TY - JOUR
T1 - Plantar shear stress distributions
T2 - Comparing actual and predicted frictional forces at the foot-ground interface
AU - Yavuz, Metin
AU - Botek, Georgeanne
AU - Davis, Brian L.
N1 - Funding Information:
This research was possible due to support from National Institutes of Health (Grant # 2R44DK061164). The authors would like to thank Gordon Hirschman and Lynn Bardsley of Infoscitex, Inc for their kind input during the course of this study.
PY - 2007
Y1 - 2007
N2 - Plantar shear stresses are believed to play a major role in diabetic ulceration. Due to the lack of commercial devices that can measure plantar shear distribution, a number of mathematical models have been developed to predict plantar frictional forces. This study assessed the accuracy of these models using a custom-built platform capable of measuring plantar stresses simultaneously. A total of 48 (38 healthy and 10 diabetic) human subjects (75±20 kg, 41±20 years, 32 males, 16 females) were recruited in the study. Plantar force data were collected for 2 s at 50 Hz. Two models (M1 and M2) reported in the literature by different groups were used to predict local shear stresses. Root mean squared errors (RMSE) were calculated to compare model data with the actual data, focusing on three parameters: location, magnitude and timing of peak shear components. RMSE values of estimated peak AP and ML shear locations were 3.1 and 2.2 cm for M1 and 3.1 and 2.1 cm for M2, respectively. Magnitude RMS error values for M1 were found to be 86.6 kPa in AP shear and 38.5 kPa in ML shear, whereas these values were determined to be 97.8 and 63.5 kPa, respectively by M2. Time to peak shear RMSE values averaged 17.2% in terms of the gait duration. In conclusion, distribution of plantar shear should be measured rather than predicted, particularly if one is interested in the magnitudes of shear components.
AB - Plantar shear stresses are believed to play a major role in diabetic ulceration. Due to the lack of commercial devices that can measure plantar shear distribution, a number of mathematical models have been developed to predict plantar frictional forces. This study assessed the accuracy of these models using a custom-built platform capable of measuring plantar stresses simultaneously. A total of 48 (38 healthy and 10 diabetic) human subjects (75±20 kg, 41±20 years, 32 males, 16 females) were recruited in the study. Plantar force data were collected for 2 s at 50 Hz. Two models (M1 and M2) reported in the literature by different groups were used to predict local shear stresses. Root mean squared errors (RMSE) were calculated to compare model data with the actual data, focusing on three parameters: location, magnitude and timing of peak shear components. RMSE values of estimated peak AP and ML shear locations were 3.1 and 2.2 cm for M1 and 3.1 and 2.1 cm for M2, respectively. Magnitude RMS error values for M1 were found to be 86.6 kPa in AP shear and 38.5 kPa in ML shear, whereas these values were determined to be 97.8 and 63.5 kPa, respectively by M2. Time to peak shear RMSE values averaged 17.2% in terms of the gait duration. In conclusion, distribution of plantar shear should be measured rather than predicted, particularly if one is interested in the magnitudes of shear components.
KW - Biomechanics
KW - Diabetes
KW - Foot and ankle
KW - Instrumentation
KW - Plantar stresses
UR - http://www.scopus.com/inward/record.url?scp=34548482541&partnerID=8YFLogxK
U2 - 10.1016/j.jbiomech.2007.02.006
DO - 10.1016/j.jbiomech.2007.02.006
M3 - Article
C2 - 17449038
AN - SCOPUS:34548482541
SN - 0021-9290
VL - 40
SP - 3045
EP - 3049
JO - Journal of Biomechanics
JF - Journal of Biomechanics
IS - 13
ER -