I do sleds at least once a week at 285lb and almost daily I walk the tread backwards almost daily. I have no knee issues with this. The sled itself is 75lb. I also do body weight squats at least twice weekly. Nordics are new to me. In addition to my weight training I do TKE 3*15, glute bridges 2*20, quad flexion at 2 minutes each leg, side stretches, straight leg stretch, abduction/adduction leg swings and frontal leg swings almost daily (issue with right leg muscles, done to correct and has helped). I am trying to incorporate the Greasy Knee protocol or replace my current protocol if needed. I am just starting with the AOM.