Effects of structural components of artificial turf on the transmission of impacts in football players

The third generation of artificial turf systems (ATS) has matched the mechanical behaviour of natural grass, but today a high heterogeneity at structural level and mechanical behaviour in the new ATS also exists. The objective was to analyse the effect of the structural components of ATS football pitches and running speed on the capacity of impact attenuation. A total of 12 athletes were evaluated at three speed conditions (3.33 m/s, 4 m/s and maximum speed) on four different ATS, classifying them by their components (length of fibre, type of in-fill and sub-base). Impact attenuation was significantly higher in ATS3, characterised by longer fibre compared to other ATS with less fibre length. The ATS4 with a higher length fibre and built on compacted granular material proportioned significantly lower values in the maximum peaks of tibia acceleration. Finally, as speed increases, the peak tibia impacts were significantly higher. Longer fibre length and the capacity to accommodate a higher quantity of infill facilitate higher impact attenuation. Equally, a compacted granular sub-base is related to lower magnitude of maximum tibia peaks. Finally, the magnitude of the tibia acceleration peaks is dependent of running speed for all ATS analysed, being higher as speed increases.     

Spatial characterisation of natural and third-generation artificial turf football pitches

In contrast to the situation with early artificial turf pitches, little information has previously been published on the characterisation of third-generation artificial surfaces. The spatial variation of ball rebound resilience and rotational resistance were measured here under dry conditions, late in the season, for two natural turf football pitches and a recently laid third-generation artificial turf pitch. Data for the natural turf pitches show a wider variation with position on the pitch than for the artificial pitch. The latter surface showed remarkable consistency in both quantities measured. Surprisingly, all ball rebound resilience data and some of the rotational resistance values were found to lie outside current FIFA specifications, possibly due to the level of wear in natural turf at this stage of the season. For the artificial turf, the deterioration in properties over a period of 6 months is significant and suggests more frequent testing is needed. Taking data from various pitch positions, the two measured quantities were shown for the first time, as far as we are aware, to be inversely related for both natural turf pitches. This correlation may be largely attributed to differences in the extent of grass cover and/or soil compaction. For artificial turf, the lack of variation in measured quantities with pitch position precluded the determination of any correlation.     

Effects of two football stud configurations on biomechanical characteristics of single-leg landing and cutting movements on infilled synthetic turf

Multiple playing surfaces and footwear used in American football warrant a better understanding of relationship between different combinations of turf and footwear. The purpose of this study was to examine effects of shoe and stud types on ground reaction force (GRF) and ankle and knee kinematics of a 180° cut and a single-leg 90° land-cut on synthetic turf. Fourteen recreational football players performed five trials of the 180° cut and 90° land-cut in three shoe conditions: non-studded running shoe, and football shoe with natural and synthetic turf studs. Variables were analyzed with a 3 × 2 (shoe × movement) repeated measures analysis of variance (p < 0.05). Peak vertical GRF (p < 0.001) and loading rate (p < 0.001) were greater during 90° land-cut than 180° cut. For 180° cut, natural turf studs produced smaller peak medial GRFs compared to synthetic turf studs and non-studded shoe (p = 0.012). For land-cut, peak eversion velocity was reduced in running shoes compared to natural (p = 0.016) and synthetic (p = 0.002) turf studs. The 90° land-cut movement resulted in greater peak vertical GRF and loading rate compared to the 180° cut. Overall, increased GRFs in the 90° land-cut movement may increase the chance of injury.     

Skin friction related behaviour of artificial turf systems

The occurrence of skin friction related injuries is an issue for artificial turf sports pitches and remains a barrier to their acceptance. The purpose of this study was to evaluate the current industry standard Securisport® Sports Surface Tester that measures skin surface related frictional behaviour of artificial turf. Little research has been published about the device and its efficacy, despite its widespread use as a standard FIFA test instrument. To achieve a range of frictional behaviours, several “third generation” (3G) carpet and infill combinations were investigated; friction time profiles throughout the Securisport rotations were assessed in combination with independent measurements of skin roughness before and after friction testing via 3D surface scanning. The results indicated that carpets without infill had greatest friction (coefficients of friction 0.97–1.20) while those completely filled with sand or rubber had similar and lower values independent of carpet type (coefficient of friction (COF) ≈0.57). Surface roughness of a silicone skin (s-skin) decreased after friction testing, with the largest change on sand infilled surfaces, indicating an “abrasive” polishing effect. The combined data show that the s-skin is damaged in a surface-specific manner, thus the Securisport COF values appear to be a poor measure of the potential for skin abrasion. It is proposed that the change in s-skin roughness improves assessment of the potential for skin damage when players slide on artificial turf.     

Comparison of athletic movement between elite junior and senior Australian football players

This study compared the athletic movement skill between elite Under-18 (U18) Australian football (AF) and senior Australian Football League (AFL) players. The U18 sample (n = 13; 17.7 ± 0.6 years) were representatives of an elite talent development programme. The AFL players were classified accordingly; Group 1 (1–4 AFL seasons; n = 20; 21.2 ± 1.9 years) and Group 2 (>5 AFL seasons; n = 14; 26.3 ± 2.6 years). Participants performed an athletic movement skill assessment, inclusive of five foundational movements. Each movement was scored across three assessment points using a three-point scale. Total score for each movement (maximum of nine) and overall score (maximum of 63) were used as criteria. Multivariate analysis of variance (MANOVA) was used to test the effect of developmental group (three levels) on the criteria. Receiver operating curves were built to examine the discriminant capability of the overall score. A significant effect of developmental group was noted, with the U18 sample having a lower mean total score for four of the five movements. Overall scores of 49/63 and 50/63 discriminated the elite U18 sample from Group 1 and Group 2, respectively. U18 players may have less developed athletic movement skills when compared to their senior AFL counterparts.     

高校女足运动员运动损伤及预防探究

对高校女子足球运动中，常见的几种运动损伤进行了研究，分析了引发这些运动损伤的原因，提出了较为有效的预防措施。     

The predicted risk of head injury from fall-related impacts on to third-generation artificial turf and grass soccer surfaces: A comparative biomechanical analysis

The risk of soccer players sustaining mild traumatic brain injury (MTBI) following head impact with a playing surface is unclear. This study investigates MTBI by performing headform impact tests from varying heights onto a range of third-generation artificial turf surfaces. Each turf was prepared as per manufacturers specifications within a laboratory, before being tested immediately following installation and then again after a bedding-in period. Each turf was tested dry and when wetted to saturation. Data from the laboratory tests were compared to an in situ third-generation surface and a professional grass surface. The surface performance threshold was set at a head impact criterion (HIC) = 400, which equates to a 10% risk of the head impact causing MTBI. All six third-generation surfaces had a >10% risk of MTBI from a fall >0.77 m; the inferior surfaces required a fall from just 0.46 m to have a 10% MTBI risk. Wetting the artificial turf did not produce a statistically significant improvement (P > 0.01). The in situ third-generation playing surface produced HIC values within the range of bedded-in experimental values. However, the natural turf pitch was the superior performer – necessitating fall heights exceeding those achievable during games to achieve HIC = 400.     

对我国成年女足“年龄结构”的综合研究

我国成年女足目前存在年龄结构过于青年化的现象,通过与2007年女足世界杯的相关信息进行比较,指出了我国女足竞赛体系和女足运动员成长模式存在的问题,并且提出了可操作的建设性建议。     

我国优秀女足运动员意志影响因素研究

对参加2005年冬训的全体成年女足队伍的教练员进行问卷调查,结果表明:影响我国女足运动员意志发展的因素是多方面的,教练员应科学认识、全面把握、分别训练和综合发展。对女足运动员意志品质训练应有计划、有重点、系统地培养,使意志品质的各维度得到全面发展、协调发展。     

Risk of injury associated with rugby union played on artificial turf

Abstract

The aim of this study was to compare the incidence, nature, and cause of injuries sustained in rugby union played on artificial turf and grass. The study comprised a two-season investigation of match injuries sustained by six teams competing in Hong Kong's Division 1 and training injuries sustained by two teams in the English Premiership. Injury definitions and recording procedures were compliant with the international consensus statement on epidemiological studies of injuries in rugby union. There were no significant differences in the overall incidence (rate ratio = 1.42; P = 0.134) or severity (P = 0.620) of match injuries sustained on the two surfaces. The lower limb and joint (non-bone)/ligament injuries were the most common location and type of match injury on both surfaces; the incidence of anterior cruciate ligament injuries was nearly four times higher on artificial turf than grass but the difference was not statistically significant (rate ratio = 3.82; P = 0.222). There were no significant differences in the overall incidence (rate ratio = 1.36; P = 0.204) or severity (P = 0.302) of training injuries sustained on artificial turf and grass. The lower limb and muscle/tendon injuries were the most common location and type of training injury on both surfaces. The results indicate that the overall risks of injury on artificial turf are not significantly different from those experienced on grass; however, the difference in the incidence of anterior cruciate ligament injuries on the two surfaces is worthy of further study.     

Effects of turf and cleat footwear on plantar load distributions in adolescent American football players during resisted pushing

Metatarsal and midfoot injuries are common in American football. Footwear design may influence injury rates by altering plantar foot loading patterns in these regions. The purpose of this study was to determine the effect of cleat design on in-shoe plantar foot loading during a football-specific, resisted pushing task. Twenty competitive football players (age 14.7 ± 1.8 years, height 1.72 ± 0.10 m, and mass 71.8 ± 26.9 kg) completed three trials of pushing a weighted sled at maximal effort in a standard shoe (CLEAT) and artificial turf-specific shoe (TURF), with flexible in-shoe force measuring insoles. Repeated measures ANOVAs identified mean differences in maximum force and relative load under all regions of the foot. Results showed higher forces in the CLEAT under the medial (p < 0.001) and lateral (p = 0.004) midfoot, central (p = 0.007) and lateral (p < 0.001) forefoot, and lesser toes (p = 0.01), but lower forces in the hallux (p = 0.02) compared to the TURF shoe. Additionally, relative loading was higher in the CLEAT under the medial (p < 0.001) and lateral (p = 0.002) midfoot and lateral (p < 0.001) forefoot, but lower in the medial forefoot (p = 0.006) and hallux (p < 0.001) compared to the TURF shoe. The two shoes elicited distinct plantar loading profiles and may influence shoe selection decisions during injury prevention or rehabilitation practices.     

Factor structure,stability, and congruence in the functional movement screen

The scoring scheme for the functional movement screen implicitly assumes that the factor structure is consistent, stable, and congruent across different populations. To determine if this is the case, we compared principal components analyses of three samples: a healthy, general population (n = 100), a group of varsity athletes (n = 101), and a group of firefighters (n = 397). The congruence of the principal components derived through these analyses were evaluated across all of the samples, using Tucker’s congruence coefficient. Factor extraction was guided by parallel analyses, and interpretation was facilitated by Varimax rotation. We observed factor instability, low factor congruence, and inconsistent factor structure. Additionally, we observed a two-factor structure of the functional movement screen in all of our sample groups. These analyses suggest that, although the independent elements of the functional movement screen may continue to be used, use of the composite score is not supported by the factor structure of the measure.     

Influence of the composition of artificial turf on rotational traction and athlete biomechanics

Artificial turf advances have enabled surfaces to behave like natural grass, however, debate remains as to whether artificial turf is as safe as natural grass. To reduce injury risk, sport surfaces should have low rotational traction with artificial surfaces having a potential advantage as components can be manipulated to change surface properties and traction. The purpose of this study was to investigate the influence that different components of artificial turf have on rotational traction and athlete lower extremity joint loading. Twelve surfaces underwent mechanical testing to determine the influence of fibre density, fibre length, infill composition and compaction on rotational traction. Following mechanical testing, Control, Low and High Traction surfaces were selected for biomechanical analysis, where sixteen athletes performed maximum effort v-cuts while kinematic/kinetic data were recorded on each surface. Mechanically, fibre density, type of infill and compaction of the surface each independently influenced traction. The traction differences were substantial enough to alter the athlete kinematics and kinetics. Low traction surfaces reduced ankle and knee loading, while high traction surfaces increased ankle and knee loading . Reducing the rotational traction of sport surfaces is possible through alterations of individual components, which may reduce the joint loading at the knee and ankle joint.     

Consequences of the limit on foreign players in Russian football

This paper examines how a limit on foreign players has influenced national football in Russia. For this purpose, the effects on competition in the league, number of new young players in the national team and commercial value are investigated. Both positive and negative effects are examined. On the one hand, a quota on foreign players raised the competition in the Russian Premier League and captured attention of club owners on the development of youth academies. On the other hand, the negative effects included the reduction in the number of young players in the Russia national team, and the restriction in the invitation of international stars slowed down the growth of match attendance and commercial value. Therefore, because of the current limit, Russia became less competitive. However, if some of the measures suggested in this paper were to be implemented, Russia might improve its development of national football.     

从第四届女足世界杯看世界女子足球运动的发展

第四届女足世界杯赛为世界女足各队提供了表演的舞台,不仅给我们展示了一个全新的女足运动,还给我们带来一个新的讯息:世界女足运动的一个崭新纪元已经来临!女足整体水平的提高,比赛日趋激烈,战术打法的新变化和比赛阵型的全面发展等形成了本届世界杯新的特点,同时也让我们看到了未来世界女足发展的方向.     

对青少年足球运动员文化素质的分析与研究

我国青少年足球运动员的培养与发展决定了国家队的综合素质和水平。通过对中外青少年运动员培养体系的对比研究发现,中国青少年运动员培养的关键问题在于培根教育。人才培养体系的形成必须适应新形势下的管理体制和运行机制,把教育体育与竞技体育结合起来,把青少年足球运动员的培养纳入一个文化教育的组成部分,重视青少年足球运动员在足球兴趣和文化学习上的培养,克服急功近利的思想,提高他们的文化素质。     

动作识别对运动员心理敏捷性的影响

动作识别运动员在做出动作反应之前,对所知觉的对象进行辨认并将知对象与其他动作区分开来,获得未来动作反应信息的过程。动作识别能力受训练水平的影响,运动员在动作识别能力上的差异是直接影响其在对抗性运动中心理敏捷性或认辞别中工速度的主要因素之一。     

对我国现役女子铁饼运动员动作技术的运动学分析及专项能力特征的研究

以近三年在亚洲田径锦标赛分别取得过前四名,在世界田径锦标赛取得第五名和第十一名的现役的四名女子铁饼运动员为研究对象,通过近景动态立体摄影的方法,将比赛录像资料按照专项技术的运动学参数统计成研究数据,进行专业分析,并结合专项技术能力指标分析其专项能力特征。     

Activity profiles of the Australian female netball team players during international competition: Implications for training practice

Abstract

In elite sport, to remain competitive at the international level, it is critical to understand the game demands on players to ensure sport specific training programmes are designed for optimal athlete preparation and conditioning. In netball, recent research examining the activity patterns of players at the elite level is lacking, with only one study undertaken on this level of competition in the past 30 years. Therefore, the aim of this study was to provide coaches with up to date knowledge of player activity patterns as a basis for the design of optimal sport specific training programmes. The Australian female netball team were analysed using video footage of three international test matches. Player activity was categorised into five movement and eight game-based activities; and further classified as work or rest. Results suggest that differences in the current game exist when compared to the previous analysis. Positional differences were also found with regard to player activity confirming the need for an individualised component of training based on player position.     

Comprehensive evaluation of player-surface interaction on artificial soccer turf

The purpose of this study was to evaluate the traction characteristics of four different stud configurations on Fédération Internationale de Football Association (FIFA) 2-Star, third-generation artificial soccer turf. The investigated stud configurations were hard ground design, firm ground design, soft ground design, and an experimental prototype. The concept of this study combines performance, perception, biomechanical, and mechanical testing procedures. Twenty-five soccer players took part in the different testing procedures. Variables of this study were: running times, subjective rankings/ratings, ground reaction forces, and mechanical traction properties. Statistical discrimination between the four stud configurations was shown for performance, perception, and biomechanical testing (p < 0.05). Unsuited stud configurations for playing on artificial turf are characterized by less plain distributed and pronounced studs.