You MUST train knee flexion if you want healthier, protected, more structurally balanced knees!
 
Just imagine what would happen if you trained only 1 side of any joint over a long enough time period
 
The idea of structural balance is a term we use within ATG to describe the act of balancing the body with exercise from left to right side of the body, front to back of the body, and from the ground up. This is how injury resilient people are essentially created
 
It just doesn’t make sense that the average person and athlete trains knee extension 9:1 to their knee flexion volume, if even that. Hit knee flexion hard, and hit it often. Protect yourself
 
Using multiple different hamstring curl machines, as well as Nordics, is ideal. This is because you attack different parts of the strength curve, aka where the motion is most difficult, when on different machines. For example, quad extension, full depth squats, and reverse Nordics all have a different part of the movement where they’re most difficult, despite all working out the quads (knee extension)
 
Charles Poliquin, the greatest strength coach of all time, had 6 different hamstring curl machines in his gym not including a Nordic bench!
 
A strong Nordic takes months to build. Or longer. Here are the reps, sets, and frequency I recommend
 
Hamstring Curl or 2Up1Down Hamstring Curl:
12x a week, 35 sets, 1215 reps
 
Eccentric (Negative Only) Nordic:
1x a week, 5x5 with as slow eccentric as possible
 
Full Nordic:
1x a week, 5x5
 
If training both Nordics and hamstring curls, once a week each
 
Keep in mind you can also scale Nordic difficulty by examining how straight you are from head to knee. Being more bent at the hips is easier