KIN 3309 1nd Edition Lecture 12 Outline of Last Lecture I II III IV V VI VII VIII IX X XI XII How to Solve Kinematics Problems Question 1 Question 2 Question 3 Question 4 Question 5 Question 6 Question 7 Question 8 Question 9 Question 10 Question 11 Outline of Current Lecture I II III IV V VI VII VIII Kinetics and Kinematics a Recap Force Plates Ground Reaction Forces Force Plates Ground Reaction Forces Devices Force Plates Ground Reaction Forces Data Collection Postural Control Force Plates Ground Reaction Forces Problems Motion Capture Motion Capture Stroke Survivors Reaching Current Lecture I Kinetics and Kinematics a Recap a Kinetics i To study the forces and interactions that affect motion one must collect data that can relate to Force mass acceleration b Kinematics i To study bodies in motion regardless of the causes of motion one needs to describe and quantify linear and angular positions of bodies c Motion Capture These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute i You can get kinematic information like joint positioning during certain movements d EMG Goniometry i EMG the electrical activity of a muscle ii Goniometry specifically measures joint angles e Dynamometry i Measuring work you can do all three kinds of loads on a muscle isometric isokinetic and isotonic ii Ex bio dex f Force Plates GRFs i GRF the ground pushes back against you II Force Plates Ground Reaction Forces a GRF i Any force exerted by the ground on a body in contact with it ii One s weight is a force that a person s body exerts on the ground and when not moving the ground exerts an equal and opposite GRF on the person s feet iii Newton s 3rd Law Action reaction III Force Plates Ground Reaction Forces Devices a NeuroCom i We have people stand and see how they respond with different simulations to test balance We can eliminate or mess with the systems that control balance b Bertec i Each foot is drivin independently on its own belt on the tredmill You can have one foot move faster than the other With this its easy to adapt to This is good for walking studies c AMTI d Other Manufacturerers i Kistler ii Biodex iii BTS iv Others IV Force Plates Ground Reaction Forces Data Collection a Force Plate i Measurement of GRFs center of pressure etc b Postural Control Research i COP in unperturbed stance ii COP in perturbed stance V VIII Postural Control a Peak to peak sway Anteroposterior AP b Peak to peak sway Mediolateral ML c There s a dead zone in the middle of the feet If you get out of the dead zone you have less stability If you re in the red zone a lot you are an unstable person VI Force Plates Ground Reaction Forces Problems a Counter movement jump b Based on GRFz What is the jumpers mass in kg i 1 N 0 101 kg ii So m 65 kg c Where is the take off landing and what is the flight time i t 0 6 s d Based on the flight time calculate the jump height in meters i Use z g t2 8 ii z 44 m VII Motion Capture a Eadweard Muybridge i Muybridge was the first to do motion capture with animals to see if a horse was on its four feet or not during a gallop b Description of position 2D 3D i Cartesian coordinate system x y z ii Defined by origin and 2 or 3 orthogonal axes iii Global Coordinate System GCS c Description of the object i Points on in object ii Local Coordinate System LCS iii Placed in segmental proximal joint or COM d Passive Motion Capture i Uses ambient or IR light ii Captures video of reflective markers affixed to body iii The light comes from the markers the foam balls with reflective tape e Active Motion Capture i Uses LEDs or IR emitting markers ii The marker the ball is what is emmiting the signal f Triangulation of Markers in GCS LCS i Identification of marker position in 2D 3D space g Photogrammetry i Frame rate frequency in Hz field of view GCS x y z Motion Capture Stroke Survivors Reaching a Right arm is blue and left arm is red b Even the persons non stroke side is still affected by the stroke