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Sports Turf Research –Focusing on Athlete Performance & Safety
John Sorochan, Ph.D.
January 18, 2018
O VERVI EW O F TH E UT C EN TER FO R ATH LETI C FI ELD SA FETY
J . C . SO RO C H A N
University of Tennessee Center for Athletic Field Safety
CAFS Facts• 25 current sports turf research projects• 5+ acres of athletic turf research • Cool- and warm-season turf and synthetic surfaces
Importance
• Youth injuries (<14) cost the US public $49,192,781,832 in 1997
• Emergency room visits (2004)• 116,000 – baseball
• 186,000 – football
AAP, US CPSC, & National Youth Sports Safety Foundation
Importance
• 5.7% of high school football injuries were definitely related to field conditions, 15.2% were possibly related to field conditions
(Harper et al., 1984)
• 10% of lawsuits related to sports injuries claim that the athletic field
was inadequately maintained
(Dougherty, 1988)
Importance
• 38 million children & adolescents(NIH, 2009)
• 3.5 million children under 14 receive medical treatment for sports injuries
(Safe Kids, 2007)
• 50% of these injuries are preventable
(Brenner, 2007; Safe Kids, 2007)
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CAFS Traffic Simulator CAFS Traffic Simulator
FIFA Soccer Cleat
World Rugby Cleat
CAFS Traffic Simulator
Spring SpecificationType: die springMaterial: steelInner diameter: 0.5 inOuter diameter: 1 inLength: 3 inRating: 10.3 lb per 0.10 in
Testing Evaluations Testing Evaluations
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Testing Methods for Surface Hardness
ASTM F‐355A ASTM F1702
Clegg Surface Hardness Comparisons
2.25 kg (5 lb) missile45 cm (18”) drop height
(ASTM F1702)
ASTM F355A Synthetic Turf Standard
9.1 kg (20 lbs) flat missile61 cm (24”) drop heightFlat surface on projectile
Used to measure high level body impacts
(ASTM 1936)
Clegg Surface Hardness Comparisons
2.25 kg (5 lb) missile45 cm (18”) drop height
(ASTM F1702)
F355 Comparisons
Synthetic Turf = Bermudagrass > Kentucky bluegrass
9.1 kg missile61 cm drop height
F355 Comparisons
• Synthetic Turf vs. Bermudagrass Not different • Synthetic Turf ‐108 GMAX and Bermudagrass ‐110.5 GMAX
• Synthetic Turf vs. KBG ***Different • Synthetic Turf ‐108 GMAX and KBG ‐90 GMAX
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Clegg Surface Hardness Comparisons
Bermudagrass > Synthetic Turf > Kentucky bluegrass
2.25 kg missile45 cm drop height
Clegg Surface Hardness Comparisons
• Synthetic Turf vs. Bermudagrass ***Different • Synthetic Turf ‐76 GMAX and Bermudagrass ‐90 GMAX
• Synthetic Turf vs. KBG ***Different • Synthetic Turf ‐76 GMAX and KBG ‐57 GMAX
Clegg versus F355 F355 to Clegg Relationship 2013F355 after 30 Sim
ulated Traffic Events
Clegg Impact Soil Tester after 30 Simulated Events
Tennessee Athletic Field Tester (TAFT)Tennessee Athletic Field Tester
•Athlete weight• 35 lbs – 330 lbs
•Running• 1 m/s
•Contact distance• 230 mm
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TAFT TAFT Vertical Force Comparisons Synthetic Turf > Bermudagrass > Kentucky bluegrass
TAFT Vertical Force Comparisons210 lb Athlete
• Synthetic Turf vs. Bermudagrass ***Different • Synthetic Turf 340 lbs. of vertical force and Bermudagrass 324 lbs. of vertical force
• Synthetic vs. Kentucky Bluegrass ***Different • Synthetic Turf 340 lbs. of vertical force and KBG 302 lbs. of vertical force
Rotational Resistance Comparisons
Synthetic Turf = Bermudagrass = Kentucky bluegrass
TAFT Horizontal Comparisons Synthetic Turf > Bermudagrass > Kentucky bluegrass
TAFT Horizontal Force Comparisons210 lb Athlete
• Synthetic Turf vs. Bermudagrass ***Different • Synthetic Turf 254 lbs. of horizontal force and Bermudagrass 234 lbs. horizontal force
• Synthetic Turf vs. KBG ***Different • Synthetic Turf 254 lbs. of horizontal force and KBG 194 lbs. of horizontal force
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Head Injury Criterion (HIC)
•When HIC = 1000, 18% of people will suffer traumatic brain injuries
•When HIC = 250, concussions have occurred in most athletes
(Viano, 2005)
Playground Head Drop Device Curved projectile mimics head shape
Standard - ASTM F1292ASTM F355E
• 4.6 kg (10 lbs.) curved missile
• World Rugby Standard for synthetic turf 1.3 m (51”) drop height
• HIC must be less than 1000
Conclusions 2016 HIC for Root Zone & Turf Species
Game 0 Game 20
ASTM
Native
Determining HIC on Trafficked Bermudagrass
ASTM F1292 1.3 m drop on synthetic turf
Clegg: ~71 avg. F355A: ~119 avg.HIC: ~1,225 avg. (1.3 m)
Clegg: ~88 avg.F355A: ~111 avg.HIC: ~370 avg. (1.3 m)
Measuring Critical Fall Height to achieve 1,000 HIC
USGA Spec: Bermudagrass = 2.5 m
ASTM Spec:Bermudagrass = 2.4 m
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Head Injury Criterium (HIC) changes on bermudagrass w/ soil type and traffic
Game 0 Game 20
ASTM
Native
ASTM F1292
Conclusions 2016 HIC for Root Zone & Turf SpeciesMeasuring HIC for Soil Type & Turf Species
Determining Critical Fall Height (1,000 HIC) based on Species, Soil Moisture, & Soil Type
World Rugby 1.3 m limit
Athlete to Surface Interactions
Athlete to Surface Interaction StudiesAthletic injury mechanisms and risk factors
• Movement coordination variability
• Computer simulation of human movement
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Athlete to Surface Interactions
Deceleration and Cutting Movements
Outdoor Human Performance Testing Outdoor Human Performance Testing
Outdoor Human Performance Testing
Soccer ball to Playing Surface Interactions
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Professional soccer players are emotional
• Playing surfaces are crucial for the best play.
• It’s never their fault for a Bad Bounce.
All types of surfaces…
(Google 2017)
UN I VERSI TY FI ELD D AYSREG ULA RLY ED UC A TE A T
University of Tennessee Research Field Day August 30, 2018
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John Sorochan, Ph.D. [email protected] @Sorochan
Adam Thoms, M.S. [email protected] @UT_CAFS
