Artificial Soccer Turf – What Shoes to Wear?sportsurf.lboro.ac.uk/workshops/STARSS/SF/TS.pdf · Artificial Soccer Turf – What Shoes to Wear? Thorsten Sterzing, Clemens Müller,

Artificial Soccer Turf – What Shoes to Wear?Thorsten Sterzing, Clemens Müller, Thomas L. Milani

thorsten.sterzing@hsw.tu-chemnitz.de

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