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Preface: Analyzing the hip, knee and ankle angles and moments during 3 different variations of a standing long jump: the normal standing long jump, a squat jump starting from the lowest squatting position and a long jump using no arms.


Problem1: The hip angles for our squat jump don't match with the angles in our normal jump. We would expect to see the hip angles in the squat jump to begin at about 100 degrees and go down to 0 as the subject is rising from the squatted position.
Normal jump

Squat Jump




Problem2: the knee angles for our normal and no arm jumps both look like they need to be flipped about 0 degrees.
Normal Jump

No Arms Jump



Problem 3: the ankle begins at a high angle in the squat jump and reaches unrealistic values. similarly to the hip angles, we are using the normal jumps to help us determine what it should begin at. In this case we would expect the squat jump to start around 40 and go down to 0.
Normal Jump *Ignore the blip at .95s

Squat jump



Our understanding is that the hip, knee and ankle angles are defined as follows:
hip

knee

ankle



Does anyone have any critical feedback they'd be willing to offer?

I suggest using the Coordinates panel to check that you're interpreting the joint angles correctly. You can use the textboxes and sliders to adjust the joint angles, then compare your expectations to the pose of the model in the View window.

Dear Gabriel,

I am trying to simulate a normal human gait with the gait2392 model and I have the problem when I plot the knee_angle.
Can you tel me please, how did you solve this problem?

Thank you.

Hela.