1. Cause-Effect ~ Total Body Level  Total Body Center of Mass (TBCM)  Free Body Diagram (FBD)  Mass-Acceleration Diagram (MAD)  General global coordinate system (up & to the right, (+) )  Center of Pressure (COP)  Ground Reaction Forces (GRF)  Position of TBCM relative to COP, and influence on GRF magnitude and direction  Net Force (  F)  Body segment parameters  Gait analysis parameters  Course Reader: p. 7-11, 21-28, &Ch 5

2. Total Body Center of Mass (TBCM) Balance point of an object Center of an object of uniform density Position is dependent upon relative mass distribution & segment orientation Can be located outside the body During human gait, estimated to be around the hip/pelvis & between base of support (M-L) Position is controlled relative to COP to change the orientation of GRF - dependent upon the mechanical objective of the task

3. Glut Max SM/ST Draw the FBD for: a)Forces acting on the runner b)Forces acting on the ground ground

4. FvFvFvFv FhFhFhFh BW Free Body Diagram (FBD) Mass Acceleration Diagram (MAD)  F h = m*a h  F v = m*a v ma h ma v Global Coordinate System

5. CMx Foot CMx CMx TBCM location is determined by the relative mass distribution and segment orientation Note any between-athlete differences in: stance thigh angle; swing leg position; trunk orientation; arm swing position; that may contribute to the noted difference in CM position relative to COP.

6. Loading Each Dive Can Be Separated Into Phases, Each with it’s Own Goal TippingPushingFlight Entry preparation During the Tipping phase, the center of mass is positioned relative to the feet according to the dive. The position of the CM relative to the force generated during the Push phase will determine rotation (angular momentum) during flight

7. “tip” “push” Controlling shank motion to re-orient TBCM position relative to COP during a “quick first step” Draw the FBD for: a)Forces acting on the runner b)Forces acting on the ground ground

8. Calculating individual segment CM location Segment CM location coordinates (x, y) X cm = x prox - (segment length x) * CM% from proximal Y cm = y prox - (segment length y) * CM% from proximal Total Body Center of Mass location coordinates (x, y) X tbcm = (  m i x i ) / TB Mass Y tbcm = (  m i y i ) / TB Mass EX: segment CM calculation

10. Gait Analysis Parameters Events - define phases –Foot-Strike, Toe-Off Phases - fall between adjacent events (e.g. single support, double support, swing, non-support) Step length (m) Step rate (/s) Walking vs. Running Gait Walking includes double- support phase Running includes flight-phase / non-support phase Average Velocity (SL * SR) Walking Gait Running Gait