SPEAKER_02 58:58–1:01:04
Absolutely. Great description. So let's think this through from foundational archetype to the representation that you have now. If I start with my narrow ISA archetype, my bias is towards external rotation. So I would have a situation where I have this counter-rotated relative ER position, which will retrovert the acetabulum. So I'm biased towards ER. Now, what you've described at the knee is that the patella is in a position of IR, with relative tibial ER. And you noted that the distal tibial looks like it's in IR. So here's what you've got: ER at the hip, IR at the knee, ER at the knee, and IR at the ankle. This is significant. If I'm biased towards external rotation, that means I have yielding action on the posterior side, which should hold me back towards my heels and lift my arch away from the ground. But if I'm walking and have to go through the middle propulsive phase, which requires IR, while being biased towards ER with a pelvic position biased towards ER, how do I put force into the ground? I have to create a compensation to produce that force. So I'll take my ER pelvis and tip it forward. By anteriorly orienting the pelvis, I can put more force into the ground without changing anything. Traditional lumbar extension is internal rotation, forced into the ground. If I'm a narrow ISA biased towards counter-rotation, that's actually lumbar flexion, which means I might go above that level and use a lower thoracic strategy to tip the pelvis forward from above to create the anti-orientation. If I'm using the lower thorax to create internal rotation, I'll use a posterior lower pelvis strategy in the same way, producing ER at the proximal femur. So I have hip ER, no hip IR. My IR is coming from above the lumbar spine and below the level of the trochanter.
archetype biomechanicsrotational compensationpelvic orientationtibial rotationpropulsive mechanics