1. DIFFERENCE OF IMPACT FORCE AND KNEE ANGLE WITH BAREFOOT VERSES SHOD RUNNERS
Shelbi Butters
Biomechanics Undergraduate, Utah State University
INTRODUCTION
The primary function of the shoe is to protect the foot against
the forces occurring when the heel impacts the ground (Belli,
A.) whereas with barefoot running shock reduction is minimal
(Aerts, Peter.). It is assumed that runners will adapt their
running style in an “impact-reducing” way when running
(Aerts, Peter.). In comparing barefoot and shod runners the
knee angle is being altered.
The purpose of our study was to compare the different forces
from barefoot running to shod running while comparing the
angle of the knee.
METHODS
There was a total six participants that were college aged
university students. The average weight was 687.09 N and the
standard deviation of weight was 195.91 N. The weight was
calculated using the force plate before we had them start the
trials. Each participant had roughly three trial runs before we
recorded any data. Each participant then did three test which
involved running barefoot, and three more shod. There were
three reflective pieces of tape placed on the greater trochanter,
lateral side of knee and the lateral malleolus. AcqKnowledge
4 Software was used to calculate the forces, with an in ground
force plate. As each participant would run they were recorded
with a high-speed camera recording 300 frames per second.
Kinovea was used to calculate the joint angle of the knee.
IBM SPSS was used to find average and standard deviations.
RESULTS AND DISCUSSION
The mean for shod trials 1.81 BW and the standard deviation
was .30. The mean for barefoot trials 1.67 BW and the std.
was .25. After running the paired samples t test there was no
significant difference. The mean for the knee joint angle in
shod was 165.22 with a std. of 5.31. The mean for the knee
joint angle barefoot was 163.95 with a std. 4.47. There was no
significant difference between the angles.
CONCLUSIONS
In our study we found that there was no significant change in
the force of the heel strike when comparing shod and barefoot
running, in agreement to De Wit et al. study (Aerts, Peter.)(
Belli, A). There was no significant difference in the knee joint
angle during our study, in agreement to the Lieberman study.
Some of the limitations of the study that could be avoided
were: participant size (it was fairly small), and having a better
force plate (the participants weren’t performing their natural
stride, because they focused so much on trying to hit the force
plate).
REFERENCES/WORKS CITED
Aerts, Peter. "Biomechanical Analysis Of The Stance Phase
During Barefoot And Shod Running." Journal of
Biomechanics 33 (): 269-278. Print.
Belli, A., C. Divert, H. Baur, and F. Mayer. "Mechanical
Comparison Of Barefoot And Shod
Running." International Journal of Sports
Medicine 26 (): 593-598. Print
Descriptive S tatistics
N Mean Std. Deviation
ShodForce 18 1.8061 .33127
UnshodForce 18 1.6667 .27560
JointAngleShod 18 165.2222 5.31984
JointAngleUnshod 18 163.9444 4.43876
Figures: shows comparison between the different test.