That exergenie is a BITCH. It's really finicky about where the feed line is placed, and if it gets too hot, the rope binds up on the inside at higher resistance levels (it sort of coils up on itself), which makes you come to a dead stop, and tries to pull you back like a bungee cord. No real problems at lower resistance levels, and it's not perfect, but it sure beats the heck out of having to store a sled and weights for pulling. And since all the resistance is in line with you, lighter resistances on the scale equate to much heavier feeling pulls. 350 pounds of pull feels like 500+ of chain drags for example. I still have a huge calf/quad pump today.