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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....
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... ̈ ller, Sterzing, Kunde, and Milani, 2009a). Thus, we hypothesized that a hard ground or firm ground design are better suited than a soft ground design on the third generation of artificial turf. Three commercially available soccer shoes and one experimental prototype were investigated. The four soccer outsole configurations were examined with regard to their traction properties (Figure 1): hard ground design (Puma Liga leather), firm ground design (Puma v1.08 leather), soft ground design (Puma v1.08 leather), and an experimental prototype. Shoe uppers of the testing shoes were built on similar lasts, which ensured almost identical fit. Thus, the only relevant difference between the shoe conditions was assumed to be the outsole configuration. Hard ground design had a continuous plastic outsole with multiple, evenly distributed, elliptic thermoplastic polyurethane elastomers (TPU) studs. Firm ground design offered two separate plastic outsole plates for forefoot and rearfoot connected by a piece of leatherette. Stud geometry of the firm ground design was bladed. The outsole construction of the soft ground design offered also two separate plastic outsole plates with two studs at the rearfoot and four at the forefoot. Experimental prototype offered numerous, evenly distributed TPU studs at forefoot. These studs were shaped as two hollow cylinders being able to be telescoped into each other ( DuoCell Technology ). Rearfoot featured a bladed outsole like firm ground design. Table I shows the stud specification of the four shoe models. Soft ground design had considerably longer studs than the other shoe conditions (up to 6 mm). Between the other three shoe conditions stud lengths differ up to 2 mm. Experimental prototype and hard ground design had more studs compared to firm ground and soft ground design. Furthermore, the distance between forefoot studs and rearfoot studs was longest for soft ground design. Experimental prototype and hard ground design offered the shortest distance between forefoot studs and rearfoot studs. The artificial turf used in the studies was Polytan Liga Turf 240 with a resilient base layer of 35 mm conforming to DIN (German Institute for Standardization) V 18035/7 and an infill mixture of sand and brown rubber (Polytan, Burgheim/Germany). The turf was constructed according to the requirements of FIFA 2-Star standards. A subject pool of 25 sub-elite (3 rd to 6 th German League) soccer players took part in the different phases of the study (age 22.9 ^ 4.1 years; height 177.9 ^ 4.5 cm; mass 71.5 ^ 6.3 kg). The investigation consisted of three different testing sessions and one material testing, focusing on performance, perception, biomechanical, and mechanical testing. Performance and perception testing sessions were performed on one testing day. The biomechanical testing session took place at another day (Figure 2). Due to subject availability, the subject pool differed slightly (five subjects between the testing days). Subjects were required to give informed consent prior to testing. All procedures adhered to the requirements of Chemnitz University of Technology for subject testing. Prior to data collection a detailed and mandatory instruction about the research design, a warming- up period, and practice trials in their own soccer shoes were provided. In the following the different test designs are presented. For all testing protocols order of shoes were randomly assigned using a Latin square design (Raghavarao, 1971). Testing took place on a testing field (20 5 m) at Chemnitz University of Technology and in Stade de Suisse stadium in Bern during dry weather conditions. The playing surfaces of both testing sites were the same type surface manufactured by the same company. Twenty subjects performed through two different functional traction courses, slalom (I) and acceleration (II), as fast as possible (Figure 3). The slalom course required the subjects to go back and forth and had a total length of 26 m, containing 11 cutting and 12 acceleration movements. The acceleration course had a total length of 6 m requiring the subjects to perform a single maximum straight acceleration. Starting position for both courses was 1 m in front of the light barriers. Subjects had to ...
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Citations
... Prior to data collection at the outdoor turf field laboratory, participants' height, mass, and foot length measurements were recorded and they were fitted with a new pair of cleats to be worn during the study. Substantial evidence has demonstrated the complexity of the cleat-ground interface and revealed that various elements of cleat design, such as stud configuration and shape, upper, heel cup, and shoe plate stiffness are known to influence the shoe-ground interaction (Hennig & Sterzing, 2010;Müller et al., 2010;Schrier et al., 2014;Silva et al., 2017). Thus, to minimise potential variations induced by differences in cleat models across participants, each individual wore one of two provided American football cleat models ( Figure 2). ...
... The results showed no significant effect of different cleats on the magnitude of tibial axial torque. Müller et al. [35] tested the translational traction and reacting force from the surface of four pairs of shoes with different outsole types (SG, AG, HG (hard ground), and prototype shoes), while performing acceleration and side-cutting on the same artificial playing surface with 0 • , 45 • , and 180 • side-cutting, respectively. The results showed that, except for SG, the differences in stud length and alignment of the other outsole types had Encyclopedia 2024, 4 893 no significant effect on the traction force. ...
... In comparison, the FG boots showed a stronger horizontal shear force in side-cutting and acceleration. Combined with the poorer traction performance shown by SG shoes on artificial surfaces and the fact that the vertical component of the force did not change when the shear force brought about by different movements changed, the authors concluded that shear force is the primary criterion for evaluating the traction of boots [35]. Subsequently, the performance of horizontal shear force was further explored, and the traction force was mainly categorized into two aspects, namely rotational torque and translational traction, from the practice of the sport [36,37]. ...
... The currently widely used surfaces can be divided into natural grass, third-generation artificial grass turf, and hybrid systems. The third-generation artificial grass turf needs to meet the following key indicators: a synthetic material grass filament length of 40-65 mm; and the filaments need to have fine sand as a base layer and be filled with rubber particles [35]. The effects of the three different materials on ACL injuries are also reflected in the knee valgus moment and the tibial external rotation angle [40]. ...
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.
... The frictional force of footwear can be changed by modifying the contacting surface material, outsole material, and outsole pattern [6,16]. Previous footwear research has been carried out investigating the frictional force depending on the outsole materials [7,17] and patterns [18,19] in soccer [20,21], American football [8,22], basketball [4,17], and tennis [14,[23][24][25] to find out the effects of frictional force on movement. The rationale for why studies on the frictional force of footwear are continuously conducted in various sports is that the required level of frictional force depends on the surface characteristics [16] and the movement required for each sport [1]. ...
(1) Background: This study aimed to examine the effects of four different outsole patterns on frictional force and lower extremities during tennis-specific movements. (2) Methods: Four tennis shoes with different widths of outsole treads were manufactured for this study (A: all thin, B: all thick, C: laterally thin and medially thick, D: medially thick and laterally thin). The frictional force was measured during a mechanical test. Eleven male recreational tennis players participated in the study. The data were collected using sixteen infrared cameras and a force plate for a biomechanical test. (3) Results: During the mechanical test, there was a significant difference between the shoes in the forward and sideward Coefficient of Translational Friction (CoF) and clockwise rotational friction (p < 0.05). There were significant differences in the maximum ankle internal rotation angle during braking motion (p < 0.05). In contrast, a significant difference in the maximum internal rotation moment of the ankle was found during forward braking motion (p < 0.05). (4) Conclusions: Based on these results, the difference in the outsole tread width (0.6 mm) affected mechanical frictional force, but this phenomenon was less influenced by the adaptation of the lower extremity joint’s movement in a tennis-specific motion. Finally, the difference in the outsole pattern affects the rotational movement and moment of the ankle joint. Thus, any slight change in friction by modified outsole patterns of tennis shoes requires close attention to develop the functional requirements for tennis performance.
... The AAA produces a short dynamic impact curve of < 50 ms, with a measured peak force in the range 2-3 kN to pass the FIFA standard requirements [3,8,9]. In contrast, during running on 3G turf a typical foot-strike peaks at around 1-2 kN and lasts about 250 ms [10][11][12]. Vertical forces of 3 kN have, however, been recorded underfoot during landing from a simulated header [13]. Furthermore, the AAA test foot generally resembles the shape and area of the human heel [3], in contrast to peak player contact forces which typically occur with the whole-or fore-foot in contact with the surface [10][11][12]14]. ...
... Vertical forces of 3 kN have, however, been recorded underfoot during landing from a simulated header [13]. Furthermore, the AAA test foot generally resembles the shape and area of the human heel [3], in contrast to peak player contact forces which typically occur with the whole-or fore-foot in contact with the surface [10][11][12]14]. ...
... For the AAA, the first modification was to increase drop height from 55 to 70 mm, increasing contact time, impact force and impact energy. Although the contact time was not expected to reach the 250 ms associated with running, and the forces and loading rates would be further increased above those typical of running [10][11][12], they would better match those from a jump landing [13]. The second modification was to increase the test foot diameter from 70 to 110 mm, providing a closer match to a typical human forefoot area [14]. ...
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.
... In NG soils, there is less rotational stiffness and, consequently, a lower overload index when compared to AG [11]. Boots appearing with six studs, generating considerable impact peaks in different traction tests carried out on AG, made a significant difference compared to designs with more studs, so their use is contraindicated on this type of terrain [12,13]. This differentiation of surfaces, linked mainly to the level of sports practice, indicates the need to analyze injuries in a sample that included both amateur and semi-professional soccer players. ...
Background:
the main aim of this study was to analyze the relationship between sole pattern parameters of football boots with the frequency of injuries that occur in semiprofessional and amateur footballers.
Methods:
The study sample was composed of 77 male football players. All were at least 18 years old, played at least 10 h per week, gave signed informed consent to take part and properly completed the Visual Analogue Scale. This study analysed data from each player's medical history, including age, injuries, years of practice, field type and surface condition information.
Results:
The visual analogic score in semiprofessional players was higher (2.05 ± 2.43) than in amateur players (1.00 ± 1.1). A total of 141 lesions were collected, equivalent to 1.81 injuries for each football player studied (n = 77). The result of the ROC curve indicated that the player's years of practice could predict significantly (p < 0.05) the presence of lower limb injuries, with an area under the curve of 0.714.
Conclusions:
This study described the predictive capacity of sole pattern characteristics concerning lower limb injuries in amateur and semiprofessional footballers. Football boot variables associated with the number of studs were associated with foot and ankle overload injuries.
... Thus, it is essential to consider the intra-and inter-subject variability when collecting GRF. Other studies used real subjects and standard force platforms (covered with an artificial layer of grass) to obtain GRF on one or two steps [34,[39][40][41]. These laboratory-based studies do not reliably replicate the normal playing conditions due to both the small number of steps taken and the fact that they used neither natural nor artificial turf on which players would usually compete. ...
Ground reaction forces (GRF) have been widely studied in football to prevent injury. However, ambulatory tools are missing, posing methodological limitations. The purpose of this study was to assess the validity of an innovative football shoe measuring normal GRF (nGRF) directly on the field through instrumented studs. A laboratory-based experiment was first conducted to compare nGRF obtained with the instrumented shoe (IS) to vertical GRF (vGRF) obtained with force platform (FP) data, the gold standard to measure vGRF. To this aim, three subjects performed 50 steps and 18 counter-movement jumps (CMJs). Secondly, eleven subjects completed running sprints at different velocities on a football field, as well as CMJs, while wearing the IS. Good to excellent agreement was found between the vGRF parameters measured with the FP and the nGRF measured by the IS (ICC > 0.75 for 9 out of 11 parameters). Moreover, on-field nGRF patterns demonstrated a progressive and significant increase in relation with the running velocity (p < 0.001). This study demonstrated that the IS is a highly valid tool to assess vGRF patterns on a football field. This innovative way to measure vGRF in situ could give new insights to quantify training load and detect neuromuscular fatigue.
... Player valuation is the primary application for methodologies designed to accomplish the latter. The reason it is critical to value players based on skill rather than past performance is that football clubs should be paying for future performance through wages and transfer fees, and the relationship between past and future performance can be defined more accurately if one recognizes that both involve some inherent skill [33]ၕ [34]ၕ . ...
One of the most significant developments in the sports world over the last two decades has been the use of mathematical methods in conjunction with the massive amounts of data now available to analyze performances, identify trends and patterns, and forecast results. Football analytics has advanced significantly in recent years and continues to evolve as it becomes a more recognized and integral part of the game. Football analytics is also used to forecast game outcomes, allowing bettors to make educated guesses. This article describes mathematical concepts related to football analytics that enable a better betting strategies. We explain how the pitch is partitioned into different zones and we define possession sequences. Furthermore, we explain what an expected goals model is and which expected goals model we use in this research. Furthermore, we define two general characteristics of a player evaluation method, each corresponding to one of the equations of the Dawson model. Based on these characteristics, we describe the developments of several general approaches for evaluating players in the context of the Dawson model.
... Shoe-surface friction or traction in various sports has been linked to performance and injury risk [1][2][3][4][5][6][7][8]. Higher friction has been shown to improve the performance of change of direction movements in association football [5], basketball [3] and futsal [8]. ...
... Shoe-surface friction or traction in various sports has been linked to performance and injury risk [1][2][3][4][5][6][7][8]. Higher friction has been shown to improve the performance of change of direction movements in association football [5], basketball [3] and futsal [8]. It has also been hypothesised that higher friction during such movements increases the risk of ACL injury due to biomechanical changes often employed by athletes when performing sidesteps on higher friction surfaces, e.g. a decrease in lower knee flexion angle [9]. ...
In hard court tennis players change direction by either stepping or sliding. The shoe surface friction during these movements is crucial to player performance. Too little friction when stepping may result in a slip. Too much friction when attempting to slide could cause the player to move only a short distance, or to fail to slide. To understand the influence of tread design on shoe surface friction in tennis, experiments were performed on individual shoe tread elements that replicated the tribological conditions they would experience during hard court step and slide movements. Tread element orientation had no effect on the static friction in step movements, but longer tread elements (in the sliding direction) had 9% lower dynamic friction during slide movements (p < 0.001). The friction between tennis shoe tread and hard court tennis surfaces is also shown to be influenced by the tread’s sliding history, and the wearing pattern that forms on the surface of the rubber.
... Manipulating stiffness of athletic surfaces has shown potential in terms of increasing athletic performance [2][3][4][5] and reducing injury risk [6]. During sport, athletes will deform the surface by exerting large forces during sprinting, running and cutting, with peak contact forces reaching over 2000 N [7]. As the surface deforms, it will store potential energy that is transferred from the athlete, returning this energy to the athlete when they leave the surface. ...
Properties of conventional playing surfaces have been investigated for many years and the stiffness of the surface has potential to influence athletic performance. However, despite the proliferation of different infilled artificial turfs with varying properties, the effect of surface stiffness of these types of surfaces on athlete performance remains unknown. Therefore, the purpose of this project was to determine the influence of surface stiffness of artificial turf systems on athlete performance. Seventeen male athletes performed four movements (running, 5-10-5 agility, vertical jumping and sprinting) on five surfaces of varying stiffness: Softest (−50%), Softer (−34%), Soft (−16%), Control, Stiff (+17%). Performance metrics (running economy, jump height, sprint/agility time) and kinematic data were recorded during each movement and participants performed a subjective evaluation of the surface. When compared to the Control surface, performance was significantly improved during running (Softer, Soft), the agility drill (Softest) and vertical jumping (Soft). Subjectively, participants could not discern between any of the softer surfaces in terms of surface cushioning, however, the stiffer surface was rated as harder and less comfortable. Overall, changes in surface stiffness altered athletic performance and, to a lesser extent, subjective assessments of performance, with changes in performance being surface and movement specific.
... 16,29,31,33,35,36 Artificial turf is developed to improve performance, provide more natural field and grass characteristics and reduce injuries. 53 So that, artificial turf surface characteristics are more related with soccer´s demands than rubber or parquet indoor. Moreover, the changes in surface characteristics may affect kinetic patterns of players, potentially perturbing their technical performance of skill specific activities during competition. ...
INTRODUCTION: This review aimed: 1) to describe the most common tests used for
assessing change of direction (COD) performance; 2) to detail the reliability of current
COD tests; 3) to provide an overview of current intervention strategies used to improve
COD performance in adolescent female soccer players.
EVIDENCE ACQUISITION: A computerized search was conducted in PubMed,
Cochrane Plus and Web of Science (from 1995 to January 2020) for English and Spanish
language and peer-reviewed investigations.
EVIDENCE SYNTHESIS: A total of 221 studies were identified, with only 16 meeting
the specific search criteria. The main findings were that eleven different tests have been
used to assess COD performance with intraclass correlation coefficient and coefficient of
variation values between 0.72-0.99 and 1-10.6%, respectively. The number of CODs
performed during each test ranged from 1 to 9 within a range of 45º to 180º and with a
duration <5 s, 5-9 s and >10 s.
CONCLUSIONS: Findings indicate that the reliability of the COD tests seems to depend
on: the equipment used, the surface tested on and the technical level of the soccer player.
These results should be interpreted with caution as they may be influenced by the period
of growth and maturation, the playing position of the player and the period of the soccer
season. Finally, strength and power drills could be considered as appropriate methods to improve COD performance.
