I'm doing SL5x5 and, for my without tonight, I swapped the normal Pendlay rows with the incline row machine. I was quite shocked at the weight difference. Normally, I'd be rowing around 115 but with the machine I could only manage about 70 (for the same sets/reps). But I wasn't just arbitrarily playing with the program, I decided to try the machine because I felt I had been cheating on the bb rows by using my lower back and glutes. To try to determine if I had been cheating, I wanted to see how my bb row compared to a roughly equivalent isolation exercise. My logic being that the machine should use every muscle that should be used in bb rows and limit me to only those. Therefore, if I wasn't cheating and all the same muscles are used, then the weight should be about the same. Such a large difference between my bb row and machine row would seem to indicate that one of the following is true:

 1. The machine row isn't as similar to the bb row as I thought. Specifically, the incline row leaves out muscles used in the bb row.
 2. I've been cheating on my bb rows.

So is it 1 or 2? And if it's 1, what is left out?

P.S. This is what I mean when I say "incline row machine": http://www.afproducts.com/site_images/uploads/Incline-Lever-row---Showroo.jpg