Loads hamstrings at the knee — the complementary lever to the good morning which loads at the hip. Complete hamstring development requires loading at both joints because the hamstrings are biarticular (cross both hip and knee).
Knee-joint hamstring loading — isolates the short head of biceps femoris which only crosses the knee joint.
Cable tension continuity — maintains constant resistance through the curl arc, unlike lying leg curl machines that lose tension at the top.
Biarticular completeness — paired with exercise 4, both lever points of the hamstrings are now covered.
Placed fifth to complement the hip-hinge hamstring work from exercise 4.