Bill Hartman 55:28–57:08
So again, you have to look at where it attaches. You have to look at the orientation of the muscle fibers themselves. And then, you have to also look at it in context. Okay. So if I fix the distal attachment, so VL comes down, it contributes to the quadriceps tendon, which attaches to the patella, the patella attaches to the tibial tuberosity, right? So if I fix the tibial tuberosity, right? So basically, it's basically putting your foot on the ground kind of thing. Put my foot on the ground. And I contract VL because of its orientation, because of its position. It's going to create an internal rotation force on the femur, but it doesn't cross the hip. Okay. So it's going to twist the femur inwards first. Then it's going to hit, I mean, eventually you run out of like bony capability, right? Like the bone can only twist so far. So the bone twists inward and then it's going to pull the hip with it eventually, right? unless you have another force that's acting on the other end, which is going to hold it into external rotation, which is really common. But that's basically what you're going to end up with. You do have a force that turns it into internal rotation. You also have the downward force into the ground that's going to contribute to that whole mechanism, too. But if we're just looking at VL and its behavior, it's going to provide you that type of a turn.
vastus lateralis mechanicsfemoral internal rotationmuscle attachment and force