Shoe-Turf Interaction, Injury Risk, and Performance of Elite ... - STMA
Shoe-Turf Interaction, Injury Risk, and Performance of Elite ... - STMA
Shoe-Turf Interaction, Injury Risk, and Performance of Elite ... - STMA
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1/10/2013<br />
<strong>Shoe</strong>-<strong>Turf</strong> <strong>Interaction</strong>, <strong>Injury</strong> <strong>Risk</strong>, <strong>and</strong><br />
<strong>Performance</strong> <strong>of</strong> <strong>Elite</strong> Athletes<br />
Richard Kent, PhD<br />
University <strong>of</strong> Virginia<br />
Center for Applied Biomechanics<br />
Foot-<strong>and</strong>-Ankle Subcommittee, NFL<br />
UVA Center for Applied Biomechanics<br />
• Mechanical <strong>and</strong> Aerospace Engineering<br />
• Founded 1989 with support from U.S. D.O.T.<br />
• Engineers, Epidemiologists, <strong>and</strong> M.D.’s<br />
• Staff <strong>of</strong> ~60<br />
– Faculty from Schools <strong>of</strong> Medicine, Engineering<br />
– 15 Research staff<br />
– 40 Support staff <strong>and</strong> students<br />
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1/10/2013<br />
UVA Center for Applied Biomechanics<br />
• Mechanical <strong>and</strong> Aerospace Engineering<br />
• Founded 1989 with support from U.S. D.O.T.<br />
• Engineers, Epidemiologists, <strong>and</strong> M.D.’s<br />
• Staff <strong>of</strong> ~60<br />
– Faculty from Schools <strong>of</strong> Medicine, Engineering<br />
– 15 Research staff<br />
– 40 Support staff <strong>and</strong> students<br />
CENTER for APPLIED BIOMECHANICS<br />
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1/10/2013<br />
CENTER for APPLIED BIOMECHANICS<br />
Applied<br />
Research<br />
Characterize<br />
<strong>Shoe</strong>-<strong>Turf</strong><br />
<strong>Interaction</strong><br />
Mechanics<br />
(BEAST)<br />
Literature<br />
Existing practices<br />
New research<br />
Develop<br />
Recommended<br />
Practices (RPs)<br />
for NFL<br />
Surfaces<br />
Measure mechanics<br />
<strong>of</strong> NFL players<br />
during performance<br />
Determine loads<br />
<strong>and</strong> toe angle that<br />
cause turf toe<br />
Determine loads<br />
<strong>and</strong> foot<br />
deformations that<br />
cause Lisfranc<br />
injuries<br />
Determine<br />
mechanisms <strong>of</strong><br />
syndesmotic ankle<br />
sprains<br />
Fundamental Research<br />
•Gait laboratory study<br />
•Literature review<br />
•Video analysis<br />
•Cadaver experiments<br />
•Relate to NFL players<br />
•Literature review<br />
•Determine next steps<br />
CENTER for APPLIED BIOMECHANICS<br />
Fundamental Research – How do injuries happen?<br />
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1/10/2013<br />
Applied Research <strong>and</strong> Testing<br />
CENTER for APPLIED BIOMECHANICS<br />
Implementation – Equipment Recommendations, Practices<br />
4
1/10/2013<br />
CENTER for APPLIED BIOMECHANICS<br />
<strong>Turf</strong> toe (Sprain <strong>of</strong> 1 st metatarsophalangeal joint)<br />
Cadaver tests<br />
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1/10/2013<br />
Probability <strong>of</strong> <strong>Injury</strong><br />
1.0<br />
0.9<br />
0.8<br />
0.7<br />
0.6<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0.0<br />
θ skin<br />
“weakest”<br />
injured<br />
at 101 deg.<br />
50% risk at 108 deg.<br />
Survival analysis (Weibull distribution)<br />
(n=15 cadaver tests)<br />
“strongest”<br />
uninjured<br />
at 132 deg.<br />
0 20 40 60 80 100 120 140 160<br />
Peak Angle (deg)<br />
<br />
<br />
<br />
9 Players<br />
Run, cut (outside<br />
foot), cut (inside<br />
foot), jump, l<strong>and</strong>,<br />
start, walk<br />
Maximum big toe<br />
joint angle measured<br />
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1/10/2013<br />
Probability<br />
1.0<br />
0.9<br />
0.8<br />
0.7<br />
0.6<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0.0<br />
Probability <strong>of</strong> not<br />
attaining that angle<br />
while running<br />
θ skin<br />
Cumulative normal distribution<br />
(n=8 players)<br />
0 20 40 60 80 100 120 140 160<br />
Peak Angle (deg)<br />
Probability<br />
1.0<br />
0.9<br />
0.8<br />
0.7<br />
0.6<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0.0<br />
Probability <strong>of</strong> not<br />
attaining that angle<br />
while running<br />
θ skin<br />
Cumulative normal distribution<br />
(n=9 players)<br />
Probability <strong>of</strong> injury<br />
in a cadaver<br />
Survival analysis (Weibull distribution)<br />
(n=15 cadaver tests)<br />
0 20 40 60 80 100 120 140 160<br />
Peak Angle (deg)<br />
7
1/10/2013<br />
Probability<br />
1.0<br />
0.9<br />
0.8<br />
0.7<br />
0.6<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0.0<br />
Probability <strong>of</strong> not<br />
attaining that angle<br />
while running<br />
θ skin<br />
Cumulative normal distribution<br />
(n=9 players)<br />
Design<br />
Space<br />
Probability <strong>of</strong> injury<br />
in a cadaver<br />
Survival analysis (Weibull distribution)<br />
(n=15 cadaver tests)<br />
0 20 40 60 80 100 120 140 160<br />
Peak Angle (deg)<br />
Lisfranc (First tarsometatarsal joint)<br />
8
1/10/2013<br />
Lisfranc (First tarsometatarsal joint)<br />
Film Analysis Summary<br />
100%<br />
90%<br />
80%<br />
70%<br />
60%<br />
50%<br />
40%<br />
30%<br />
20%<br />
10%<br />
0%<br />
At Initiation During General<br />
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1/10/2013<br />
Probability <strong>of</strong> Lisfranc <strong>Injury</strong><br />
P(I)<br />
1<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0<br />
60<br />
0<br />
40<br />
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9<br />
1<br />
Axial force<br />
0<br />
20<br />
Twist Angle<br />
Cuneiform Coordinates<br />
Cuneiform<br />
Cuneiform<br />
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1/10/2013<br />
Second Metatarsal Coordinates<br />
\<br />
Medial Cuneiform<br />
2 nd Metatarsal<br />
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1/10/2013<br />
Motion <strong>of</strong> 1 st <strong>and</strong> 2 nd Metatarsals<br />
0.03<br />
Distance (m)<br />
0.02<br />
0.01<br />
0<br />
-0.01<br />
-0.02<br />
0⁰ 0⁰<br />
40⁰<br />
0 1 2 3<br />
M1_C1_X_load&rot<br />
M1_C1_Y_load&rot<br />
M1_C1_Z_load&rot<br />
M2_C1_X_load&rot<br />
M2_C1_Y_load&rot<br />
M2_C1_Z_load&rot<br />
-0.03<br />
CENTER for APPLIED BIOMECHANICS<br />
Syndesmotic (“High”) Ankle Sprains<br />
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1/10/2013<br />
CENTER for APPLIED BIOMECHANICS<br />
Syndesmotic (“High”) Ankle Sprains<br />
CENTER for APPLIED BIOMECHANICS<br />
Applied Research – <strong>Shoe</strong>-<strong>Turf</strong> <strong>Interaction</strong><br />
Torg et al., 1974 Heidt et al., 1996<br />
Livesay et al., 2006 Shorten <strong>and</strong> Himmelsbach---Biomechanica 2002<br />
13
1/10/2013<br />
CENTER for APPLIED BIOMECHANICS<br />
• Test Type 1 – Start from Stop (Translation)<br />
Inputs: Vertical force <strong>and</strong> pressure in actuator<br />
Outputs: Does shoe break free? If so, how far <strong>and</strong> fast does it move?<br />
2.8-kN (630 lb)<br />
static preload applied to<br />
bearing track<br />
Imposed F(t)<br />
170 psi cylinder pressure<br />
• Test 2 – Stop/Cut (Drop)<br />
CENTER for APPLIED BIOMECHANICS<br />
Inputs: Mass, drop height, speed over ground<br />
Outputs: Does shoe snag? Vertical force, lateral force, <strong>and</strong><br />
inversion bending moment.<br />
(37.5 kg, 82.5 lb.)<br />
1.5 m/s<br />
then release <strong>and</strong> drop<br />
(2 5/8”, 6.7 cm)<br />
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1/10/2013<br />
• Test 3 – Twist (Rotation)<br />
Inputs: Vertical force <strong>and</strong> pressure in actuator<br />
Outputs: Does shoe break free? If so, how far <strong>and</strong><br />
fast does it rotate?<br />
2.8-kN (630 lb) static<br />
preload applied to bearing track<br />
CENTER for APPLIED BIOMECHANICS<br />
95 psi cylinder pressure<br />
CENTER for APPLIED BIOMECHANICS<br />
BioCore <strong>Elite</strong> Athlete <strong>Shoe</strong>-turf Tester (B.E.A.S.T.)<br />
15
1/10/2013<br />
Detachable cleat<br />
CENTER for APPLIED BIOMECHANICS<br />
Nike Air Zoom Vapor Jet<br />
Molded cleat<br />
Nike Air Zoom Merciless Destroyer<br />
<strong>Turf</strong> shoe<br />
CENTER for APPLIED BIOMECHANICS<br />
BioCore <strong>Elite</strong> Athlete <strong>Shoe</strong>-turf Tester (B.E.A.S.T.)<br />
16
1/10/2013<br />
CENTER for APPLIED BIOMECHANICS<br />
• SELECTED RESULTS: Start from Stop Test<br />
Comparison Across 5 <strong>Turf</strong>s<br />
Horizontal Displacement (mm)<br />
250<br />
200<br />
150<br />
100<br />
50<br />
Cleat moves<br />
Cleat catches,<br />
then releases<br />
BEAST33: Baltimore Ravens, <strong>Shoe</strong> VJTD2<br />
BEAST45: NY Giants Grass, <strong>Shoe</strong> VJTD3<br />
0<br />
BEAST62: NY Giants <strong>Turf</strong>, <strong>Shoe</strong> VJTD3<br />
BEAST74: Atlanta Falcons, <strong>Shoe</strong> VJTD3<br />
BEAST90: Carolina Panthers, <strong>Shoe</strong> VJTD3<br />
-50<br />
0.0 0.2 0.4 0.6 0.8 1.0<br />
Time (s)<br />
Displacement<br />
Cleat<br />
“snags”<br />
CENTER for APPLIED BIOMECHANICS<br />
• SELECTED RESULTS : Start from Stop<br />
Comparison Across 5 <strong>Turf</strong>s<br />
Horizontal Displacement (mm)<br />
250<br />
200<br />
150<br />
100<br />
50<br />
Old Bermuda Grass<br />
New Bluegrass<br />
Infill manuf 1<br />
BEAST33: Baltimore Ravens, <strong>Shoe</strong> VJTD2<br />
BEAST45: NY Giants Grass, <strong>Shoe</strong> VJTD3<br />
0<br />
BEAST62: NY Giants <strong>Turf</strong>, <strong>Shoe</strong> VJTD3<br />
BEAST74: Atlanta Falcons, <strong>Shoe</strong> VJTD3<br />
BEAST90: Carolina Panthers, <strong>Shoe</strong> VJTD3<br />
-50<br />
0.0 0.2 0.4 0.6 0.8 1.0<br />
Time (s)<br />
Displacement<br />
Infill manuf 2<br />
Infill manuf 2<br />
17
1/10/2013<br />
CENTER for APPLIED BIOMECHANICS<br />
<strong>Interaction</strong> Between <strong>Shoe</strong> <strong>and</strong> <strong>Turf</strong><br />
Nike Air Zoom Merciless Destroyer<br />
Nike Air Zoom Vapor Jet<br />
CENTER for APPLIED BIOMECHANICS<br />
• RESULTS: Start from Stop (Translation)<br />
250<br />
Displacement<br />
Horizontal Displacement (mm)<br />
200<br />
150<br />
100<br />
50<br />
0<br />
-50<br />
Molded on Grass<br />
Molded on Fieldturf Artificial <strong>Turf</strong><br />
<strong>Turf</strong> shoe on Fieldturf Artificial <strong>Turf</strong><br />
<strong>Turf</strong> shoe on Momentum Artificial <strong>Turf</strong> turf<br />
0.0 0.1 0.2 0.3 0.4 0.5 0.6<br />
Time (s)<br />
18
1/10/2013<br />
<br />
<br />
<br />
<br />
<br />
Recommendations for<br />
Field <strong>Performance</strong><br />
Evaluation Rubric for<br />
Cleats <strong>and</strong> <strong>Shoe</strong>s<br />
Based on Research<br />
NFL “university”<br />
10+ Scientific Papers on<br />
Foot-Ankle in 5 Years<br />
Regular Dissemination<br />
to Equipment <strong>and</strong> Field<br />
Managers<br />
•Goal: Policies <strong>and</strong> procedures based on technically<br />
rigorous research (i.e., knowledge) rather than<br />
marketing, historical precedent, or rules <strong>of</strong> thumb<br />
19