Walking up and down stairs, ACL/PCL?

[YSPo]

This forum is ridiculously helpful for a student like me who's taking a class on athletic training! It's good practice to see people's questions and then seeing what the diagnosis should be. This is exactly what my exam entails

The knee is really tricky for me cause I am horrible at visualizing things... I would like to ask the following questions...

When walking down the stairs, I realized the "force" would be femur driving anteriorly, and tibia posterior. And this is at a flexion kind of motion, so the strain would be on PCL?

When walking up the stairs, I am still flexing... and the force is still the same, is the strain still on the PCL?

if that's right, what kind of activities will strain the ACL? the only one I can think of is when a someone pronates when walking....

Thanks in advance!!

[Heidi]

ACL injuries usually occur from twisting motions, when the foot is planted and the upper limb is twisted.

PCL injuries usually occur from a direct blow to the front of the shin, when the knee is bent - this is when the PCL in under more strain.

As for your questions about stair walking, biomechanics like this isn't really my strong point. I don't know if anyone else will be able to help.