Ground Reaction Force in Human Gait Walking Direction Vertical reaction force to heel Vertical reaction force to toe pushing down on the ground pushing down on the ground (normal force) (normal force) Normal Force GRF (N) Midstance Heel Strike Toe Off Frictional Force (N) (Horizontal Reaction Force to Time for 1 Gait Cycle (s) Parallel Component of Applied Force During Gait) Note that the solid line represents the vertical component of the GRF (normal force) and the dashed line represents the horizontal component (frictional force) of the GRF.Check for Understanding Questions: I. The person in this graph is taking one full step to the right. Keeping in mind that the solid line represents the ground reaction force to the heel strike, define your coordinate system for this graph of human gait. You'll need to define the coordinate system for both vertical and horizontal directions. II. Mark the following regions: a. Mark regions of largest Normal Force and compare them with the cycle of gait. b. Mark regions of largest Frictional Force and compare them with the cycle of gait. lll. Why do you think the frictional force changes from negative to positive? Discuss with your group. a. Why do you think the Normal Force dips in Mid-Stance? IV. b. What happens to the Frictional Force in Mid-Stance? Explain your thoughts. In the space below, draw a vector diagram for each of the three stages of normal human gait. For each picture, Include the horizontal and vertical components of both the GRF and the person's applied force. Use dotted lines for the components and solid lines for the forces. Label the GRF, the horizontal component of the GRF (force of friction), the vertical component of the GRF (normal force), the force of the person pushing on the ground, the horizontal component of the push on the ground and the vertical component of the push on the ground. V \\ Heel pushes on ground FHG Heel Strike Ground Reaction Force in Human Gait Walking Direction Vertical reaction force to heel Vertical reaction force to toe pushing down on the ground pushing down on the ground (normal force) (normal force) Normal Force GRF (N) Midstance Heel Strike Toe Off Frictional Force (N) (Horizontal Reaction Force to Time for 1 Gait Cycle (s) Parallel Component of Applied Force During Gait)