Artificial Soccer Turf – What Shoes to Wear?Thorsten Sterzing, Clemens Müller, Thomas L. Milani
Chemnitz University of Technology
1st Generation1960
concrete layerno infill
3rd Generation1990
elastic layersand/rubber infill
2nd Generation1980
elastic layersand infill
Development of Artificial Soccer Turf (AT)
Introduction ConclusionResults and DiscussionMethods
AT included in FIFA Rules of The Game (2004)
U 20 World CupCanada 2007
Young Boys BernSwitzerland
Red Bull SalzburgAustria
U 17 World CupPeru 2005
Introduction ConclusionResults and DiscussionMethods
Introduction ConclusionResults and DiscussionMethods
Continent 1-Star 2-Star
UEFA 109 121
AFC 35 12
CONCACAF 29 6
CAF 29 4
CONMEBOL 10 1
OFC 1 0
FIFA 1-Star and 2-Star Installations
www.fifa.com (18. April 2010)
Game Characteristics
- FIFA 2007- Anderson et al. 2008- Müller et al. 2009
- Only slight changes depending on playing level- Discrepancy of objective and subjective data
Introduction ConclusionResults and DiscussionMethods
3rd Generation
Exception: Sliding Tacking
Introduction ConclusionResults and DiscussionMethods
- Ekstrand et al. 2006- Fuller et al. 2007a- Fuller et al. 2007b- Steffen et al. 2007
- No major differences in injury incidences
3rd Generation
Injury Observations
Prospective Studies
Critical Improvement compared to1st and 2nd Generations of Artificial Turf
3rd Generation
elastic layersand infill
rubber infill (traction)
NewArtificial Surface
TraditionalNatural Grass Shoes
!?
Introduction ConclusionResults and DiscussionMethods
Purpose:
Development of an AT Soccer Shoe Outsole- A Three Phases Project -
Phase I2007
Phase II2008
Prototype Modification
Status Quo Evaluation
Project Chronology
Phase III2009
Market Comparison
Introduction ConclusionResults and DiscussionMethods
Comprehensive Evaluation of Athletic Footwear
Hennig & Milani 1996, Lafortune 2001, Sterzing et al. 2007
MechanicalBiomechanical
Performance Perception
Introduction ConclusionResults and DiscussionMethods
Performance – Slalom Parcours
• 3 repetitive runs per shoe condition
• 2 minutes rest between runs
• Shoe change between each run
• Variables
- Running time
- Running time perception
Krahenbuhl 1974, Sterzing et al. 2009
Start/ Finish
Pylon
Double Light Barrier
Running Direction
72°
2.20 m
2.00 m
Introduction ConclusionResults and DiscussionMethods
Perception – Traction
• Several rapid cutting movements
• Questionnaire: 9-point perception scale
• Variable
- Traction suitability
Introduction ConclusionResults and DiscussionMethods
Biomechanical – Cutting
• 45°cutting movement, two step approach
• 5 repetitive trials
• Variable
- Force ratio: m-l shear/vertical
45°
Force plate (Kistler,1 kHz)
Running direction
• high shear forces during cutting movements in soccer (Valiant, 1987)
Introduction ConclusionResults and DiscussionMethods
Testing Protocol
• subject pool of 37 experienced soccer players(23.0 ± 3.4 years, 177.4 cm ± 4.3, 71.4 ± 6.1 kg)
• 4 different shoe models in each phase
• Randomization of shoe models
• FIFA 2-Star Liga Turf 240 22/4 RPU brown (Polytan)
Introduction ConclusionResults and DiscussionMethods
• Mean and standard deviation
• Repeated measures ANOVA (p < 0.05)
• Post-hoc test: Bonferroni (p < 0.05)
Statistics
Phase I – Status Quo Evaluation
soft ground (SG)firm ground (FG)hard ground (HG)
Natural Grass Outsole Designs
currently used on artificial turf
Introduction ConclusionResults and DiscussionMethods
innovative design (ID)
DuoCell technology at forefoot
first prototype
8
9
10
11
12
HG FG SG ID
[s]
Slalom running timep<0.0001
1
2
3
4
5
HG FG SG ID
Perception: Slalom running timep<0.0001
faster
slower
1
2
3
4
5
6
7
8
9
HG FG SG ID
Traction suitabilityp<0.0001very bad
very good
Introduction ConclusionResults and DiscussionMethods
0
0,1
0,2
0,3
0,4
0,5
0,6
HG FG SG ID
Biomechanical force ratio Fx/Fzp=0.0012[-]
Findings: Phase I – Status Quo Evaluation
soft ground (SG)firm ground (FG)hard ground (HG) innovative design (ID)
Natural Grass Outsole Designs
Introduction ConclusionResults and DiscussionMethods
Phase II prototypes based on the innovative design
less suited better suitedbetter suited
first prototype
Traction Concept
Availability-
Mechanics
Utilization-
Biomechanics
Fong et al. 2009
• Interface Material Geometry Loading
• Athlete Anatomy Anthropometrics Body Composition Motor Performance Skills Training Status
Optimization of Traction forMaximization of Performance
≠
Introduction ConclusionResults and DiscussionMethods
Phase II – Modified Prototypes
DC-FGinnovative designPhase I (ID)
DC 85 DC 90
• DuoCell at forefoot and rearfoot• Slightly different TPU hardness
Introduction ConclusionResults and DiscussionMethods
• DuoCell only at forefoot• FG design at rearfoot
[s]
Slalom running timep=0.04
8
9
10
11
12
13
ID DC-FG DC 85 DC 900
1
2
3
4
Perception: Slalom running timep=0.02
faster
slower
ID DC-FG DC 85 DC 90
very good
bad
1
2
3
4
5
6
7
Traction suitabilityp=0.10
ID DC-FG DC 85 DC 90
Introduction ConclusionResults and DiscussionMethods
0
0,1
0,2
0,3
0,4
0,5
0,6
ID DC-FG DC 85 DC 90
Biomechanical force ratio Fx/Fzp=0.70
Introduction ConclusionResults and DiscussionMethods
Findings: Phase II – Modified Prototypes
• no negative effect of rearfoot DuoCell compared to rearfoot FG• no effect of TPU hardness
Phase III prototype based on DC 90 design
DC-FG DC 85 DC 90innovative design
Phase I (ID)
final Prototype(DC 90)
Phase III – Market Comparison
Predator AbsolionPS TRX AG
(AP)Tiempo Mystic II MG
(NT)
King XLSynthetic Grass HG
(PK)
Introduction ConclusionResults and DiscussionMethods
commercially available artificial turf designs
Introduction ConclusionResults and DiscussionMethods
8
9
10
11
12
AP NT PK DC 90
Slalom running timep=0.0035
1
2
3
4
5
AP NT PK DC 90
Perception: Slalom running timep=0.0051
faster
slower
1
2
3
4
5
6
7
AP NT PK DC 90very good
bad
Traction suitabilityp=0.0006
0
0,1
0,2
0,3
0,4
0,5
0,6
AP NT PK DC 90
Biomechanical force ratio Fx/Fzp<0.0500
final Prototype(DC 90)
Findings: Phase III – Market Comparison
• Final prototype outperformed three commercially available shoes.
• Relatively short and evenly distributed stud configurations were identified toprovide good functional traction to players.
• Comprehensive approach was shown to be successful for the developmentprocess of an artificial soccer turf outsole.
Predator AbsolionPS TRX AG
(AP)
Tiempo Mystic II MG(NT)
King XLSynthetic Grass HG
(PK)
Introduction ConclusionResults and DiscussionMethods
Thank you very much for your attention!
This research was supported by
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