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Biomechanics of Karate:Biomechanics of Karate:Measuring Impact Force in Shotokan Measuring Impact Force in Shotokan
Karate StrikesKarate Strikes
Yasaman ShiraziYasaman ShiraziJanuary 26, 2007January 26, 2007
OVERVIEWOVERVIEW
PurposePurposeShotokan TechniqueShotokan TechniqueHypothesesHypothesesApparatusApparatusExperiment ProtocolExperiment ProtocolDataDataResultsResultsFuture Plans and StudiesFuture Plans and Studies
PURPOSEPURPOSE
Studying Martial Arts from an Engineering Studying Martial Arts from an Engineering PerspectivePerspectiveQuantifying Strength of Various Quantifying Strength of Various TechniquesTechniquesFinding Scientific Proof behind the Finding Scientific Proof behind the Traditional Arts and their ApplicationsTraditional Arts and their ApplicationsAssisting Proper Teaching of Shotokan Assisting Proper Teaching of Shotokan Karate StrikesKarate Strikes
REVERSE PUNCHREVERSE PUNCH
One of the Most Basic and Common One of the Most Basic and Common StrikesStrikesDelivered in 3 Orientations:Delivered in 3 Orientations:
Horizontal Horizontal –– KihonKihon (Basics)(Basics)Vertical (Jab) Vertical (Jab) –– Kumite (Sparring)Kumite (Sparring)45 Deg 45 Deg –– BunkaiBunkai (Real Life Application)(Real Life Application)
REVERSE PUNCHREVERSE PUNCH
REVERSE PUNCHREVERSE PUNCH
HYPOTHESESHYPOTHESES
Strike Effectiveness will be influenced by:Strike Effectiveness will be influenced by:ExperienceExperienceAngle of DeliveryAngle of Delivery
Horizontal Horizontal –– StrongestStrongestVertical Vertical –– FastestFastest45 Deg 45 Deg –– Most PracticalMost Practical
GenderGenderSizeSize
APPARATUS DESIGNAPPARATUS DESIGN
Criteria:Criteria:Deliver Direct Linear Impact to a Force SensorDeliver Direct Linear Impact to a Force SensorProduce No Moment if Hit OffProduce No Moment if Hit Off--centeredcenteredBe Adjustable According to Different HeightsBe Adjustable According to Different HeightsBe Robust and StableBe Robust and StableCan Be Built Within Our Time Limit and Can Be Built Within Our Time Limit and Available MaterialsAvailable Materials
DATA COLLECTIONDATA COLLECTION
2000lb Load Cell2000lb Load CellLocated Directly Behind the TargetLocated Directly Behind the Target
Motion Capture SystemMotion Capture System3 High Speed Cameras to Record the Motion3 High Speed Cameras to Record the Motion6 Reflective Markers on Joints of Interest on 6 Reflective Markers on Joints of Interest on the Subjectsthe Subjects
APPARATUS DESIGNAPPARATUS DESIGN
APPARATUS CONSTRUCTIONAPPARATUS CONSTRUCTION
EXPERIMENTSEXPERIMENTSSet UpSet Up
Calibrating the CamerasCalibrating the CamerasPilot TestingPilot Testing
EXPERIMENTSEXPERIMENTSSubjects:Subjects:
Beginner (1F, 2M)Beginner (1F, 2M)Intermediate (3F, 3M)Intermediate (3F, 3M)Advanced (3F, 3M)Advanced (3F, 3M)Read & Sign the Consent FormRead & Sign the Consent FormWarm upWarm upFree TrialsFree TrialsWear 6 Reflective MarkersWear 6 Reflective Markers
Testing ProtocolTesting Protocol3 Sets (Horiz, 45 Deg, Vert)3 Sets (Horiz, 45 Deg, Vert)5 Punches Each5 Punches Each
DATA PROCESSINGDATA PROCESSING
SIMISIMIRecording the Force DataRecording the Force DataProcessing Video Files and Tracking MarkersProcessing Video Files and Tracking Markers
C++C++Finding Peak Forces and Time of ImpactFinding Peak Forces and Time of ImpactAdjusting the Off Set of the ForceAdjusting the Off Set of the ForceImporting Data and Creating Excel FilesImporting Data and Creating Excel Files
ExcelExcelProcessing Numeric ResultsProcessing Numeric ResultsNormalizing and Finding Correlations among Different Normalizing and Finding Correlations among Different VariablesVariables
RESULTSRESULTSProcessed DataProcessed Data
Force vs. Time - 45 Deg
-300
-250
-200
-150
-100
-50
0
50
0 1000 2000 3000 4000 5000 6000
Time (ms)
Forc
e (lb
s)
RESULTSRESULTS
Overall Average Force
160
170
180
190
200
210
220
Categories
Forc
e (lb
s)
Horizontal45 DegVertical
RESULTSRESULTS
Maximum Peak Force
0
50
100
150
200
250
300
ADVANCED BEGINNER
Category
Forc
e (lb
s)
malefemale
• Comparing Force Based on Gender and ExperienceComparing Force Based on Gender and Experience
RESULTSRESULTS
-0.023-0.082-0.173-0.054-0.107Experience (Months)
0.3320.3920.5620.3180.436BMI
0.5090.1910.1680.6280.587Height (in)
0.6070.7050.5230.6860.741Weight (lbs)
0.8190.6780.3200.9020.863Grip Strength (lbs)
Ave. Impules(lb.s)
Max Impulse(lb.s)Force STD
Average F (lbs)
Max F (lbs)
Pearson Correlation Coefficient
RESULTSRESULTSImpulse = Impulse = ∫∫ F. dtF. dtAve. Impulse vs. Ave. Force Ave. Impulse vs. Ave. Force
Pearson Correlation Coefficient Pearson Correlation Coefficient = 0.8685= 0.8685
•• Y = 0.0208 x + 0.955Y = 0.0208 x + 0.955
•• RR2 2 = 0.7543= 0.7543
Average Force vs. Average Impulse
1
2
3
4
5
6
7
0 50 100 150 200 250 300
Average Force (lbs)
Ave
rage
Impu
lse
(lb.s
)
CHALLENGESCHALLENGES
Not Having Enough Support to Keep the Not Having Enough Support to Keep the Apparatus in PlaceApparatus in Place
Having OffHaving Off--set Force Dataset Force Data
Verifying if the Strike is Delivered Verifying if the Strike is Delivered CorrectlyCorrectlyHaving to Recalibrate the CamerasHaving to Recalibrate the CamerasExporting Force Data from SIMIExporting Force Data from SIMI
FUTURE STUDIESFUTURE STUDIES
Processing the Motion Capture Video FilesProcessing the Motion Capture Video FilesTesting Larger Group of SubjectsTesting Larger Group of SubjectsUsing Random CombinationsUsing Random CombinationsExperiment Different Padding or GlovesExperiment Different Padding or GlovesModifying Apparatus DesignModifying Apparatus DesignSecuring the Apparatus to the WallSecuring the Apparatus to the WallPossibly Studying Other Strikes, i.e. KicksPossibly Studying Other Strikes, i.e. Kicks……
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