injuries are more likely on natural grass than artificial turf. Two papers did not report confidence intervals for ratios comparing injury rates between playing surfaces.There is no consensus in the current literature regarding the prevalence of ACL injuries on artificial turf versus natural grass surfaces. The primary limitation of this study was that the papers used a variety of methods to compare rates of ACL injuries on artificial and natural surfaces, making comparisons between the nine papers difficult.

Poster 373: Lower Extremity Injury Rates on Turf Versus Natural Grass Surfaces - An Analysis of Professional Football Athletes in the 2021 and 2022 Seasons

Objectives: As the emphasis on player safety in the national football league (NFL) has increased in recent years, numerous risk factors for injury have been closely scrutinized for their roles in placing players at increased risk. One such factor, the use of artificial turf football fields, has become a controversial topic, with many current and former players stating that turf fields place players at higher risk for injury while alternative sources have suggested there is no significant injury rate between artificial and natural grass surfaces. The purpose of this study was to quantify the rate of lower extremity injuries occurring in NFL players on artificial turf compared to natural grass surfaces and to characterize the degree of time missed with injury and the proportion of injuries requiring surgery. We hypothesized that major lower extremity injuries requiring surgical intervention occurred on artificial turf surfaces at a higher rate than on natural grass. Methods: Lower extremity Injury data for the 2021 and 2022 NFL seasons were obtained using publicly available records from the internet. All reported lower extremity injuries during the regular and playoff seasons were analyzed. Upper extremity, head, and back injuries were excluded. Preseason data was also excluded. Data collected included player position and age, playing surface of the field on which, the injury occurred, injury type, weeks missed with injury, and whether the patient underwent season-ending or minor surgery. Statistical analysis was performed using R Software (Rlabs). Descriptive statistics were used to summarize data, including percentages and counts for categorical and ordinal data and means with interquartile ranges for continuous data. Incidences of injury on both grass and turf fields were calculated for the 2021 and 2022 seasons by taking a ratio of the number of injuries that occurred and the number of games played on respective fields. Additionally, injuries were stratified by subsequent number of games missed: 0 games missed, 1-2 games missed, &gt;6 games missed. Multivariable logistic regression was performed to determine the influence of field type on the risk of major surgery. A p-value less than 0.05 was statistically significant. Results: In total there were 327 (44.12%) lower extremity injuries in 2021 and 391 (54.45%) lower extremity injuries in 2022, resulting in a total of 718 lower extremity injuries. A demographic summary of these injuries by position, age, field, and history of previous injury is displaced in Table 1. Combining the 2021/2022 seasons, the incidence rate of lower extremity injury on natural grass surfaces was 1.22 injuries/game while for turf surfaces, the incidence rate was 1.42 injuries/game (Table 2). Injury severity was stratified by weeks missed. Odds of a season-ending surgery were found to be significantly higher on turf surfaces compared to natural grass surfaces (OR 1.60, 95% CI 1.28-1.99, p&lt;0.05), while additional variables, including weather, age, position, and week of injury occurrence and history of prior injury were not found to influence the odds of season-ending surgery. In total, there were 50 players injured on the grass who required lower extremity surgery and 83 players injured on turf who required lower extremity surgeries. The most common surgeries after a lower extremity on grass were ACL repair (17), Achilles repair (9), and ankle or syndesmosis ORIF (7). The most common surgeries after a lower extremity on turf were ACL repair (30), Achilles repair (12), patella ORIF, or patellar tendon repair (8) (Table 3). Conclusions: The debate about playing on artificial turf versus natural grass has persisted for several years; however, there is a discrepancy in data reported on these overall injury rates. Our study showed that NFL athletes were more likely to get injured on artificial surfaces and that turf dramatically increased the likelihood of suffering a serious injury requiring surgery. These findings support earlier research, highlighting the necessity of putting player safety first and reducing dangers on pitches with artificial turf. For players, coaches, and teams to make wise decisions about playing surfaces, the study offers useful information regarding playing safety. Overall, it indicates that there is a higher risk of lower extremity injuries on artificial grass in the NFL, confirming the continuing discussion about field safety.

A Systematic Review of Effects on ACL Injury of Soccer Shoe Outsoles, Soccer Playing Field Surfaces, and Outsole–Surface Interface

Soccer is a sport with a high incidence of injuries. The most common injury occurs when the anterior cruciate ligament of the knee has undergone a sprain, strain, or partial or total rupture. Besides fitness factors (e.g., proprioception, balance and strength capabilities), a principal cause of ACL injuries is sport shoes and playing surfaces. Especially with the emergence of artificial surfaces (rubbers, turfs, concrete, asphalt, red turf), the ACL injuries dramatically increase. The cost of ACL injuries is high both in terms of career termination and in social and economic costs. Thus, it is necessary to understand the impact of sport shoes and playing surfaces on the ACL and how it can be mitigated. The present literature review followed the PRISMA methodology to identify the major biomechanical factors influencing the behavior of surfaces and shoes in relation to the ACL damage. Fifty-eight papers were identified. After reviewing the mechanism of injuries, we identified several distinct factors: type of outsole and mechanical arrangement of the outsoles; shear forces; characteristics of artificial turf surfaces; effect of weather on artificial surface aging and change in mechanical characteristics; outsole/ground interface; and the frictional, tractional and rotational forces in the pathogenesis of ACL injuries in soccer.

Surface Temperature Experienced and Irrigation Effects on Artificial Turf

Artificial turf has gained widespread use in sporting fields as it is considered a water-saving and maintenance-free alternative to natural turfgrass. However, the high surface temperatures that occur during the day are a potentially important unfavorable feature of artificial turfgrass. The objective of this study was to establish the temperatures experienced on an artificial turf surface and to evaluate the effect of irrigation on artificial turf surface temperature. Data was collected over five surfaces across a sports facility on the campus of the University of Thessaly in Larissa, Greece. Results showed surface temperatures on artificial turf (AT) as significantly higher than running track (RT), asphalt (AS), bare soil (BS), and natural grass (NG), with maximum surface temperatures of 72oC. Solar radiation accounted for most of the variation in surface temperature of the artificial turf (r2=0.92) as opposed to air temperature (r2=0.38), and relative humidity (r2=0.50). To lower surface temperature, four irrigation regimes were used (1x60 min, 1x30 min, 2x15 min, and 3x5 min water application). Irrigation reduced the surface temperature by as much as 30°C compared to the unirrigated surface, but these low temperatures were maintained for 90 to 120 minutes long. The most effective cooling effect occurred when water was applied in a 3-cycle, 5-minute duration, where the irrigated surface temperature remained below the unirrigated surface throughout the time after the first watering.

An Apparent Achilles Heel of the NFL: Have Achilles Tendon Injuries Significantly Increased to Unacceptably High Incidence Levels in the NFL and if so, why? A Clinical Insight.

Many if not most of us watched in utter disbelief and horror last September 11th as Aaron Rogers, the newly acquired $75 million dollar quarterback with the New York Jets just 4 snaps into the new season, suffered an Achilles Tendon ruptures (ATR) in his inaugural game on nationally televised Monday Night Football with his new and excited team and demanding fanbase. With cell phones in hand, we watched as our X apps lit up with claims of an excess of ATRs in the NFL in recent years and much of the blame placed on the new rubberized turf surfaces in place in most of the NFL stadiums. That first week of the NFL season the NFL Players Association, the NFLPA, put out a statement to this effect that demanded removal of rubberized turf surfaces throughout the NFL! With Kirk Cousins devastating ATR a few weeks later, amongst 21 others this season, and Aaron Rogers return to practice after a mere seven to eight weeks post-injury, this conundrum remains foremost in our hyper-questioning minds!

Long-term effects of running exercises on natural grass, artificial turf, and synthetic surfaces on ground reaction force components in individuals with overpronated feet: A randomized controlled trial

BackgroundOverpronated feet are associated with alteration of lower limb mechanics. Also, quantifying ground reaction force-related changes due to exercise on different surfaces is important for understanding the potential risk of injuries. Research questionWhat are the long-term effects of running exercises on natural grass, artificial turf, and synthetic surfaces on ground reaction force components in individuals with overpronated feet? MethodsOf 82 contacted individuals with overpronated feet aged 18–30, 22 were excluded because they did not meet inclusion criteria (20), and two declined to participate. Sixty individuals were included in randomization, the control (n = 15), hard court or synthetic surface (n = 15), natural grass (n = 15), and artificial turf (n = 15) groups. There was a sample loss of 8 individuals because of personal problems (2 in each group). The intervention groups performed running exercises on natural grass, artificial turf, and synthetic surfaces over eight weeks, three sessions per week. No training or test-related injuries were reported throughout the study. A force plate was embedded midway through the 18-running concrete path to collect ground reaction force data while running on stable ground before and after interventions. ResultsFindings demonstrated significant group-by-time interactions for vertical loading rate (p = 0.016, ETA=0.297). Post-hoc analyses showed increased loading rate amplitude in two natural grass and artificial turf groups (but not in the control and synthetic surface groups) post-intervention. SignificanceRunning training on natural grass and artificial turf surfaces may place individuals with overpronated feet at a higher risk of injury while running on a stable surface.

A Comparison of Devices for Race Day Characterization of North American Turfgrass Thoroughbred Racing Surfaces.

Both pre-race meet and daily turf surface condition measurements are required by regulations adopted as part of the Horseracing Integrity and Safety Act (HISA). The Orono Biomechanical Surface Tester (OBST) is the primary device used for characterizing a racing surface and is used for the pre-meet inspections. Tools that are better suited for the daily testing of turf surfaces are also needed to meet the new federal regulations. The purpose of this study was to compare five simple tools commonly used in turf applications to the OBST. Data were collected with each of the six devices at plots chosen to approximate the current and potential compositions of North American turf racetracks. Correlations and linear regression models were then established between the simple tool measurements and the parameters measured by the OBST. The moisture probe was found to be the primary device for race day characterization due to its strong correlation to OBST measurements. The Longchamp Penetrometer is also prioritized for daily measurements due to its established correlation to horse performance and injuries. The Clegg Impact Hammer provides further improvement of the linear regression model. The Turf Shear Tester and GoingStick® were not found to correlate well to the biomechanically based device.

The effect of rotational velocity on rotational traction across a range of artificial turf surface systems

Mechanical testing by sporting governing bodies ensures artificial turf surfaces conform with performance standards. Rotational traction is measured using two equivalent devices: a rotational traction tester (RTT) and a lightweight rotational traction tester (LRTT). The devices differ in target rotational velocity; 72 deg/s for the RTT and 30 deg/s for the LRTT. The purpose of this study was to investigate the influence of rotational velocity on peak torque during rotational traction testing. An automated rotational traction tester examined nine rotational velocities between 10 and 210 deg/s, and ten artificial turf surface systems with a range of performance infill materials, infill depths and carpet specifications. Rotations at 10 deg/s produced the lowest peak torques on nine of the ten surfaces. Infill materials with intrinsic viscoelastic properties produced significantly higher peak torques at higher rotational velocities, whereas less elastic infill materials saw no significant increase in peak torque. A mean difference in peak torque of 2.6 Nm was found between the target velocities of the RTT and LRTT. The results support the synchronisation of target velocities for the RTT and LRTT. During standards testing, trials completed below a particular velocity should be repeated to negate velocity effects on peak torque.

Factors influencing subcanopy leaf and stolon exposure and associated absorption and translocation of herbicides in semidormant zoysiagrass

AbstractTurfgrass managers are concerned about zoysiagrass (Zoysia japonica Steud.) injury from nonselective herbicide treatment during winter dormancy. Research was conducted to assess factors affecting spray penetration into semidormant ‘Meyer’ zoysiagrass canopies and to evaluate absorption and translocation of [14C]glyphosate and [14C]glufosinate into green leaves and subtending stolons. Absorption of [14C]glyphosate and [14C]glufosinate was up to four times greater in stolons than in leaves. Zoysiagrass leaves treated with [14C]glufosinate had more rapid 14C absorption than those treated with [14C]glyphosate. More 14C translocated out of the treated area following [14C]glyphosate treatment compared with [14C]glufosinate and moved more readily from stolon to leaves than from leaves to stolon. When extended-range, flat-fan spray tips (XR) were positioned 61 cm above zoysiagrass, 73% and 11% of recovered colorant was extracted from dormant vegetation in the upper and lower canopy levels. Turbo TeeJet® spray tips (TTI) deposited fewer droplets into the upper canopy and more droplets into the middle and lower canopy regardless of position above the turf surface. Increasing pressure from 103 to 414 kPa increased droplet velocities from XR and TTI nozzles and decreased droplet diameters of XR nozzles. Droplet diameters were also substantially increased when using TTI nozzles compared with XR nozzles. Droplet diameter and associated mass were more determinant of turfgrass canopy penetration than droplet velocity. At 60 L ha−1 of carrier volume, 23% of colorant reached the lower canopy level, and this quantity increased by 2.3% per additional 100 L ha−1. When carrier volume was reduced from 584 to 60 L ha−1, 48% less colorant was delivered to the lower canopy level. Given that subcanopy stolons are always present and absorb more glyphosate and glufosinate than leaves, practices such as avoiding induction-type nozzles, raising spray height, and reducing spray volume can reduce herbicide delivery and potential injury to semidormant zoysiagrass.

Timing Differences in Stride Cycle Phases in Retired Racehorses Ridden in Rising and Two-Point Seat Positions at Trot on Turf, Artificial and Tarmac Surfaces.

Injuries to racehorses and their jockeys are not limited to the racetrack and high-speed work. To optimise racehorse-jockey dyads' health, well-being, and safety, it is important to understand their kinematics under the various exercise conditions they are exposed to. This includes trot work on roads, turf and artificial surfaces when accessing gallop tracks and warming up. This study quantified the forelimb hoof kinematics of racehorses trotting over tarmac, turf and artificial surfaces as their jockey adopted rising and two-point seat positions. A convenience sample of six horses was recruited from the British Racing School, Newmarket, and the horses were all ridden by the same jockey. Inertial measurement units (HoofBeat) were secured to the forelimb hooves of the horses and enabled landing, mid-stance, breakover, swing and stride durations, plus stride length, to be quantified via an in-built algorithm. Data were collected at a frequency of 1140 Hz. Linear Mixed Models were used to test for significant differences in the timing of these stride phases and stride length amongst the different surface and jockey positions. Speed was included as a covariate. Significance was set at p < 0.05. Hoof landing and mid-stance durations were negatively correlated, with approximately a 0.5 ms decrease in mid-stance duration for every 1 ms increase in landing duration (r2 = 0.5, p < 0.001). Hoof landing duration was significantly affected by surface (p < 0.001) and an interaction between jockey position and surface (p = 0.035). Landing duration was approximately 4.4 times shorter on tarmac compared to grass and artificial surfaces. Mid-stance duration was significantly affected by jockey position (p < 0.001) and surface (p = 0.001), speed (p < 0.001) and jockey position*speed (p < 0.001). Mean values for mid-stance increased by 13 ms with the jockey in the two-point seat position, and mid-stance was 19 ms longer on the tarmac than on the artificial surface. There was no significant difference in the breakover duration amongst surfaces or jockey positions (p ≥ 0.076) for the ridden dataset. However, the mean breakover duration on tarmac in the presence of a rider decreased by 21 ms compared to the in-hand dataset. Swing was significantly affected by surface (p = 0.039) and speed (p = 0.001), with a mean swing phase 20 ms longer on turf than on the artificial surface. Total stride duration was affected by surface only (p = 0.011). Tarmac was associated with a mean stride time that was significantly reduced, by 49 ms, compared to the turf, and this effect may be related to the shorter landing times on turf. Mean stride length was 14 cm shorter on tarmac than on grass, and stride length showed a strong positive correlation with speed, with a 71 cm increase in stride length for every 1 m s-1 increase in speed (r2 = 0.8, p < 0.001). In summary, this study demonstrated that the durations of the different stride cycle phases and stride length can be sensitive to surface type and jockey riding position. Further work is required to establish links between altered stride time variables and the risk of musculoskeletal injury.

Neuromuscular Changes in Drop Jumps on Different Common Material Surfaces with Incremental Drop Heights

The purpose of this study was to compare changes in muscle pre-activation and short-latency responses in the lower limbs during drop jumps performed on different common soft and hard surfaces and at various platform heights. The study aimed to collect electromyography data from the rectus femoris, biceps femoris, tibialis anterior, gastrocnemius, and soleus of the dominant leg during drop jumps on sand, turf, polyurethane, and wood surfaces from platform heights of 30, 40, 50, and 60 cm. Muscle pre-activation refers to muscle activity 100 ms before ground contact during a drop jump, while short-latency responses refer to muscle activation occurring 30–60 ms after ground contact. These definitions were used to measure and analyze neuromuscular responses in the lower limb muscles during drop jumps using various surfaces and platform heights. Sand as a ground material and platform heights of 50 and 60 cm significantly enhanced pre-activation and activation in short-latency responses of the lower limb muscles (all p &lt; 0.01). The difficulty of the drop jump task can enhance pre-activation and activation in the latency responses of lower limb muscles. It is recommended that athletes perform drop jumps on sandy surfaces or from platforms higher than 50 cm to induce muscle pre-activation of the lower limbs and to improve muscle activation levels in the latency responses after landing.

Comparison of Sports Injury Anxiety in Athletes Doing Sports on Different Surfaces

The aim of the present study was to compare sports injury anxiety levels of athletes doing sports on different surface regardless from sports type. The study was carried out with 150 male athletes between the ages of 15-35 who had at least one sports injury. The participants were divided into three groups depending on the surface including turf (n=50), artificial turf (n=50), and parquet floor (n=50). The "Sport Injury Anxiety Scale" was used in order to determine the sports injury anxiety levels of the participants. The scale was implemented online through Google Forms. The differences between groups were evaluated with the Kruskal-Wallis test. Also differences between paired groups were evaluated with the Mann Whitney U test. It was observed that athletes doing sports on parquet floor had higher levels of sports injury anxiety compared to those doing sports on turf and artificial turf surface (p &amp;lt;0.01). Considering that athletes who do sports on parquet floor have high levels of sports injury anxiety, we think that these athletes should be supported in terms of coping with anxiety.

Development and evaluation of a sensory panel for collecting reliable player perceptions of third-generation synthetic turf football surfaces

Perceptions of synthetic surfaces used in football can vary considerably between players, and obtaining reliable feedback is challenging. The aim of this study was to develop a suitable process and evaluate the merits of establishing a sensory panel to assess the subjective attributes of third generation synthetic turf surfaces (3G turf) used in football. Focus groups with 12 male and 13 female footballers were conducted on an outdoor 3G turf pitch to develop a common language to describe sensory feedback related to player–surface interactions. Post-session analysis revealed two main themes related to player–surface interactions: hardness and grip. These themes were broken down further into five sensory attributes (Movement Speed, Slip, Movement Confidence, Leg Shock and Give) which were investigated further in an indoor test area containing ten 3G turf surfaces with controlled surface properties. A panel consisting of 18 University footballers (11 male and 7 female) undertook a screening and training session to refine the language associated with the sensory attributes and become familiar with the testing protocol. During a final evaluation session, players were asked to discriminate between surfaces using the paired comparison method for each of the sensory attributes. Player consistency remained similar between the screening and evaluation sessions whilst the panel’s ability to discriminate between surfaces improved during the evaluation session. Sensory training can therefore be a useful approach to aid players in differentiating between surfaces and lead to a greater understanding of athlete perceptions of surface attributes.

Comparison of player perceptions to mechanical measurements of third generation synthetic turf football surfaces

Mechanical testing of synthetic turf football surfaces is considered essential to ensure player performance and safety. However, it remains unknown how well the mechanical outputs reflect player perceptions of these surfaces. The first objective of this study was to investigate the agreement between the outputs from the Rotational Traction Tester and the Advanced Artificial Athlete with player perceptions across a range of controlled third generation turf football surfaces. The second objective was to identify the modifications to the Rotational Traction Tester and the Advanced Artificial Athlete configurations and output variables that give the strongest agreement with player perceptions. An indoor test area containing ten third generation turf surfaces with controlled hardness and traction properties was constructed. Each surface was tested using the Advanced Artificial Athlete and Rotational Traction Tester in their current configuration and in several modified configurations aimed at better replicating the player–surface interaction. Using a trained panel paired comparisons technique, 18 University footballers (11 males and 7 females) identified differences in the surfaces based on four sensory attributes Movement Speed, Slip, Leg Shock and Give. Results indicated strong agreement (correlation coefficients between 0.7 and 1.0) across several Rotational Traction Tester and Advanced Artificial Athlete testing configurations and output variables with player perceptions. It is recommended that the current Rotational Traction Tester is improved through added instrumentation to allow surface stiffness to be evaluated (the rate of generation of traction resistance). It is further recommended that the Advanced Artificial Athlete adopts a new algorithm to improve the accuracy of the surface’s Vertical Deformation and Energy Restitution, and the number of drops is reduced from three to one.

Retention and Water Needs of Natural Grass Turf of Football Fields

The paper contains a detailed assessment of three full-size football fields constructed in 2019-2022 to meet the basic conditions for proper operation and maintenance. As a result of field and laboratory tests on permeability and retention capacity of the fields' base and drainage layers, they were found to meet the requirements set out in the standard DIN 18035. It ensures that rainwater and snowmelt are quickly drained from the turf's surface. The grass turfs of the football fields under study meet the conditions for properly performing one of the basic care treatments – irrigation. The base layer can retain an average of 10.3 mm of water in comfortable water availability conditions, depending on the football field. It is the value of a single dose net, which should be used for sprinkler irrigation of grass turf of football fields. However, considering the drainage layer, this dose could be increased to 12.5 mm. Considering the percentage content of generally available water and assuming less comfortable water availability conditions, the appropriate doses net are 12.5 mm on average. In comparison, for both layers together, they are 15.4 mm on average.

An experimental analysis of component contributions to shock absorption performance in third generation sport artificial turf

The increasing use of artificial turf across all levels of sports play has been hypothesized to contribute to an increase in athlete injuries. Current testing standards evaluate the shock absorbing performance of artificial turf surfaces through a single measure of acceleration after a drop test impact. However, these standards focus on the performance of the aggregate turf system, thereby neglecting the component-level contributions of the shock pad, carpet, and infill constituents. The purpose of this study was to explore a novel testing methodology that has the potential to isolate first-order and second-order contributions of components to total system performance. Various subsystems of the traditional, three layer artificial turf were treated as energy absorbing surfaces. A series of no-fatigue and fatigue tests were performed using a custom-built apparatus to characterize each energy absorbing surface at five different drop heights. During no-fatigue testing, it was found that the complete three-layer system outperformed all subsystems by mitigating resultant acceleration and force compared to the baseline. However, any energy absorbing subsystem that contained rubber infill outperformed any subsystem that included shock pad, the designated energy dissipating layer in third generation artificial turf. For fatigue testing, it was observed that energy absorbing surfaces began to deteriorate in as few as 20 impacts. In comparison to existing standards, the inclusion of a second data acquisition instrument yielded more accurate calculations of shock absorption. By capturing an input and output measurement during the impact, calculation of the surface’s characteristic transfer function is attainable and therefore, more information in gleaned from the impact test. Additional research is required to be able to deploy this testing methodology on-site, with fully installed artificial turf systems.

Daytime irrigation leads to significantly cooler private backyards in summer

Backyards play important roles for individual households because they provide a private and safe green space for social and environmental interactions, relaxation, gardening and children's activities. The use of backyards is highly dependent on their thermal conditions. Turf is a common surface type in backyards but unirrigated turf can be as warm as pavement, bringing thermal discomfort and discouraging people from using them. Under certain conditions, turf irrigation provides an opportunity to reduce thermal stress by increasing evapotranspiration. This study aims to measure the impacts of turf irrigation on microclimate in a backyard environment in the warm season in Melbourne, Australia. The experiment consisted of four 6 m × 6 m turf-covered plots. Daily irrigation was applied at four amounts: 0, 2, 4 and 7 mm for six weeks. In Week 6, the 4-mm irrigation reduced daytime soil temperature, turf surface temperature, air temperature and universal thermal climate index by 1.7, 2.3, 0.6 and 0.4 °C, respectively. All daytime impacts were significant (p < 0.05, t-test). Irrigation has the potential to significantly improve the thermal conditions of backyards in combination with the use of tree shade.

Hoof Impact and Foot-Off Accelerations in Galloping Thoroughbred Racehorses Trialling Eight Shoe-Surface Combinations.

Simple SummaryTo achieve optimal performance and low injury occurrence in horse racing, it is important to understand hoof–surface interactions. This study measured hoof accelerations in retired Thoroughbred racehorses as they galloped over turf and artificial surfaces in four shoeing conditions (aluminium, barefoot, steel and GluShu), using hoof-mounted accelerometers. During hoof landing, accelerations were increased for hindlimbs and leading limbs and on turf compared to the artificial surface. Barefoot hooves experienced the lowest impact accelerations and contrasted most with steel. During the propulsive stage of the stride, accelerations at “foot-off” were increased for low stride times, particularly in the hindlimbs, and on the artificial track. Increased impact accelerations on turf and in shod conditions could be detrimental to health and have implications for musculoskeletal injuries, whereas increased foot-off accelerations on the artificial surface may reflect this surface returning energy to the hoof and aiding propulsion, which could confer a performance benefit. Further work is needed to relate these findings to injury risk and racing outcomes specifically, particularly in racehorses galloping at top speeds.The athletic performance and safety of racehorses is influenced by hoof–surface interactions. This intervention study assessed the effect of eight horseshoe–surface combinations on hoof acceleration patterns at impact and foot-off in 13 galloping Thoroughbred racehorses retired from racing. Aluminium, barefoot, GluShu (aluminium–rubber composite) and steel shoeing conditions were trialled on turf and artificial (Martin Collins Activ-Track) surfaces. Shod conditions were applied across all four hooves. Tri-axial accelerometers (SlamStickX, range ±500 g, sampling rate 5000 Hz) were attached to the dorsal hoof wall (x: medio-lateral, medial = positive; y: along dorsal hoof wall, proximal = positive; and z: perpendicular to hoof wall, dorsal = positive). Linear mixed models assessed whether surface, shoeing condition or stride time influenced maximum (most positive) or minimum (most negative) accelerations in x, y and z directions, using ≥40,691 strides (significance at p < 0.05). Day and horse–rider pair were included as random factors, and stride time was included as a covariate. Collective mean accelerations across x, y and z axes were 22–98 g at impact and 17–89 g at foot-off. The mean stride time was 0.48 ± 0.07 s (mean ±2 SD). Impact accelerations were larger on turf in all directions for forelimbs and hindlimbs (p ≤ 0.015), with the exception of the forelimb z-minimum, and in absolute terms, maximum values were typically double the minimum values. The surface type affected all foot-off accelerations (p ≤ 0.022), with the exception of the hindlimb x-maximum; for example, there was an average increase of 17% in z-maximum across limbs on the artificial track. The shoeing condition influenced all impact and foot-off accelerations in the forelimb and hindlimb datasets (p ≤ 0.024), with the exception of the hindlimb impact y-maximum. Barefoot hooves generally experienced the lowest accelerations. The stride time affected all impact and foot-off accelerations (p < 0.001). Identifying factors influencing hoof vibrations upon landing and hoof motion during propulsion bears implication for injury risk and racing outcomes.

Poster 115: Elective Imaging and Surgical Procedures Following Surface-Related College Football Game Trauma on Artificial Turf and Natural Grass. A 15-Season Prospective Study

Objectives:With increasing concerns of rising medical costs, the potential for long-term articular changes, and the perceived higher incidence of injury while playing on artificial turf, no long term studies have specifically compared elective medical procedures following injury from competitive play on artificial and natural grass surfaces. Therefore, this study quantified elective imaging and surgery following surface-related college football game trauma on artificial and natural grass fields.Methods:39 universities were evaluated over 15 competitive seasons (2006-2020) across all Football Bowl Subdivision (FBS) conferences. Playing surfaces were divided into two groups based on a heavyweight, artificial turf infill system (≥9.0 lbs infill/ft2) and natural grass. Outcomes of interest included elective imaging and surgery across injury category, primary type of injury, anatomical location, and specific procedures. Data were subject to multivariate analyses of variance (MANOVA) and Wilks’ λ criteria using GLM procedures, and expressed as elective imaging and surgical incidence rates (lR) per 10 game season.Results:Of the 2,215 games documented, 1,097 games (49.5%) were played on a 3-layer artificial turf (≥9.0 lbs/ft2) infill system versus 1,118 games (50.5%) played on natural grass. In sum, of the 9,137 total injuries reported, 4,010 were surface-related cases, with 1,757 injuries reported on artificial turf and 2,253 on natural grass, totaling 1,081 player-to-surface impacts, 2,429 shoe:surface injuries during physical contact, and 500 shoe:surface during noncontact cases. Surface-related trauma on artificial turf resulted in 773 elective imaging and 231 surgical procedures, with 965 imaging and 308 surgeries ordered following injuries on natural grass. MANOVA indicated significant main effects by elective imaging (F2,1738 = 4.718; P = .009) and surgical procedure (F1,539 = 5.974; P = .003) between surfaces. Post hoc analyses indicated a significantly lower (P < .05) incidence of radiographs [4.1, (95% CI, 3.8-4.4) vs 4.7 (4.4-5.0)], MRIs [2.8, (95% CI, 2.6-3.1) vs 3.6 (3.4-3.9)] and elective imaging procedures combined [7.1, (95% CI, 6.8-7.3) vs 8.6 (8.4-8.8)] following trauma on heavyweight artificial turf fields versus natural grass, respectively. A significantly lower (P < .05) incidence of imaging procedures were ordered on player-to-surface impact trauma [1.5, (95% CI, 1.3-1.8) vs 2.1 (1.9-2.4)], shoe:surface trauma during physical contact [4.4, (95% CI, 4.1-4.7) vs 5.2 (4.9-5.5)], foot injuries [0.6, (95% CI, 0.5-0.7) vs 1.1 (0.9-1.2)], contusions [0.4, (95% CI, 0.3-0.6) vs 0.9 (0.7-1.1)], ligament sprains/tears [4.6, (95% CI, 4.3-4.9) vs 5.3 (5.0-5.6)], and muscle strains/tears [0.2, (95% CI, 0.2-0.3) vs 0.7 (0.6-0.9)] following injury on heavyweight artificial turf when compared to natural grass fields, respectively. Post hoc analyses indicated a significantly lower (P < .05) incidence of total surgeries [2.1, (95% CI, 1.9-2.4) vs 2.8 (2.5-3.0)], surgeries following shoe:surface trauma during physical contact [1.1, (95% CI, 0.9-1.3) vs 1.6 (1.4-1.8)], and surgeries as a result of ligament tears [1.0, (95% CI, 0.9-1.2) vs 1.5 (1.3-1.7)] following competitive play on heavyweight artificial turf when compared to natural grass fields, respectively. Surgical procedures involving artificial turf injuries required single tissue arthroscopic repair (n=92; 40%), multiple tissue reconstructive repair (n=90; 39%), and ORIF (n=49; 21%), whereas (n=152, 49%) of natural grass trauma involved single tissue arthroscopic repair, followed by multiple tissue reconstructive repair (n=94; 31%) and ORIF (n=62; 20%).Conclusions:The significantly lower incidence of elective imaging and surgical procedures following competitive play on heavyweight artificial turf surfaces translates to lower health care costs from less severe trauma than observed on natural grass surfaces. This is the first longitudinal study that directly compares and addresses elective medical procedures as they relate specifically to football injury. The findings of this study, however, may be generalizable only to this level of football competition.