WENTWORTH INSTITUTE OF FONESTY Bo EROY ECONOMY FOUNDED 1904 TECHNOLOGY BMED 4400 - Biomechanics Force Plate Purpose The objective of this lab experiment is to calculate and analyze the ground

reaction forces and trajectory of the center of pressure during normal walking and running cycles. NNERS S Method Download the force plate data from Blackboard. Direction of Gait Figure 1: Measuring the ground reaction force using force plate system. WENTWORTH INSTITUTE OF FONESTY Bo EROY Part I.a: ● ECONOMY FOUNDED 1904 TECHNOLOGY ● Open the data located in folder “Part I", the data contains the ground reaction forces/moments and center of pressure (COP) data for two subjects who performed: O a normal walking cycle on the force plate O a normal running cycle on the force plate BMED 4400 - Biomechanics Force Plate (note: the time is measured in seconds, data collection is done at the frequency rate of 50Hz; e.g each data line in the force data files correspond to the data recorded at 1/50 of a sec) Open the "walking-FM" file of each subject and copy and paste the data to an excel document and plot the following graphs (use "scatter with smooth line" for all graphs): O Vertical ground reaction force (Fz) vs. Time O Medial/Lateral ground reaction force (Fy) vs. Time O Anterior/posterior ground reaction force (Fx) vs. Time Reaction moment along "x" axis (Mx) vs Time O Reaction moment along "y" axis (My) vs Time. Open the walking data of the second object, copy the data to excel and add the graphs for the above-mentioned parameters versus time to existing graphs of the first subject for comparison. In each graph, use solid lines for subject one and dash lines for subject two. Data order in Force data (file names with "FM"): Fx (N) Fy (N) Fz (N) Mx (Nm) COPX (cm) My (Nm) Open the Center of pressure data (COP) of both subjects, copy and paste the data to excel and plot the COPY vs COPx of both subject (Note: before plotting the data, convert the COP coordinates given in the txt files to mm (originally in CM); delete the rows which contain zero values) Data order in COP data (file names with "COP"): COPY (cm) Mz (Nm) Repeat all steps described above for running cycles (look at "Running-FM” and “Running-COP" data) WENTWORTH INSTITUTE OF FONESTY Bo EROY ● ECONOMY FOUNDED 1904 Copy all graphs (walking & running) to the report and explain the following questions. Consider the following gait schematic when answering the questions. TECHNOLOGY Heel strike O O Double support Loading response BMED 4400 - Biomechanics Force Plate Running experiment: Stance Phase Mid-stance Single support Terminal stance Pre-swing Double support Toe-off Swing Phase Mid-swing Walking experiment: O The maximum force occurs along which direction and why? O How the force reaction data of the two subjects compare? Is there any between the two? Compare the reaction moments along "x" and "y" direction; in which direction the moments are larger and why? How the ground reaction moments of the two subjects compare? Do you see any similar pattern? Single support Terminal swing pattern Compare the vertical ground reaction force (Fz) of each subject in running experiment against walking and explain the difference? O How does the trajectory of COP of each subject differ in walking vs. running? WENTWORTH INSTITUTE OF FONESTY Bo EROY ECONOMY FOUNDED 1904 TECHNOLOGY BMED 4400 - Biomechanics Force Plate Part I.b (take home) Read the article related to "Pedotti Diagram” and for the walking cycle of each subject calculate the following parameters as shown and plot the Pedotti diagram using matlab or excel: X₂ - X₁ = COPY (W x F₂) Sacle Factor (W = 0.025, Scale Factor = 100, change the SF if required to bring the data in range) Y₁ = 0 Y₂ = F₂z Note: Fx in the article represents the force along the vertical axis, normal to the plate (hint: use the force and COP data for each subject and caclulet the x1,y1 and x2,y2 coordinate at each frame or each line in excel; then create a graph in excel which includes a series of independent lines as shown below, each line represents one frame or data line in excel; alternativly you can use matlab to create the graph, in that case take the data to matlab and create a blank plot and plot the first line, then use the "hold on" command to keep the plot on and create the subsequnet lines using a loop) (X1, Y1) + COPY (X2, Y2) Paste the Pedotti graphs for the two subjects into the report and compare the graphs, what do you conclude form the comparison, briefly explain? WENTWORTH INSTITUTE OF FONESTY Bo ● ● ● EROY Part II: The subjects were asked to stand on the force plate and perform the following tasks: ● ECONOMY Put their right leg on the center of the force plate and do a single leg stance at upright posture Repeated the experiment after flexing forward to 90 deg Bent to the right and repeated the experiment The force data was calculated following each experiment; look at the data in “Part II" folder and: For each subject, find the maximum reaction force along "z" direction for each motion. How does the peak ground reaction force along “z” direction for all three movements of the subject one compares against the same data of subject two? ● FOUNDED 1904 TECHNOLOGY BMED 4400 - Biomechanics Force Plate Compare the maximum reaction force (absolute value) along "x" and "y" directions for each movement, which force component has a higher magnitude in each motion (do the comparison for both subjects)?