The Biomechanics of Punching
Vincent Bradbury
Andrew Calogero
John Filostrat
Charles Henkel
Kevin Holly
Mary-Anne Nguyen
Outline
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
Background
Materials and Methods
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Accelerometer
Foot-force plates
Video Analysis
Results
Analysis
Conclusion
Background



Martial arts have been
practiced for hundreds of
years
The key to success in
martial arts is to master
proper techniques
Our study will provide a
focus on the effectiveness of
using proper technique
while performing a rearcross punch
Materials


Wood frame & sand bag
Accelerometer
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
Foot-Force Plate
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Context Logger
Kistrel Piezoelectric Force
Plates
BioWare Software Package
A-D hardware and
Computer
Video Analysis
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
iPhone
Reflective body markers
Background length markers
http://www.mobilewhack.com/wpcontent/images/2009/02/iphone_video.jpg
Method

Proper technique
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subject stood on the footforce plates on the balls of
his feet and front hip pointed
toward the bag
Punching by twisting the
hips and shoulders forward
while pushing off of the
back-foot to drive the fist
forward
Improper technique
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subject first stood on the
foot-force plates with flat
feet and hips facing the bag
Punched the bag with full
force using his shoulder
Results: Accelerometer
Analysis: Accelerometer
Punch #
Improper 1
Improper 2
Proper 1
Proper 2
Impact Force N
249.393
272.3341
401.1037
251.5989
Results: Foot-Force Plates
Analysis: Foot Force Plates

Peak of the total ground
force reaction was
calculated by finding the
instantaneous vector
forces of the Fx, Fy, and Fz
Max Rx
Max Ry
Max Rz
Max Lx
Max Ly
Max Lz
proper 1
30.20498
81.17479
556.361
131.8171
76.15867
544.8445
proper 2
77.16128
91.67496
495.637
117.624
63.17786
467.3839
improper 1
28.09289
71.6343
470.6215
95.60793
54.62115
590.1548
improper 2
26.21577
54.16175
566.4687
113.0273
101.229
607.615
Results: Video Analysis
Analysis: Video Analysis

Initial velocity after the punch
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Mgh=0.5mv^2
V=sqrt(2gd)
Distance traveled by the bag

Trial
Improper 1
Improper 2
Proper 1
Proper 2
Arc length=(θ/360)2*π*radius ,where θ is the
angle in degrees
delta t (s) Theta (degrees) scale (1:6") height, h (m)
0.333
32
1.02245
0.103169
0.367
54
1.0462
0.240118
0.3
46
1.10565
0.208773
0.4
51
1.0462
0.243243
radius (m)
0.38612538
0.414083909
0.457682579
0.440678648
arc (m)
0.215543767
0.390067043
0.367264843
0.392057104
V1 (m/s)
1.42273532
2.17051035
2.0238889
2.18458867
Conclusion
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Accelerometer
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Foot force plate
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Improper technique has an average force that
is a bit lower than the average proper punch
forces
Maximum improper force is actually greater
than the minimum proper force
GRF that was observed during this strike may
also show a smaller reaction for from the
punch
More twisting involved during the proper
technique
Proper technique enhances the force available
to give off in the x-y plane based on Newton’s
third law of motion.
Video analysis
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Video recorder captured each punch at an
angle not perpendicular to the plane of action
Scaling every dimension to the six inch
reference marking behind each shot
To reduce error in a hypothetical duplicate lab,
a camera stand and highspeed camera faced
directly into the plane of action