Hip Strategy

  1. Determine XZ values of pelvis and spine-high joint center at timepoint of max knee flexion
  2. Calculate the difference in X and Z between pelvis and spine-high joint centers
  3. Calculate trunk angle by inverse tangent of difference in X over difference in Z
  4. Determine XZ values of Ankle and Hip joint center values at timepoint of max knee flexion
  5. Calculate the difference in X and Z between Ankle and Hip joint centers
  6. Calculate shank angle by inverse tangent of difference in X over difference in Z
  7. Compare shank angle to trunk angle
  8. Metric calculated for Step Down, Drop Jump, Lateral Shuffle, Triple Jump, Deceleration, Cut.
Score Scoring Definition Significance
0 Shank angle is greater than (Trunk angle + 10 degrees) Poor Hip Strategy
1 Trunk and Shank angles are within 10 degrees of each other Fair Hip Strategy
2 Trunk angle is greater than (Shank angle + 10 degrees) Good Hip Strategy