Biomechanics of Karate - of Karate: Measuring Impact Force in Shotokan Karate Strikes Yasaman Shirazi January 26, 2007

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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