Time 1  shank  thigh  Knee Segment Angles are ABSOLUTE ANGLES, measured with respect to a (stationary) global vertical or horizontal reference axis. Joint Angles are RELATIVE ANGLES, measured between two adjacent segments with the angle’s vertex at the joint center. Angular Kinematics

Time 1Time 2  shank =  shank 2 -  shank 1  shank 2 Shank segment angular velocity (  )  Shank =  shank 2 -  shank 1 time 2 - time 1  time = Segment Angular Velocity (  )

Calculating Segment Angular Position with segment endpoint coordinate data (x, y) (0.65, 0.90) (0.85, 0.50) (0, 0) +X +Y

Calculating JOINT Angular Position with Segment Angular Position Data +Y (0, 0) +X

Adjacent joint angle-angle diagrams are used to characterize joint coordination patterns  Knee  Hip  Knee  Ankle

Knee angle (degrees) Hip angle (degrees) Similar knee-hip coordination patterns during push phase Hurdle Take-off Long jump Take-off H LJ

Analysis - Total Body Level Initial horizontal position of TBCM relative to foot at touchdown is significantly related to ground contact duration Time (s) after contact Horizontal GRF (N) CMx Foot CMx CMx 1)How is TBCM position controlled or repositioned relative to the foot? 2)Why?

Assessing Segment Contribution to Joint Motion in order to understand the primary source of observed joint motion  Shank Time 1 Time 2  knee  Shank  Knee  Thigh  Ankle  Foot

Shank rotation during impact phase significantly delays peak thigh rotation post-impact (p<.01) time (s) after contact Horizontal GRF (N) Segment angular velocity (rad/s) Shank sav Thigh sav A B Segment contribution to TBCM control

A B Adjacent Joint Coordination: Angle-Angle Diagrams Ankle angle (deg) Knee angle (deg)