Turf Surfaces Research Articles

First Report of Xanthomonas translucens Causing Etiolation on Creeping Bentgrass Turf in Illinois, Kentucky, and North Carolina.

Symptoms of etiolation, which is an abnormal elongation and yellowing of tillers, have been observed on creeping bentgrass [Agrostis stolonifera L. (CBG)] putting greens for decades; however, symptoms are typically transient and non-problematic. Reports of etiolation have become more frequent recently and research supports the involvement of bacteria (1). During stressful summer periods in 2011 and 2012, 62 CBG putting green samples were submitted to the NCSU Turf Clinic exhibiting symptoms of etiolation, chlorosis, and/or general decline. Microscopic examination of stem and leaf tissue often showed bacterial streaming from the xylem tissue. Symptomatic tissue was surface disinfested in sodium hypochlorite (10% Clorox) for 5 min, blotted dry, and rinsed in sterile dH2O. Disinfested tissue was placed in a small drop of sterile dH2O on a glass microscope slide and cut to allow bacteria to stream into the water for 2 min. The resulting bacterial suspension was streaked onto three nutrient agar (NA) plates and incubated at 30°C overnight. Bacterial colonies varied in morphology and those present in the greatest number based on morphology were re-streaked to isolate individual colonies. Bacterial isolates were tentatively identified to species using rDNA sequencing of 16S and ITS regions (3). Sequencing results showed isolates obtained from 6 locations (in Illinois, Kentucky, and North Carolina) having a positive match (≥99% 16S and ≥93% ITS) to Xanthomonas translucens (GenBank accessions AY572961, HM181927, JX976312, AY253329, and AB680445). Additional research is needed to confirm pathovar designation as X. translucens isolates were similar to both poae and graminis pathovars. A representative isolate (LW10-12A) was also examined for carbon source utilization using the BIOLOG 3rd Gen Microplate (Biolog Inc., Hayward, CA) resulting in a positive identification of X. translucens. Isolate LW10-12A was used to inoculate 6-week-old seeded creeping bentgrass cv. A1 plants maintained at 1 cm height in 3.5 cm diameter containers. Scissors were dipped in a cell suspension (~109 CFU ml-1 in sterile dH2O) and used to cut healthy CBG plants at 1 cm height and the remaining suspension was applied to the foliage until runoff using an atomizer bottle. Non-inoculated plants were cut and misted using sterile dH2O. After inoculation, plants were placed in a sealed clear plastic Camwear container (Cambro Co., Huntington Beach, CA) for 48 h and then transferred to the growth chamber bench (30°C) receiving irrigation twice daily with dH2O. Etiolation was rated within each of the four replicates by counting the number of etiolated leaves that were easily observed as significantly higher than the rest of the turf canopy. Plants inoculated with X. translucens exhibited etiolation of the youngest leaf within 48 h, whereas the non-inoculated plants did not. Symptoms were similar to observations in the field, as etiolated leaves were chlorotic and easily extracted from the turf surface. Microscopic examination showed bacterial streaming and identification of bacteria, using the previously described methods, was positive for X. translucens. Etiolation symptoms persisted over multiple weeks, but a decline in turf quality was not observed. Etiolation has been previously suggested as a precursor to bacterial wilt, caused by X. translucens pv. poae, on annual bluegrass [Poa annua L. f. reptans (Hausskn) T. Koyama] (2) and Acidovorax avenae has also been shown to produce etiolation on CBG (1). To our knowledge, this is the first confirmation of X. translucens as a cause of etiolation in CBG.

The Effect of Training on Stride Parameters in a Cohort of 40 Two Year Old Racehorses

IntroductionThe biomechanical effects of training on gait in the Thoroughbred are not fully understood. We aimed to assess the effect of training, surface and incline on stride parameters.Methods40 two‐year‐old Thoroughbred racehorses entering training were recruited and followed from December 2012 until September 2013. Gait analysis was performed at eleven time points by equipping each horse with an inertial measurement unit (IMU) with inbuilt GPS, mounted on the dorsum immediately caudal to the most caudal palpable lumbar dorsal spinous process. Horses were exercised as per their regular training regimen on a variety of training surfaces and inclines. Data were analysed using custom software written in Matlab (Mathworks, UK), and statistical analysis was performed using R (R Foundation for Statistical Computing, Austria). A linear mixed model was used, with horse as a random effect and weeks in training, training surface, curve and incline as fixed effects.ResultsA total of 85,497 strides at speeds of between 6.00 and 19.03 ms‐1 were analysed. Stride length increased by 0.33 m ± 4.3 x 104 with each 1 ms‐1 increase in velocity. Training causes a reduction in stride length of 0.004 ± 0.0001 m per week and an increase in stride frequency of 1.29 x 103 ± 4.1 x 105 per week. Shallow inclines, steep inclines and declines cause a decrease in stride length of 0.07 ± 0.003 m, 0.10 ± 0.005 m and 0.04 ± 0.004 m respectively. Turf and peat moss training surfaces caused an increase in stride length of 0.03 ± 0.004 m and 0.06 ± 0.007 m respectively.ConclusionsThis study provides an insight into the effects of external factors on the gait of young Thoroughbreds in training. Ongoing research will further investigate these effects and interactions.Ethical Animal ResearchThe study was approved by the local ethics committee. Explicit owner informed consent for participation in this study is not stated. Sources of funding: Horserace Betting Levy Board. Competing interests: none.

Understanding the Acute Skin Injury Mechanism Caused by Player-Surface Contact During Soccer: A Survey and Systematic Review.

Background:Superficial skin injuries are considered minor, and their incidence is probably underestimated. Insight into the incidence and mechanism of acute skin injury can be helpful in developing suitable preventive measures and safer playing surfaces for soccer and other field sports.Purpose:To gain insight into the incidence and severity of skin injuries related to soccer and to describe the skin injury mechanism due to player-surface contact.Study Design:Systematic review; Level of evidence, 4.Methods:The prevention model by van Mechelen et al (1992) combined with the injury causation model of Bahr and Krosshaug (2005) were used as a framework for the survey to describe the skin injury incidence and mechanism caused by player-surface contact.Results:The reviewed literature showed that common injury reporting methods are mainly based on time lost from participation or the need for medical attention. Because skin abrasions seldom lead to absence or medical attention, they are often not reported. When reported, the incidence of abrasion/laceration injuries varies from 0.8 to 6.1 injuries per 1000 player-hours. Wound assessment techniques such as the Skin Damage Area and Severity Index can be a valuable tool to obtain a more accurate estimation of the incidence and severity of acute skin injuries.Conclusion:The use of protective equipment, a skin lubricant, or wet surface conditions has a positive effect on preventing abrasion-type injuries from artificial turf surfaces. The literature also shows that essential biomechanical information of the sliding event is lacking, such as how energy is transferred to the area of contact. From a clinical and histological perspective, there are strong indications that a sliding-induced skin lesion is caused by mechanical rather than thermal injury to the skin.

Cutting performance wearing different studded soccer shoes on dry and wet artificial turf

The ability to perform fast cutting manoeuvres is essential in soccer and requires sufficient traction between shoe and surface. Artificial turf (AT) surfaces are widely used in soccer and among others turf moisture and shoe studs can influence traction. The aim of this study was to quantify the influence of moisture (DRY and WET AT), for three realistic shoe stud characteristics sets [Turf Field (TF), Artificial Grass (AG) and Firm Ground (FG)], on cutting performance, executed traction and perception of the players. Twelve experienced soccer players performed 10 × 5 m shuttle run tests. Ground reaction forces of the open stance phase of the 180° turns were measured and required traction was calculated. Players' perception was also measured. A two-way 2×3 analysis of variance (ANOVA) Repeated Measures with Bonferroni correction was conducted. On dry AT no performance differences between the three tested shoe stud characteristics sets could be measured. On wet AT the AG and FG designs performed evenly well but when wearing the TF shoe, equipped with 74 short studs, significant surface x shoe interaction effects indicated decreased performance and traction on the wet surface. The experienced players perceived shoe x surface evoked differences in performance and traction very well.

Shoe traction and surface compliance affect performance of soccer-related movements

Purpose: To determine how shoe-surface interaction, specifically traction and compliance, affects performance and biomechanics of soccer-related movements.Methods: Third generation artificial turf was installed in the laboratory to allow for kinetic and kinematic data collection both on the turf and on a laboratory surface (Pulastic sports surface). Twelve male athletes performed five 5 m sprint accelerations and five 180° sprint turns in three different shoe-surface conditions (indoor soccer shoe on the laboratory surface, indoor soccer shoe on the turf surface, soccer cleat on turf surface). Comparisons between the indoor shoe across surfaces indicated compliance effects and comparisons between the cleat and indoor shoe on turf indicated traction effects.Results: Performance increased for the sprint acceleration in the indoor shoe on the turf compared to the laboratory (1.04 s vs. 1.08 s); however, no further increase in acceleration performance occurred with the soccer cleat. For the turn movement, no change in performance occurred comparing the indoor shoe across surfaces however an increase in turn performance was seen when using the soccer cleat on turf compared to the indoor shoe (2.67 s vs. 2.56 s). The cleat had both increased utilised translational and rotational traction compared to the indoor shoe on turf for the turn movement. The cleat also resulted in increased ankle eversion moments as well as increased knee abduction and external rotation moments compared to the indoor shoe on the turf surface for the turn movement.Conclusion: Both compliance and traction shoe-surface characteristics affect performance; however, the effects of the different characteristics are different depending on the movement type.

Elite Football Players’ Perceptions of Football Turf and Natural Grass Surface Properties

Given the global spread of football (soccer) there are substantial differences in the playing surfaces used between FIFA member associations. This paper contains results from the second part of a study on elite football players’ perceptions of playing surfaces from across the globe. Using a questionnaire, which was developed based on an initial qualitative study, elite players’ perceptions of differences in surface properties between natural and artificial (football) turf were examined. In total, 1129 elite footballers, representing 43 countries across six FIFA confederations completed the questionnaire. Exploratory analysis of overall responses revealed that the players had strong opinions with regards to surface properties when directly comparing natural and football turf. In particular, a higher proportion of players stated that football turf was “Too hard/Harder”, “More level”, “More abrasive” and had “Less grip” compared to natural grass. The results also showed that overall players’ perceptions of surface properties, between natural grass and football turf were dependent on their experience of different playing surfaces during their junior and senior careers, in particular, the variability within football turf pitches.

The Effect of Stud Shape on Penetration Characteristics Through Synthesized Natural Turf in Football

The aim of this study was to provide information to footwear manufacturers to assist improvements in player performance and injury rates. Custom-made studs were dropped onto a synthesised natural turf surface using a bespoke instrument drop-rig. Ten drops were performed with each stud and the acceleration profile from contact to a depth of 30mm was recorded. Theoretical predictions were made based on the soil mechanics used in civil engineering. A difference/reverse Helmert contrast ANOVA revealed two significant differences in the rate of penetration and a regression analysis indicated that perimeter length made a significant contribution (p < 0.01) to predicting the negative jerk of the studs. There were no significant differences or relationships associated with time taken to reach a depth of 30mm. This study provides a plausible explanation for the somewhat expected differences in penetration behaviour. It also highlights a key development in establishing a methodology for this type of work.

Models for Predicting Surface Temperatures on Synthetic Turf Playing Surfaces

Despite widespread use on athletic fields, synthetic turf surface temperatures are considerably higher than those measured on natural turfgrass when exposed to solar radiation. Elevated temperatures may pose health risks to athletes competing on synthetic turf. Research was conducted at the University of Tennessee Centre for Athletic Field Safety to create a model for predicting synthetic turf surface temperature using atmospheric data. Synthetic turf surface temperature was measured on ten different synthetic turf plots (42 m2) varying in fibre type and infill characteristics. Plots were arranged in a randomized complete block design with three replications. Two temperature sensors placed in the centre of each plot measured surface temperature on 10-minute intervals for three 8-week periods over the course of two years. Atmospheric data including air temperature (°C), relative humidity (%), precipitation (mm), and solar radiation (W m-2) were collected on the same interval. Synthetic turf surface temperature varied due to both air temperature and solar radiation. Predictive models using these data accounted for 86, 95, and 94% of the variation in daily maximum, minimum, and mean synthetic turf surface temperature. Accuracy of these models for predicting daily mean and minimum synthetic turf surface temperature using 48 and 72-hour forecasted air temperature data was excellent (+/- 1°C). Models using 48 and 72-hour forecasted were less accurate in predicting daily maximum synthetic turf surface temperature (+/- 4.75 to 5.33°C). Our findings indicate that 72 hour forecasted air temperature data can be used to predict daily minimum and mean surface temperature of synthetic turf. Such models could be used to schedule athletic events around periods of potentially hazardous surface temperatures.

Rotational Traction Behaviour of Artificial Turf

Within artificial turf testing for player-surface interaction, traction is a key system property that needs to be measured for comfort, performance and injury risk. The purpose of this study was to modify a FIFA rotational traction test device to provide the full torque-angle time history and to use the modified device to compare the behaviour of five different football and rugby studs. A strain-gauge sensor and rotational sensor were incorporated to provide continuous measurement of the torque resistance and rotational angle throughout the rotation of the test disc. Data was collected on a standard laboratory made (3G) artificial turf surface. From the torque-angle plot, an initial high stiffness region followed by a lower stiffness region was identified and comparisons made between studs. In general, as stud length increased, the stiffness increased in both regions.Furthermore, as the stud length increased for both football and rugby studs there was a pattern of increasing peak torque but no clear trend for the peak angle. The actual foot rotation measured in subject testing is observed in general to be much smaller than the angular rotation required to produce the peak torque resistance from the mechanical testing, suggesting that the initial stiffness resistance behaviour may be a better indicator of the mechanisms involved in the traction mobilised by subjects.

Comparison of Rotational Traction of Athletic Footwear on Varying Playing Surfaces Using Different Normal Loads

As an athlete accelerates, stops, and changes direction, numerous forces are transmitted to the lower extremities. The interaction between an athlete’s shoe and the playing surface has been indicated as a factor in lower extremity injury risk. In particular, high rotational forces may result in increased injuries to the lower extremities. Rotational traction forces produced by eight different cleated shoes on Kentucky bluegrass (Poa pratensis L.), AstroTurf GameDay Grass 3D, FieldTurf Revolution, and Sportexe Omnigrass 51 under three normal loads (vertical forces) of 787, 1054, and 1321 N were measured using Pennfoot, a portable traction testing device. Of the treatments in this study, shoe type influenced rotational traction most, with differences among shoes being nearly four times as large as those among playing surfaces. Traction was either the same or within several Nm on each surface tested. Traction on the three synthetic turf surfaces ranged from 49.3 to 53.1 Nm and the traction level of Kentucky bluegrass was 52.3 Nm. Traction levels among shoes ranged from 43.8 to 58.6 Nm. The results of this study indicate that footwear selection has a larger effect on rotational traction, and potentially injury risk, than the playing surfaces evaluated in this study. Traction Testing on Natural and Synthetic Turf The interaction between an athlete’s shoe and the playing surface likely influences lower extremity injury risk. Specifically, injuries to lower extremities may result from an athlete’s foot becoming “entrapped” in the playing surface during pivoting movements (Lambson et al, 1996; Orchard et al., 2001; Torg et al., 1974). Researchers have attempted to quantify lower extremity injury risk by measuring the rotational traction forces that occur between shoes and playing surfaces (Andreasson et al., 1986; Bonstingl et al, 1975; Heidt et al., 1996; Livesay et al., 2006; McNitt et al., 2004a; Torg et al., 1996; Villwock et al., 2009a, 2009b). Rotational traction is the traction related to rotational motion about an axis normal to the surface (American Society for Testing and Materials, 2009). In the following studies, Published in Applied Turfgrass Science DOI 10.2134/ATS-2013-0073-RS © 2014 American Society of Agronomy and Crop Science Society of America 5585 Guilford Rd., Madison, WI 53711 All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. T.J. Serensits and A.S. McNitt, Dep. of Plant Science, The Pennsylvania State Univ., 116 ASI Building, University Park, PA 16802. Received 25 Oct. 2013. *Corresponding author (serensits@psu.edu). Published July 9, 2014

Understanding how the Components of a Synthetic Turf System Contribute to Increased Surface Temperature

Surface temperatures of synthetic turf have become a factor of growing interest and concern, particularly in warmer regions like Australia. However, it is unclear which components of the synthetic turf system contribute to surface temperature. The aim of this paper was to compare the surface temperature of 34 different synthetic turf products that were exposed to the same environmental conditions to ascertain which components of the synthetic turf system and which environmental factors contributed to increased surface temperature. A total of 6,120 observations were taken on the 34 products over the summer months, giving 30 observations for each of the variables on each product. An analysis of covariance (ANCOVA) indicated that the type of infill and shockpad had small-medium, but significant, effects on surface temperature (p<0.001 and p=0.003, respectively), and the interaction between shockpad and tuft gauge was also significant (p=0.047). Level of solar radiation, ambient temperature and relative humidity (p<0.001 in all instances) were the only environmental variables that significantly influenced surface temperature. These findings confirm that both the composition of the synthetic turf system and environmental factors contribute to synthetic turf surface temperature, thus providing important information for synthetic turf manufacturers developing new cool climate products, or for local government authorities selecting products and/or informing safe play for end-users.

The Effect of Skid Distance on Distance Control in Golf Putting

In putting, a common assumption is made that a performance improvement will be made when the ball begins to roll more quickly following the impact with the club. Previous research has reported that distance control accounts for 80% of putting performance. Other research has claimed that maximum percentage of roll in a putt will increase predictability and accuracy; however, this has never been directly studied. An experimental study was conducted to investigate the relationship between putter loft angles, roll ratio, and distance control on both an artificial putting turf surface and natural putting green. Four identical blade putters with different loft angles (-1, 1, 3, 5 degrees) were tested using a high speed camera and a mechanical putting machine to determine the skid length of a large number of putts. The final ball position was recorded to ascertain the distance variability of each club at each putt length and quantify each club's roll ratio. A ball ramp was used to quantify the variability attributed to the putting surface. The roll ratios of each club were found to be significantly different from each other (p<0.05) with the exception of the three and five degree putters. The negatively lofted putter in this study showed the greatest roll ratio and most consistent final distance. Recommendation of negative delivered loft could lead to changes in putter fitting philosophy.

Artificial Turf Research at Loughborough University

Research into artificial turf surfaces can be divided into the categories infrastructure, user safety and play performance. This paper discusses these three categories, presents current knowledge and appraises some remaining questions. A simple diagrammatic framework is proposed for describing and relating the fundamental components of sport surface related research. Infrastructure includes the design, construction, operation, and whole life costs associated with a facility. A key area for future research is to better understand maintenance and the benefits of various strategies / techniques. User safety, or injury risk, is a key concern for many stakeholders. Injury risk is a complex interaction of many factors related to the user, sport, equipment and environment. Whilst the introduction of an injury consensus in the late 1990s permitted much greater impact of studies in soccer and rugby, these have contributed little to understanding injury mechanisms. Furthermore, previous research is hampered with regard to the effect of the surface by utilizing simple mechanical tests that appear inappropriate to user activity, e.g. traction. Advancement of knowledge within this category demands better integration with play performance related measurements and research methods that support a more mechanistic approach. Play performance has been the focus of much recent research. For example, mechanical evaluation of surface systems in the laboratory / field, player testing with regard to player and surface response and perception of surface performance. There exists a real need to develop a ‘consensus’ in establishing suitable boundary conditions for both mechanical and player testing. This would help to identify the fundamental research questions related to play performance and allow improved comparison between research studies.

Artificial turf—Surface properties and player–surface interaction

Introduction: There is in general a lack of good scientific data available on artificial turf (and natural) system engineering behaviour. The plethora of surface system test methods remains a long way short of replicating even simple human movement and loading patterns. In most player movement studies reported the surface system is poorly described or not controlled such that the data do not add to understanding how surface system response mechanism are mobilized to provide the measured reaction forces or the observed kinematic adjustments.

Volatilization of pesticides from golf courses in the United States: mass fluxes and inhalation health risks.

Golfers may be subject to chronic health risks from inhalation of vapors from pesticides applied to turf surfaces. The objective of this study was to provide a comprehensive evaluation of the volatilization potential of pesticides used on golf courses in the United States and to assess the resulting inhalation health risks. Long-term exposures were simulated using a fate and transport model for inhaled concentrations. The model was tested using data from field experiments for eight pesticides. Mean concentrations were overestimated by a factor of two, and the model explained 82% of observed variations. The model was subsequently used to estimate volatilization mass fluxes and air concentrations for 37 chemicals using weather information from nine climatic zones in the United States. Simulation results indicated substantial regional variations in volatilization fluxes, concentrations, and health risks, largely due to weather and pesticide application variations. Hazard quotients associated with chronic noncarcinogenic health risks were found to be less than 10 for all chemicals and locations. Similarly, carcinogenic health risks for the 10 pesticides considered likely or possible carcinogens were determined to be less than 10. Based on currently available levels of chronic toxicity endpoints for human health (chronic reference doses and cancer potency factors), we could find no evidence of health risk to golfers from inhalation of these 37 pesticides.

Torque prediction at the shoe–surface interface using insole pressure technology

Excessive rotational traction between the foot and the playing surface has been shown to increase the risk of athletic injuries to ligaments in the knee and ankle. It is not currently feasible to accurately determine the free torque generated at the shoe–surface interface utilizing live participants without an embedded force plate. The goal of the current research was to predict the free torques that developed at the shoe–surface interface during voluntary internal and external rotations of the body relative to a planted foot using an insole pressure measurement system. Six participants fitted with a shoe containing an insole pressure measurement device performed trials on an embedded force plate. A pressure sensor mask of specific sensors was determined based on the degree of linear correlation between sensor pressure and the free torque. Linear regression analyses were utilized to develop a General Linear Regression Model and Participant-Specific Linear Regression Models. The results of this study indicated that insole pressure technology, in conjunction with linear regression models, can be utilized to predict free torques generated at the shoe–surface interface during isolated rotational motions of the body with respect to a planted foot. Furthermore, Participant-Specific Linear Regression models may be more accurate in these predictions than a general model, based on a group of participants. When used with computational modeling, this technique might allow the investigation of strains produced in ligaments of the ankle and knee that are generated during internal and external rotations of the body with a planted foot on various turf surfaces outside a laboratory setting.

One, two, three or four: Does the number of Clegg hammer drops alter ground hardness readings on natural grass?

The Clegg hammer is currently used to measure hardness of natural turf surfaces to inform performance and safety decisions. However, the number of Clegg hammer drops reported in natural grass testing varies from one to four drops, and the impact of the choice of the number of drops is unknown. The aim of this article is to determine whether significant differences exist between the four Clegg hammer drops on natural grass across a variety of conditions. Hardness readings (using a 2.25 kg Clegg hammer), soil moisture and botanical composition were recorded at nine different sites on seven football fields during an 18-week playing season. A total of 1255 hardness readings were collected for each of four consecutive Clegg hammer drops. Overall, there were significant differences between drop 1 and the other three consecutive drops, on all fields and on all sites. Deep soil moisture was the only factor that significantly influenced the hardness readings. The results of this study demonstrate that the decision regarding the number of drops recorded needs careful consideration as conclusions drawn on playability of a ground or the association with injury risk may vary considerably depending on the number of drops.

Laboratory Study of the Removal Efficiencies for Ammonium and Total Phosphorus from Runoff Using Layered Filtration Systems

The removal efficiencies for ammonium (NH4+) and total phosphorus (TP) from runoff using two layered filtration systems (LFS-A, with a turf surface, and LFS-B, with a permeable brick surface) were investigated in six repeated experiments. The results indicated that the removal efficiencies for NH4+ and TP from infiltrated water using LFS-A were as high as 90.92 and 91.60%, respectively, while the efficiencies resulting from LFS-B ranged from 86.67 to nearly 100% and 90.29 to 99.09%, respectively. However, there was a significant difference in the comprehensive removal rates (CRRs) for NH4+ and TP between LFS-A (400 and 70 mg·m-2·h-1, respectively) and LFS-B (174 and 54 mg·m-2·h-1, respectively). Some engineering measures, such as the utilization of replanted turf, may reduce the CRRs for pollutants for long periods of time; while no significant relationships between the CRRs of NH4+ and TP and their initial concentrations were observed.

A Meta-Analysis of Soccer Injuries on Artificial Turf and Natural Grass.

The goal of this investigation was to determine if playing or training on third-generation artificial turf (AT) surfaces increases the incidence rate of injuries compared to natural grass (NG) surfaces. This was accomplished by a meta-analysis performed on previously published research. Eight studies met the criteria of competitive soccer players, participation on both surfaces, and presentation of both exposure time and injury occurrence. Exposure time and injury incidence values were used to generate injury rate ratios (IRRs, AT/NG) for all injuries as well as specific injuries. Subgroup analyses were also performed by condition (match or training), gender, and age (youth or adult). The overall IRR was 0.86 (P < 0.05) suggesting a lower injury risk on AT than NG. However, there was considerable heterogeneity between studies. Analyses of individual injuries and subgroups found that in many cases IRR values were significantly less than 1.0. In no case was the IRR significantly greater than 1.0. Based on this, it appears that the risk of sustaining an injury on AT under some conditions might be lowered compared to NG. However, until more is known about how issues such as altered playing styles affect injury incidence, it is difficult to make firm conclusions regarding the influence of AT on player safety.

Shuttle Run Performance Induced Injury Rates of School Boys on Different Sport Surfaces

Background: Sports surfaces not only play a significant role in influencing sports performance but also determining the risk of injury. The best running surface should be moderately soft & smooth and widely used in a variety of games & sports in schools. Aim: The aim of this study was to compare the shuttle run performance induced injury rates of school boys on five different sport surfaces in physical education classes. Method: Thirty six healthy school boys (Age: 14.06±0.41 years, Height: 1.60±0.08 meters, Weight: 47.17±7.13 kilograms, BMI: 18.59±3.21 kg/m²) performed 4x10m shuttle run on five different sport surfaces (PVC, asphalt, turf, concrete bed & soft clay) to evaluate speed-agility and subjective symptoms to determine injury rates. Result: The best average result of shuttle run performance was achieved on asphalt surface followed by PVC, soft clay, turf and concrete bed surface was found weak average result. In addition to safety, PVC surface provided greater security with reduced incidence of sports injuries and better performance of school boys. Conclusion: The impact of possible difference among the sport surfaces to obtain optimum shuttle run performance for school boys during competition, test and regular physical education activities under the condition of safety & reduced risk of sports injuries.