Virtual Poster Session

Welcome to the Virtual Poster Session, a new and powerful tool for networking and information exchange. Here you can share your work, search though the poster library, and start a dialogue with others in your field. Each uploaded poster that pertains to force measurement and testing can currently be used to apply for an academic travel scholarship; please see the Scholarships page for application details and deadlines.

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Submitted by Jennifer Bent

Purpose: Total Hip Replacements (THR) are common procedures for older people who suffer from degenerative joint disease. Golf is a popular leisure sport played by older Americans including those with THR. Hip torques encountered in a golf swing after THR has not been reported. The purpose of this study is to describe 3D hip joint torques generated during a golf swinging by those with THR.
Methods: Three male amateur golfers who were at least 1 year post THR (ages 59-71 year old and right hand dominant, (2 were left THR) participated. Golf handicap ranged from 16-18. All participants completed the Hip Harris Score. Passive reflective markers were placed on key boney anatomical landmarks. During data collection, participants completed ten swings using a standardized driver, after a warm up. Kinetics and kinematics were captured using a 10 camera Motion Analysis system and two AMTI forceplates. Inverse dynamics procedure was used to calculate peak hip torques in all three planes. Hip torques were normalized and presented as internal torques. Comparisons were made to previously collected similarly aged senior group.
Results: Average Club head velocity was slower than senior group. Sagittal Plane: THR golfers exhibited the greatest torque similar to senior group. Frontal plane: THR golfers demonstrated a lower hip adductor torque on the lead leg compared to the trail leg and senior group. Transverse plane: THR exhibited higher hip external rotation torques compared to the internal rotation torques and the senior group.
Conclusion: 3-D peak hip torques generated during the golf swing by persons with a THR are greatest in the sagittal plane. THR golfers demonstrated slower club head speed but generated higher hip torques in the transverse plane as compared to those without a THR. Hip external rotation torque was higher in all of the THR compared to the senior group.
Clinical Significance: Subjects with a THR may be prone to abnormal forces in the transverse plane during the golf swing. Future studies are needed to determine impact on return to golf decisions following a THR.

Submitted by Dan Su

The Federal Rail Association (FRA) mandated an increase in freight railcar weight limits from 1170 kN (263,000 lb) to 1272 kN (286,000 lb). However, most of the railway bridges were built prior to World War II and are not designed to handle this increased railcar weight. Thus, there is a need for accurate and efficient methods to evaluate and load rate existing bridges that will reveal their actual capacities.
In this study, the research approach adopted is aimed at providing an efficient method to load rate railway bridges. Three load rating methods were utilized and compared: (1) traditional method based on American Railway Engineering and Maintenance-of-Way Association (AREMA) specifications, (2) refined traditional method using data from field tests, and (3) load rating using testing data and finite element (FE) modeling. Various types of bridges were field tested and evaluated. Results from a typical railway bridge will be used to demonstrate and compare each one of the three load rating methods. For this bridge, non-destructive testing was performed. The collected responses were used to improve the traditional method and calibrate a 3-D FE model. The rating results indicated that method (1) can be relatively conservative and does not reflect the actual behavior of the structure while method (3) provided accurate results it was more tedious. It is suggested that the refined traditional method (2) be used since it provided similar accurate rating results without developing a detailed FE model.

Submitted by Nikita Kuznetsov

Fractal time series analysis methods are commonly used for analyzing center of pressure (COP) signals with the goal of revealing the underlying neuromuscular processes for upright stance control. The use of fractal methods is often coupled with the assumption that the COP is an instance of fractional Gaussian noise (fGn) or fractional Brownian motion (fBm). Our purpose was to evaluate the applicability of the fGn-fBm framework to the COP in light of several characteristics of COP signals revealed by a new method, adaptive fractal analysis (AFA; Riley et al., 2012). Our results showed that there are potentially three fractal scaling regions in the COP as opposed to one as expected from a pure fGn or fBm process. The scaling region at the fastest scale was anti-persistent and spanned ~30-90 msec, the intermediate was persistent and spanned ~200 msec-1.9 sec, and the slowest was anti-persistent and spanned ~5-40 sec. The intermediate fractal scaling region was the most clearly defined, but it only contributed around 11% of the total spectral energy of the COP signal, indicating that other features of the COP signal contribute more importantly to the overall dynamics. Also, more than half of the Hurst exponents estimated for the intermediate region were greater than the theoretically expected range [0,1] for fGn-fBm processes. These results suggest the fGn-fBm framework is not appropriate for modeling COP signals. ON-OFF intermittency might provide a better modeling framework for the COP, and multiscale approaches may be more appropriate for analyzing COP data.

Submitted by Tomislav Milekovic

Development of neuronal prosthetics, where neuronal activity is used to control artificial limbs, has so far relied on decoding kinematic parameters of movements, such as movement position or velocity. In addition to kinematic control, proper control of forces exerted by the prosthetic device is necessary for successful interaction with the environment. In our study, we analysed the possibility of classifying and decoding different grasp related forces during active grasping. Two macaque monkeys were trained to reach, grasp and pull an object in response to visual cues. Cues instructed the monkeys to grasp the object with one out of two grip types (precision or side grip) and pull the object with one of two different forces (0.5N or 2N). Monkeys obtained a food reward after successfully performing the instructed grip and pull. During the task execution, we recorded electrophysiological signals from the multielectrode arrays implanted intracortically in the hand and arm area of the monkey’s motor cortex. Six different parameters of the grip: four pressure forces on each side of the object, pull force on the object and the object displacement, were recorded simultaneously with the neuronal activity. Recorded neuronal activity was used to classify different grip types or loading forces, and to decode the continuous traces of different forces during the grip. Our results show that kinetic grip parameters can be decoded with high accuracy, thereby improving the feasibility of constructing fully functional anthropomorphic neuronal prosthesis that relies on kinetic (force) control.